aboutsummaryrefslogtreecommitdiff
path: root/libio
diff options
context:
space:
mode:
authorFlorian Weimer <fweimer@redhat.com>2017-04-18 14:09:01 +0200
committerFlorian Weimer <fweimer@redhat.com>2017-04-18 14:09:01 +0200
commit46d8874d5b2fcb7831dd84c5e2f6df51922a7936 (patch)
tree298787303d12ee07ef36fb95033467feed045211 /libio
parent025b33ae84bb8f15b2748a1d8605dca453fce112 (diff)
downloadglibc-46d8874d5b2fcb7831dd84c5e2f6df51922a7936.zip
glibc-46d8874d5b2fcb7831dd84c5e2f6df51922a7936.tar.gz
glibc-46d8874d5b2fcb7831dd84c5e2f6df51922a7936.tar.bz2
Assume that pipe2 is always available
The Debian patches for Hurd (which are already required to build glibc before this commit) contain an implementation of pipe2.
Diffstat (limited to 'libio')
-rw-r--r--libio/iopopen.c80
1 files changed, 19 insertions, 61 deletions
diff --git a/libio/iopopen.c b/libio/iopopen.c
index 08e29b4..95a12c9 100644
--- a/libio/iopopen.c
+++ b/libio/iopopen.c
@@ -140,29 +140,17 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode)
if (_IO_file_is_open (fp))
return NULL;
-#ifdef O_CLOEXEC
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 >= 0)
-# endif
- {
- int r = __pipe2 (pipe_fds, O_CLOEXEC);
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 == 0)
- __have_pipe2 = r != -1 || errno != ENOSYS ? 1 : -1;
-
- if (__have_pipe2 > 0)
-# endif
- if (r < 0)
- return NULL;
- }
-#endif
-#ifndef __ASSUME_PIPE2
-# ifdef O_CLOEXEC
- if (__have_pipe2 < 0)
-# endif
- if (__pipe (pipe_fds) < 0)
- return NULL;
-#endif
+ /* Atomically set the O_CLOEXEC flag for the pipe end used by the
+ child process (to avoid leaking the file descriptor in case of a
+ concurrent fork). This is later reverted in the child process.
+ When popen returns, the parent pipe end can be O_CLOEXEC or not,
+ depending on the 'e' open mode, but there is only one flag which
+ controls both descriptors. The parent end is adjusted below,
+ after creating the child process. (In the child process, the
+ parent end should be closed on execve, so O_CLOEXEC remains set
+ there.) */
+ if (__pipe2 (pipe_fds, O_CLOEXEC) < 0)
+ return NULL;
if (do_read)
{
@@ -183,27 +171,13 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode)
int child_std_end = do_read ? 1 : 0;
struct _IO_proc_file *p;
-#ifndef __ASSUME_PIPE2
- /* If we have pipe2 the descriptor is marked for close-on-exec. */
- _IO_close (parent_end);
-#endif
if (child_end != child_std_end)
- {
- _IO_dup2 (child_end, child_std_end);
-#ifndef __ASSUME_PIPE2
- _IO_close (child_end);
-#endif
- }
+ _IO_dup2 (child_end, child_std_end);
#ifdef O_CLOEXEC
else
- {
- /* The descriptor is already the one we will use. But it must
- not be marked close-on-exec. Undo the effects. */
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 > 0)
-# endif
- __fcntl (child_end, F_SETFD, 0);
- }
+ /* The descriptor is already the one we will use. But it must
+ not be marked close-on-exec. Undo the effects. */
+ __fcntl (child_end, F_SETFD, 0);
#endif
/* POSIX.2: "popen() shall ensure that any streams from previous
popen() calls that remain open in the parent process are closed
@@ -229,26 +203,10 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode)
return NULL;
}
- if (do_cloexec)
- {
-#ifndef __ASSUME_PIPE2
-# ifdef O_CLOEXEC
- if (__have_pipe2 < 0)
-# endif
- __fcntl (parent_end, F_SETFD, FD_CLOEXEC);
-#endif
- }
- else
- {
-#ifdef O_CLOEXEC
- /* Undo the effects of the pipe2 call which set the
- close-on-exec flag. */
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 > 0)
-# endif
- __fcntl (parent_end, F_SETFD, 0);
-#endif
- }
+ if (!do_cloexec)
+ /* Undo the effects of the pipe2 call which set the
+ close-on-exec flag. */
+ __fcntl (parent_end, F_SETFD, 0);
_IO_fileno (fp) = parent_end;