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 "fdop.h"
   8 #include "libc.h"
   9
  10 extern char **environ;
  11
  12 static void dummy_0()
  13 {
  14 }
  15 weak_alias(dummy_0, __acquire_ptc);
  16 weak_alias(dummy_0, __release_ptc);
  17
  18 pid_t __vfork(void);
  19
  20 int __posix_spawnx(pid_t *restrict res, const char *restrict path,
  21         int (*exec)(const char *, char *const *),
  22         const posix_spawn_file_actions_t *fa,
  23         const posix_spawnattr_t *restrict attr,
  24         char *const argv[restrict], char *const envp[restrict])
  25 {
  26         pid_t pid;
  27         sigset_t oldmask;
  28         int i;
  29         posix_spawnattr_t dummy_attr = { 0 };
  30
  31         if (!attr) attr = &dummy_attr;
  32
  33         sigprocmask(SIG_BLOCK, (void *)(uint64_t []){-1}, &oldmask);
  34
  35         __acquire_ptc();
  36         pid = __vfork();
  37         __release_ptc();
  38
  39         if (pid) {
  40                 sigprocmask(SIG_SETMASK, &oldmask, 0);
  41                 if (pid < 0) return -pid;
  42                 *res = pid;
  43                 return 0;
  44         }
  45
  46         for (i=1; i<=64; i++) {
  47                 struct sigaction sa;
  48                 sigaction(i, 0, &sa);
  49                 if (sa.sa_handler!=SIG_IGN ||
  50                     ((attr->__flags & POSIX_SPAWN_SETSIGDEF)
  51                      && sigismember(&attr->__def, i) )) {
  52                         sa.sa_handler = SIG_DFL;
  53                         sigaction(i, &sa, 0);
  54                 }
  55         }
  56
  57         if ((attr->__flags&POSIX_SPAWN_SETPGROUP) && setpgid(0, attr->__pgrp))
  58                 _exit(127);
  59
  60         /* Use syscalls directly because pthread state is not consistent
  61          * for making calls to the library wrappers... */
  62         if ((attr->__flags&POSIX_SPAWN_RESETIDS) && (
  63                 __syscall(SYS_setgid, __syscall(SYS_getgid)) ||
  64                 __syscall(SYS_setuid, __syscall(SYS_getuid)) ))
  65                 _exit(127);
  66
  67         if (fa && fa->__actions) {
  68                 struct fdop *op;
  69                 int ret, fd;
  70                 for (op = fa->__actions; op->next; op = op->next);
  71                 for (; op; op = op->prev) {
  72                         switch(op->cmd) {
  73                         case FDOP_CLOSE:
  74                                 ret = __syscall(SYS_close, op->fd);
  75                                 break;
  76                         case FDOP_DUP2:
  77                                 ret = __syscall(SYS_dup2, op->fd, op->newfd)<0;
  78                                 break;
  79                         case FDOP_OPEN:
  80                                 fd = __syscall(SYS_open, op->path,
  81                                         op->oflag | O_LARGEFILE, op->mode);
  82                                 if (fd == op->fd) {
  83                                         ret = 0;
  84                                 } else {
  85                                         ret = __syscall(SYS_dup2, fd, op->fd)<0;
  86                                         __syscall(SYS_close, fd);
  87                                 }
  88                                 break;
  89                         }
  90                         if (ret) _exit(127);
  91                 }
  92         }
  93
  94         sigprocmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
  95                 ? &attr->__mask : &oldmask, 0);
  96
  97         if (envp) environ = (char **)envp;
  98         exec(path, argv);
  99         _exit(127);
 100
 101         return 0;
 102 }
 103
 104 int posix_spawn(pid_t *restrict res, const char *restrict path,
 105         const posix_spawn_file_actions_t *fa,
 106         const posix_spawnattr_t *restrict attr,
 107         char *const argv[restrict], char *const envp[restrict])
 108 {
 109         return __posix_spawnx(res, path, execv, fa, attr, argv, envp);
 110 }