virtiofsd: Fix side-effect in assert()

It is bad practice to put an expression with a side-effect in
assert() because the side-effect won't happen if the code is
compiled with -DNDEBUG.

Use an intermediate variable. Consolidate this in an macro to
have proper line numbers when the assertion is hit.

virtiofsd: ../../tools/virtiofsd/passthrough_ll.c:2797: lo_getxattr:
 Assertion `fchdir_res == 0' failed.
Aborted

  2796          /* fchdir should not fail here */
=>2797          FCHDIR_NOFAIL(lo->proc_self_fd);
  2798          ret = getxattr(procname, name, value, size);
  2799          FCHDIR_NOFAIL(lo->root.fd);

Fixes: bdfd667883 ("virtiofsd: Fix xattr operations")
Cc: misono.tomohiro@jp.fujitsu.com
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210409100627.451573-1-groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
This commit is contained in:
Greg Kurz 2021-04-09 12:06:27 +02:00 committed by Dr. David Alan Gilbert
parent d90f154867
commit 0adb3aff39

View file

@ -2723,6 +2723,11 @@ static int xattr_map_server(const struct lo_data *lo, const char *server_name,
return -ENODATA;
}
#define FCHDIR_NOFAIL(fd) do { \
int fchdir_res = fchdir(fd); \
assert(fchdir_res == 0); \
} while (0)
static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
size_t size)
{
@ -2789,9 +2794,9 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
ret = fgetxattr(fd, name, value, size);
} else {
/* fchdir should not fail here */
assert(fchdir(lo->proc_self_fd) == 0);
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = getxattr(procname, name, value, size);
assert(fchdir(lo->root.fd) == 0);
FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
@ -2864,9 +2869,9 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
ret = flistxattr(fd, value, size);
} else {
/* fchdir should not fail here */
assert(fchdir(lo->proc_self_fd) == 0);
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = listxattr(procname, value, size);
assert(fchdir(lo->root.fd) == 0);
FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
@ -3000,9 +3005,9 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
ret = fsetxattr(fd, name, value, size, flags);
} else {
/* fchdir should not fail here */
assert(fchdir(lo->proc_self_fd) == 0);
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = setxattr(procname, name, value, size, flags);
assert(fchdir(lo->root.fd) == 0);
FCHDIR_NOFAIL(lo->root.fd);
}
saverr = ret == -1 ? errno : 0;
@ -3066,9 +3071,9 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name)
ret = fremovexattr(fd, name);
} else {
/* fchdir should not fail here */
assert(fchdir(lo->proc_self_fd) == 0);
FCHDIR_NOFAIL(lo->proc_self_fd);
ret = removexattr(procname, name);
assert(fchdir(lo->root.fd) == 0);
FCHDIR_NOFAIL(lo->root.fd);
}
saverr = ret == -1 ? errno : 0;