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[Qemu-devel] [PULL v2 10/11] 9pfs: local: simplify file opening
From: |
Greg Kurz |
Subject: |
[Qemu-devel] [PULL v2 10/11] 9pfs: local: simplify file opening |
Date: |
Tue, 30 May 2017 15:40:39 +0200 |
The logic to open a path currently sits between local_open_nofollow() and
the relative_openat_nofollow() helper, which has no other user.
For the sake of clarity, this patch moves all the code of the helper into
its unique caller. While here we also:
- drop the code to skip leading "/" because the backend isn't supposed to
pass anything but relative paths without consecutive slashes. The assert()
is kept because we really don't want a buggy backend to pass an absolute
path to openat().
- use strchrnul() to get a simpler code. This is ok since virtfs is for
linux+glibc hosts only.
- don't dup() the initial directory and add an assert() to ensure we don't
return the global mountfd to the caller. BTW, this would mean that the
caller passed an empty path, which isn't supposed to happen either.
Signed-off-by: Greg Kurz <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
[groug: fixed typos in changelog]
---
hw/9pfs/9p-local.c | 34 +++++++++++++++++++++++++++++-----
hw/9pfs/9p-util.c | 43 -------------------------------------------
hw/9pfs/9p-util.h | 2 --
3 files changed, 29 insertions(+), 50 deletions(-)
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 68e92652ed73..ddc5038cff39 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -53,13 +53,37 @@ int local_open_nofollow(FsContext *fs_ctx, const char
*path, int flags,
mode_t mode)
{
LocalData *data = fs_ctx->private;
-
- /* All paths are relative to the path data->mountfd points to */
- while (*path == '/') {
- path++;
+ int fd = data->mountfd;
+
+ while (*path && fd != -1) {
+ const char *c;
+ int next_fd;
+ char *head;
+
+ /* Only relative paths without consecutive slashes */
+ assert(*path != '/');
+
+ head = g_strdup(path);
+ c = strchrnul(path, '/');
+ if (*c) {
+ /* Intermediate path element */
+ head[c - path] = 0;
+ path = c + 1;
+ next_fd = openat_dir(fd, head);
+ } else {
+ /* Rightmost path element */
+ next_fd = openat_file(fd, head, flags, mode);
+ path = c;
+ }
+ g_free(head);
+ if (fd != data->mountfd) {
+ close_preserve_errno(fd);
+ }
+ fd = next_fd;
}
- return relative_openat_nofollow(data->mountfd, path, flags, mode);
+ assert(fd != data->mountfd);
+ return fd;
}
int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
diff --git a/hw/9pfs/9p-util.c b/hw/9pfs/9p-util.c
index fdb4d5737635..f709c27a1fbd 100644
--- a/hw/9pfs/9p-util.c
+++ b/hw/9pfs/9p-util.c
@@ -14,49 +14,6 @@
#include "qemu/xattr.h"
#include "9p-util.h"
-int relative_openat_nofollow(int dirfd, const char *path, int flags,
- mode_t mode)
-{
- int fd;
-
- fd = dup(dirfd);
- if (fd == -1) {
- return -1;
- }
-
- while (*path) {
- const char *c;
- int next_fd;
- char *head;
-
- /* Only relative paths without consecutive slashes */
- assert(path[0] != '/');
-
- head = g_strdup(path);
- c = strchr(path, '/');
- if (c) {
- head[c - path] = 0;
- next_fd = openat_dir(fd, head);
- } else {
- next_fd = openat_file(fd, head, flags, mode);
- }
- g_free(head);
- if (next_fd == -1) {
- close_preserve_errno(fd);
- return -1;
- }
- close(fd);
- fd = next_fd;
-
- if (!c) {
- break;
- }
- path = c + 1;
- }
-
- return fd;
-}
-
ssize_t fgetxattrat_nofollow(int dirfd, const char *filename, const char *name,
void *value, size_t size)
{
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index 517027c52032..91299a24b8af 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -50,8 +50,6 @@ static inline int openat_file(int dirfd, const char *name,
int flags,
return fd;
}
-int relative_openat_nofollow(int dirfd, const char *path, int flags,
- mode_t mode);
ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
void *value, size_t size);
int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,
--
2.7.5
- [Qemu-devel] [PULL v2 00/11] 9pfs patches for 2.10 20170530, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 01/11] virtio-9p/xen-9p: move 9p specific bits to core 9p code, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 05/11] fsdev: fix virtfs-proxy-helper cwd, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 02/11] fsdev: don't allow unknown format in marshal/unmarshal, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 04/11] 9pfs: local: fix unlink of alien files in mapped-file mode, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 07/11] util: drop old utimensat() compat code, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 03/11] 9pfs: drop pdu_push_and_notify(), Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 06/11] 9pfs: assume utimensat() and futimens() are present, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 11/11] 9pfs: local: metadata file for the VirtFS root, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 10/11] 9pfs: local: simplify file opening,
Greg Kurz <=
- [Qemu-devel] [PULL v2 09/11] 9pfs: local: resolve special directories in paths, Greg Kurz, 2017/05/30
- [Qemu-devel] [PULL v2 08/11] 9pfs: check return value of v9fs_co_name_to_path(), Greg Kurz, 2017/05/30