[Libguestfs] [PATCH v7 11/29] daemon: Reimplement ‘case_sensitive_path’ API in OCaml.
Richard W.M. Jones
rjones at redhat.com
Mon Jun 19 15:39:36 UTC 2017
---
daemon/Makefile.am | 2 +
daemon/realpath.c | 187 ----------------------------------------------
daemon/realpath.ml | 83 ++++++++++++++++++++
daemon/realpath.mli | 19 +++++
generator/actions_core.ml | 1 +
5 files changed, 105 insertions(+), 187 deletions(-)
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 1035d7ea2..d56c99123 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -265,6 +265,7 @@ SOURCES_MLI = \
mount.mli \
mountable.mli \
parted.mli \
+ realpath.mli \
utils.mli
SOURCES_ML = \
@@ -280,6 +281,7 @@ SOURCES_ML = \
link.ml \
mount.ml \
parted.ml \
+ realpath.ml \
callbacks.ml \
daemon.ml
diff --git a/daemon/realpath.c b/daemon/realpath.c
index 24ab133e2..f9d22d28d 100644
--- a/daemon/realpath.c
+++ b/daemon/realpath.c
@@ -48,190 +48,3 @@ do_realpath (const char *path)
return ret; /* caller frees */
}
-
-static int find_path_element (int fd_cwd, int is_end, const char *name, char **name_ret);
-
-char *
-do_case_sensitive_path (const char *path)
-{
- size_t next;
- int fd_cwd, fd2, err, is_end;
- char *ret;
-
- ret = strdup ("/");
- if (ret == NULL) {
- reply_with_perror ("strdup");
- return NULL;
- }
- next = 1; /* next position in 'ret' buffer */
-
- /* 'fd_cwd' here is a surrogate for the current working directory, so
- * that we don't have to actually call chdir(2).
- */
- fd_cwd = open (sysroot, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
- if (fd_cwd == -1) {
- reply_with_perror ("%s", sysroot);
- goto error;
- }
-
- /* First character is a '/'. Take each subsequent path element
- * and follow it.
- */
- while (*path) {
- char *t;
- size_t i, len;
- CLEANUP_FREE char *name_in = NULL, *name_out = NULL;
-
- i = strcspn (path, "/");
- if (i == 0) {
- path++;
- continue;
- }
-
- if ((i == 1 && path[0] == '.') ||
- (i == 2 && path[0] == '.' && path[1] == '.')) {
- reply_with_error ("path contained . or .. elements");
- goto error;
- }
-
- name_in = strndup (path, i);
- if (name_in == NULL) {
- reply_with_perror ("strdup");
- goto error;
- }
-
- /* Skip to next element in path (for the next loop iteration). */
- path += i;
- is_end = *path == 0;
-
- /* Read the current directory looking (case insensitively) for
- * this element of the path. This replaces 'name' with the
- * correct case version.
- */
- if (find_path_element (fd_cwd, is_end, name_in, &name_out) == -1)
- goto error;
- len = strlen (name_out);
-
- /* Add the real name of this path element to the return value. */
- if (next > 1)
- ret[next++] = '/';
-
- t = realloc (ret, next+len+1);
- if (t == NULL) {
- reply_with_perror ("realloc");
- goto error;
- }
- ret = t;
-
- strcpy (&ret[next], name_out);
- next += len;
-
- /* Is it a directory? Try going into it. */
- fd2 = openat (fd_cwd, name_out, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
- err = errno;
- close (fd_cwd);
- fd_cwd = fd2;
- errno = err;
- if (fd_cwd == -1) {
- /* Some errors are OK provided we've reached the end of the path. */
- if (is_end && (errno == ENOTDIR || errno == ENOENT))
- break;
-
- reply_with_perror ("openat: %s", name_out);
- goto error;
- }
- }
-
- if (fd_cwd >= 0)
- close (fd_cwd);
-
- return ret; /* caller frees */
-
- error:
- if (fd_cwd >= 0)
- close (fd_cwd);
- free (ret);
-
- return NULL;
-}
-
-/* 'fd_cwd' is a file descriptor pointing to an open directory.
- * 'name' is the path element to search for. 'is_end' is a flag
- * indicating if this is the last path element.
- *
- * We search the directory looking for a path element that case
- * insensitively matches 'name', returning the actual name in '*name_ret'.
- *
- * If this is successful, return 0. If it fails, reply with an error
- * and return -1.
- */
-static int
-find_path_element (int fd_cwd, int is_end, const char *name, char **name_ret)
-{
- int fd2;
- DIR *dir;
- struct dirent *d;
-
- fd2 = dup_cloexec (fd_cwd); /* because closedir will close it */
- if (fd2 == -1) {
- reply_with_perror ("dup");
- return -1;
- }
- dir = fdopendir (fd2);
- if (dir == NULL) {
- reply_with_perror ("opendir");
- close (fd2);
- return -1;
- }
-
- for (;;) {
- errno = 0;
- d = readdir (dir);
- if (d == NULL)
- break;
- if (STRCASEEQ (d->d_name, name))
- break;
- }
-
- if (d == NULL && errno != 0) {
- reply_with_perror ("readdir");
- closedir (dir);
- return -1;
- }
-
- if (d == NULL && is_end) {
- /* Last path element: return it as-is, assuming that the user will
- * create a new file or directory (RHBZ#840115).
- */
- closedir (dir);
- *name_ret = strdup (name);
- if (*name_ret == NULL) {
- reply_with_perror ("strdup");
- return -1;
- }
- return 0;
- }
-
- if (d == NULL) {
- reply_with_error ("%s: no file or directory found with this name", name);
- closedir (dir);
- return -1;
- }
-
- *name_ret = strdup (d->d_name);
- if (*name_ret == NULL) {
- reply_with_perror ("strdup");
- closedir (dir);
- return -1;
- }
-
- /* NB: closedir frees the structure associated with 'd', so we must
- * do this last.
- */
- if (closedir (dir) == -1) {
- reply_with_perror ("closedir");
- return -1;
- }
-
- return 0;
-}
diff --git a/daemon/realpath.ml b/daemon/realpath.ml
new file mode 100644
index 000000000..cffe86322
--- /dev/null
+++ b/daemon/realpath.ml
@@ -0,0 +1,83 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+open Printf
+
+open Std_utils
+
+(* The infamous case_sensitive_path function, which works around
+ * the bug in ntfs-3g that all paths are case sensitive even though
+ * the underlying filesystem is case insensitive.
+ *)
+let rec case_sensitive_path path =
+ let elems = String.nsplit "/" path in
+
+ (* The caller ensures that the first element of [path] is [/],
+ * and therefore the first element of the split list must be
+ * empty.
+ *)
+ assert (List.length elems > 0);
+ assert (List.hd elems = "");
+ let elems = List.tl elems in
+
+ let sysroot = Sysroot.sysroot () in
+ let chroot = Chroot.create sysroot
+ ~name:(sprintf "case_sensitive_path: %s" path) in
+
+ (* Now we iterate down the tree starting at the sysroot. *)
+ let elems =
+ Chroot.f chroot (
+ fun () ->
+ let rec loop = function
+ | [] -> []
+ | [ "."|".." ] ->
+ failwithf "path contains \".\" or \"..\" elements"
+ | "" :: elems ->
+ (* For compatibility with C implementation, we ignore
+ * "//" in the middle of the path.
+ *)
+ loop elems
+ | [ file ] ->
+ (* If it's the final element, it's allowed to be missing. *)
+ (match find_path_element file with
+ | None -> [ file ] (* return the original *)
+ | Some file -> [ file ]
+ );
+ | elem :: elems ->
+ (match find_path_element elem with
+ | None ->
+ failwithf "%s: not found" elem
+ | Some elem ->
+ (* This will fail intentionally if not a directory. *)
+ Unix.chdir elem;
+ elem :: loop elems
+ )
+ in
+ loop elems
+ ) () in
+
+ (* Reconstruct the case sensitive path. *)
+ "/" ^ String.concat "/" elems
+
+and find_path_element name =
+ let dir = Sys.readdir "." in
+ let dir = Array.to_list dir in
+ let lc_name = String.lowercase_ascii name in
+ let cmp n = String.lowercase_ascii n = lc_name in
+ try Some (List.find cmp dir)
+ with Not_found -> None
diff --git a/daemon/realpath.mli b/daemon/realpath.mli
new file mode 100644
index 000000000..371e619fc
--- /dev/null
+++ b/daemon/realpath.mli
@@ -0,0 +1,19 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+val case_sensitive_path : string -> string
diff --git a/generator/actions_core.ml b/generator/actions_core.ml
index 4bf0c7b70..54d0a6ca8 100644
--- a/generator/actions_core.ml
+++ b/generator/actions_core.ml
@@ -4797,6 +4797,7 @@ The result list is not sorted.
{ defaults with
name = "case_sensitive_path"; added = (1, 0, 75);
style = RString (RPlainString, "rpath"), [String (Pathname, "path")], [];
+ impl = OCaml "Realpath.case_sensitive_path";
tests = [
InitISOFS, Always, TestResultString (
[["case_sensitive_path"; "/DIRECTORY"]], "/directory"), [];
--
2.13.0
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