#include "syscall.h"
#include "pthread_impl.h"
#include "fdop.h"
-#include "libc.h"
-
-static void dummy_0()
-{
-}
-weak_alias(dummy_0, __acquire_ptc);
-weak_alias(dummy_0, __release_ptc);
struct args {
int p[2];
sigset_t oldmask;
const char *path;
- int (*exec)(const char *, char *const *, char *const *);
const posix_spawn_file_actions_t *fa;
const posix_spawnattr_t *restrict attr;
char *const *argv, *const *envp;
};
+static int __sys_dup2(int old, int new)
+{
+#ifdef SYS_dup2
+ return __syscall(SYS_dup2, old, new);
+#else
+ return __syscall(SYS_dup3, old, new, 0);
+#endif
+}
+
static int child(void *args_vp)
{
int i, ret;
- struct sigaction sa;
+ struct sigaction sa = {0};
struct args *args = args_vp;
int p = args->p[1];
const posix_spawn_file_actions_t *fa = args->fa;
const posix_spawnattr_t *restrict attr = args->attr;
+ sigset_t hset;
close(args->p[0]);
/* All signal dispositions must be either SIG_DFL or SIG_IGN
* before signals are unblocked. Otherwise a signal handler
* from the parent might get run in the child while sharing
- * memory, with unpredictable and dangerous results. */
+ * memory, with unpredictable and dangerous results. To
+ * reduce overhead, sigaction has tracked for us which signals
+ * potentially have a signal handler. */
+ __get_handler_set(&hset);
for (i=1; i<_NSIG; i++) {
- __libc_sigaction(i, 0, &sa);
- if (sa.sa_handler!=SIG_DFL && (sa.sa_handler!=SIG_IGN ||
- ((attr->__flags & POSIX_SPAWN_SETSIGDEF)
- && sigismember(&attr->__def, i) ))) {
+ if ((attr->__flags & POSIX_SPAWN_SETSIGDEF)
+ && sigismember(&attr->__def, i)) {
sa.sa_handler = SIG_DFL;
- __libc_sigaction(i, &sa, 0);
+ } else if (sigismember(&hset, i)) {
+ if (i-32<3U) {
+ sa.sa_handler = SIG_IGN;
+ } else {
+ __libc_sigaction(i, 0, &sa);
+ if (sa.sa_handler==SIG_IGN) continue;
+ sa.sa_handler = SIG_DFL;
+ }
+ } else {
+ continue;
}
+ __libc_sigaction(i, &sa, 0);
}
+ if (attr->__flags & POSIX_SPAWN_SETSID)
+ if ((ret=__syscall(SYS_setsid)) < 0)
+ goto fail;
+
if (attr->__flags & POSIX_SPAWN_SETPGROUP)
if ((ret=__syscall(SYS_setpgid, 0, attr->__pgrp)))
goto fail;
- /* Use syscalls directly because pthread state because the
- * library functions attempt to do a multi-threaded synchronized
- * id-change, which would trash the parent's state. */
+ /* Use syscalls directly because the library functions attempt
+ * to do a multi-threaded synchronized id-change, which would
+ * trash the parent's state. */
if (attr->__flags & POSIX_SPAWN_RESETIDS)
if ((ret=__syscall(SYS_setgid, __syscall(SYS_getgid))) ||
(ret=__syscall(SYS_setuid, __syscall(SYS_getuid))) )
}
switch(op->cmd) {
case FDOP_CLOSE:
- if ((ret=__syscall(SYS_close, op->fd)))
- goto fail;
+ __syscall(SYS_close, op->fd);
break;
case FDOP_DUP2:
- if ((ret=__syscall(SYS_dup2, op->srcfd, op->fd))<0)
+ fd = op->srcfd;
+ if (fd == p) {
+ ret = -EBADF;
goto fail;
+ }
+ if (fd != op->fd) {
+ if ((ret=__sys_dup2(fd, op->fd))<0)
+ goto fail;
+ } else {
+ ret = __syscall(SYS_fcntl, fd, F_GETFD);
+ ret = __syscall(SYS_fcntl, fd, F_SETFD,
+ ret & ~FD_CLOEXEC);
+ if (ret<0)
+ goto fail;
+ }
break;
case FDOP_OPEN:
- fd = __syscall(SYS_open, op->path,
- op->oflag | O_LARGEFILE, op->mode);
+ fd = __sys_open(op->path, op->oflag, op->mode);
if ((ret=fd) < 0) goto fail;
if (fd != op->fd) {
- if ((ret=__syscall(SYS_dup2, fd, op->fd))<0)
+ if ((ret=__sys_dup2(fd, op->fd))<0)
goto fail;
__syscall(SYS_close, fd);
}
pthread_sigmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
? &attr->__mask : &args->oldmask, 0);
- args->exec(args->path, args->argv, args->envp);
+ int (*exec)(const char *, char *const *, char *const *) =
+ attr->__fn ? (int (*)())attr->__fn : execve;
+
+ exec(args->path, args->argv, args->envp);
+ ret = -errno;
fail:
/* Since sizeof errno < PIPE_BUF, the write is atomic. */
ret = -ret;
- if (ret) while (write(p, &ret, sizeof ret) < 0);
+ if (ret) while (__syscall(SYS_write, p, &ret, sizeof ret) < 0);
_exit(127);
}
-int __posix_spawnx(pid_t *restrict res, const char *restrict path,
- int (*exec)(const char *, char *const *, char *const *),
+int posix_spawn(pid_t *restrict res, const char *restrict path,
const posix_spawn_file_actions_t *fa,
const posix_spawnattr_t *restrict attr,
char *const argv[restrict], char *const envp[restrict])
{
pid_t pid;
- char stack[1024];
+ char stack[1024+PATH_MAX];
int ec=0, cs;
struct args args;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
args.path = path;
- args.exec = exec;
args.fa = fa;
args.attr = attr ? attr : &(const posix_spawnattr_t){0};
args.argv = argv;
args.envp = envp;
pthread_sigmask(SIG_BLOCK, SIGALL_SET, &args.oldmask);
- /* This lock prevents setuid/setgid operations while the parent
- * is sharing memory with the child. Situations where processes
- * with different permissions share VM are fundamentally unsafe. */
- __acquire_ptc();
- pid = __clone(child, stack+sizeof stack, CLONE_VM|SIGCHLD, &args);
+ pid = __clone(child, stack+sizeof stack,
+ CLONE_VM|CLONE_VFORK|SIGCHLD, &args);
close(args.p[1]);
if (pid > 0) {
ec = -pid;
}
- /* At this point, the child has either exited or successfully
- * performed exec, so the lock may be released. */
- __release_ptc();
close(args.p[0]);
- if (!ec) *res = pid;
+ if (!ec && res) *res = pid;
pthread_sigmask(SIG_SETMASK, &args.oldmask, 0);
pthread_setcancelstate(cs, 0);
return ec;
}
-
-int posix_spawn(pid_t *restrict res, const char *restrict path,
- const posix_spawn_file_actions_t *fa,
- const posix_spawnattr_t *restrict attr,
- char *const argv[restrict], char *const envp[restrict])
-{
- return __posix_spawnx(res, path, execve, fa, attr, argv, envp);
-}
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