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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* POSIX waitpid()
*
* pid < -1 WUNTRACED may not be fully supported
* process group specifics ignored by non-{waitpid,wait4}
*/
#include <ast.h>
#include <wait.h>
#if _lib_waitpid
NoN(waitpid)
#else
#if _lib_wait4
struct rusage;
extern int wait4(int, int*, int, struct rusage*);
pid_t
waitpid(pid_t pid, int* status, int flags)
{
return(wait4(pid, status, flags, NiL));
}
#else
#undef SIGCLD
#if _lib_wait3
extern int wait3(int*, int, struct rusage*);
#else
#if _lib_wait2
#define wait3(s,f,u) wait2(s,f)
extern int wait2(int*, int);
#else
#include <sig.h>
#define wait3(s,f,u) wait(s)
static int caught;
static void
catch(sig)
int sig;
{
NoP(sig);
caught = 1;
}
#endif
#endif
#include <error.h>
struct zombie
{
struct zombie* next;
int status;
pid_t pid;
};
pid_t
waitpid(pid_t pid, int* status, int flags)
{
register struct zombie* zp;
register struct zombie* pp;
register int p;
int s;
#if !_lib_wait2 && !_lib_wait3
#if !defined(SIGCLD)
int n;
int oerrno;
#endif
Sig_handler_t handler;
#endif
static struct zombie* zombies;
pp = 0;
zp = zombies;
while (zp)
{
if (zp->pid >= 0 && (zp->pid == pid || pid <= 0))
{
if (pp) pp->next = zp->next;
else zombies = zp->next;
if (status) *status = zp->status;
pid = zp->pid;
free(zp);
return(pid);
}
}
if (pid > 0 && kill(pid, 0) < 0) return(-1);
for (;;)
{
#if !_lib_wait2 && !_lib_wait3
#if !defined(SIGCLD)
oerrno = errno;
#endif
if (flags & WNOHANG)
{
caught = 0;
#if defined(SIGCLD)
handler = signal(SIGCLD, catch);
if (!caught)
{
signal(SIGCLD, handler);
return(0);
}
#else
#if defined(SIGALRM)
handler = signal(SIGALRM, catch);
n = alarm(1);
#endif
#endif
}
#endif
p = wait3(&s, flags, NiL);
#if !_lib_wait3
#if !_lib_wait2
#if defined(SIGCLD)
if (flags & WNOHANG) signal(SIGCLD, handler);
#else
#if defined(SIGALRM)
if (flags & WNOHANG)
{
if (n == 0 && !caught || n == 1) alarm(n);
else if (n > 1) alarm(n - caught);
signal(SIGALRM, handler);
}
if (p == -1 && errno == EINTR)
{
errno = oerrno;
p = 0;
s = 0;
}
#endif
#endif
#else
if (p == -1 && errno == EINVAL && (flags & ~WNOHANG))
p = wait3(&s, flags & WNOHANG, NiL);
#endif
#endif
if (p <= 0)
{
if (p == 0 && status) *status = s;
return(p);
}
if (pid <= 0 || p == pid)
{
if (status) *status = s;
return(p);
}
if (!(zp = newof(0, struct zombie, 1, 0))) return(-1);
zp->pid = p;
zp->status = s;
zp->next = zombies;
zombies = zp;
}
/*NOTREACHED*/
}
#endif
#endif
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