[PATCH 16/18] flag parameters: NONBLOCK in pipe
From: Ulrich Drepper <hidden>
Date: 2008-05-06 21:21:07
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
This patch adds O_NONBLOCK support to pipe2. It is minimally more involved
than the patches for eventfd et.al but still trivial. The interfaces of the
create_write_pipe and create_read_pipe helper functions were changed and the
one other caller as well.
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 fds[2];
if (syscall (__NR_pipe2, fds, 0) == -1)
{
puts ("pipe2(0) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
printf ("pipe2(0) set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}
if (syscall (__NR_pipe2, fds, O_NONBLOCK) == -1)
{
puts ("pipe2(O_NONBLOCK) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
printf ("pipe2(O_NONBLOCK) does not set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/pipe.c | 14 +++++++-------
include/linux/fs.h | 4 ++--
kernel/kmod.c | 4 ++--
3 files changed, 11 insertions(+), 11 deletions(-)
Signed-off-by: Ulrich Drepper <redacted>
diff --git a/fs/pipe.c b/fs/pipe.c
index 059411e..796c0a0 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c@@ -949,7 +949,7 @@ fail_inode: return NULL; } -struct file *create_write_pipe(void) +struct file *create_write_pipe(int flags) { int err; struct inode *inode;
@@ -982,7 +982,7 @@ struct file *create_write_pipe(void) goto err_dentry; f->f_mapping = inode->i_mapping; - f->f_flags = O_WRONLY; + f->f_flags = O_WRONLY | (flags & O_NONBLOCK); f->f_version = 0; return f;
@@ -1007,7 +1007,7 @@ void free_write_pipe(struct file *f) put_filp(f); } -struct file *create_read_pipe(struct file *wrf) +struct file *create_read_pipe(struct file *wrf, int flags) { struct file *f = get_empty_filp(); if (!f)
@@ -1019,7 +1019,7 @@ struct file *create_read_pipe(struct file *wrf) f->f_mapping = wrf->f_path.dentry->d_inode->i_mapping; f->f_pos = 0; - f->f_flags = O_RDONLY; + f->f_flags = O_RDONLY | (flags & O_NONBLOCK); f->f_op = &read_pipe_fops; f->f_mode = FMODE_READ; f->f_version = 0;
@@ -1033,13 +1033,13 @@ int do_pipe_flags(int *fd, int flags) int error; int fdw, fdr; - if (flags & ~O_CLOEXEC) + if (flags & ~(O_CLOEXEC | O_NONBLOCK)) return -EINVAL; - fw = create_write_pipe(); + fw = create_write_pipe(flags); if (IS_ERR(fw)) return PTR_ERR(fw); - fr = create_read_pipe(fw); + fr = create_read_pipe(fw, flags); error = PTR_ERR(fr); if (IS_ERR(fr)) goto err_write_pipe;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 134d2d5..3694eeb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -1776,8 +1776,8 @@ static inline void allow_write_access(struct file *file) } extern int do_pipe(int *); extern int do_pipe_flags(int *, int); -extern struct file *create_read_pipe(struct file *f); -extern struct file *create_write_pipe(void); +extern struct file *create_read_pipe(struct file *f, int flags); +extern struct file *create_write_pipe(int flags); extern void free_write_pipe(struct file *); extern struct file *do_filp_open(int dfd, const char *pathname,
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 8df97d3..7356146 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c@@ -417,12 +417,12 @@ int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, { struct file *f; - f = create_write_pipe(); + f = create_write_pipe(0); if (IS_ERR(f)) return PTR_ERR(f); *filp = f; - f = create_read_pipe(f); + f = create_read_pipe(f, 0); if (IS_ERR(f)) { free_write_pipe(*filp); return PTR_ERR(f);