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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
parent025b33ae84bb8f15b2748a1d8605dca453fce112 (diff)
downloadglibc-46d8874d5b2fcb7831dd84c5e2f6df51922a7936.tar.gz
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.
-rw-r--r--ChangeLog10
-rw-r--r--include/unistd.h1
-rw-r--r--libio/iopopen.c80
-rw-r--r--posix/wordexp.c32
-rw-r--r--socket/have_sock_cloexec.c4
-rw-r--r--sysdeps/unix/sysv/linux/kernel-features.h1
6 files changed, 32 insertions, 96 deletions
diff --git a/ChangeLog b/ChangeLog
index 0a5e5691d9..8ce9bea809 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
2017-04-18 Florian Weimer <fweimer@redhat.com>
+ * include/unistd.h (__have_pipe2): Remove declaration.
+ * socket/have_sock_cloexec.c (__have_pipe2): Remove definition.
+ * libio/iopopen.c (_IO_new_proc_open): Assume that pipe2 is
+ available.
+ * posix/wordexp.c (exec_comm_child, exec_comm): Likewise.
+ * sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_PIPE2):
+ Remove definition.
+
+2017-04-18 Florian Weimer <fweimer@redhat.com>
+
* malloc/malloc.c (cfree): Turn into compat symbol.
(__cfree): Remove alias.
* stdlib/stdlib.h (cfree): Remove declaration.
diff --git a/include/unistd.h b/include/unistd.h
index 16d68a1505..e15fa0e23d 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -171,7 +171,6 @@ extern int __libc_pause (void);
/* Not cancelable variant. */
extern int __pause_nocancel (void) attribute_hidden;
-extern int __have_pipe2 attribute_hidden;
extern int __have_dup3 attribute_hidden;
extern int __getlogin_r_loginuid (char *name, size_t namesize)
diff --git a/libio/iopopen.c b/libio/iopopen.c
index 08e29b44b0..95a12c90b5 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;
diff --git a/posix/wordexp.c b/posix/wordexp.c
index ba3f3ed4b6..8567c9fc50 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -836,10 +836,7 @@ exec_comm_child (char *comm, int *fildes, int showerr, int noexec)
{
#ifdef O_CLOEXEC
/* Reset the close-on-exec flag (if necessary). */
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 > 0)
-# endif
- __fcntl (fildes[1], F_SETFD, 0);
+ __fcntl (fildes[1], F_SETFD, 0);
#endif
}
@@ -905,31 +902,8 @@ exec_comm (char *comm, char **word, size_t *word_length, size_t *max_length,
if (!comm || !*comm)
return 0;
-#ifdef O_CLOEXEC
-# ifndef __ASSUME_PIPE2
- if (__have_pipe2 >= 0)
-# endif
- {
- int r = __pipe2 (fildes, 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)
- /* Bad */
- return WRDE_NOSPACE;
- }
-#endif
-#ifndef __ASSUME_PIPE2
-# ifdef O_CLOEXEC
- if (__have_pipe2 < 0)
-# endif
- if (__pipe (fildes) < 0)
- /* Bad */
- return WRDE_NOSPACE;
-#endif
+ if (__pipe2 (fildes, O_CLOEXEC) < 0)
+ return WRDE_NOSPACE;
again:
if ((pid = __fork ()) < 0)
diff --git a/socket/have_sock_cloexec.c b/socket/have_sock_cloexec.c
index 70c730ed12..579577d895 100644
--- a/socket/have_sock_cloexec.c
+++ b/socket/have_sock_cloexec.c
@@ -19,10 +19,6 @@
#include <sys/socket.h>
#include <kernel-features.h>
-#if defined O_CLOEXEC && !defined __ASSUME_PIPE2
-int __have_pipe2;
-#endif
-
#if defined O_CLOEXEC && !defined __ASSUME_DUP3
int __have_dup3;
#endif
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index e6a2720e94..233e302c0d 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -74,7 +74,6 @@
/* Support for various CLOEXEC and NONBLOCK flags was added in
2.6.27. */
#define __ASSUME_IN_NONBLOCK 1
-#define __ASSUME_PIPE2 1
#define __ASSUME_DUP3 1
/* Support for accept4 functionality was added in 2.6.28, but for some