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Violators will be prosecuted for from ; Mon, 29 May 2017 10:06:08 +0100 From: Greg Kurz Date: Mon, 29 May 2017 11:05:39 +0200 In-Reply-To: <1496048740-26578-1-git-send-email-groug@kaod.org> References: <1496048740-26578-1-git-send-email-groug@kaod.org> Message-Id: <1496048740-26578-11-git-send-email-groug@kaod.org> Subject: [Qemu-devel] [PULL 10/11] 9pfs: local: simplify file opening List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Stefan Hajnoczi , Greg Kurz 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 Reviewed-by: Eric Blake [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, -- 2.7.4