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compat: fs: Generic compat_sys_sendfile implementation

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This function is used by sparc, powerpc and arm64 for compat support.
The patch adds a generic implementation which calls do_sendfile()
directly and avoids set_fs().

The sparc architecture has wrappers for the sign extensions while
powerpc relies on the compiler to do the this. The patch adds wrappers
for powerpc to handle the u32->int type conversion.

compat_sys_sendfile64() can be replaced by a sys_sendfile() call since
compat_loff_t has the same size as off_t on a 64-bit system.

On powerpc, the patch also changes the 64-bit sendfile call from
sys_sendile64 to sys_sendfile.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Catalin Marinas 2012-09-19 12:01:52 +01:00 • committed by Al Viro
commit 8f9c0119d7
10 changed files with 41 additions and 89 deletions
Download patch file Download diff file Expand all files Collapse all files

4
arch/powerpc/include/asm/systbl.h
View file

@ -189,7 +189,7 @@ SYSCALL_SPU(getcwd)
SYSCALL_SPU(capget)
SYSCALL_SPU(capset)
COMPAT_SYS(sigaltstack)
SYSX_SPU(sys_sendfile64,compat_sys_sendfile,sys_sendfile)
SYSX_SPU(sys_sendfile,compat_sys_sendfile_wrapper,sys_sendfile)
SYSCALL(ni_syscall)
SYSCALL(ni_syscall)
PPC_SYS(vfork)
@ -229,7 +229,7 @@ COMPAT_SYS_SPU(sched_setaffinity)
COMPAT_SYS_SPU(sched_getaffinity)
SYSCALL(ni_syscall)
SYSCALL(ni_syscall)
SYS32ONLY(sendfile64)
SYSX(sys_ni_syscall,compat_sys_sendfile64_wrapper,sys_sendfile64)
COMPAT_SYS_SPU(io_setup)
SYSCALL_SPU(io_destroy)
COMPAT_SYS_SPU(io_getevents)

1
arch/powerpc/include/asm/unistd.h
View file

@ -419,6 +419,7 @@
#define __ARCH_WANT_COMPAT_SYS_TIME
#define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
#define __ARCH_WANT_SYS_NEWFSTATAT
#define __ARCH_WANT_COMPAT_SYS_SENDFILE
#endif
/*

45
arch/powerpc/kernel/sys_ppc32.c
View file

@ -143,48 +143,17 @@ long compat_sys_ipc(u32 call, u32 first, u32 second, u32 third, compat_uptr_t pt
* proper conversion (sign extension) between the register representation of a signed int (msr in 32-bit mode)
* and the register representation of a signed int (msr in 64-bit mode) is performed.
*/
asmlinkage long compat_sys_sendfile(u32 out_fd, u32 in_fd, compat_off_t __user * offset, u32 count)
asmlinkage long compat_sys_sendfile_wrapper(u32 out_fd, u32 in_fd,
compat_off_t __user *offset, u32 count)
{
mm_segment_t old_fs = get_fs();
int ret;
off_t of;
off_t __user *up;
if (offset && get_user(of, offset))
return -EFAULT;
/* The __user pointer cast is valid because of the set_fs() */
set_fs(KERNEL_DS);
up = offset ? (off_t __user *) &of : NULL;
ret = sys_sendfile((int)out_fd, (int)in_fd, up, count);
set_fs(old_fs);
if (offset && put_user(of, offset))
return -EFAULT;
return ret;
return compat_sys_sendfile((int)out_fd, (int)in_fd, offset, count);
}
asmlinkage int compat_sys_sendfile64(int out_fd, int in_fd, compat_loff_t __user *offset, s32 count)
asmlinkage long compat_sys_sendfile64_wrapper(u32 out_fd, u32 in_fd,
compat_loff_t __user *offset, u32 count)
{
mm_segment_t old_fs = get_fs();
int ret;
loff_t lof;
loff_t __user *up;
if (offset && get_user(lof, offset))
return -EFAULT;
/* The __user pointer cast is valid because of the set_fs() */
set_fs(KERNEL_DS);
up = offset ? (loff_t __user *) &lof : NULL;
ret = sys_sendfile64(out_fd, in_fd, up, count);
set_fs(old_fs);
if (offset && put_user(lof, offset))
return -EFAULT;
return ret;
return sys_sendfile((int)out_fd, (int)in_fd,
(off_t __user *)offset, count);
}
long compat_sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,

1
arch/sparc/include/asm/unistd.h
View file

@ -447,6 +447,7 @@
#else
#define __ARCH_WANT_COMPAT_SYS_TIME
#define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
#define __ARCH_WANT_COMPAT_SYS_SENDFILE
#endif
/*

2
arch/sparc/kernel/sys32.S
View file

@ -90,7 +90,7 @@ SIGN1(sys32_mkdir, sys_mkdir, %o1)
SIGN3(sys32_futex, compat_sys_futex, %o1, %o2, %o5)
SIGN1(sys32_sysfs, compat_sys_sysfs, %o0)
SIGN2(sys32_sendfile, compat_sys_sendfile, %o0, %o1)
SIGN2(sys32_sendfile64, compat_sys_sendfile64, %o0, %o1)
SIGN2(sys32_sendfile64, sys_sendfile, %o0, %o1)
SIGN1(sys32_prctl, sys_prctl, %o0)
SIGN1(sys32_sched_rr_get_interval, compat_sys_sched_rr_get_interval, %o0)
SIGN2(sys32_waitpid, sys_waitpid, %o0, %o2)

46
arch/sparc/kernel/sys_sparc32.c
View file

@ -506,52 +506,6 @@ long compat_sys_fadvise64_64(int fd,
advice);
}
asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
compat_off_t __user *offset,
compat_size_t count)
{
mm_segment_t old_fs = get_fs();
int ret;
off_t of;
if (offset && get_user(of, offset))
return -EFAULT;
set_fs(KERNEL_DS);
ret = sys_sendfile(out_fd, in_fd,
offset ? (off_t __user *) &of : NULL,
count);
set_fs(old_fs);
if (offset && put_user(of, offset))
return -EFAULT;
return ret;
}
asmlinkage long compat_sys_sendfile64(int out_fd, int in_fd,
compat_loff_t __user *offset,
compat_size_t count)
{
mm_segment_t old_fs = get_fs();
int ret;
loff_t lof;
if (offset && get_user(lof, offset))
return -EFAULT;
set_fs(KERNEL_DS);
ret = sys_sendfile64(out_fd, in_fd,
offset ? (loff_t __user *) &lof : NULL,
count);
set_fs(old_fs);
if (offset && put_user(lof, offset))
return -EFAULT;
return ret;
}
/* This is just a version for 32-bit applications which does
* not force O_LARGEFILE on.
*/

22
fs/compat.c
View file

@ -1792,3 +1792,25 @@ compat_sys_open_by_handle_at(int mountdirfd,
return do_handle_open(mountdirfd, handle, flags);
}
#endif
#ifdef __ARCH_WANT_COMPAT_SYS_SENDFILE
asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
compat_off_t __user *offset, compat_size_t count)
{
loff_t pos;
off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#endif /* __ARCH_WANT_COMPAT_SYS_SENDFILE */

4
fs/read_write.c
View file

@ -862,8 +862,8 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
return ret;
}
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
size_t count, loff_t max)
ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count,
loff_t max)
{
struct fd in, out;
struct inode *in_inode, *out_inode;

2
fs/read_write.h
View file

@ -12,3 +12,5 @@ ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn);
ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
unsigned long nr_segs, loff_t *ppos, io_fn_t fn);
ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count,
loff_t max);

3
include/linux/compat.h
View file

@ -590,6 +590,9 @@ asmlinkage ssize_t compat_sys_process_vm_writev(compat_pid_t pid,
unsigned long liovcnt, const struct compat_iovec __user *rvec,
unsigned long riovcnt, unsigned long flags);
asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
compat_off_t __user *offset, compat_size_t count);
#else
#define is_compat_task() (0)