Messages in this thread Patch in this message | | | Date | Sun, 4 May 2008 23:42:46 -0400 | From | Ulrich Drepper <> | Subject | [PATCH 07/18] flag parameters: timerfd_create |
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The timerfd_create syscall already has a flags parameter. It just is unused so far. This patch changes this by introducing the TFD_CLOEXEC flag to set the close-on-exec flag for the returned file descriptor.
A new flag TFD_CLOEXEC is used instead of reusing O_CLOEXEC to prevent exhaustion of the int bit field in case we need more flags.
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 <time.h> #include <unistd.h> #include <sys/syscall.h>
#ifndef __NR_timerfd_create # ifdef __x86_64__ # define __NR_timerfd_create 283 # elif defined __i386__ # define __NR_timerfd_create 322 # else # error "need __NR_timerfd_create" # endif #endif
#define TFD_CLOEXEC (1 << 0)
int main (void) { int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0); if (fd == -1) { puts ("timerfd_create(0) failed"); return 1; } int coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if (coe & FD_CLOEXEC) { puts ("timerfd_create(0) set close-on-exec flag"); return 1; } close (fd);
fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_CLOEXEC); if (fd == -1) { puts ("timerfd_create(TFD_CLOEXEC) failed"); return 1; } coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if ((coe & FD_CLOEXEC) == 0) { puts ("timerfd_create(TFD_CLOEXEC) set close-on-exec flag"); return 1; } close (fd);
puts ("OK");
return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/timerfd.c | 12 ++++++++++-- include/linux/timerfd.h | 4 +++- 2 files changed, 13 insertions(+), 3 deletions(-)
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
diff --git a/fs/timerfd.c b/fs/timerfd.c index d87d354..f998991 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -21,6 +21,7 @@ #include <linux/anon_inodes.h> #include <linux/timerfd.h> #include <linux/syscalls.h> +#include <linux/flagsremap.h> struct timerfd_ctx { struct hrtimer tmr; @@ -179,12 +180,19 @@ static struct file *timerfd_fget(int fd) return file; } +static const struct flags_rmap timerfd_file_flags_remap[] = { + { TFD_CLOEXEC, O_CLOEXEC }, +}; + asmlinkage long sys_timerfd_create(int clockid, int flags) { int ufd; struct timerfd_ctx *ctx; + int fflags; - if (flags) + if (flags_remap(timerfd_file_flags_remap, + ARRAY_SIZE(timerfd_file_flags_remap), + flags, &fflags)) return -EINVAL; if (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME) @@ -198,7 +207,7 @@ asmlinkage long sys_timerfd_create(int clockid, int flags) ctx->clockid = clockid; hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS); - ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, 0); + ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, fflags); if (ufd < 0) kfree(ctx); diff --git a/include/linux/timerfd.h b/include/linux/timerfd.h index cf2b10d..c2fb04e 100644 --- a/include/linux/timerfd.h +++ b/include/linux/timerfd.h @@ -8,9 +8,11 @@ #ifndef _LINUX_TIMERFD_H #define _LINUX_TIMERFD_H - +/* Flags for timerfd_settime. */ #define TFD_TIMER_ABSTIME (1 << 0) +/* Flags for timerfd_create. */ +#define TFD_CLOEXEC (1 << 0) #endif /* _LINUX_TIMERFD_H */
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