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Allow for the process information sysctls to accept a thread id in addition

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to the process id.  It follows the ptrace(2) interface and allows debugging
libraries to use thread ids directly, without slow and verbose conversion
of thread id into pid.

The PGET_NOTID flag is provided to allow a specific sysctl to disallow
this behaviour.  All current callers of pget(9) have useful semantic to
operate on tid and do not need this flag.

Reviewed by:	jhb, trocini
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2012-04-23 20:56:05 +00:00
parent 51a6f57e4a
commit b3bfb267cb
2 changed files with 31 additions and 1 deletions
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31
sys/kern/kern_proc.c
View File

@ -309,6 +309,30 @@ pfind(pid)
return (p);
}
static struct proc *
pfind_tid(pid_t tid)
{
struct proc *p;
struct thread *td;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
PROC_UNLOCK(p);
continue;
}
FOREACH_THREAD_IN_PROC(p, td) {
if (td->td_tid == tid)
goto found;
}
PROC_UNLOCK(p);
}
found:
sx_sunlock(&allproc_lock);
return (p);
}
/*
* Locate a process group by number.
* The caller must hold proctree_lock.
@ -339,7 +363,12 @@ pget(pid_t pid, int flags, struct proc **pp)
struct proc *p;
int error;
p = pfind(pid);
if (pid <= PID_MAX)
p = pfind(pid);
else if ((flags & PGET_NOTID) == 0)
p = pfind_tid(pid);
else
p = NULL;
if (p == NULL)
return (ESRCH);
if ((flags & PGET_CANSEE) != 0) {

1
sys/sys/proc.h
View File

@ -840,6 +840,7 @@ struct proc *zpfind(pid_t); /* Find zombie process by id. */
#define PGET_ISCURRENT 0x00008 /* Check that the found process is current. */
#define PGET_NOTWEXIT 0x00010 /* Check that the process is not in P_WEXIT. */
#define PGET_NOTINEXEC 0x00020 /* Check that the process is not in P_INEXEC. */
#define PGET_NOTID 0x00040 /* Do not assume tid if pid > PID_MAX. */
#define PGET_WANTREAD (PGET_HOLD | PGET_CANDEBUG | PGET_NOTWEXIT)