diff options
| author | Eric Rannaud <e@nanocritical.com> | 2015-02-24 13:12:26 +0530 |
|---|---|---|
| committer | Siddhesh Poyarekar <siddhesh@redhat.com> | 2015-02-24 13:19:22 +0530 |
| commit | 65f6f938cd562a614a68e15d0581a34b177ec29d (patch) | |
| tree | c33b9da9e6b00195e90e87b811a3d7def6529425 /io/fcntl.h | |
| parent | 3e3002ffead0526d088c353f97475400367087da (diff) | |
linux: open and openat ignore 'mode' with O_TMPFILE in flags
Both open and openat load their last argument 'mode' lazily, using
va_arg() only if O_CREAT is found in oflag. This is wrong, mode is also
necessary if O_TMPFILE is in oflag.
By chance on x86_64, the problem wasn't evident when using O_TMPFILE
with open, as the 3rd argument of open, even when not loaded with
va_arg, is left untouched in RDX, where the syscall expects it.
However, openat was not so lucky, and O_TMPFILE couldn't be used: mode
is the 4th argument, in RCX, but the syscall expects its 4th argument in
a different register than the glibc wrapper, in R10.
Introduce a macro __OPEN_NEEDS_MODE (oflag) to test if either O_CREAT or
O_TMPFILE is set in oflag.
Tested on Linux x86_64.
[BZ #17523]
* io/fcntl.h (__OPEN_NEEDS_MODE): New macro.
* io/bits/fcntl2.h (open): Use it.
(openat): Likewise.
* io/open.c (__libc_open): Likewise.
* io/open64.c (__libc_open64): Likewise.
* io/open64_2.c (__open64_2): Likewise.
* io/open_2.c (__open_2): Likewise.
* io/openat.c (__openat): Likewise.
* io/openat64.c (__openat64): Likewise.
* io/openat64_2.c (__openat64_2): Likewise.
* io/openat_2.c (__openat_2): Likewise.
* sysdeps/mach/hurd/open.c (__libc_open): Likewise.
* sysdeps/mach/hurd/openat.c (__openat): Likewise.
* sysdeps/posix/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise.
* sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise.
(__open_nocancel): Likewise.
* sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/openat.c (__OPENAT): Likewise.
Diffstat (limited to 'io/fcntl.h')
| -rw-r--r-- | io/fcntl.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/io/fcntl.h b/io/fcntl.h index 71f5e52e88..c6812c467b 100644 --- a/io/fcntl.h +++ b/io/fcntl.h @@ -34,6 +34,15 @@ __BEGIN_DECLS numbers and flag bits for `open', `fcntl', et al. */ #include <bits/fcntl.h> +/* Detect if open needs mode as a third argument (or for openat as a fourth + argument). */ +#ifdef __O_TMPFILE +# define __OPEN_NEEDS_MODE(oflag) \ + (((oflag) & O_CREAT) != 0 || ((oflag) & __O_TMPFILE) == __O_TMPFILE) +#else +# define __OPEN_NEEDS_MODE(oflag) (((oflag) & O_CREAT) != 0) +#endif + /* POSIX.1-2001 specifies that these types are defined by <fcntl.h>. Earlier POSIX standards permitted any type ending in `_t' to be defined by any POSIX header, so we don't conditionalize the definitions here. */ @@ -160,8 +169,9 @@ typedef __pid_t pid_t; extern int fcntl (int __fd, int __cmd, ...); /* Open FILE and return a new file descriptor for it, or -1 on error. - OFLAG determines the type of access used. If O_CREAT is on OFLAG, - the third argument is taken as a `mode_t', the mode of the created file. + OFLAG determines the type of access used. If O_CREAT or O_TMPFILE is set + in OFLAG, the third argument is taken as a `mode_t', the mode of the + created file. This function is a cancellation point and therefore not marked with __THROW. */ |