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author | Arnd Bergmann <arnd@arndb.de> | 2018-04-18 14:43:52 +0300 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2018-12-18 18:13:04 +0300 |
commit | e11d4284e2f4de5048c6d1787c82226f0a198292 (patch) | |
tree | bc52de794fd0fc90e2842a9d680239d6c3e9c215 /include/linux/compat.h | |
parent | bec2f7cbb73eadf5e1cc7d54ecb0980ede244257 (diff) | |
download | linux-e11d4284e2f4de5048c6d1787c82226f0a198292.tar.xz |
y2038: socket: Add compat_sys_recvmmsg_time64
recvmmsg() takes two arguments to pointers of structures that differ
between 32-bit and 64-bit architectures: mmsghdr and timespec.
For y2038 compatbility, we are changing the native system call from
timespec to __kernel_timespec with a 64-bit time_t (in another patch),
and use the existing compat system call on both 32-bit and 64-bit
architectures for compatibility with traditional 32-bit user space.
As we now have two variants of recvmmsg() for 32-bit tasks that are both
different from the variant that we use on 64-bit tasks, this means we
also require two compat system calls!
The solution I picked is to flip things around: The existing
compat_sys_recvmmsg() call gets moved from net/compat.c into net/socket.c
and now handles the case for old user space on all architectures that
have set CONFIG_COMPAT_32BIT_TIME. A new compat_sys_recvmmsg_time64()
call gets added in the old place for 64-bit architectures only, this
one handles the case of a compat mmsghdr structure combined with
__kernel_timespec.
In the indirect sys_socketcall(), we now need to call either
do_sys_recvmmsg() or __compat_sys_recvmmsg(), depending on what kind of
architecture we are on. For compat_sys_socketcall(), no such change is
needed, we always call __compat_sys_recvmmsg().
I decided to not add a new SYS_RECVMMSG_TIME64 socketcall: Any libc
implementation for 64-bit time_t will need significant changes including
an updated asm/unistd.h, and it seems better to consistently use the
separate syscalls that configuration, leaving the socketcall only for
backward compatibility with 32-bit time_t based libc.
The naming is asymmetric for the moment, so both existing syscalls
entry points keep their names, while the new ones are recvmmsg_time32
and compat_recvmmsg_time64 respectively. I expect that we will rename
the compat syscalls later as we start using generated syscall tables
everywhere and add these entry points.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/linux/compat.h')
-rw-r--r-- | include/linux/compat.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h index 8be8daa38c9a..4b0463608589 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -893,6 +893,9 @@ asmlinkage long compat_sys_move_pages(pid_t pid, compat_ulong_t nr_pages, asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid, compat_pid_t pid, int sig, struct compat_siginfo __user *uinfo); +asmlinkage long compat_sys_recvmmsg_time64(int fd, struct compat_mmsghdr __user *mmsg, + unsigned vlen, unsigned int flags, + struct __kernel_timespec __user *timeout); asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg, unsigned vlen, unsigned int flags, struct old_timespec32 __user *timeout); |