fcntl-linux.h: add F_OFD_*32 constants
PATCH 1/1 fcntl-linux.h: add F_OFD_*32 constants
The original assumption with OFD lock support was that userland would always pass in a struct flock that has been set up for large file support (LFS). It's possible however for someone to build a 32-bit program without large file support, and still try to use OFD locks. If that happens then it will send a non-LFS struct flock to the kernel, which will then try to interpret it as a LFS one, which can cause unexpected results.
My original idea was to just ensure that the build would fail in this case by not defining the F_OFD_* constants when LFS support was not enabled.
Instead though, it's probably better long-term to just go ahead and support OFD locks with non-LFS struct flock. To do that without breaking programs that are already working, we add a set of F_OFD_*32 constants, and add the plumbing to the kernel to make those do the right thing.
This patch adds the same constants to glibc, and has it redefine the "normal" F_OFD_* constants to their *32 equvalents when LFS support is not in use.
--- ChangeLog | 4 ++++ sysdeps/unix/sysv/linux/bits/fcntl-linux.h | 17 +++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-)
ChangeLog +4 -0
@@ -1,3 +1,7 @@ +2016-08-18 Jeff Layton <[email protected]> + * sysdeps/unix/sysv/linux/bits/fcntl-linux.h: + Add F_OFD_GETLK32, F_OFD_SETLK32, F_OFD_SETLKW32 + 2016-08-18 Stefan Liebler <[email protected]> * sysdeps/ieee754/dbl-64/k_rem_pio2.c (__kernel_rem_pio2):
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +13 -4
@@ -127,11 +127,20 @@This means that they are inherited across fork or clone with CLONE_FILES like BSD (flock) locks, and they are only released automatically when the last reference to the the file description against which they were acquired -is put. */ +is put. */ #ifdef __USE_GNU -# define F_OFD_GETLK 36 -# define F_OFD_SETLK 37 -# define F_OFD_SETLKW 38 +# if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64 +# define F_OFD_GETLK 36 +# define F_OFD_SETLK 37 +# define F_OFD_SETLKW 38 +# else +# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# define F_OFD_GETLK F_OFD_GETLK32 +# define F_OFD_SETLK F_OFD_SETLK32 +# define F_OFD_SETLKW F_OFD_SETLKW32 +# endif #endif #ifdef __USE_LARGEFILE64
Signature · 1 line
2.7.4
ChangeLog line 3
Quoted 3 lines · Jeff Layton
+2016-08-18 Jeff Layton <[email protected]>
ChangeLog +2
-0+ * sysdeps/unix/sysv/linux/bits/fcntl-linux.h: + Add F_OFD_GETLK32, F_OFD_SETLK32, F_OFD_SETLKW32
Should be a blank line after the first one. look at all the other entries in this file as an example.
Quoted 15 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +4
-4@@ -127,11 +127,20 @@This means that they are inherited across fork or clone with CLONE_FILES like BSD (flock) locks, and they are only released automatically when the last reference to the the file description against which they were acquired -is put. */ +is put. */ #ifdef __USE_GNU -# define F_OFD_GETLK 36 -# define F_OFD_SETLK 37 -# define F_OFD_SETLKW 38 +# if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64 +# define F_OFD_GETLK 36 +# define F_OFD_SETLK 37
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 144
Quoted 10 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +9
-0+# define F_OFD_SETLKW 38 +# else +# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# define F_OFD_GETLK F_OFD_GETLK32 +# define F_OFD_SETLK F_OFD_SETLK32 +# define F_OFD_SETLKW F_OFD_SETLKW32 +# endif #endif
i think we should define *64 and *32 variants all the time, and then route the F_OFD_GETLK/etc... to them based on compile mode. -mike
Quoted 9 lines · Mike Frysinger
Quoted 4 lines · Jeff Layton
Quoted 4 lines
ChangeLog line 3
Quoted 4 lines
+2016-08-18 Jeff Layton <[email protected]>
ChangeLog +2
-0+ * sysdeps/unix/sysv/linux/bits/fcntl-linux.h: + Add F_OFD_GETLK32, F_OFD_SETLK32, F_OFD_SETLKW32Should be a blank line after the first one. look at all the other entries in this file as an example.
Ok, will fix...
Quoted 27 lines
Quoted 18 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +0
-0@@ -127,11 +127,20 @@This means that they are inherited across fork or clone with
CLONE_FILESlike BSD (flock) locks, and they are only released automatically when the last reference to the the file description against which they were acquired - is put. */
+ is put. */
#ifdef__USE_GNUQuoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 134
Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +0
-3-# define F_OFD_GETLK 36 -# define F_OFD_SETLK 37 -# define F_OFD_SETLKW 38+# if
__OFF_T_MATCHES_OFF64_T|| defined__USE_FILE_OFFSET64Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 135
Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +3
-0+# define F_OFD_GETLK 36 +# define F_OFD_SETLK 37 +# define F_OFD_SETLKW 38+# else
Quoted 8 lines
Quoted 6 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 142
Quoted 6 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +6
-0+# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# define F_OFD_GETLK F_OFD_GETLK32 +# define F_OFD_SETLK F_OFD_SETLK32 +# define F_OFD_SETLKW F_OFD_SETLKW32+# endif
#endif
Quoted 3 lines
i think we should define *64 and *32 variants all the time, and then route the F_OFD_GETLK/etc... to them based on compile mode. -mike
Sorry, I don't quite understand here. The whole point is that the existing F_OFD_* constants are already implicitly 64-bit. Why do we need separate constants postfixed with "64" that no one will ever use?
Signature · 1 line
Jeff Layton <[email protected]>
Quoted 28 lines · Jeff Layton
Quoted 27 lines · Mike Frysinger
Quoted 25 lines · Jeff Layton
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +0
-0@@ -127,11 +127,20 @@This means that they are inherited across fork or clone with
CLONE_FILESlike BSD (flock) locks, and they are only released automatically when the last reference to the the file description against which they were acquired - is put. */
+ is put. */
#ifdef__USE_GNUQuoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 134
Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +0
-3-# define F_OFD_GETLK 36 -# define F_OFD_SETLK 37 -# define F_OFD_SETLKW 38+# if
__OFF_T_MATCHES_OFF64_T|| defined__USE_FILE_OFFSET64Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 135
Quoted 3 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +3
-0+# define F_OFD_GETLK 36 +# define F_OFD_SETLK 37 +# define F_OFD_SETLKW 38+# else
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sysdeps/unix/sysv/linux/bits/fcntl-linux.h line 142
Quoted 6 lines
sysdeps/unix/sysv/linux/bits/fcntl-linux.h +6
-0+# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# define F_OFD_GETLK F_OFD_GETLK32 +# define F_OFD_SETLK F_OFD_SETLK32 +# define F_OFD_SETLKW F_OFD_SETLKW32+# endif
#endif
Quoted 6 lines
Quoted 2 lines
i think we should define *64 and *32 variants all the time, and then route the F_OFD_GETLK/etc... to them based on compile mode.
Sorry, I don't quite understand here. The whole point is that the existing F_OFD_* constants are already implicitly 64-bit. Why do we need separate constants postfixed with "64" that no one will ever use?
you're making them not explicitly 64-bit when off_t!=off64_t. all the other commands in this file have used the convention:
<cmd>: automatically 32-bit or 64-bit <cmd>64: always 64-bit
so the header would do:
#define F_OFD_GETLK64 36
#define F_OFD_SETLK64 37
#define F_OFD_SETLKW64 38
#if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64
# define F_OFD_GETLK F_OFD_GETLK64 # define F_OFD_SETLK F_OFD_SETLK64 # define F_OFD_SETLKW F_OFD_SETLKW64 #else # define F_OFD_GETLK 39 # define F_OFD_SETLK 40 # define F_OFD_SETLKW 41 #endif
the defines deviate a bit from the names used on the kernel side, but we've already done that, and you're proposed patch does too. -mike