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author | Ulrich Drepper <drepper@redhat.com> | 2008-07-23 21:29:30 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 10:47:28 -0700 |
commit | ed8cae8ba01348bfd83333f4648dd807b04d7f08 (patch) | |
tree | c71a1c8e771c1c55728bb7c40612fbdcefbc858a /fs | |
parent | 336dd1f70ff62d7dd8655228caed4c5bfc818c56 (diff) | |
download | linux-ed8cae8ba01348bfd83333f4648dd807b04d7f08.tar.bz2 |
flag parameters: pipe
This patch introduces the new syscall pipe2 which is like pipe but it also
takes an additional parameter which takes a flag value. This patch implements
the handling of O_CLOEXEC for the flag. I did not add support for the new
syscall for the architectures which have a special sys_pipe implementation. I
think the maintainers of those archs have the chance to go with the unified
implementation but that's up to them.
The implementation introduces do_pipe_flags. I did that instead of changing
all callers of do_pipe because some of the callers are written in assembler.
I would probably screw up changing the assembly code. To avoid breaking code
do_pipe is now a small wrapper around do_pipe_flags. Once all callers are
changed over to do_pipe_flags the old do_pipe function can be removed.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_pipe2
# ifdef __x86_64__
# define __NR_pipe2 293
# elif defined __i386__
# define __NR_pipe2 331
# else
# error "need __NR_pipe2"
# endif
#endif
int
main (void)
{
int fd[2];
if (syscall (__NR_pipe2, fd, 0) != 0)
{
puts ("pipe2(0) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int coe = fcntl (fd[i], F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
printf ("pipe2(0) set close-on-exit for fd[%d]\n", i);
return 1;
}
}
close (fd[0]);
close (fd[1]);
if (syscall (__NR_pipe2, fd, O_CLOEXEC) != 0)
{
puts ("pipe2(O_CLOEXEC) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int coe = fcntl (fd[i], F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
printf ("pipe2(O_CLOEXEC) does not set close-on-exit for fd[%d]\n", i);
return 1;
}
}
close (fd[0]);
close (fd[1]);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/pipe.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 700f4e0d9572..68e82061070c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1027,12 +1027,15 @@ struct file *create_read_pipe(struct file *wrf) return f; } -int do_pipe(int *fd) +int do_pipe_flags(int *fd, int flags) { struct file *fw, *fr; int error; int fdw, fdr; + if (flags & ~O_CLOEXEC) + return -EINVAL; + fw = create_write_pipe(); if (IS_ERR(fw)) return PTR_ERR(fw); @@ -1041,12 +1044,12 @@ int do_pipe(int *fd) if (IS_ERR(fr)) goto err_write_pipe; - error = get_unused_fd(); + error = get_unused_fd_flags(flags); if (error < 0) goto err_read_pipe; fdr = error; - error = get_unused_fd(); + error = get_unused_fd_flags(flags); if (error < 0) goto err_fdr; fdw = error; @@ -1074,16 +1077,21 @@ int do_pipe(int *fd) return error; } +int do_pipe(int *fd) +{ + return do_pipe_flags(fd, 0); +} + /* * sys_pipe() is the normal C calling standard for creating * a pipe. It's not the way Unix traditionally does this, though. */ -asmlinkage long __weak sys_pipe(int __user *fildes) +asmlinkage long __weak sys_pipe2(int __user *fildes, int flags) { int fd[2]; int error; - error = do_pipe(fd); + error = do_pipe_flags(fd, flags); if (!error) { if (copy_to_user(fildes, fd, sizeof(fd))) { sys_close(fd[0]); @@ -1094,6 +1102,11 @@ asmlinkage long __weak sys_pipe(int __user *fildes) return error; } +asmlinkage long __weak sys_pipe(int __user *fildes) +{ + return sys_pipe2(fildes, 0); +} + /* * pipefs should _never_ be mounted by userland - too much of security hassle, * no real gain from having the whole whorehouse mounted. So we don't need |