Libguestfs - Feb 2012 - Fix virt-edit so it preserves permissions (RHBZ#788641)

The first patch preserves file mode, UID, GID and SELinux context
across edited files.

The second patch adds a useful new command in guestfish ('llz') which
shows SELinux context (like 'ls -laZ') that was useful when debugging
this.

Rich.

From: "Richard W.M. Jones" <rjones at redhat.com>

---
 edit/virt-edit.c |   82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 82 insertions(+), 0 deletions(-)

diff --git a/edit/virt-edit.c b/edit/virt-edit.c
index baa0b3e..a23e66a 100644
--- a/edit/virt-edit.c
+++ b/edit/virt-edit.c
@@ -55,6 +55,8 @@ static const char *perl_expr = NULL;
 static void edit (const char *filename, const char *root);
 static char *edit_interactively (const char *tmpfile);
 static char *edit_non_interactively (const char *tmpfile);
+static int copy_attributes (const char *src, const char *dest);
+static int feature_available (guestfs_h *g, const char *feature);
 static int is_windows (guestfs_h *g, const char *root);
 static char *windows_path (guestfs_h *g, const char *root, const char
*filename);
 static char *generate_random_name (const char *filename);
@@ -357,6 +359,12 @@ edit (const char *filename, const char *root)
     if (guestfs_upload (g, upload_from, newname) == -1)
       goto error;
 
+    /* Set the permissions, UID, GID and SELinux context of the new
+     * file to match the old file (RHBZ#788641).
+     */
+    if (copy_attributes (filename, newname) == -1)
+      goto error;
+
     /* Backup or overwrite the file. */
     if (backup_extension) {
       backupname = generate_backup_name (filename);
@@ -511,6 +519,80 @@ edit_non_interactively (const char *tmpfile)
 }
 
 static int
+copy_attributes (const char *src, const char *dest)
+{
+  struct guestfs_stat *stat;
+  int has_linuxxattrs;
+  char *selinux_context = NULL;
+  size_t selinux_context_size;
+
+  has_linuxxattrs = feature_available (g, "linuxxattrs");
+
+  /* Get the mode. */
+  stat = guestfs_stat (g, src);
+  if (stat == NULL)
+    return -1;
+
+  /* Get the SELinux context.  XXX Should we copy over other extended
+   * attributes too?
+   */
+  if (has_linuxxattrs) {
+    guestfs_error_handler_cb old_error_cb;
+    void *old_error_data;
+    old_error_cb = guestfs_get_error_handler (g, &old_error_data);
+    guestfs_set_error_handler (g, NULL, NULL);
+
+    selinux_context = guestfs_getxattr (g, src, "security.selinux",
+                                        &selinux_context_size);
+    /* selinux_context could be NULL.  This isn't an error. */
+
+    guestfs_set_error_handler (g, old_error_cb, old_error_data);
+  }
+
+  /* Set the permissions, UID, GID. */
+  if (guestfs_chmod (g, stat->mode & 0777, dest) == -1) {
+    guestfs_free_stat (stat);
+    return -1;
+  }
+  if (guestfs_chown (g, stat->uid, stat->gid, dest) == -1) {
+    guestfs_free_stat (stat);
+    return -1;
+  }
+  guestfs_free_stat (stat);
+
+  /* Set the SELinux context. */
+  if (has_linuxxattrs && selinux_context) {
+    if (guestfs_setxattr (g, "security.selinux", selinux_context,
+                          (int) selinux_context_size, dest) == -1) {
+      free (selinux_context);
+      return -1;
+    }
+  }
+  free (selinux_context);
+
+  return 0;
+}
+
+static int
+feature_available (guestfs_h *g, const char *feature)
+{
+  /* If there's an error we should ignore it, so to do that we have to
+   * temporarily replace the error handler with a null one.
+   */
+  guestfs_error_handler_cb old_error_cb;
+  void *old_error_data;
+  old_error_cb = guestfs_get_error_handler (g, &old_error_data);
+  guestfs_set_error_handler (g, NULL, NULL);
+
+  const char *groups[] = { feature, NULL };
+  int r = guestfs_available (g, (char * const *) groups);
+
+  guestfs_set_error_handler (g, old_error_cb, old_error_data);
+
+  return r == 0 ? 1 : 0;
+}
+
+static int
 is_windows (guestfs_h *g, const char *root)
 {
   char *type;
-- 
1.7.9

From: "Richard W.M. Jones" <rjones at redhat.com>

---
 daemon/ls.c                    |   26 ++++++++++++++++++++++++++
 generator/generator_actions.ml |    9 +++++++++
 src/MAX_PROC_NR                |    2 +-
 3 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/daemon/ls.c b/daemon/ls.c
index d0c7b52..1df0b6a 100644
--- a/daemon/ls.c
+++ b/daemon/ls.c
@@ -102,3 +102,29 @@ do_ll (const char *path)
   free (err);
   return out;			/* caller frees */
 }
+
+char *
+do_llz (const char *path)
+{
+  int r;
+  char *out, *err;
+  char *spath;
+
+  spath = sysroot_path (path);
+  if (!spath) {
+    reply_with_perror ("malloc");
+    return NULL;
+  }
+
+  r = command (&out, &err, "ls", "-laZ", spath,
NULL);
+  free (spath);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    free (out);
+    free (err);
+    return NULL;
+  }
+
+  free (err);
+  return out;			/* caller frees */
+}
diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 3a7be79..f9ba5c3 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -6651,6 +6651,15 @@ This option may not be specified at the same time as the
C<correct> option.
 
 =back");
 
+  ("llz", (RString "listing", [Pathname
"directory"], []), 305, [],
+   [],
+   "list the files in a directory (long format with SELinux
contexts)",
+   "\
+List the files in C<directory> in the format of 'ls -laZ'.
+
+This command is mostly useful for interactive sessions.  It
+is I<not> intended that you try to parse the output string.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 873b744..67d04b9 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-304
+305
-- 
1.7.9