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authorGerd Hoffmann <kraxel@redhat.com>2009-04-02 16:59:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 19:05:07 -0700
commitdac1213842f5caf081804a11d87d2a39a21d6f55 (patch)
tree0b357e0a70fc872c400eb764ec7243969a5439d6 /fs
parent98310e581e098514867573031b2bfa4ba89c0d93 (diff)
downloadlinux-dac1213842f5caf081804a11d87d2a39a21d6f55.tar.bz2
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')
-rw-r--r--fs/compat.c26
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;
}