diff options
author | Gerd Hoffmann <kraxel@redhat.com> | 2009-04-02 16:59:20 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:05:07 -0700 |
commit | dac1213842f5caf081804a11d87d2a39a21d6f55 (patch) | |
tree | 0b357e0a70fc872c400eb764ec7243969a5439d6 /fs/compat.c | |
parent | 98310e581e098514867573031b2bfa4ba89c0d93 (diff) | |
download | linux-stable-dac1213842f5caf081804a11d87d2a39a21d6f55.tar.gz linux-stable-dac1213842f5caf081804a11d87d2a39a21d6f55.tar.bz2 linux-stable-dac1213842f5caf081804a11d87d2a39a21d6f55.zip |
preadv/pwritev: create compat_readv()
This patch series:
Implement the preadv() and pwritev() syscalls. *BSD has this syscall for
quite some time.
Test code:
#if 0
set -x
gcc -Wall -O2 -o preadv $0
exit 0
#endif
/*
* preadv demo / test
*
* (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
*
* build with "sh $thisfile"
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/uio.h>
/* ----------------------------------------------------------------- */
/* syscall windup */
#include <sys/syscall.h>
#if 0
/* WARNING: Be sure you know what you are doing if you enable this.
* linux syscall code isn't upstream yet, syscall numbers are subject
* to change */
# ifndef __NR_preadv
# ifdef __i386__
# define __NR_preadv 333
# define __NR_pwritev 334
# endif
# ifdef __x86_64__
# define __NR_preadv 295
# define __NR_pwritev 296
# endif
# endif
#endif
#ifndef __NR_preadv
# error preadv/pwritev syscall numbers are unknown
#endif
static ssize_t preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
uint32_t pos_high = (offset >> 32) & 0xffffffff;
uint32_t pos_low = offset & 0xffffffff;
return syscall(__NR_preadv, fd, iov, iovcnt, pos_high, pos_low);
}
static ssize_t pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
uint32_t pos_high = (offset >> 32) & 0xffffffff;
uint32_t pos_low = offset & 0xffffffff;
return syscall(__NR_pwritev, fd, iov, iovcnt, pos_high, pos_low);
}
/* ----------------------------------------------------------------- */
/* demo/test app */
static char filename[] = "/tmp/preadv-XXXXXX";
static char outbuf[11] = "0123456789";
static char inbuf[11] = "----------";
static struct iovec ovec[2] = {{
.iov_base = outbuf + 5,
.iov_len = 5,
},{
.iov_base = outbuf + 0,
.iov_len = 5,
}};
static struct iovec ivec[3] = {{
.iov_base = inbuf + 6,
.iov_len = 2,
},{
.iov_base = inbuf + 4,
.iov_len = 2,
},{
.iov_base = inbuf + 2,
.iov_len = 2,
}};
void cleanup(void)
{
unlink(filename);
}
int main(int argc, char **argv)
{
int fd, rc;
fd = mkstemp(filename);
if (-1 == fd) {
perror("mkstemp");
exit(1);
}
atexit(cleanup);
/* write to file: "56789-01234" */
rc = pwritev(fd, ovec, 2, 0);
if (rc < 0) {
perror("pwritev");
exit(1);
}
/* read from file: "78-90-12" */
rc = preadv(fd, ivec, 3, 2);
if (rc < 0) {
perror("preadv");
exit(1);
}
printf("result : %s\n", inbuf);
printf("expected: %s\n", "--129078--");
exit(0);
}
This patch:
Factor out some code from compat_sys_readv() which can be shared with the
upcoming compat_sys_preadv().
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/compat.c')
-rw-r--r-- | fs/compat.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/fs/compat.c b/fs/compat.c index 55efdfebdf5a..e99048c21c56 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1195,16 +1195,12 @@ out: return ret; } -asmlinkage ssize_t -compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen) +static size_t compat_readv(struct file *file, + const struct compat_iovec __user *vec, + unsigned long vlen, loff_t *pos) { - struct file *file; ssize_t ret = -EBADF; - file = fget(fd); - if (!file) - return -EBADF; - if (!(file->f_mode & FMODE_READ)) goto out; @@ -1212,12 +1208,26 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsign if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) goto out; - ret = compat_do_readv_writev(READ, file, vec, vlen, &file->f_pos); + ret = compat_do_readv_writev(READ, file, vec, vlen, pos); out: if (ret > 0) add_rchar(current, ret); inc_syscr(current); + return ret; +} + +asmlinkage ssize_t +compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, + unsigned long vlen) +{ + struct file *file; + ssize_t ret; + + file = fget(fd); + if (!file) + return -EBADF; + ret = compat_readv(file, vec, vlen, &file->f_pos); fput(file); return ret; } |