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     dtrace_proc — a DTrace provider for tracing events related to user processes


     proc:::create(struct proc *, struct proc *, int);

     proc:::exec(char *);


     proc:::exec-success(char *);


     proc:::signal-clear(int, ksiginfo_t *);

     proc:::signal-discard(struct thread *, struct proc *, int);

     proc:::signal-send(struct thread *, struct proc *, int);


     The DTrace proc provider provides insight into events related to user processes: process and
     thread creation and termination events, and process signalling.

     The proc:::create() probe fires when a user process is created via the fork(2), vfork(2),
     pdfork(2), or rfork(2) system calls.  In particular, kernel processes created with the
     kproc(9) KPI will not trigger this probe.  The proc:::create() probe's first two arguments
     are the new child process and its parent, respectively.  The third argument is a mask of
     rfork(2) flags indicating which process resources are to be shared between the parent and
     child processes.

     The proc:::exec() probe fires when a process attempts to execute a file.  Its argument is
     the specified filename for the file.  If the attempt fails because of an error, the
     proc:::exec-failure() probe will subsequently fire, providing the corresponding errno(2)
     value in its first argument.  Otherwise, the proc:::exec-success() probe will fire.

     The proc:::exit() probe fires when a process exits or is terminated.  Its argument is the
     corresponding SIGCHLD signal code; valid values are documented in the siginfo(3) manual page
     and defined in signal.h.  For example, when a process exits normally, the value of args[0]
     will be CLD_EXITED.

     The proc:::signal-send() probe fires when a signal is about to be sent to a process.  The
     proc:::signal-discard() probe fires when a signal is sent to a process that ignores it.
     This probe will fire after the proc:::signal-send() probe for the signal in question.  The
     arguments to these probes are the thread and process to which the signal will be sent, and
     the signal number of the signal.  Valid signal numbers are defined in the signal(3) manual
     page.  The proc:::signal-clear() probe fires when a pending signal has been cleared by one
     of the sigwait(2), sigtimedwait(2), or sigwaitinfo(2) system calls.  Its arguments are the
     signal number of the cleared signal, and a pointer to the corresponding signal information.
     The siginfo_t for the signal can be obtained from args[1]->ksi_info.


     Though the proc provider probes use native FreeBSD arguments types, standard D types for
     processes and threads are available.  These are psinfo_t and lwpsinfo_t respectively, and
     are defined in /usr/lib/dtrace/psinfo.d.  This file also defines two global variables,
     curpsinfo and curlwpsinfo, which provide representations of the current process and thread
     using these types.

     The fields of psinfo_t are:

           int pr_nlwp        Number of threads in the process.

           pid_t pr_pid       Process ID.

           pid_t pr_ppid      Process ID of the parent process, or 0 if the process does not have
                              a parent.

           pid_t pr_pgid      Process ID of the process group leader.

           pid_t pr_sid       Session ID, or 0 if the process does not belong to a session.

           pid_t pr_uid       Real user ID.

           pid_t pr_euid      Effective user ID.

           pid_t pr_gid       Real group ID.

           pid_t pr_egid      Effective group ID.

           uintptr_t pr_addr  Pointer to the struct proc for the process.

           string pr_psargs   Process arguments.

           u_int pr_arglen    Length of the process argument string.

           u_int pr_jailid    Jail ID of the process.

     The fields of lwpsinfo_t are:

           id_t pr_lwpid       Thread ID.

           int pr_flag         Thread flags.

           int pr_pri          Real scheduling priority of the thread.

           char pr_state       Currently always 0.

           char pr_sname       Currently always ‘’?.

           short pr_syscall    Currently always 0.

           uintptr_t pr_addr   Pointer to the struct thread for the thread.

           uintptr_t pr_wchan  Current wait address on which the thread is sleeping.


     /usr/lib/dtrace/psinfo.d  DTrace type and translator definitions for the proc provider.


     The following script logs process execution events as they occur:

           #pragma D option quiet

                   printf("%s", curpsinfo->pr_psargs);

     Note that the pr_psargs field is subject to the limit defined by the kern.ps_arg_cache_limit
     sysctl.  In particular, processes with an argument list longer than the value defined by
     this sysctl cannot be logged in this way.


     The proc provider in FreeBSD is not compatible with the proc provider in Solaris.  In
     particular, FreeBSD uses the native struct proc and struct thread types for probe arguments
     rather than translated types.  Additionally, a number of proc provider probes found in
     Solaris are not currently available on FreeBSD.


     dtrace(1), errno(2), fork(2), pdfork(2), rfork(2), vfork(2), siginfo(3), signal(3),
     dtrace_sched(4), kproc(9)


     The proc provider first appeared in FreeBSD 7.1.


     This manual page was written by Mark Johnston <>.