/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2010 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
/*
* spawnveg -- spawnve with process group or session control
*
* pgid <0 setsid() [session group leader]
* 0 nothing [retain session and process group]
* 1 setpgid(0,0) [process group leader]
* >1 setpgid(0,pgid) [join process group]
*/
#include <ast.h>
#if _lib_spawnveg
NoN(spawnveg)
#else
#if _lib_posix_spawn > 1 /* reports underlying exec() errors */
#include <spawn.h>
#include <error.h>
#include <wait.h>
pid_t
spawnveg(const char* path, char* const argv[], char* const envv[], pid_t pgid)
{
int err;
pid_t pid;
posix_spawnattr_t attr;
if (err = posix_spawnattr_init(&attr))
goto nope;
if (pgid)
{
if (pgid <= 1)
pgid = 0;
if (err = posix_spawnattr_setpgroup(&attr, pgid))
goto bad;
if (err = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETPGROUP))
goto bad;
}
if (err = posix_spawn(&pid, path, NiL, &attr, argv, envv ? envv : environ))
goto bad;
posix_spawnattr_destroy(&attr);
#if _lib_posix_spawn < 2
if (waitpid(pid, &err, WNOHANG|WNOWAIT) == pid && EXIT_STATUS(err) == 127)
{
while (waitpid(pid, NiL, 0) == -1 && errno == EINTR);
if (!access(path, X_OK))
errno = ENOEXEC;
pid = -1;
}
#endif
return pid;
bad:
posix_spawnattr_destroy(&attr);
nope:
errno = err;
return -1;
}
#else
#if _lib_spawn_mode
#include <process.h>
#ifndef P_NOWAIT
#define P_NOWAIT _P_NOWAIT
#endif
#ifndef P_DETACH
#define P_DETACH _P_DETACH
#endif
pid_t
spawnveg(const char* path, char* const argv[], char* const envv[], pid_t pgid)
{
return spawnve(pgid ? P_DETACH : P_NOWAIT, path, argv, envv ? envv : environ);
}
#else
#if _lib_spawn && _hdr_spawn && _mem_pgroup_inheritance
#include <spawn.h>
/*
* open-edition/mvs/zos fork+exec+(setpgid)
*/
pid_t
spawnveg(const char* path, char* const argv[], char* const envv[], pid_t pgid)
{
struct inheritance inherit;
inherit.flags = 0;
if (pgid)
{
inherit.flags |= SPAWN_SETGROUP;
inherit.pgroup = (pgid > 1) ? pgid : SPAWN_NEWPGROUP;
}
return spawn(path, 0, (int*)0, &inherit, (const char**)argv, (const char**)envv);
}
#else
#include <error.h>
#include <wait.h>
#include <sig.h>
#include <ast_vfork.h>
#ifndef ENOSYS
#define ENOSYS EINVAL
#endif
#if _lib_spawnve && _hdr_process
#include <process.h>
#if defined(P_NOWAIT) || defined(_P_NOWAIT)
#undef _lib_spawnve
#endif
#endif
#if !_lib_vfork
#undef _real_vfork
#endif
/*
* fork+exec+(setsid|setpgid)
*/
pid_t
spawnveg(const char* path, char* const argv[], char* const envv[], pid_t pgid)
{
#if _lib_fork || _lib_vfork
int n;
int m;
pid_t pid;
pid_t rid;
#if _real_vfork
volatile int exec_errno;
volatile int* volatile exec_errno_ptr;
#else
int err[2];
#endif
#endif
#if 0
if (access(path, X_OK))
return -1;
#endif
if (!envv)
envv = environ;
#if _lib_spawnve
#if _lib_fork || _lib_vfork
if (!pgid)
#endif
return spawnve(path, argv, envv);
#endif
#if _lib_fork || _lib_vfork
n = errno;
#if _real_vfork
exec_errno = 0;
exec_errno_ptr = &exec_errno;
#else
if (pipe(err) < 0)
err[0] = -1;
else
{
fcntl(err[0], F_SETFD, FD_CLOEXEC);
fcntl(err[1], F_SETFD, FD_CLOEXEC);
}
#endif
sigcritical(1);
#if _lib_vfork
pid = vfork();
#else
pid = fork();
#endif
sigcritical(0);
if (pid == -1)
n = errno;
else if (!pid)
{
if (pgid < 0)
setsid();
else if (pgid > 0)
{
if (pgid == 1)
pgid = 0;
if (setpgid(0, pgid) < 0 && pgid && errno == EPERM)
setpgid(0, 0);
}
execve(path, argv, envv);
#if _real_vfork
*exec_errno_ptr = errno;
#else
if (err[0] != -1)
{
n = errno;
write(err[1], &n, sizeof(n));
}
#endif
_exit(errno == ENOENT ? EXIT_NOTFOUND : EXIT_NOEXEC);
}
rid = pid;
#if _real_vfork
if (pid != -1 && (m = *exec_errno_ptr))
{
while (waitpid(pid, NiL, 0) == -1 && errno == EINTR);
rid = pid = -1;
n = m;
}
#else
if (err[0] != -1)
{
close(err[1]);
if (pid != -1 && read(err[0], &m, sizeof(m)) == sizeof(m) && m)
{
while (waitpid(pid, NiL, 0) == -1 && errno == EINTR);
rid = pid = -1;
n = m;
}
close(err[0]);
}
#endif
if (pid != -1 && pgid > 0)
{
/*
* parent and child are in a race here
*/
if (pgid == 1)
pgid = pid;
if (setpgid(pid, pgid) < 0 && pid != pgid && errno == EPERM)
setpgid(pid, pid);
}
errno = n;
return rid;
#else
errno = ENOSYS;
return -1;
#endif
}
#endif
#endif
#endif
#endif