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From: Michael Olbrich <m.olbrich@pengutronix.de>
Date: Tue, 25 Oct 2016 12:39:03 +0200
Subject: [PATCH] 9pfs: allow real symlinks for security_model=mapped-file
And create real symlinks if possible. This makes it possible to use the
same filesystem with security_model=mapped-file and security_model=none.
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
---
hw/9pfs/9p-local.c | 44 +++++++++++++++++++++++++++++---------------
1 file changed, 29 insertions(+), 15 deletions(-)
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index d42ce6d8b822..559573008eec 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -462,8 +462,7 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
{
ssize_t tsize = -1;
- if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
- (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
+ if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
int fd;
fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
@@ -475,6 +474,7 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
} while (tsize == -1 && errno == EINTR);
close_preserve_errno(fd);
} else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
+ (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) ||
(fs_ctx->export_flags & V9FS_SM_NONE)) {
char *dirpath = g_path_get_dirname(fs_path->data);
char *name = g_path_get_basename(fs_path->data);
@@ -486,6 +486,17 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
}
tsize = readlinkat(dirfd, name, buf, bufsz);
+
+ if (tsize == -1 && (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
+ int fd = openat_file(dirfd, name, O_RDONLY, 0);
+ if (fd == -1) {
+ goto out;
+ }
+ do {
+ tsize = read(fd, (void *)buf, bufsz);
+ } while (tsize == -1 && errno == EINTR);
+ close_preserve_errno(fd);
+ }
close_preserve_errno(dirfd);
out:
g_free(name);
@@ -901,20 +912,23 @@ static int local_symlink(FsContext *fs_ctx, const char *oldpath,
int fd;
ssize_t oldpath_size, write_size;
- fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
- fs_ctx->fmode);
- if (fd == -1) {
- goto out;
- }
- /* Write the oldpath (target) to the file. */
- oldpath_size = strlen(oldpath);
- do {
- write_size = write(fd, (void *)oldpath, oldpath_size);
- } while (write_size == -1 && errno == EINTR);
- close_preserve_errno(fd);
+ if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
+ (symlinkat(oldpath, dirfd, name) != 0)) {
+ fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
+ fs_ctx->fmode);
+ if (fd == -1) {
+ goto out;
+ }
+ /* Write the oldpath (target) to the file. */
+ oldpath_size = strlen(oldpath);
+ do {
+ write_size = write(fd, (void *)oldpath, oldpath_size);
+ } while (write_size == -1 && errno == EINTR);
+ close_preserve_errno(fd);
- if (write_size != oldpath_size) {
- goto err_end;
+ if (write_size != oldpath_size) {
+ goto err_end;
+ }
}
/* Set cleint credentials in symlink's xattr */
credp->fc_mode = credp->fc_mode | S_IFLNK;
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