prevent dup2 action for posix_spawn internal pipe fd

[android-x86/external-musl-libc.git] / src / process / posix_spawn.c

diff --git a/src/process/posix_spawn.c b/src/process/posix_spawn.c
index eb98f9f..306faa0 100644 (file)
--- a/src/process/posix_spawn.c
+++ b/src/process/posix_spawn.c
@@ -8,19 +8,24 @@
 #include "syscall.h"
 #include "pthread_impl.h"
 #include "fdop.h"
-#include "libc.h"
 
 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;
 };
 
-void __get_handler_set(sigset_t *);
+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)
 {
@@ -59,13 +64,17 @@ static int child(void *args_vp)
                __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))) )
@@ -88,19 +97,30 @@ static int child(void *args_vp)
                        }
                        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);
                                }
@@ -118,25 +138,27 @@ static int child(void *args_vp)
        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;
 
@@ -146,7 +168,6 @@ int __posix_spawnx(pid_t *restrict res, const char *restrict path,
        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;
@@ -166,18 +187,10 @@ int __posix_spawnx(pid_t *restrict res, const char *restrict path,
 
        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);
-}