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>

11 files changed, 11 insertions, 9 deletions

diff --git a/arch/ia64/ia32/sys_ia32.c b/arch/ia64/ia32/sys_ia32.c
index 7e028ceb93b..465116aecb8 100644
--- a/arch/ia64/ia32/sys_ia32.c
+++ b/arch/ia64/ia32/sys_ia32.c
@@ -1139,7 +1139,7 @@ sys32_pipe (int __user *fd)
         int retval;
         int fds[2];
 
-        retval = do_pipe(fds);
+        retval = do_pipe_flags(fds, 0);
         if (retval)
                 goto out;
         if (copy_to_user(fd, fds, sizeof(fds)))
diff --git a/arch/ia64/kernel/sys_ia64.c b/arch/ia64/kernel/sys_ia64.c
index 1eda194b955..bcbb6d8792d 100644
--- a/arch/ia64/kernel/sys_ia64.c
+++ b/arch/ia64/kernel/sys_ia64.c
@@ -160,7 +160,7 @@ sys_pipe (void)
         int fd[2];
         int retval;
 
-        retval = do_pipe(fd);
+        retval = do_pipe_flags(fd, 0);
         if (retval)
                 goto out;
         retval = fd[0];
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 3523c8d12ed..343015a2f41 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -52,7 +52,7 @@ asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
         int fd[2];
         int error, res;
 
-        error = do_pipe(fd);
+        error = do_pipe_flags(fd, 0);
         if (error) {
                 res = error;
                 goto out;
diff --git a/arch/parisc/hpux/sys_hpux.c b/arch/parisc/hpux/sys_hpux.c
index 0c5b9dabb47..be255ebb609 100644
--- a/arch/parisc/hpux/sys_hpux.c
+++ b/arch/parisc/hpux/sys_hpux.c
@@ -448,7 +448,7 @@ int hpux_pipe(int *kstack_fildes)
         int error;
 
         lock_kernel();
-        error = do_pipe(kstack_fildes);
+        error = do_pipe_flags(kstack_fildes, 0);
         unlock_kernel();
         return error;
 }
diff --git a/arch/sh/kernel/sys_sh32.c b/arch/sh/kernel/sys_sh32.c
index 125e493ead8..f0aa5c39865 100644
--- a/arch/sh/kernel/sys_sh32.c
+++ b/arch/sh/kernel/sys_sh32.c
@@ -29,7 +29,7 @@ asmlinkage int sys_pipe(unsigned long r4, unsigned long r5,
         int fd[2];
         int error;
 
-        error = do_pipe(fd);
+        error = do_pipe_flags(fd, 0);
         if (!error) {
                 regs->regs[1] = fd[1];
                 return fd[0];
diff --git a/arch/sparc/kernel/sys_sparc.c b/arch/sparc/kernel/sys_sparc.c
index 3c6b49a53ae..4d73421559c 100644
--- a/arch/sparc/kernel/sys_sparc.c
+++ b/arch/sparc/kernel/sys_sparc.c
@@ -97,7 +97,7 @@ asmlinkage int sparc_pipe(struct pt_regs *regs)
         int fd[2];
         int error;
 
-        error = do_pipe(fd);
+        error = do_pipe_flags(fd, 0);
         if (error)
                 goto out;
         regs->u_regs[UREG_I1] = fd[1];
diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c
index e1f4eba2e57..39749e32dc7 100644
--- a/arch/sparc64/kernel/sys_sparc.c
+++ b/arch/sparc64/kernel/sys_sparc.c
@@ -418,7 +418,7 @@ asmlinkage long sparc_pipe(struct pt_regs *regs)
         int fd[2];
         int error;
 
-        error = do_pipe(fd);
+        error = do_pipe_flags(fd, 0);
         if (error)
                 goto out;
         regs->u_regs[UREG_I1] = fd[1];
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 5614a8f7bed..18808b16457 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -830,4 +830,5 @@ ia32_sys_call_table:
         .quad sys_eventfd2
         .quad sys_epoll_create2
         .quad sys_dup3                  /* 330 */
+        .quad sys_pipe2
 ia32_syscall_end:
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index f00afdf61e6..d3c64088b98 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -238,7 +238,7 @@ asmlinkage long sys32_pipe(int __user *fd)
         int retval;
         int fds[2];
 
-        retval = do_pipe(fds);
+        retval = do_pipe_flags(fds, 0);
         if (retval)
                 goto out;
         if (copy_to_user(fd, fds, sizeof(fds)))
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index 24a3f1ea6a0..66154769d52 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -330,3 +330,4 @@ ENTRY(sys_call_table)
         .long sys_eventfd2
         .long sys_epoll_create2
         .long sys_dup3                  /* 330 */
+        .long sys_pipe2
diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index f3e16efcd47..ac15ecbdf91 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -49,7 +49,7 @@ asmlinkage long xtensa_pipe(int __user *userfds)
         int fd[2];
         int error;
 
-        error = do_pipe(fd);
+        error = do_pipe_flags(fd, 0);
         if (!error) {
                 if (copy_to_user(userfds, fd, 2 * sizeof(int)))
                         error = -EFAULT;