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(shm_open): Use O_CLOEXEC is available.

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This commit is contained in:
Ulrich Drepper
2007-08-10 20:10:11 +00:00
parent 1e28665349
commit bfcd38238b
1 changed files with 38 additions and 15 deletions
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53
sysdeps/unix/sysv/linux/shm_open.c
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@ -1,4 +1,4 @@
/* Copyright (C) 2000,2001,2002,2003,2004,2006 Free Software Foundation, Inc. /* Copyright (C) 2000-2004,2006,2007 Free Software Foundation, Inc.
This file is part of the GNU C Library. This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or The GNU C Library is free software; you can redistribute it and/or
@ -46,6 +46,11 @@ static const char defaultdir[] = "/dev/shm/";
__libc_once_define (static, once); __libc_once_define (static, once);
#if defined O_CLOEXEC && !defined __ASSUME_O_CLOEXEC
static bool have_o_cloexec;
#endif
/* Determine where the shmfs is mounted (if at all). */ /* Determine where the shmfs is mounted (if at all). */
static void static void
where_is_shmfs (void) where_is_shmfs (void)
@ -160,6 +165,10 @@ shm_open (const char *name, int oflag, mode_t mode)
__mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen), __mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
name, namelen + 1); name, namelen + 1);
#ifdef O_CLOEXEC
oflag |= O_CLOEXEC;
#endif
/* And get the file descriptor. /* And get the file descriptor.
XXX Maybe we should test each descriptor whether it really is for a XXX Maybe we should test each descriptor whether it really is for a
file on the shmfs. If this is what should be done the whole function file on the shmfs. If this is what should be done the whole function
@ -168,23 +177,37 @@ shm_open (const char *name, int oflag, mode_t mode)
fd = open (fname, oflag | O_NOFOLLOW, mode); fd = open (fname, oflag | O_NOFOLLOW, mode);
if (fd != -1) if (fd != -1)
{ {
/* We got a descriptor. Now set the FD_CLOEXEC bit. */ #if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
int flags = fcntl (fd, F_GETFD, 0); # ifdef O_CLOEXEC
if (have_o_cloexec <= 0)
if (__builtin_expect (flags, 0) >= 0) # endif
{ {
flags |= FD_CLOEXEC; /* We got a descriptor. Now set the FD_CLOEXEC bit. */
flags = fcntl (fd, F_SETFD, flags); int flags = fcntl (fd, F_GETFD, 0);
}
if (flags == -1) if (__builtin_expect (flags, 0) >= 0)
{ {
/* Something went wrong. We cannot return the descriptor. */ # ifndef O_CLOEXEC
int save_errno = errno; if (have_o_cloexec == 0)
close (fd); have_o_cloexec = (flags & FD_CLOEXEC) == 0 ? -1 : 1;
fd = -1; if (have_o_cloexec < 0)
__set_errno (save_errno); # endif
{
flags |= FD_CLOEXEC;
flags = fcntl (fd, F_SETFD, flags);
}
}
if (flags == -1)
{
/* Something went wrong. We cannot return the descriptor. */
int save_errno = errno;
close (fd);
fd = -1;
__set_errno (save_errno);
}
} }
#endif
} }
else if (__builtin_expect (errno == EISDIR, 0)) else if (__builtin_expect (errno == EISDIR, 0))
/* It might be better to fold this error with EINVAL since /* It might be better to fold this error with EINVAL since