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/* ISC license. */
#include <skalibs/sysdeps.h>
#include <errno.h>
#include <skalibs/cspawn.h>
#ifdef SKALIBS_HASPOSIXSPAWN
#include <signal.h>
#include <stdlib.h>
#include <spawn.h>
#include <skalibs/config.h>
#include <skalibs/djbunix.h>
#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
#include <sys/wait.h>
#include <skalibs/allreadwrite.h>
static inline pid_t cspawn_workaround (pid_t pid, int const *p)
{
siginfo_t si ;
int e ;
ssize_t r ;
char c ;
fd_close(p[1]) ;
r = fd_read(p[0], &c, 1) ;
fd_close(p[0]) ;
if (r == -1) return 0 ;
if (r) return (errno = EILSEQ, 0) ; /* child wrote, wtf */
do e = waitid(P_PID, pid, &si, WEXITED | WNOHANG | WNOWAIT) ;
while (e == -1 && errno == EINTR) ;
if (e == -1) return pid ; /* we're in trouble, but don't leak a child */
if (!si.si_pid) return pid ; /* child is running */
if (si.si_code != CLD_EXITED || si.si_status != 127) return pid ; /* child died after execve(), let caller handle it */
/*
child exited 127, so either execve() failed, which is what we want to catch,
or it raced like a mofo, execve()d and then exited 127 on its own, in which
case, tough luck, it never existed.
*/
wait_pid(pid, 0) ;
return (errno = 0, 0) ;
}
#endif
pid_t cspawn (char const *prog, char const *const *argv, char const *const *envp, uint32_t flags, cspawn_fileaction const *fa, size_t n)
{
pid_t pid ;
posix_spawnattr_t attr ;
posix_spawn_file_actions_t actions ;
int e ;
int nopath = !getenv("PATH") ;
#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
int p[2] ;
if (pipecoe(p) == -1) return 0 ;
#endif
if (flags)
{
e = posix_spawnattr_init(&attr) ;
if (e) goto err ;
if (flags & 3)
{
sigset_t set ;
sigemptyset(&set) ;
e = posix_spawnattr_setsigmask(&attr, &set) ;
if (e) goto errattr ;
e = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK) ;
if (e) goto errattr ;
}
}
if (n)
{
e = posix_spawn_file_actions_init(&actions) ;
if (e) goto errattr ;
for (size_t i = 0 ; i < n ; i++)
{
switch (fa[i].type)
{
case CSPAWN_FA_CLOSE :
e = posix_spawn_file_actions_addclose(&actions, fa[i].x.fd) ;
if (e) goto erractions ;
break ;
case CSPAWN_FA_COPY :
e = posix_spawn_file_actions_adddup2(&actions, fa[i].x.fd2[1], fa[i].x.fd2[0]) ;
if (e) goto erractions ;
break ;
case CSPAWN_FA_MOVE :
e = posix_spawn_file_actions_adddup2(&actions, fa[i].x.fd2[1], fa[i].x.fd2[0]) ;
if (e) goto erractions ;
if (fa[i].x.fd2[0] != fa[i].x.fd2[1])
{
e = posix_spawn_file_actions_addclose(&actions, fa[i].x.fd2[1]) ;
if (e) goto erractions ;
}
break ;
case CSPAWN_FA_OPEN :
e = posix_spawn_file_actions_addopen(&actions, fa[i].x.openinfo.fd, fa[i].x.openinfo.file, fa[i].x.openinfo.oflag, fa[i].x.openinfo.mode) ;
if (e) goto erractions ;
break ;
default :
e = EINVAL ;
goto erractions ;
}
}
}
if (nopath && (setenv("PATH", SKALIBS_DEFAULTPATH, 0) == -1)) { e = errno ; goto erractions ; }
e = posix_spawnp(&pid, prog, &actions, &attr, (char *const *)argv, (char *const *)envp) ;
if (nopath) unsetenv("PATH") ;
if (e) goto errattr ;
if (n) posix_spawn_file_actions_destroy(&actions) ;
if (flags) posix_spawnattr_destroy(&attr) ;
#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
return cspawn_workaround(pid, p) ;
#else
return pid ;
#endif
erractions:
if (n) posix_spawn_file_actions_destroy(&actions) ;
errattr:
if (flags) posix_spawnattr_destroy(&attr) ;
err:
#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
fd_close(p[1]) ;
fd_close(p[0]) ;
#endif
errno = e ;
return 0 ;
}
#else
#include <fcntl.h>
#include <unistd.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sig.h>
#include <skalibs/selfpipe.h>
#include <skalibs/exec.h>
static inline void cspawn_child_exec (char const *prog, char const *const *argv, char const *const *envp, uint32_t flags, cspawn_fileaction const *fa, size_t n)
{
for (size_t i = 0 ; i < n ; i++)
{
switch (fa[i].type)
{
case CSPAWN_FA_CLOSE : fd_close(fa[i].x.fd) ; break ;
case CSPAWN_FA_COPY :
if (fd_copy(fa[i].x.fd2[0], fa[i].x.fd2[1]) == -1) return ;
break ;
case CSPAWN_FA_MOVE :
if (fd_move(fa[i].x.fd2[0], fa[i].x.fd2[1]) == -1) return ;
break ;
case CSPAWN_FA_OPEN :
{
int fd = open(fa[i].x.openinfo.file, fa[i].x.openinfo.oflag, fa[i].x.openinfo.mode) ;
if (fd == -1) return ;
if (fd_move(fa[i].x.openinfo.fd, fd) == -1) return ;
break ;
}
default :
errno = EINVAL ; return ;
}
}
if (flags & CSPAWN_FLAGS_SELFPIPE_FINISH) selfpipe_finish() ;
if (flags & CSPAWN_FLAGS_SIGBLOCKNONE) sig_blocknone() ;
}
pid_t cspawn (char const *prog, char const *const *argv, char const *const *envp, uint32_t flags, cspawn_fileaction const *fa, size_t n)
{
pid_t pid ;
int p[2] ;
char c ;
if (pipecoe(p) == -1) return 0 ;
pid = fork() ;
if (pid == -1)
{
fd_close(p[1]) ;
fd_close(p[0]) ;
return 0 ;
}
if (!pid)
{
cspawn_child_exec(prog, argv, envp, flags, fa, n) ;
c = errno ;
fd_write(p[1], &c, 1) ;
_exit(127) ;
}
fd_close(p[1]) ;
p[1] = fd_read(p[0], &c, 1) ;
if (p[1] < 0)
{
fd_close(p[0]) ;
return 0 ;
}
fd_close(p[0]) ;
if (p[1])
{
wait_pid(pid, &p[0]) ;
errno = (unsigned char)c ;
return 0 ;
}
return pid ;
}
#endif
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