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proc(4)                          File Formats                          proc(4)



NAME
       proc - /proc, the process file system

DESCRIPTION
       /proc  is  a  file  system  that  provides  access to the state of each
       process and light-weight process (lwp) in the system. The name of  each
       entry  in  the  /proc  directory is a decimal number corresponding to a
       process-ID. These entries  are  themselves  subdirectories.  Access  to
       process  state  is  provided  by additional files contained within each
       subdirectory; the hierarchy is described  more  completely  below.   In
       this document, ``/proc file'' refers to a non-directory file within the
       hierarchy rooted at /proc. The owner of each /proc file  and  subdirec-
       tory is determined by the user-ID of the process.

       /proc  can  be  mounted on any mount point, in addition to the standard
       /proc mount point, and can be mounted  several  places  at  once.  Such
       additional mounts are allowed in order to facilitate the confinement of
       processes to subtrees of the file system via chroot(1M) and  yet  allow
       such processes access to commands like ps(1).

       Standard  system  calls  are  used  to  access  /proc  files:  open(2),
       close(2),  read(2),  and  write(2)  (including   readv(2),   writev(2),
       pread(2),  and  pwrite(2)).  Most  files describe process state and can
       only be opened for reading.  ctl  and  lwpctl  (control)  files  permit
       manipulation  of  process  state and can only be opened for writing. as
       (address space) files contain the image of the running process and  can
       be  opened  for  both  reading  and writing. An open for writing allows
       process control; a read-only open allows inspection but not control. In
       this  document,  we refer to the process as open for reading or writing
       if any of its associated /proc files is open for reading or writing.

       In general, more than one process can open the same /proc file  at  the
       same  time.  Exclusive  open is an advisory mechanism provided to allow
       controlling processes to avoid collisions with each  other.  A  process
       can obtain exclusive control of a target process, with respect to other
       cooperating processes, if it successfully opens any /proc file  in  the
       target  process for writing (the as or ctl files, or the lwpctl file of
       any lwp) while specifying O_EXCL in the open(2).   Such  an  open  will
       fail  if the target process is already open for writing (that is, if an
       as, ctl, or lwpctl file is already open for writing). There can be  any
       number  of  concurrent  read-only opens; O_EXCL is ignored on opens for
       reading. It is recommended that the first open for writing  by  a  con-
       trolling  process  use  the O_EXCL flag; multiple controlling processes
       usually result in chaos.

       If a process opens one of its own /proc files  for  writing,  the  open
       succeeds  regardless  of  O_EXCL  and  regardless of whether some other
       process has the process open for writing.  Self-opens do not count when
       another process attempts an exclusive open. (A process cannot exclude a
       debugger by opening itself for writing and the application of a  debug-
       ger  cannot  prevent a process from opening itself.) All self-opens for
       writing are forced to be close-on-exec (see the  F_SETFD  operation  of
       fcntl(2)).

       Data  may  be transferred from or to any locations in the address space
       of the traced process by applying lseek(2) to position the as  file  at
       the  virtual address of interest followed by read(2) or write(2) (or by
       using pread(2) or pwrite(2) for the combined operation).  The  address-
       map  file  /proc/pid/map  can be read to determine the accessible areas
       (mappings) of the address space. I/O transfers may span contiguous map-
       pings.  An  I/O request extending into an unmapped area is truncated at
       the boundary. A write request beginning at an unmapped virtual  address
       fails with EIO; a read request beginning at an unmapped virtual address
       returns zero (an end-of-file indication).

       Information and control  operations  are  provided  through  additional
       files.  <&lt;procfs.h>&gt;  contains definitions of data structures and message
       formats used with these files. Some of these  definitions  involve  the
       use  of  sets  of flags. The set types sigset_t, fltset_t, and sysset_t
       correspond, respectively, to signal, fault, and  system  call  enumera-
       tions  defined  in  <&lt;sys/signal.h>&gt;, <&lt;sys/fault.h>&gt;, and <&lt;sys/syscall.h>&gt;.
       Each set type is large enough to hold flags for  its  own  enumeration.
       Although  they are of different sizes, they have a common structure and
       can be manipulated by these macros:

       prfillset(&set);             /* turn on all flags in set */
       premptyset(&set);            /* turn off all flags in set */
       praddset(&set, flag);        /* turn on the specified flag */
       prdelset(&set, flag);        /* turn off the specified flag */
       r = prismember(&set, flag);  /* != 0 iff flag is turned on */


       One of prfillset() or premptyset()  must  be  used  to  initialize  set
       before  it is used in any other operation. flag must be a member of the
       enumeration corresponding to set.

       Every process contains at least one light-weight process, or lwp.  Each
       lwp  represents  a flow of execution that is independently scheduled by
       the operating system. All lwps in a process share its address space  as
       well as many other attributes.  Through the use of lwpctl and ctl files
       as described below, it is possible  to  affect  individual  lwps  in  a
       process or to affect all of them at once, depending on the operation.

       When  the process has more than one lwp, a representative lwp is chosen
       by the system for certain process status files and control  operations.
       The  representative  lwp  is a stopped lwp only if all of the process's
       lwps are stopped; is stopped on an event of interest only if all of the
       lwps are so stopped (excluding PR_SUSPENDED lwps); is in a PR_REQUESTED
       stop only if there are no other events of interest  to  be  found;  or,
       failing  everything  else, is in a PR_SUSPENDED stop (implying that the
       process is deadlocked). See the description of the status file for def-
       initions  of  stopped  states. See the PCSTOP control operation for the
       definition of ``event of interest''.

       The representative lwp remains fixed (it will be chosen  again  on  the
       next  operation)  as  long  as all of the lwps are stopped on events of
       interest or are in a PR_SUSPENDED stop and the PCRUN control  operation
       is not applied to any of them.

       When applied to the process control file, every /proc control operation
       that must act on an lwp uses the same algorithm to choose which lwp  to
       act  upon. Together with synchronous stopping (see PCSET), this enables
       a debugger to control a multiple-lwp process using  only  the  process-
       level status and control files if it so chooses. More fine-grained con-
       trol can be achieved using the lwp-specific files.

       The system supports two process data  models,  the  traditional  32-bit
       data  model in which ints, longs and pointers are all 32 bits wide (the
       ILP32 data model), and on some platforms the 64-bit data model in which
       longs  and  pointers, but not ints, are 64 bits in width (the LP64 data
       model). In the LP64 data model some system data types, notably  size_t,
       off_t, time_t and dev_t, grow from 32 bits to 64 bits as well.

       The  /proc  interfaces  described here are available to both 32-bit and
       64-bit controlling processes. However, many operations attempted  by  a
       32-bit  controlling  process  on a 64-bit target process will fail with
       EOVERFLOW because the address space range of a  32-bit  process  cannot
       encompass  a  64-bit  process or because the data in some 64-bit system
       data type cannot be compressed to fit  into  the  corresponding  32-bit
       type  without loss of information. Operations that fail in this circum-
       stance include reading and  writing  the  address  space,  reading  the
       address-map  file, and setting the target process's registers. There is
       no restriction on operations applied by a 64-bit process  to  either  a
       32-bit or a 64-bit target processes.

       The  format of the contents of any /proc file depends on the data model
       of the observer (the controlling process), not on the data model of the
       target process. A 64-bit debugger does not have to translate the infor-
       mation it reads from a /proc file for a 32-bit process from 32-bit for-
       mat  to  64-bit format. However, it usually has to be aware of the data
       model of the target process. The pr_dmodel field of  the  status  files
       indicates the target process's data model.

       To help deal with system data structures that are read from 32-bit pro-
       cesses, a 64-bit controlling program can be compiled with  the  C  pre-
       processor  symbol  _SYSCALL32  defined  before  system header files are
       included. This makes explicit 32-bit fixed-width data structures  (like
       cstruct stat32) visible to the 64-bit program. See types32.h(3HEAD).

DIRECTORY STRUCTURE
       At  the  top  level, the directory /proc contains entries each of which
       names an existing process in the system. These entries  are  themselves
       directories.  Except  where  otherwise noted, the files described below
       can be opened for reading only. In addition, if  a  process  becomes  a
       zombie  (one  that  has exited but whose parent has not yet performed a
       wait(3C) upon it), most of its associated /proc  files  disappear  from
       the  hierarchy;  subsequent  attempts to open them, or to read or write
       files opened before the process exited, will elicit the error ENOENT.

       Although process state and consequently the contents of /proc files can
       change  from  instant  to  instant, a single read(2) of a /proc file is
       guaranteed to return a sane representation of state; that is, the  read
       will  be atomic with respect to the state of the process. No such guar-
       antee applies to successive reads applied to a /proc file for a running
       process.  In  addition,  atomicity is not guaranteed for I/O applied to
       the as (address-space) file for a running  process  or  for  a  process
       whose address space contains memory shared by another running process.

       A number of structure definitions are used to describe the files. These
       structures may grow by the addition of elements at the  end  in  future
       releases of the system and it is not legitimate for a program to assume
       that they will not.

STRUCTURE OF /proc/pid
       A given directory /proc/pid contains the following entries.  A  process
       can  use the invisible alias /proc/self if it wishes to open one of its
       own /proc files (invisible in the sense that the name ``self'' does not
       appear  in  a  directory  listing  of  /proc  obtained from ls(1), get-
       dents(2), or readdir(3C)).

   contracts
       A directory containing references to the contracts held by the process.
       Each  entry is a symlink to the contract's directory under /system/con-
       tract. See contract(4).

   as
       Contains the address-space image of the process; it can be  opened  for
       both  reading and writing. lseek(2) is used to position the file at the
       virtual address of interest and then the address space can be  examined
       or  changed  through  read(2)  or  write(2)  (or  by  using pread(2) or
       pwrite(2) for the combined operation).

   ctl
       A write-only file to which structured messages  are  written  directing
       the  system to change some aspect of the process's state or control its
       behavior in some way. The seek offset is not relevant when  writing  to
       this file. Individual lwps also have associated lwpctl files in the lwp
       subdirectories.  A  control  message  may  be  written  either  to  the
       process's ctl file or to a specific lwpctl file with operation-specific
       effects. The effect of a control message is  immediately  reflected  in
       the  state of the process visible through appropriate status and infor-
       mation files. The types of control messages  are  described  in  detail
       later. See CONTROL MESSAGES.

   status
       Contains  state  information  about  the process and the representative
       lwp. The file contains a pstatus structure which contains  an  embedded
       lwpstatus structure for the representative lwp, as follows:

       typedef struct pstatus {
            int pr_flags;             /* flags (see below) */
            int pr_nlwp;              /* number of active lwps in the process */
            int pr_nzomb;             /* number of zombie lwps in the process */
            pid_tpr_pid;              /* process id */
            pid_tpr_ppid;             /* parent process id */
            pid_tpr_pgid;             /* process group id */
            pid_tpr_sid;              /* session id */
            id_t pr_aslwpid;          /* obsolete */
            id_t pr_agentid;          /* lwp-id of the agent lwp, if any */
            sigset_t pr_sigpend;      /* set of process pending signals */
            uintptr_t pr_brkbase;     /* virtual address of the process heap */
            size_t pr_brksize;        /* size of the process heap, in bytes */
            uintptr_t pr_stkbase;     /* virtual address of the process stack */
            size_tpr_stksize;         /* size of the process stack, in bytes */
            timestruc_t pr_utime;     /* process user cpu time */
            timestruc_t pr_stime;     /* process system cpu time */
            timestruc_t pr_cutime;    /* sum of children's user times */
            timestruc_t pr_cstime;    /* sum of children's system times */
            sigset_t pr_sigtrace;     /* set of traced signals */
            fltset_t pr_flttrace;     /* set of traced faults */
            sysset_t pr_sysentry;     /* set of system calls traced on entry */
            sysset_t pr_sysexit;      /* set of system calls traced on exit */
            char pr_dmodel;           /* data model of the process */
            taskid_t pr_taskid;       /* task id */
            projid_t pr_projid;       /* project id */
            zoneid_t pr_zoneid;       /* zone id */
            lwpstatus_t pr_lwp;       /* status of the representative lwp */
       } pstatus_t;


       pr_flags  is a bit-mask holding the following process flags. For conve-
       nience, it also contains the lwp  flags  for  the  representative  lwp,
       described later.

       PR_ISSYS        process is a system process (see PCSTOP).



       PR_VFORKP       process is the parent of a vforked child (see PCWATCH).



       PR_FORK         process has its inherit-on-fork mode set (see PCSET).



       PR_RLC          process has its run-on-last-close mode set (see PCSET).



       PR_KLC          process   has  its  kill-on-last-close  mode  set  (see
                       PCSET).



       PR_ASYNC        process has its asynchronous-stop mode set (see PCSET).



       PR_MSACCT       Set by  default  in  all  processes  to  indicate  that
                       microstate  accounting  is  enabled. However, this flag
                       has been deprecated  and  no  longer  has  any  effect.
                       Microstate  accounting may not be disabled; however, it
                       is still possible to toggle the flag.



       PR_MSFORK       Set by  default  in  all  processes  to  indicate  that
                       microstate  accounting  will  be  enabled for processes
                       that this parent forks(). However, this flag  has  been
                       deprecated and no longer has any effect. It is possible
                       to toggle this flag; however, it  is  not  possible  to
                       disable microstate accounting.



       PR_BPTADJ       process  has  its  breakpoint  adjustment mode set (see
                       PCSET).



       PR_PTRACE       process has  its  ptrace-compatibility  mode  set  (see
                       PCSET).



       pr_nlwp  is the total number of active lwps in the process. pr_nzomb is
       the total number of zombie lwps in the process.  A zombie lwp is a non-
       detached  lwp  that  has  terminated  but  has  not  been  reaped  with
       thr_join(3C) or pthread_join(3C).

       pr_pid, pr_ppid, pr_pgid, and pr_sid are, respectively, the process ID,
       the ID of the process's parent, the process's process group ID, and the
       process's session ID.

       pr_aslwpid is obsolete and is always zero.

       pr_agentid is the lwp-ID for the /proc agent lwp (see the PCAGENT  con-
       trol operation).  It is zero if there is no agent lwp in the process.

       pr_sigpend identifies asynchronous signals pending for the process.

       pr_brkbase is the virtual address of the process heap and pr_brksize is
       its size in bytes. The address formed by the sum of these values is the
       process  break  (see  brk(2)).  pr_stkbase  and pr_stksize are, respec-
       tively, the virtual address of the process stack and its size in bytes.
       (Each  lwp  runs on a separate stack; the distinguishing characteristic
       of the process stack is that the operating system  will  grow  it  when
       necessary.)

       pr_utime,  pr_stime,  pr_cutime,  and  pr_cstime are, respectively, the
       user CPU and system CPU time consumed by the process, and  the  cumula-
       tive  user  CPU and system CPU time consumed by the process's children,
       in seconds and nanoseconds.

       pr_sigtrace and pr_flttrace contain, respectively, the set  of  signals
       and  the set of hardware faults that are being traced (see PCSTRACE and
       PCSFAULT).

       pr_sysentry and pr_sysexit contain, respectively, the  sets  of  system
       calls being traced on entry and exit (see PCSENTRY and PCSEXIT).

       pr_dmodel  indicates  the  data  model of the process.  Possible values
       are:

       PR_MODEL_ILP32          process data model is ILP32.



       PR_MODEL_LP64           process data model is LP64.



       PR_MODEL_NATIVE         process data model is native.



       The pr_taskid, pr_projid, and pr_zoneid  fields  contain  respectively,
       the numeric IDs of the task, project, and zone in which the process was
       running.

       The constant PR_MODEL_NATIVE reflects the data model of the controlling
       process,  that is, its value is PR_MODEL_ILP32 or PR_MODEL_LP64 accord-
       ing to whether the controlling process has been compiled  as  a  32-bit
       program or a 64-bit program, respectively.

       pr_lwp contains the status information for the representative lwp:

       typedef struct lwpstatus {
           int pr_flags;               /* flags (see below) */
           id_t pr_lwpid;              /* specific lwp identifier */
           short pr_why;               /* reason for lwp stop, if stopped */
           short pr_what;              /* more detailed reason */
           short pr_cursig;            /* current signal, if any */
           siginfo_t pr_info;          /* info associated with signal or fault */
           sigset_t pr_lwppend;        /* set of signals pending to the lwp */
           sigset_t pr_lwphold;        /* set of signals blocked by the lwp */
           struct sigaction pr_action; /* signal action for current signal */
           stack_t pr_altstack;        /* alternate signal stack info */
           uintptr_t pr_oldcontext;    /* address of previous ucontext */
           short pr_syscall;           /* system call number (if in syscall) */
           short pr_nsysarg;           /* number of arguments to this syscall */
           int pr_errno;               /* errno for failed syscall */
           long pr_sysarg[PRSYSARGS];  /* arguments to this syscall */
           long pr_rval1;              /* primary syscall return value */
           long pr_rval2;              /* second syscall return value, if any */
           char pr_clname[PRCLSZ];     /* scheduling class name */
           timestruc_t pr_tstamp;      /* real-time time stamp of stop */
           timestruc_t pr_utime;       /* lwp user cpu time */
           timestruc_t pr_stime;       /* lwp system cpu time */
           uintptr_t pr_ustack;        /* stack boundary data (stack_t) address */
           ulong_t pr_instr;           /* current instruction */
           prgregset_t pr_reg;         /* general registers */
           prfpregset_t pr_fpreg;      /* floating-point registers */
       } lwpstatus_t;


       pr_flags  is  a  bit-mask  holding  the following lwp flags. For conve-
       nience, it also contains the process flags, described previously.

       PR_STOPPED      The lwp is stopped.



       PR_ISTOP        The lwp  is  stopped  on  an  event  of  interest  (see
                       PCSTOP).



       PR_DSTOP        The lwp has a stop directive in effect (see PCSTOP).



       PR_STEP         The  lwp  has  a  single-step  directive in effect (see
                       PCRUN).



       PR_ASLEEP       The lwp is in an interruptible sleep  within  a  system
                       call.



       PR_PCINVAL      The lwp's current instruction (pr_instr) is undefined.



       PR_DETACH       This  is  a  detached  lwp  (see pthread_create(3C) and
                       pthread_join(3C)).



       PR_DAEMON       This is a daemon lwp (see pthread_create(3C)).



       PR_ASLWP        This flag is obsolete and is never set.



       PR_AGENT        This is the /proc agent lwp for the process.



       pr_lwpid names the specific lwp.

       pr_why and pr_what together describe, for a stopped lwp, the reason for
       the stop. Possible values of pr_why and the associated pr_what are:

       PR_REQUESTED    indicates  that the stop occurred in response to a stop
                       directive,  normally  because  PCSTOP  was  applied  or
                       because another lwp stopped on an event of interest and
                       the asynchronous-stop flag (see PCSET) was not set  for
                       the process. pr_what is unused in this case.



       PR_SIGNALLED    indicates  that  the lwp stopped on receipt of a signal
                       (see PCSTRACE); pr_what holds the  signal  number  that
                       caused  the  stop  (for  a  newly-stopped lwp, the same
                       value is in pr_cursig).



       PR_FAULTED      indicates that the lwp stopped on incurring a  hardware
                       fault  (see  PCSFAULT);  pr_what holds the fault number
                       that caused the stop.



       PR_SYSENTRY     indicate a stop on entry to or exit from a system  call
       PR_SYSEXIT      (see  PCSENTRY  and  PCSEXIT); pr_what holds the system
                       call number.




       PR_JOBCONTROL   indicates that the  lwp  stopped  due  to  the  default
                       action of a job control stop signal (see sigaction(2));
                       pr_what holds the stopping signal number.



       PR_SUSPENDED    indicates that the lwp stopped due to internal synchro-
                       nization  of lwps within the process. pr_what is unused
                       in this case.



       pr_cursig names the current signal, that is,  the  next  signal  to  be
       delivered  to  the  lwp,  if any. pr_info, when the lwp is in a PR_SIG-
       NALLED or PR_FAULTED stop, contains additional information pertinent to
       the particular signal or fault (see <&lt;sys/siginfo.h>&gt;).

       pr_lwppend  identifies  any synchronous or directed signals pending for
       the lwp. pr_lwphold identifies those signals whose  delivery  is  being
       blocked by the lwp (the signal mask).

       pr_action contains the signal action information pertaining to the cur-
       rent signal (see sigaction(2)); it is undefined if pr_cursig  is  zero.
       pr_altstack contains the alternate signal stack information for the lwp
       (see sigaltstack(2)).

       pr_oldcontext, if not zero, contains the address on the lwp stack of  a
       ucontext  structure  describing  the  previous  user-level context (see
       ucontext.h(3HEAD)).  It is non-zero only if the lwp is executing in the
       context of a signal handler.

       pr_syscall  is the number of the system call, if any, being executed by
       the lwp; it is non-zero if and only if the lwp is stopped on  PR_SYSEN-
       TRY  or  PR_SYSEXIT,  or  is asleep within a system call ( PR_ASLEEP is
       set). If pr_syscall is non-zero, pr_nsysarg is the number of  arguments
       to the system call and pr_sysarg contains the actual arguments.

       pr_rval1, pr_rval2, and pr_errno are defined only if the lwp is stopped
       on PR_SYSEXIT or if the PR_VFORKP flag is set.  If  pr_errno  is  zero,
       pr_rval1  and  pr_rval2 contain the return values from the system call.
       Otherwise, pr_errno contains the error number for  the  failing  system
       call (see <&lt;sys/errno.h>&gt;).

       pr_clname contains the name of the lwp's scheduling class.

       pr_tstamp,  if  the  lwp is stopped, contains a time stamp marking when
       the lwp stopped, in real time seconds and nanoseconds  since  an  arbi-
       trary time in the past.

       pr_utime is the amount of user level CPU time used by this LWP.

       pr_stime is the amount of system level CPU time used by this LWP.

       pr_ustack is the virtual address of the stack_t that contains the stack
       boundaries for this LWP. See getustack(2) and _stack_grow(3C).

       pr_instr contains the machine instruction to which  the  lwp's  program
       counter  refers.  The  amount  of  data  retrieved  from the process is
       machine-dependent. On SPARC based machines, it is a 32-bit word. On x86
       based  machines,  it  is a single byte. In general, the size is that of
       the machine's smallest instruction. If PR_PCINVAL is set,  pr_instr  is
       undefined; this occurs whenever the lwp is not stopped or when the pro-
       gram counter refers to an invalid virtual address.

       pr_reg is an array holding the contents of a stopped lwp's general reg-
       isters.

       SPARC                   On  SPARC-based  machines,  the predefined con-
                               stants R_G0 ... R_G7, R_O0 ... R_O7,  R_L0  ...
                               R_L7,  R_I0  ... R_I7, R_PC, R_nPC, and R_Y can
                               be used as indices to refer to the  correspond-
                               ing registers; previous register windows can be
                               read from their overflow locations on the stack
                               (however,   see   the   gwindows  file  in  the
                               /proc/pid/lwp/lwpid subdirectory).



       SPARC V8 (32-bit)       For SPARC V8  (32-bit)  controlling  processes,
                               the  predefined  constants  R_PSR,  R_WIM,  and
                               R_TBR can be used as indices to  refer  to  the
                               corresponding  special  registers. For SPARC V9
                               (64-bit) controlling processes, the  predefined
                               constants  R_CCR, R_ASI, and R_FPRS can be used
                               as indices to refer to the  corresponding  spe-
                               cial registers.



       x86                     On x86 based machines, the predefined constants
                               SS, UESP, EFL, CS, EIP, ERR, TRAPNO, EAX,  ECX,
                               EDX,  EBX,  ESP, EBP, ESI, EDI, DS, ES, FS, and
                               GS can be used as indices to refer to the  cor-
                               responding registers.



       pr_fpreg is a structure holding the contents of the floating-point reg-
       isters.

       SPARC registers, both general and floating-point, as seen by  a  64-bit
       controlling  process  are the V9 versions of the registers, even if the
       target process is a 32-bit (V8) process. V8 registers are a  subset  of
       the V9 registers.

       If the lwp is not stopped, all register values are undefined.

   psinfo
       Contains  miscellaneous information about the process and the represen-
       tative lwp needed by the ps(1) command. psinfo is  accessible  after  a
       process  becomes  a  zombie. The file contains a psinfo structure which
       contains an embedded lwpsinfo structure for the representative lwp,  as
       follows:

       typedef struct psinfo {
           int pr_flag;              /* process flags (DEPRECATED: see below) */
           int pr_nlwp;              /* number of active lwps in the process */
           int pr_nzomb;             /* number of zombie lwps in the process */
           pid_t pr_pid;             /* process id */
           pid_t pr_ppid;            /* process id of parent */
           pid_t pr_pgid;            /* process id of process group leader */
           pid_t pr_sid;             /* session id */
           uid_t pr_uid;             /* real user id */
           uid_t pr_euid;            /* effective user id */
           gid_t pr_gid;             /* real group id */
           gid_t pr_egid;            /* effective group id */
           uintptr_t pr_addr;        /* address of process */
           size_t pr_size;           /* size of process image in Kbytes */
           size_t pr_rssize;         /* resident set size in Kbytes */
           dev_t pr_ttydev;          /* controlling tty device (or PRNODEV) */
           ushort_t pr_pctcpu;       /* % of recent cpu time used by all lwps */
           ushort_t pr_pctmem;       /* % of system memory used by process */
           timestruc_t pr_start;     /* process start time, from the epoch */
           timestruc_t pr_time;      /* cpu time for this process */
           timestruc_t pr_ctime;     /* cpu time for reaped children */
           char pr_fname[PRFNSZ];    /* name of exec'ed file */
           char pr_psargs[PRARGSZ];  /* initial characters of arg list */
           int pr_wstat;             /* if zombie, the wait() status */
           int pr_argc;              /* initial argument count */
           uintptr_t pr_argv;        /* address of initial argument vector */
           uintptr_t pr_envp;        /* address of initial environment vector */
           char pr_dmodel;           /* data model of the process */
           lwpsinfo_t pr_lwp;        /* information for representative lwp */
           taskid_t pr_taskid;       /* task id */
           projid_t pr_projid;       /* project id */
           poolid_t pr_poolid;       /* pool id */
           zoneid_t pr_zoneid;       /* zone id */
           ctid_t pr_contract;       /* process contract id */
       } psinfo_t;


       Some  of the entries in psinfo, such as pr_addr, refer to internal ker-
       nel data structures and should not be expected to retain their meanings
       across different versions of the operating system.

       psinfo_t.pr_flag  is  a  deprecated  interface that should no longer be
       used. Applications currently relying on the SSYS bit in pr_flag  should
       migrate to checking PR_ISSYS in the pstatus structure's pr_flags field.

       pr_pctcpu and pr_pctmem are 16-bit binary fractions in the range 0.0 to
       1.0 with the binary point to the right of the high-order  bit  (1.0  ==
       0x8000). pr_pctcpu is the summation over all lwps in the process.

       pr_lwp  contains  the ps(1) information for the representative lwp.  If
       the process is a zombie, pr_nlwp,  pr_nzomb,  and  pr_lwp.pr_lwpid  are
       zero and the other fields of pr_lwp are undefined:

       typedef struct lwpsinfo {
           int pr_flag;              /* lwp flags (DEPRECATED: see below) */
           id_t pr_lwpid;            /* lwp id */
           uintptr_t pr_addr;        /* internal address of lwp */
           uintptr_t pr_wchan;       /* wait addr for sleeping lwp */
           char pr_stype;            /* synchronization event type */
           char pr_state;            /* numeric lwp state */
           char pr_sname;            /* printable character for pr_state */
           char pr_nice;             /* nice for cpu usage */
           short pr_syscall;         /* system call number (if in syscall) */
           char pr_oldpri;           /* pre-SVR4, low value is high priority */
           char pr_cpu;              /* pre-SVR4, cpu usage for scheduling */
           int pr_pri;               /* priority, high value = high priority */
           ushort_t pr_pctcpu;       /* % of recent cpu time used by this lwp */
           timestruc_t pr_start;     /* lwp start time, from the epoch */
           timestruc_t pr_time;      /* cpu time for this lwp */
           char pr_clname[PRCLSZ];   /* scheduling class name */
           char pr_name[PRFNSZ];     /* name of system lwp */
           processorid_t pr_onpro;   /* processor which last ran this lwp */
           processorid_t pr_bindpro; /* processor to which lwp is bound */
           psetid_t pr_bindpset;     /* processor set to which lwp is bound */
       } lwpsinfo_t;


       Some  of  the entries in lwpsinfo, such as pr_addr, pr_wchan, pr_stype,
       pr_state, and pr_name, refer to internal  kernel  data  structures  and
       should  not  be expected to retain their meanings across different ver-
       sions of the operating system.

       lwpsinfo_t.pr_flag is a deprecated interface that should no  longer  be
       used.

       pr_pctcpu  is  a  16-bit binary fraction, as described above. It repre-
       sents the CPU time used by  the  specific  lwp.  On  a  multi-processor
       machine, the maximum value is 1/N, where N is the number of CPUs.

       pr_contract is the id of the process contract of which the process is a
       member. See contract(4) and process(4).

   cred
       Contains a description of the credentials associated with the process:

       typedef struct prcred {
            uid_t pr_euid;      /* effective user id */
            uid_t pr_ruid;      /* real user id */
            uid_t pr_suid;      /* saved user id (from exec) */
            gid_t pr_egid;      /* effective group id */
            gid_t pr_rgid;      /* real group id */
            gid_t pr_sgid;      /* saved group id (from exec) */
            int pr_ngroups;     /* number of supplementary groups */
            gid_t pr_groups[1]; /* array of supplementary groups */
       } prcred_t;

       The array of associated supplementary groups in pr_groups is  of  vari-
       able  length;  the  cred file contains all of the supplementary groups.
       pr_ngroups indicates the number of supplementary groups. (See also  the
       PCSCRED and PCSCREDX control operations.)

   priv
       Contains a description of the privileges associated with the process:

       typedef struct prpriv {
            uint32_t        pr_nsets;      /* number of privilege set */
            uint32_t        pr_setsize;    /* size of privilege set */
            uint32_t        pr_infosize;   /* size of supplementary data */
            priv_chunk_t    pr_sets[1];    /* array of sets */
       } prpriv_t;


       The actual dimension of the pr_sets[] field is

       pr_sets[pr_nsets][pr_setsize]


       which  is  followed  by  additional information about the process state
       pr_infosize bytes in size.

       The   full   size   of   the   structure   can   be   computed    using
       PRIV_PRPRIV_SIZE(prpriv_t *).

   sigact
       Contains an array of sigaction structures describing the current dispo-
       sitions of all signals associated with the traced process  (see  sigac-
       tion(2)).   Signal  numbers  are  displaced by 1 from array indices, so
       that the action for signal number n appears  in  position  n-1  of  the
       array.

   auxv
       Contains  the initial values of the process's aux vector in an array of
       auxv_t structures (see <&lt;sys/auxv.h>&gt;). The values are  those  that  were
       passed  by  the  operating system as startup information to the dynamic
       linker.

   ldt
       This file exists only on x86 based machines. It is  non-empty  only  if
       the  process  has  established  a local descriptor table (LDT). If non-
       empty, the file contains the array of currently active LDT  entries  in
       an array of elements of type struct ssd, defined in <&lt;sys/sysi86.h>&gt;, one
       element for each active LDT entry.

   map
       Contains information about the virtual address map of the process.  The
       file  contains  an array of prmap structures, each of which describes a
       contiguous virtual address region in the address space  of  the  traced
       process:

       typedef struct prmap {
            uintptr_tpr_vaddr;         /* virtual address of mapping */
            size_t pr_size;            /* size of mapping in bytes */
            char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
            offset_t pr_offset;        /* offset into mapped object, if any */
            int pr_mflags;             /* protection and attribute flags */
            int pr_pagesize;           /* pagesize for this mapping in bytes */
            int pr_shmid;              /* SysV shared memory identifier */
       } prmap_t;

       pr_vaddr  is  the  virtual  address  of  the  mapping within the traced
       process and pr_size is its size in bytes. pr_mapname, if  it  does  not
       contain a null string, contains the name of a file in the object direc-
       tory (see below) that can be opened read-only to obtain a file descrip-
       tor  for  the  mapped  file associated with the mapping. This enables a
       debugger to find object file symbol tables without having to  know  the
       real  path  names  of  the  executable file and shared libraries of the
       process. pr_offset is the 64-bit offset within the mapped file (if any)
       to which the virtual address is mapped.

       pr_mflags is a bit-mask of protection and attribute flags:

       MA_READ         mapping is readable by the traced process.



       MA_WRITE        mapping is writable by the traced process.



       MA_EXEC         mapping is executable by the traced process.



       MA_SHARED       mapping changes are shared by the mapped object.



       MA_ISM          mapping   is   intimate   shared   memory  (shared  MMU
                       resources)



       MAP_NORESERVE   mapping does not have swap space reserved (mapped  with
                       MAP_NORESERVE)



       MA_SHM          mapping System V shared memory



       A  contiguous  area  of  the  address  space having the same underlying
       mapped object may appear as multiple  mappings  due  to  varying  read,
       write,  and  execute  attributes. The underlying mapped object does not
       change over the range of a single mapping. An I/O operation to  a  map-
       ping  marked MA_SHARED fails if applied at a virtual address not corre-
       sponding to a valid page in the underlying mapped object. A write to  a
       MA_SHARED  mapping  that is not marked MA_WRITE fails. Reads and writes
       to private mappings always  succeed.   Reads  and  writes  to  unmapped
       addresses fail.

       pr_pagesize is the page size for the mapping, currently always the sys-
       tem pagesize.

       pr_shmid is the shared memory identifier, if any, for the mapping.  Its
       value  is  -1  if  the  mapping  is  not  System  V  shared memory. See
       shmget(2).

   rmap
       Contains information about the reserved address ranges of the  process.
       The  file  contains  an array of prmap structures, as defined above for
       the map file. Each structure describes  a  contiguous  virtual  address
       region  in  the address space of the traced process that is reserved by
       the system in the sense that an mmap(2) system call that does not spec-
       ify MAP_FIXED will not use any part of it for the new mapping. Examples
       of such reservations  include  the  address  ranges  reserved  for  the
       process  stack  and  the  individual  thread stacks of a multi-threaded
       process.

   cwd
       A symbolic  link  to  the  process's  current  working  directory.  See
       chdir(2).  A  readlink(2)  of /proc/pid/cwd yields a null string.  How-
       ever, it can be opened, listed, and searched as a directory, and can be
       the target of chdir(2).

   root
       A  symbolic  link  to  the process's root directory. /proc/pid/root can
       differ from the system root directory if the  process  or  one  of  its
       ancestors  executed  chroot(2) as super user. It has the same semantics
       as /proc/pid/cwd.

   fd
       A directory containing references to the open  files  of  the  process.
       Each entry is a decimal number corresponding to an open file descriptor
       in the process.

       If an entry refers to a regular file, it can be opened with normal file
       system  semantics  but,  to  ensure that the controlling process cannot
       gain greater access than the controlled process, with  no  file  access
       modes  other  than its read/write open modes in the controlled process.
       If an entry refers to a directory, it can be  accessed  with  the  same
       semantics  as /proc/pid/cwd. An attempt to open any other type of entry
       fails with EACCES.

   object
       A directory containing read-only files with names corresponding to  the
       pr_mapname  entries  in the map and pagedata files. Opening such a file
       yields a file descriptor for the underlying mapped file associated with
       an address-space mapping in the process. The file name a.out appears in
       the directory as an alias for the process's executable file.

       The object directory makes it possible for  a  controlling  process  to
       gain  access  to  the  object file and any shared libraries (and conse-
       quently the symbol tables) without having to know the actual path names
       of the executable files.

   path
       A  directory  containing symbolic links to files opened by the process.
       The directory includes one entry for cwd and root. The  directory  also
       contains  a  numerical  entry for each file descriptor in the fd direc-
       tory, and entries matching those  in  the  object  directory.  If  this
       information  is  not  avilable, any attempt to read the contents of the
       symbolic link will fail. This is most common  for  files  that  do  not
       exist  in the filesystem namespace (such as FIFOs and sockets), but can
       also happen for regular files. For the  file  descriptor  entries,  the
       path  may  be  different  from  the one used by the process to open the
       file.

   pagedata
       Opening the page data file enables tracking of address space references
       and modifications on a per-page basis.

       A read(2) of the page data file descriptor returns structured page data
       and atomically clears the page data maintained for the file by the sys-
       tem.  That  is  to say, each read returns data collected since the last
       read; the first read returns data collected since the file was  opened.
       When  the call completes, the read buffer contains the following struc-
       ture as its header and thereafter contains a number of  section  header
       structures  and associated byte arrays that must be accessed by walking
       linearly through the buffer.

       typedef struct prpageheader {
           timestruc_t pr_tstamp; /* real time stamp, time of read() */
           ulong_t pr_nmap;       /* number of address space mappings */
           ulong_t pr_npage;      /* total number of pages */
       } prpageheader_t;


       The header is followed by pr_nmap  prasmap  structures  and  associated
       data arrays. The prasmap structure contains the following elements:

       typedef struct prasmap {
           uintptr_t pr_vaddr;        /* virtual address of mapping */
           ulong_t pr_npage;          /* number of pages in mapping */
           char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
           offset_t pr_offset;        /* offset into mapped object, if any */
           int pr_mflags;             /* protection and attribute flags */
           int pr_pagesize;           /* pagesize for this mapping in bytes */
           int pr_shmid;              /* SysV shared memory identifier */
       } prasmap_t;


       Each  section  header  is followed by pr_npage bytes, one byte for each
       page in the mapping, plus 0-7 null bytes at the end so  that  the  next
       prasmap  structure  begins on an eight-byte aligned boundary. Each data
       byte may contain these flags:

       PG_REFERENCED           page has been referenced.



       PG_MODIFIED             page has been modified.



       If the read buffer is not large enough to contain all of the page data,
       the  read  fails  with  E2BIG  and  the  page  data is not cleared. The
       required size of the read buffer can be  determined  through  fstat(2).
       Application  of  lseek(2)  to the page data file descriptor is ineffec-
       tive; every read starts from the beginning of  the  file.  Closing  the
       page  data  file  descriptor  terminates the system overhead associated
       with collecting the data.

       More than one page data file descriptor for the  same  process  can  be
       opened,  up to a system-imposed limit per traced process. A read of one
       does not affect the data being collected by the system for the  others.
       An  open  of  the  page  data file will fail with ENOMEM if the system-
       imposed limit would be exceeded.

   watch
       Contains an array of prwatch structures,  one  for  each  watched  area
       established by the PCWATCH control operation. See PCWATCH for details.

   usage
       Contains  process  usage  information  described by a prusage structure
       which contains at least the following fields:

       typedef struct prusage {
           id_t pr_lwpid;           /* lwp id.  0: process or defunct */
           int pr_count;            /* number of contributing lwps */
           timestruc_t pr_tstamp;   /* real time stamp, time of read() */
           timestruc_t pr_create;   /* process/lwp creation time stamp */
           timestruc_t pr_term;     /* process/lwp termination time stamp */
           timestruc_t pr_rtime;    /* total lwp real (elapsed) time */
           timestruc_t pr_utime;    /* user level CPU time */
           timestruc_t pr_stime;    /* system call CPU time */
           timestruc_t pr_ttime;    /* other system trap CPU time */
           timestruc_t pr_tftime;   /* text page fault sleep time */
           timestruc_t pr_dftime;   /* data page fault sleep time */
           timestruc_t pr_kftime;   /* kernel page fault sleep time */
           timestruc_t pr_ltime;    /* user lock wait sleep time */
           timestruc_t pr_slptime;  /* all other sleep time */
           timestruc_t pr_wtime;    /* wait-cpu (latency) time */
           timestruc_t pr_stoptime; /* stopped time */
           ulong_t pr_minf;         /* minor page faults */
           ulong_t pr_majf;         /* major page faults */
           ulong_t pr_nswap;        /* swaps */
           ulong_t pr_inblk;        /* input blocks */
           ulong_t pr_oublk;        /* output blocks */
           ulong_t pr_msnd;         /* messages sent */
           ulong_t pr_mrcv;         /* messages received */
           ulong_t pr_sigs;         /* signals received */
           ulong_t pr_vctx;         /* voluntary context switches */
           ulong_t pr_ictx;         /* involuntary context switches */
           ulong_t pr_sysc;         /* system calls */
           ulong_t pr_ioch;         /* chars read and written */
       } prusage_t;


       Microstate accounting is now continuously enabled. While this  informa-
       tion  was  previously  an  estimate,  if microstate accounting were not
       enabled, the current information is now never  an  estimate  represents
       time the process has spent in various states.

   lstatus
       Contains  a prheader structure followed by an array of lwpstatus struc-
       tures,  one  for  each  active   lwp   in   the   process   (see   also
       /proc/pid/lwp/lwpid/lwpstatus, below). The prheader structure describes
       the number and size of the array entries that follow.

       typedef struct prheader {
           long pr_nent;        /* number of entries */
           size_t pr_entsize;   /* size of each entry, in bytes */
       } prheader_t;


       The lwpstatus structure may grow by the addition of elements at the end
       in  future  releases of the system. Programs must use pr_entsize in the
       file header to index through the array. These  comments  apply  to  all
       /proc  files  that  include  a  prheader structure (lpsinfo and lusage,
       below).

   lpsinfo
       Contains a prheader structure followed by an array of  lwpsinfo  struc-
       tures,  one  for  eachactive  and  zombie  lwp in the process. See also
       /proc/pid/lwp/lwpid/lwpsinfo, below.

   lusage
       Contains a prheader structure followed by an array  of  prusage  struc-
       tures,  one for each active lwp in the process, plus an additional ele-
       ment at the beginning that contains the summation over all defunct lwps
       (lwps  that once existed but no longer exist in the process). Excluding
       the pr_lwpid, pr_tstamp, pr_create, and pr_term entries, the  entry-by-
       entry  summation  over  all  these  structures is the definition of the
       process usage information obtained  from  the  usage  file.  (See  also
       /proc/pid/lwp/lwpid/lwpusage, below.)

   lwp
       A  directory containing entries each of which names an active or zombie
       lwp within the process. These entries are themselves  directories  con-
       taining  additional  files  as  described below. Only the lwpsinfo file
       exists in the directory of a zombie lwp.

STRUCTURE OF /proc/pid/lwp/ lwpid
       A given directory /proc/pid/lwp/lwpid contains the following entries:

   lwpctl
       Write-only control file. The messages written to this file  affect  the
       specific lwp rather than the representative lwp, as is the case for the
       process's ctl file.

   lwpstatus
       lwp-specific state information. This file contains the lwpstatus struc-
       ture for the specific lwp as described above for the representative lwp
       in the process's status file.

   lwpsinfo
       lwp-specific ps(1) information. This file contains the lwpsinfo  struc-
       ture for the specific lwp as described above for the representative lwp
       in the process's psinfo file. The lwpsinfo file is accessible after  an
       lwp becomes a zombie.

   lwpusage
       This  file  contains  the  prusage  structure  for  the specific lwp as
       described above for the process's usage file.

   gwindows
       This file exists only on SPARC based machines. If it is  non-empty,  it
       contains  a  gwindows_t  structure, defined in <&lt;sys/regset.h>&gt;, with the
       values of those SPARC register windows that could not be stored on  the
       stack when the lwp stopped. Conditions under which register windows are
       not stored on the stack are: the stack pointer  refers  to  nonexistent
       process  memory or the stack pointer is improperly aligned.  If the lwp
       is not stopped or if there are no register windows that  could  not  be
       stored on the stack, the file is empty (the usual case).

   xregs
       Extra  state  registers.  The  extra state register set is architecture
       dependent; this file is empty if the  system  does  not  support  extra
       state registers.  If the file is non-empty, it contains an architecture
       dependent structure of type prxregset_t, defined  in  <&lt;procfs.h>&gt;,  with
       the  values  of  the  lwp's  extra  state  registers. If the lwp is not
       stopped, all register values are undefined. See also the  PCSXREG  con-
       trol operation, below.

   asrs
       This  file  exists  only  for 64-bit SPARC V9 processes. It contains an
       asrset_t structure, defined in <&lt;sys/regset.h>&gt;, containing the values of
       the  lwp's  platform-dependent ancillary state registers. If the lwp is
       not stopped, all register values are undefined. See  also  the  PCSASRS
       control operation, below.

   templates
       A  directory  which contains references to the active templates for the
       lwp, named by the contract type.  Changes made to  an  active  template
       descriptor  do  not  affect  the original template which was activated,
       though they do affect the active template.  It is not possible to acti-
       vate an active template descriptor.
        See contract(4).

CONTROL MESSAGES
       Process  state  changes  are  effected  through  messages  written to a
       process's ctl file or to an individual lwp's lwpctl file.  All  control
       messages  consist  of a long that names the specific operation followed
       by additional data containing the operand, if any.

       Multiple control messages may be combined  in  a  single  write(2)  (or
       writev(2)) to a control file, but no partial writes are permitted. That
       is, each control message, operation code plus operand, if any, must  be
       presented  in  its entirety to the write(2) and not in pieces over sev-
       eral system calls. If a control operation fails, no  subsequent  opera-
       tions contained in the same write(2) are attempted.

       Descriptions  of  the  allowable control messages follow. In all cases,
       writing a message to a control file for a process or lwp that has  ter-
       minated elicits the error ENOENT.

   PCSTOP PCDSTOP PCWSTOP PCTWSTOP
       When  applied  to  the process control file, PCSTOP directs all lwps to
       stop and waits for them to stop, PCDSTOP directs all lwps to stop with-
       out  waiting for them to stop, and PCWSTOP simply waits for all lwps to
       stop. When applied to an lwp control file, PCSTOP directs the  specific
       lwp  to  stop  and waits until it has stopped, PCDSTOP directs the spe-
       cific lwp to stop without waiting for it to stop,  and  PCWSTOP  simply
       waits  for  the  specific  lwp  to stop. When applied to an lwp control
       file, PCSTOP and PCWSTOP complete when the lwp stops  on  an  event  of
       interest,  immediately  if  already  so  stopped;  when  applied to the
       process control file, they complete when every lwp has  stopped  either
       on an event of interest or on a PR_SUSPENDED stop.

       PCTWSTOP  is  identical to PCWSTOP except that it enables the operation
       to time out, to avoid waiting forever for a process  or  lwp  that  may
       never stop on an event of interest. PCTWSTOP takes a long operand spec-
       ifying a number of milliseconds; the wait will  terminate  successfully
       after  the  specified number of milliseconds even if the process or lwp
       has not stopped; a timeout value of zero makes the operation  identical
       to PCWSTOP.

       An  ``event  of interest'' is either a PR_REQUESTED stop or a stop that
       has been specified in the process's tracing  flags  (set  by  PCSTRACE,
       PCSFAULT,  PCSENTRY, and PCSEXIT). PR_JOBCONTROL and PR_SUSPENDED stops
       are specifically not events of interest. (An lwp may stop twice due  to
       a  stop  signal, first showing PR_SIGNALLED if the signal is traced and
       again showing PR_JOBCONTROL if the lwp is set running without  clearing
       the signal.) If PCSTOP or PCDSTOP is applied to an lwp that is stopped,
       but not on an event of interest, the stop directive takes  effect  when
       the  lwp is restarted by the competing mechanism. At that time, the lwp
       enters a PR_REQUESTED stop before executing any user-level code.

       A write of a control message that blocks is interruptible by  a  signal
       so  that,  for example, an alarm(2) can be set to avoid waiting forever
       for a process or lwp that may never stop on an event  of  interest.  If
       PCSTOP  is  interrupted,  the lwp stop directives remain in effect even
       though the write(2) returns an error. (Use of PCTWSTOP with a  non-zero
       timeout is recommended over PCWSTOP with an alarm(2).)

       A  system  process  (indicated  by the PR_ISSYS flag) never executes at
       user level, has no user-level address space visible through /proc,  and
       cannot be stopped. Applying one of these operations to a system process
       or any of its lwps elicits the error EBUSY.

   PCRUN
       Make an lwp runnable again after a stop. This operation  takes  a  long
       operand containing zero or more of the following flags:

       PRCSIG          clears the current signal, if any (see PCCSIG).



       PRCFAULT        clears the current fault, if any (see PCCFAULT).



       PRSTEP          directs  the  lwp  to execute a single machine instruc-
                       tion. On completion of the instruction,  a  trace  trap
                       occurs.  If  FLTTRACE  is  being traced, the lwp stops;
                       otherwise, it is sent  SIGTRAP.  If  SIGTRAP  is  being
                       traced  and is not blocked, the lwp stops. When the lwp
                       stops on an event of interest, the  single-step  direc-
                       tive  is  cancelled, even if the stop occurs before the
                       instruction is executed. This operation requires  hard-
                       ware and operating system support and may not be imple-
                       mented on all processors.  It is implemented  on  SPARC
                       and x86 based machines.



       PRSABORT        is  meaningful only if the lwp is in a PR_SYSENTRY stop
                       or is marked PR_ASLEEP; it instructs the lwp  to  abort
                       execution   of   the  system  call  (see  PCSENTRY  and
                       PCSEXIT).



       PRSTOP          directs the lwp to stop again as soon as possible after
                       resuming execution (see PCDSTOP). In particular, if the
                       lwp is stopped on PR_SIGNALLED or PR_FAULTED, the  next
                       stop  will  show  PR_REQUESTED, no other stop will have
                       intervened, and the lwp  will  not  have  executed  any
                       user-level code.



       When  applied  to  an  lwp  control  file, PCRUN clears any outstanding
       directed-stop request and makes the specific lwp runnable.  The  opera-
       tion fails with EBUSY if the specific lwp is not stopped on an event of
       interest or has not been directed to stop or if the  agent  lwp  exists
       and this is not the agent lwp (see PCAGENT).

       When  applied to the process control file, a representative lwp is cho-
       sen for the operation as described for /proc/pid/status. The  operation
       fails  with  EBUSY if the representative lwp is not stopped on an event
       of interest or has not been directed  to  stop  or  if  the  agent  lwp
       exists.  If  PRSTEP  or PRSTOP was requested, the representative lwp is
       made runnable and its outstanding  directed-stop  request  is  cleared;
       otherwise all outstanding directed-stop requests are cleared and, if it
       was stopped on an event of interest, the representative lwp  is  marked
       PR_REQUESTED.   If,  as a consequence, all lwps are in the PR_REQUESTED
       or PR_SUSPENDED stop state, all  lwps  showing  PR_REQUESTED  are  made
       runnable.

   PCSTRACE
       Define a set of signals to be traced in the process. The receipt of one
       of these signals by an lwp causes the lwp to stop. The set  of  signals
       is  defined using an operand sigset_t contained in the control message.
       Receipt of SIGKILL cannot be  traced;  if  specified,  it  is  silently
       ignored.

       If  a  signal  that is included in an lwp's held signal set (the signal
       mask) is sent to the lwp, the signal is not received and does not cause
       a  stop until it is removed from the held signal set, either by the lwp
       itself or by setting the held signal set with PCSHOLD.

   PCCSIG
       The current signal, if any, is cleared from the specific or representa-
       tive lwp.

   PCSSIG
       The  current  signal and its associated signal information for the spe-
       cific or representative lwp are set according to the  contents  of  the
       operand siginfo structure (see <&lt;sys/siginfo.h>&gt;).  If the specified sig-
       nal number is zero, the current signal is  cleared.  The  semantics  of
       this  operation  are different from those of kill(2) in that the signal
       is delivered to the lwp immediately after execution is resumed (even if
       it  is  being  blocked)  and  an  additional PR_SIGNALLED stop does not
       intervene even if the signal is traced. Setting the current  signal  to
       SIGKILL terminates the process immediately.

   PCKILL
       If applied to the process control file, a signal is sent to the process
       with semantics identical to those of kill(2).  If  applied  to  an  lwp
       control file, a directed signal is sent to the specific lwp. The signal
       is named in a long operand contained in the  message.  Sending  SIGKILL
       terminates the process immediately.

   PCUNKILL
       A  signal  is  deleted,  that is, it is removed from the set of pending
       signals. If applied to the process control file, the signal is  deleted
       from  the process's pending signals. If applied to an lwp control file,
       the signal is deleted from the lwp's pending signals. The current  sig-
       nal  (if  any)  is unaffected. The signal is named in a long operand in
       the control message. It is an  error  (EINVAL)  to  attempt  to  delete
       SIGKILL.

   PCSHOLD
       Set  the  set  of  held  signals for the specific or representative lwp
       (signals whose delivery will be blocked if sent to the lwp). The set of
       signals  is specified with a sigset_t operand. SIGKILL and SIGSTOP can-
       not be held; if specified, they are silently ignored.

   PCSFAULT
       Define a set of hardware faults to be traced in the process. On  incur-
       ring  one of these faults, an lwp stops. The set is defined via the op-
       erand fltset_t structure. Fault names are defined in <&lt;sys/fault.h>&gt;  and
       include  the  following. Some of these may not occur on all processors;
       there may be processor-specific faults in addition to these.

       FLTILL          illegal instruction



       FLTPRIV         privileged instruction



       FLTBPT          breakpoint trap



       FLTTRACE        trace trap (single-step)



       FLTWATCH        watchpoint trap



       FLTACCESS       memory access fault (bus error)



       FLTBOUNDS       memory bounds violation



       FLTIOVF         integer overflow



       FLTIZDIV        integer zero divide



       FLTFPE          floating-point exception



       FLTSTACK        unrecoverable stack fault



       FLTPAGE         recoverable page fault



       When not traced, a fault normally results in the posting of a signal to
       the lwp that incurred the fault. If an lwp stops on a fault, the signal
       is posted to the lwp when execution is  resumed  unless  the  fault  is
       cleared  by  PCCFAULT or by the PRCFAULT option of PCRUN. FLTPAGE is an
       exception; no signal is posted.  The pr_info  field  in  the  lwpstatus
       structure  identifies  the  signal to be sent and contains machine-spe-
       cific information about the fault.

   PCCFAULT
       The current fault, if any, is cleared; the associated signal  will  not
       be sent to the specific or representative lwp.

   PCSENTRY PCSEXIT
       These  control  operations instruct the process's lwps to stop on entry
       to or exit from specified system calls. The set of system calls  to  be
       traced is defined via an operand sysset_t structure.

       When  entry to a system call is being traced, an lwp stops after having
       begun the call to the system but before the system call arguments  have
       been  fetched  from  the  lwp.  When  exit  from a system call is being
       traced, an lwp stops on completion of the system  call  just  prior  to
       checking  for  signals  and returning to user level. At this point, all
       return values have been stored into the lwp's registers.

       If an lwp is stopped on entry to a system call  (PR_SYSENTRY)  or  when
       sleeping  in an interruptible system call (PR_ASLEEP is set), it may be
       instructed to go  directly  to  system  call  exit  by  specifying  the
       PRSABORT  flag  in a PCRUN control message. Unless exit from the system
       call is being traced, the lwp returns to user level showing EINTR.

   PCWATCH
       Set or clear a watched area in the controlled process  from  a  prwatch
       structure operand:

       typedef struct prwatch {
           uintptr_t pr_vaddr;  /* virtual address of watched area */
           size_t pr_size;      /* size of watched area in bytes */
           int pr_wflags;       /* watch type flags */
       } prwatch_t;


       pr_vaddr  specifies  the  virtual  address  of  an area of memory to be
       watched in the controlled process. pr_size specifies the  size  of  the
       area,  in  bytes.  pr_wflags  specifies the type of memory access to be
       monitored as a bit-mask of the following flags:

       WA_READ                 read access



       WA_WRITE                write access



       WA_EXEC                 execution access



       WA_TRAPAFTER            trap after the instruction completes



       If pr_wflags is non-empty, a watched area is established for  the  vir-
       tual  address  range specified by pr_vaddr and pr_size. If pr_wflags is
       empty, any previously-established watched area starting at  the  speci-
       fied virtual address is cleared; pr_size is ignored.

       A  watchpoint  is  triggered  when an lwp in the traced process makes a
       memory reference that covers at least one byte of a  watched  area  and
       the memory reference is as specified in pr_wflags. When an lwp triggers
       a watchpoint, it incurs a watchpoint trap. If FLTWATCH is being traced,
       the  lwp  stops;  otherwise, it is sent a SIGTRAP signal; if SIGTRAP is
       being traced and is not blocked, the lwp stops.

       The watchpoint trap occurs  before  the  instruction  completes  unless
       WA_TRAPAFTER  was specified, in which case it occurs after the instruc-
       tion completes. If it occurs before completion, the memory is not modi-
       fied.  If  it  occurs  after completion, the memory is modified (if the
       access is a write access).

       Physical i/o is an exception for watchpoint traps.  In  this  instance,
       there  is  no guarantee that memory before the watched area has already
       been modified (or in the case of WA_TRAPAFTER, that the memory  follow-
       ing  the  watched  area has not been modified) when the watchpoint trap
       occurs and the lwp stops.

       pr_info in the lwpstatus structure contains  information  pertinent  to
       the watchpoint trap. In particular, the si_addr field contains the vir-
       tual address of the memory reference that triggered the watchpoint, and
       the   si_code  field  contains  one  of  TRAP_RWATCH,  TRAP_WWATCH,  or
       TRAP_XWATCH, indicating read, write, or execute  access,  respectively.
       The  si_trapafter  field  is  zero unless WA_TRAPAFTER is in effect for
       this watched area; non-zero indicates that the current  instruction  is
       not  the instruction that incurred the watchpoint trap. The si_pc field
       contains the virtual address of the instruction that incurred the trap.

       A watchpoint trap may be triggered while executing a system  call  that
       makes reference to the traced process's memory. The lwp that is execut-
       ing the system call incurs the watchpoint trap while still in the  sys-
       tem  call.   If  it stops as a result, the lwpstatus structure contains
       the system call number and its arguments. If the lwp does not stop,  or
       if  it  is  set running again without clearing the signal or fault, the
       system call fails with EFAULT. If WA_TRAPAFTER was specified, the  mem-
       ory  reference  will have completed and the memory will have been modi-
       fied (if the access was  a  write  access)  when  the  watchpoint  trap
       occurs.

       If  more  than one of WA_READ, WA_WRITE, and WA_EXEC is specified for a
       watched area, and a single instruction incurs  more  than  one  of  the
       specified  types, only one is reported when the watchpoint trap occurs.
       The precedence is WA_EXEC, WA_READ, WA_WRITE (WA_EXEC and WA_READ  take
       precedence  over WA_WRITE), unless WA_TRAPAFTER was specified, in which
       case it is WA_WRITE, WA_READ, WA_EXEC (WA_WRITE takes precedence).

       PCWATCH fails with EINVAL if an attempt is made to specify  overlapping
       watched areas or if pr_wflags contains flags other than those specified
       above. It fails with ENOMEM if an attempt is  made  to  establish  more
       watched areas than the system can support (the system can support thou-
       sands).

       The child of a vfork(2) borrows the  parent's  address  space.  When  a
       vfork(2) is executed by a traced process, all watched areas established
       for the parent are suspended until the child terminates or performs  an
       exec(2).  Any  watched areas established independently in the child are
       cancelled when the parent resumes  after  the  child's  termination  or
       exec(2).  PCWATCH  fails  with  EBUSY  if  applied  to  the parent of a
       vfork(2) before the child has terminated or performed an  exec(2).  The
       PR_VFORKP  flag  is  set  in  the  pstatus  structure for such a parent
       process.

       Certain accesses of the traced process's address space by the operating
       system  are immune to watchpoints. The initial construction of a signal
       stack frame when a signal is delivered to an lwp  will  not  trigger  a
       watchpoint  trap  even  if  the  new  frame covers watched areas of the
       stack. Once the signal handler is entered, watchpoint traps occur  nor-
       mally.  On SPARC based machines, register window overflow and underflow
       will not trigger watchpoint traps, even if  the  register  window  save
       areas cover watched areas of the stack.

       Watched  areas are not inherited by child processes, even if the traced
       process's inherit-on-fork mode, PR_FORK, is set (see PCSET, below). All
       watched areas are cancelled when the traced process performs a success-
       ful exec(2).

   PCSET PCUNSET
       PCSET sets one or more modes of operation for the traced process. PCUN-
       SET  unsets  these modes. The modes to be set or unset are specified by
       flags in an operand long in the control message:

       PR_FORK         (inherit-on-fork):  When  set,  the  process's  tracing
                       flags and its inherit-on-fork mode are inherited by the
                       child of a fork(2), fork1(2), or vfork(2). When  unset,
                       child processes start with all tracing flags cleared.



       PR_RLC          (run-on-last-close):  When  set  and  the last writable
                       /proc file descriptor referring to the  traced  process
                       or  any  of  its  lwps  is closed, all of the process's
                       tracing flags and watched areas are cleared,  any  out-
                       standing  stop directives are canceled, and if any lwps
                       are stopped on events of interest, they are set running
                       as  though  PCRUN had been applied to them. When unset,
                       the process's  tracing  flags  and  watched  areas  are
                       retained and lwps are not set running on last close.



       PR_KLC          (kill-on-last-close):  When  set  and the last writable
                       /proc file descriptor referring to the  traced  process
                       or any of its lwps is closed, the process is terminated
                       with SIGKILL.



       PR_ASYNC        (asynchronous-stop): When set, a stop on  an  event  of
                       interest  by one lwp does not directly affect any other
                       lwp in the process. When unset and an lwp stops  on  an
                       event  of  interest  other than PR_REQUESTED, all other
                       lwps in the process are directed to stop.



       PR_MSACCT       (microstate accounting): Microstate accounting  is  now
                       continuously  enabled.  This  flag is deprecated and no
                       longer  has  any  effect  upon  microstate  accounting.
                       Applications  may toggle this flag; however, microstate
                       accounting will remain enabled regardless.



       PR_MSFORK       (inherit microstate  accounting):   All  processes  now
                       inherit  microstate  accounting,  as it is continuously
                       enabled.  This flag has been deprecated and its use  no
                       longer  has  any effect upon the behavior of microstate
                       accounting.



       PR_BPTADJ       (breakpoint trap pc adjustment): On x86 based machines,
                       a  breakpoint trap leaves the program counter (the EIP)
                       referring to  the  breakpointed  instruction  plus  one
                       byte. When PR_BPTADJ is set, the system will adjust the
                       program counter back to  the  location  of  the  break-
                       pointed instruction when the lwp stops on a breakpoint.
                       This flag has no effect on SPARC based machines,  where
                       breakpoint traps leave the program counter referring to
                       the breakpointed instruction.



       PR_PTRACE       (ptrace-compatibility): When set, a stop on an event of
                       interest  by the traced process is reported to the par-
                       ent of the traced process by wait(3C), SIGTRAP is  sent
                       to  the  traced  process  when it executes a successful
                       exec(2), setuid/setgid flags are not honored for  execs
                       performed  by the traced process, any exec of an object
                       file that the traced process cannot read fails, and the
                       process  dies when its parent dies. This mode is depre-
                       cated; it is provided only to allow  ptrace(3C)  to  be
                       implemented as a library function using /proc.



       It  is  an  error  (EINVAL) to specify flags other than those described
       above or to apply these operations to a  system  process.  The  current
       modes  are  reported  in  the  pr_flags  field  of /proc/pid/status and
       /proc/pid/lwp/lwp/lwpstatus.

   PCSREG
       Set the general  registers  for  the  specific  or  representative  lwp
       according to the operand prgregset_t structure.

       On  SPARC based systems, only the condition-code bits of the processor-
       status register (R_PSR) of SPARC V8 (32-bit) processes can be  modified
       by PCSREG. Other privileged registers cannot be modified at all.

       On x86 based systems, only certain bits of the flags register (EFL) can
       be modified by PCSREG: these include the  condition  codes,  direction-
       bit, and overflow-bit.

       PCSREG fails with EBUSY if the lwp is not stopped on an event of inter-
       est.

   PCSVADDR
       Set the address at which execution will resume for the specific or rep-
       resentative lwp from the operand long. On SPARC based systems, both %pc
       and %npc are set, with %npc set to the instruction following  the  vir-
       tual  address.  On  x86 based systems, only %eip is set. PCSVADDR fails
       with EBUSY if the lwp is not stopped on an event of interest.

   PCSFPREG
       Set the floating-point registers for the specific or representative lwp
       according  to the operand prfpregset_t structure.  An error (EINVAL) is
       returned if the system does not support floating-point  operations  (no
       floating-point  hardware and the system does not emulate floating-point
       machine instructions). PCSFPREG fails with EBUSY  if  the  lwp  is  not
       stopped on an event of interest.

   PCSXREG
       Set  the  extra  state registers for the specific or representative lwp
       according to the architecture-dependent operand prxregset_t  structure.
       An  error  (EINVAL)  is  returned  if the system does not support extra
       state registers. PCSXREG fails with EBUSY if the lwp is not stopped  on
       an event of interest.

   PCSASRS
       Set  the  ancillary  state registers for the specific or representative
       lwp according to  the  SPARC  V9  platform-dependent  operand  asrset_t
       structure.  An  error (EINVAL) is returned if either the target process
       or the controlling process is not a 64-bit SPARC V9  process.  Most  of
       the  ancillary  state registers are privileged registers that cannot be
       modified. Only those that can be  modified  are  set;  all  others  are
       silently ignored. PCSASRS fails with EBUSY if the lwp is not stopped on
       an event of interest.

   PCAGENT
       Create an agent lwp in the controlled process with register values from
       the operand prgregset_t structure (see PCSREG, above). The agent lwp is
       created in the stopped state showing PR_REQUESTED  and  with  its  held
       signal  set  (the  signal  mask)  having all signals except SIGKILL and
       SIGSTOP blocked.

       The PCAGENT operation fails with EBUSY  unless  the  process  is  fully
       stopped  via  /proc, that is, unless all of the lwps in the process are
       stopped either on events of interest or on PR_SUSPENDED, or are stopped
       on  PR_JOBCONTROL and have been directed to stop via PCDSTOP.  It fails
       with EBUSY if an agent lwp already exists. It fails with ENOMEM if sys-
       tem resources for creating new lwps have been exhausted.

       Any  PCRUN operation applied to the process control file or to the con-
       trol file of an lwp other than the agent lwp fails with EBUSY  as  long
       as  the agent lwp exists.  The agent lwp must be caused to terminate by
       executing the SYS_lwp_exit system call trap before the process  can  be
       restarted.

       Once  the  agent lwp is created, its lwp-ID can be found by reading the
       process status file. To facilitate opening the agent lwp's control  and
       status  files,  the directory name /propc/pid/lwp/agent is accepted for
       lookup operations as an invisible alias for /proc/pid/lwp/lwpid,  lwpid
       being the lwp-ID of the agent lwp (invisible in the sense that the name
       ``agent'' does not appear  in  a  directory  listing  of  /proc/pid/lwp
       obtained from ls(1), getdents(2), or readdir(3C)).

       The purpose of the agent lwp is to perform operations in the controlled
       process on behalf of the controlling process: to gather information not
       directly  available  via /proc files, or in general to make the process
       change state in ways not directly available via  /proc  control  opera-
       tions.  To  make  use  of an agent lwp, the controlling process must be
       capable  of  making  it  execute  system   calls   (specifically,   the
       SYS_lwp_exit  system call trap). The register values given to the agent
       lwp on creation are typically the registers of the representative  lwp,
       so that the agent lwp can use its stack.

       The  agent  lwp is not allowed to execute any variation of the SYS_fork
       or SYS_exec system call traps. Attempts to do so yield ENOTSUP  to  the
       agent lwp.

       Symbolic  constants  for system call trap numbers like SYS_lwp_exit and
       SYS_lwp_create can be found in the header file <&lt;sys/syscall.h>&gt;.

   PCREAD PCWRITE
       Read or write the target process's address space via a  priovec  struc-
       ture operand:

       typedef struct priovec {
           void *pio_base;      /* buffer in controlling process */
           size_t pio_len;      /* size of read/write request in bytes */
           off_t pio_offset;    /* virtual address in target process */
       } priovec_t;


       These  operations  have  the  same  effect  as  pread(2) and pwrite(2),
       respectively, of the target process's address space file.  The  differ-
       ence  is  that more than one PCREAD or PCWRITE control operation can be
       written to the control file at once, and they can be interspersed  with
       other control operations in a single write to the control file. This is
       useful, for example, when planting many breakpoint instructions in  the
       process's  address space, or when stepping over a breakpointed instruc-
       tion. Unlike pread(2) and pwrite(2), no provision is made  for  partial
       reads  or  writes;  if the operation cannot be performed completely, it
       fails with EIO.

   PCNICE
       The traced process's nice(2) value is incremented by the amount in  the
       operand  long.   Only a process with the {PRIV_PROC_PRIOCNTL} privilege
       asserted in its effective set can better a process's priority  in  this
       way,  but  any user may lower the priority. This operation is not mean-
       ingful for all scheduling classes.

   PCSCRED
       Set the target process credentials  to  the  values  contained  in  the
       prcred_t  structure  operand (see /proc/pid/cred). The effective, real,
       and saved user-IDs and group-IDs of the target  process  are  set.  The
       target  process's  supplementary groups are not changed; the pr_ngroups
       and pr_groups members of the structure operand are  ignored.  Only  the
       privileged  processes  can  perform  this  operation; for all others it
       fails with EPERM.

   PCSCREDX
       Operates like PCSCRED but  also  sets  the  supplementary  groups;  the
       length  of  the  data  written  with  this  control operation should be
       "sizeof (prcred_t) + sizeof (gid_t) * (#groups - 1)".

   PCSPRIV
       Set the target  process  privilege  to  the  values  contained  in  the
       prpriv_t operand (see /proc/pid/priv). The effective, permitted, inher-
       itable, and limit sets are all changed. Privilege  flags  can  also  be
       set. The process is made privilege aware unless it can relinquish priv-
       ilege awareness. See privileges(5).

       The limit set of the target process cannot be grown. The  other  privi-
       lege  sets  must be subsets of the intersection of the effective set of
       the calling process with the new limit set of  the  target  process  or
       subsets of the original values of the sets in the target process.

       If any of the above restrictions are not met, EPERM is returned. If the
       structure written is improperly formatted, EINVAL is returned.

PROGRAMMING NOTES
       For security reasons, except for the psinfo,  usage,  lpsinfo,  lusage,
       lwpsinfo,  and lwpusage files, which are world-readable, and except for
       privileged processes, an open of a /proc file  fails  unless  both  the
       user-ID  and  group-ID  of the caller match those of the traced process
       and the process's object file is readable by the caller.  The effective
       set of the caller is a superset of both the inheritable and the permit-
       ted set of the target process. The limit set of the caller is a  super-
       set  of the limit set of the target process. Except for the world-read-
       able files just mentioned, files corresponding  to  setuid  and  setgid
       processes can be opened only by the appropriately privileged process.

       A  process  that is missing the basic privilege {PRIV_PROC_INFO} cannot
       see any processes under /proc that it cannot send a signal to.

       A process that has {PRIV_PROC_OWNER} asserted in its effective set  can
       open any file for reading. To manipulate or control a process, the con-
       trolling process must have at least as many privileges in its effective
       set  as  the target process has in its effective, inheritable, and per-
       mitted sets. The limit set of the controlling process must be a  super-
       set  of  the  limit  set of the target process. Additional restrictions
       apply if any of the uids of  the  target  process  are  0.  See  privi-
       leges(5).

       Even  if  held  by  a  privileged  process, an open process or lwp file
       descriptor (other than file descriptors for the  world-readable  files)
       becomes  invalid  if  the  traced  process  performs  an  exec(2)  of a
       setuid/setgid object file or an object file  that  the  traced  process
       cannot  read.  Any  operation  performed on an invalid file descriptor,
       except close(2), fails with EAGAIN. In this situation, if  any  tracing
       flags  are  set  and the process or any lwp file descriptor is open for
       writing, the process will have been directed to stop  and  its  run-on-
       last-close flag will have been set (see PCSET). This enables a control-
       ling process (if it has permission) to reopen the /proc  files  to  get
       new  valid  file descriptors, close the invalid file descriptors, unset
       the run-on-last-close flag (if desired), and proceed. Just closing  the
       invalid  file descriptors causes the traced process to resume execution
       with all tracing flags cleared.  Any process  not  currently  open  for
       writing via /proc, but that has left-over tracing flags from a previous
       open, and that executes a setuid/setgid or unreadable object file, will
       not be stopped but will have all its tracing flags cleared.

       To wait for one or more of a set of processes or lwps to stop or termi-
       nate, /proc file descriptors (other than those obtained by opening  the
       cwd  or root directories or by opening files in the fd or object direc-
       tories) can be used in  a  poll(2)  system  call.  When  requested  and
       returned,  either of the polling events POLLPRI or POLLWRNORM indicates
       that the process or lwp stopped on an event of interest. Although  they
       cannot  be requested, the polling events POLLHUP, POLLERR, and POLLNVAL
       may be returned. POLLHUP indicates that the process or lwp  has  termi-
       nated.  POLLERR  indicates that the file descriptor has become invalid.
       POLLNVAL is returned immediately if POLLPRI or POLLWRNORM is  requested
       on  a  file  descriptor referring to a system process (see PCSTOP). The
       requested events may be empty to wait simply for termination.

FILES
       /proc                                   directory (list of processes)



       /proc/pid                               specific process directory



       /proc/self                              alias  for  a   process's   own
                                               directory



       /proc/pid/as                            address space file



       /proc/pid/ctl                           process control file



       /proc/pid/status                        process status



       /proc/pid/lstatus                       array of lwp status structs



       /proc/pid/psinfo                        process ps(1) info



       /proc/pid/lpsinfo                       array of lwp ps(1) info structs



       /proc/pid/map                           address space map



       /proc/pid/rmap                          reserved address map



       /proc/pid/cred                          process credentials



       /proc/pid/priv                          process privileges



       /proc/pid/sigact                        process signal actions



       /proc/pid/auxv                          process aux vector



       /proc/pid/ldt                           process LDT (x86 only)



       /proc/pid/usage                         process usage



       /proc/pid/lusage                        array of lwp usage structs



       /proc/pid/path                          symbolic  links to process open
                                               files



       /proc/pid/pagedata                      process page data



       /proc/pid/watch                         active watchpoints



       /proc/pid/cwd                           alias for the  current  working
                                               directory



       /proc/pid/root                          alias for the root directory



       /proc/pid/fd                            directory (list of open files)



       /proc/pid/fd/*                          aliases   for   process's  open
                                               files



       /proc/pid/object                        directory   (list   of   mapped
                                               files)



       /proc/pid/object/a.out                  alias  for process's executable
                                               file



       /proc/pid/object/*                      aliases for other mapped files



       /proc/pid/lwp                           directory (list of lwps)



       /proc/pid/lwp/lwpid                     specific lwp directory



       /proc/pid/lwp/agent                     alias for the agent lwp  direc-
                                               tory



       /proc/pid/lwp/lwpid/lwpctl              lwp control file



       /proc/pid/lwp/lwpid/lwpstatus           lwp status



       /proc/pid/lwp/lwpid/lwpsinfo            lwp ps(1) info



       /proc/pid/lwp/lwpid/lwpusage            lwp usage



       /proc/pid/lwp/lwpid/gwindows            register windows (SPARC only)



       /proc/pid/lwp/lwpid/xregs               extra state registers



       /proc/pid/lwp/lwpid/asrs                ancillary    state    registers
                                               (SPARC V9 only)



SEE ALSO
       ls(1),  ps(1),  chroot(1M),  alarm(2),  brk(2),  chdir(2),   chroot(2),
       close(2),  creat(2),  dup(2),  exec(2),  fcntl(2),  fork(2),  fork1(2),
       fstat(2),  getdents(2),  getustack(2),  kill(2),   lseek(2),   mmap(2),
       nice(2),  open(2),  poll(2),  pread(2), ptrace(3C), pwrite(2), read(2),
       readlink(2),   readv(2),   shmget(2),   sigaction(2),   sigaltstack(2),
       vfork(2),    write(2),    writev(2),    _stack_grow(3C),   readdir(3C),
       pthread_create(3C),    pthread_join(3C),     siginfo.h(3HEAD),     sig-
       nal.h(3HEAD),  thr_create(3C),  thr_join(3C),  types32.h(3HEAD),  ucon-
       text.h(3HEAD), wait(3C), contract(4), process(4), lfcompile(5),  privi-
       leges(5)

DIAGNOSTICS
       Errors  that  can  occur  in addition to the errors normally associated
       with file system access:

       E2BIG           Data to be returned in a read(2) of the page data  file
                       exceeds  the  size  of  the read buffer provided by the
                       caller.



       EACCES          An attempt was made to examine a process that ran under
                       a  different  uid  than  the  controlling  process  and
                       {PRIV_PROC_OWNER} was not  asserted  in  the  effective
                       set.



       EAGAIN          The  traced  process  has  performed  an  exec(2)  of a
                       setuid/setgid object file or of an object file that  it
                       cannot  read;  all further operations on the process or
                       lwp  file  descriptor  (except  close(2))  elicit  this
                       error.



       EBUSY           PCSTOP,  PCDSTOP, PCWSTOP, or PCTWSTOP was applied to a
                       system process; an exclusive open(2) was attempted on a
                       /proc  file  for  a  process  already open for writing;
                       PCRUN,  PCSREG,  PCSVADDR,  PCSFPREG,  or  PCSXREG  was
                       applied  to a process or lwp not stopped on an event of
                       interest; an attempt was made to mount  /proc  when  it
                       was  already  mounted; PCAGENT was applied to a process
                       that was not fully stopped or that already had an agent
                       lwp.



       EINVAL          In  general,  this means that some invalid argument was
                       supplied to a system call.  A  non-exhaustive  list  of
                       conditions  eliciting  this  error  includes: a control
                       message operation code is  undefined;  an  out-of-range
                       signal  number  was  specified  with PCSSIG, PCKILL, or
                       PCUNKILL; SIGKILL was specified with PCUNKILL; PCSFPREG
                       was applied on a system that does not support floating-
                       point operations; PCSXREG was applied on a system  that
                       does not support extra state registers.



       EINTR           A  signal was received by the controlling process while
                       waiting for the traced  process  or  lwp  to  stop  via
                       PCSTOP, PCWSTOP, or PCTWSTOP.



       EIO             A  write(2)  was attempted at an illegal address in the
                       traced process.



       ENOENT          The traced process or lwp has  terminated  after  being
                       opened.  The  basic  privilege  {PRIV_PROC_INFO} is not
                       asserted in the effective set of  the  calling  process
                       and  the  calling  process  cannot send a signal to the
                       target process.



       ENOMEM          The system-imposed limit on the  number  of  page  data
                       file   descriptors   was   reached   on   an   open  of
                       /proc/pid/pagedata; an attempt was made with PCWATCH to
                       establish  more  watched areas than the system can sup-
                       port; the PCAGENT operation was issued when the  system
                       was out of resources for creating lwps.



       ENOSYS          An attempt was made to perform an unsupported operation
                       (such as creat(2), link(2), or unlink(2)) on  an  entry
                       in /proc.



       EOVERFLOW       A 32-bit controlling process attempted to read or write
                       the as file or attempted to  read  the  map,  rmap,  or
                       pagedata file of a 64-bit target process. A 32-bit con-
                       trolling process attempted to apply one of the  control
                       operations PCSREG, PCSXREG, PCSVADDR, PCWATCH, PCAGENT,
                       PCREAD, PCWRITE to a 64-bit target process.



       EPERM           The process that issued the PCSCRED or PCSCREDX  opera-
                       tion  did  not  have  the  {PRIV_PROC_SETID}  privilege
                       asserted in its effective  set,  or  the  process  that
                       issued   the   PCNICE   operation   did  not  have  the
                       {PRIV_PROC_PRIOCNTL} in its effective set.

                       An attempt was made to control a process of  which  the
                       E,  P,  and  I  privilege sets were not a subset of the
                       effective set of the controlling process or  the  limit
                       set  of  the  controlling  process is not a superset of
                       limit set of the controlled process.

                       Any of the uids of the  target  process  are  0  or  an
                       attempt  was  made to change any of the uids to 0 using
                       PCSCRED and  the  security  policy  imposed  additional
                       restrictions. See privileges(5).



NOTES
       Descriptions  of  structures  in this document include only interesting
       structure elements, not filler and padding fields, and  may  show  ele-
       ments  out of order for descriptive clarity. The actual structure defi-
       nitions are contained in <&lt;procfs.h>&gt;.

BUGS
       Because the old ioctl(2)-based version of /proc is currently  supported
       for binary compatibility with old applications, the top-level directory
       for a process, /proc/pid, is  not  world-readable,  but  it  is  world-
       searchable.  Thus,  anyone  can open /proc/pid/psinfo even though ls(1)
       applied to /proc/pid will fail for anyone but the owner or an appropri-
       ately privileged process. Support for the old ioctl(2)-based version of
       /proc will be dropped in a future release, at which time the  top-level
       directory for a process will be made world-readable.

       On  SPARC based machines, the types gregset_t and fpregset_t defined in
       <&lt;sys/regset.h>&gt; are similar to but not the same as the types prgregset_t
       and prfpregset_t defined in <&lt;procfs.h>&gt;.



SunOS 5.10                       30 Sept 2004                          proc(4)