nsz Git - musl/blob - src/process/posix_spawn.c

   1 #include <spawn.h>
   2 #include <unistd.h>
   3 #include <signal.h>
   4 #include <stdint.h>
   5 #include <fcntl.h>
   6 #include "syscall.h"
   7 #include "pthread_impl.h"
   8 #include "fdop.h"
   9 #include "libc.h"
  10
  11 extern char **environ;
  12
  13 static void dummy_0()
  14 {
  15 }
  16 weak_alias(dummy_0, __acquire_ptc);
  17 weak_alias(dummy_0, __release_ptc);
  18
  19 pid_t __vfork(void);
  20
  21 int __posix_spawnx(pid_t *restrict res, const char *restrict path,
  22         int (*exec)(const char *, char *const *),
  23         const posix_spawn_file_actions_t *fa,
  24         const posix_spawnattr_t *restrict attr,
  25         char *const argv[restrict], char *const envp[restrict])
  26 {
  27         pid_t pid;
  28         sigset_t oldmask;
  29         int i;
  30         posix_spawnattr_t dummy_attr = { 0 };
  31
  32         if (!attr) attr = &dummy_attr;
  33
  34         sigprocmask(SIG_BLOCK, SIGALL_SET, &oldmask);
  35
  36         __acquire_ptc();
  37         pid = __vfork();
  38         __release_ptc();
  39
  40         if (pid) {
  41                 sigprocmask(SIG_SETMASK, &oldmask, 0);
  42                 if (pid < 0) return -pid;
  43                 *res = pid;
  44                 return 0;
  45         }
  46
  47         for (i=1; i<=8*__SYSCALL_SSLEN; i++) {
  48                 struct sigaction sa;
  49                 __libc_sigaction(i, 0, &sa);
  50                 if (sa.sa_handler!=SIG_DFL && (sa.sa_handler!=SIG_IGN ||
  51                     ((attr->__flags & POSIX_SPAWN_SETSIGDEF)
  52                      && sigismember(&attr->__def, i) ))) {
  53                         sa.sa_handler = SIG_DFL;
  54                         __libc_sigaction(i, &sa, 0);
  55                 }
  56         }
  57
  58         if ((attr->__flags&POSIX_SPAWN_SETPGROUP) && setpgid(0, attr->__pgrp))
  59                 _exit(127);
  60
  61         /* Use syscalls directly because pthread state is not consistent
  62          * for making calls to the library wrappers... */
  63         if ((attr->__flags&POSIX_SPAWN_RESETIDS) && (
  64                 __syscall(SYS_setgid, __syscall(SYS_getgid)) ||
  65                 __syscall(SYS_setuid, __syscall(SYS_getuid)) ))
  66                 _exit(127);
  67
  68         if (fa && fa->__actions) {
  69                 struct fdop *op;
  70                 int ret, fd;
  71                 for (op = fa->__actions; op->next; op = op->next);
  72                 for (; op; op = op->prev) {
  73                         switch(op->cmd) {
  74                         case FDOP_CLOSE:
  75                                 ret = __syscall(SYS_close, op->fd);
  76                                 break;
  77                         case FDOP_DUP2:
  78                                 ret = __syscall(SYS_dup2, op->fd, op->newfd)<0;
  79                                 break;
  80                         case FDOP_OPEN:
  81                                 fd = __syscall(SYS_open, op->path,
  82                                         op->oflag | O_LARGEFILE, op->mode);
  83                                 if (fd == op->fd) {
  84                                         ret = 0;
  85                                 } else {
  86                                         ret = __syscall(SYS_dup2, fd, op->fd)<0;
  87                                         __syscall(SYS_close, fd);
  88                                 }
  89                                 break;
  90                         }
  91                         if (ret) _exit(127);
  92                 }
  93         }
  94
  95         sigprocmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
  96                 ? &attr->__mask : &oldmask, 0);
  97
  98         if (envp) environ = (char **)envp;
  99         exec(path, argv);
 100         _exit(127);
 101
 102         return 0;
 103 }
 104
 105 int posix_spawn(pid_t *restrict res, const char *restrict path,
 106         const posix_spawn_file_actions_t *fa,
 107         const posix_spawnattr_t *restrict attr,
 108         char *const argv[restrict], char *const envp[restrict])
 109 {
 110         return __posix_spawnx(res, path, execv, fa, attr, argv, envp);
 111 }