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authorZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2013-07-14 23:36:14 -0400
committerZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2013-07-14 23:53:45 -0400
commit6c5a28255bea4385289149b4617c86a24eec519f (patch)
treec5a793935691f511c89d0bd32a46f38b1da31075
parentaedc2eddd16e48d468e6ad0aea2caf00c7d37365 (diff)
systemd: fix NULL dereference when disabling a nonexistent instance
Assertion 'p' failed at src/shared/path-util.c:51, function path_get_file_name(). Aborting. The unit file could not be found, and i->path would not be set. In 02b9e969 a code path was added which attempts to remove symlinks to a nonexistent (removed) unit file. This worked OK in case of non-instance services, but broke in the case of instance services. Behaviour wrt. to instance units is changed in the way that 02b9e969 changed it for non-instance units: it is now possible to remove instance symlinks to a template unit that has been removed. This patch isn't a full fix, because the behaviour wrt. to enabling and disabling instance units is still broken: e.g it is possible to start autovt@tty5.service, but it is not possible to enable it, because autovt@.service is a symlink, and on the other hand, disabling getty@tty5.service removes all symlinks to getty@.service, which is wrong too. But segfaults make bad pr, so let's add at least this partial fix for now.
-rw-r--r--src/shared/install.c38
1 files changed, 26 insertions, 12 deletions
diff --git a/src/shared/install.c b/src/shared/install.c
index 116106824f..07e06c425f 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -1062,8 +1062,8 @@ static int unit_file_search(
info->path = path;
else {
if (r == -ENOENT && unit_name_is_instance(info->name)) {
- /* unit file doesn't exist, however instance enablement was request */
- /* we will check if it is possible to load template unit file */
+ /* Unit file doesn't exist, however instance enablement was requested.
+ * We will check if it is possible to load template unit file. */
char *template = NULL,
*template_path = NULL,
*template_dir = NULL;
@@ -1074,7 +1074,7 @@ static int unit_file_search(
return -ENOMEM;
}
- /* we will reuse path variable since we don't need it anymore */
+ /* We will reuse path variable since we don't need it anymore. */
template_dir = path;
*(strrchr(path, '/') + 1) = '\0';
@@ -1085,7 +1085,7 @@ static int unit_file_search(
return -ENOMEM;
}
- /* let's try to load template unit */
+ /* Let's try to load template unit. */
r = unit_file_load(c, info, template_path, allow_symlink);
if (r >= 0) {
info->path = strdup(template_path);
@@ -1425,16 +1425,30 @@ static int install_context_mark_for_removal(
r += q;
if (unit_name_is_instance(i->name)) {
- char *unit_file = NULL;
+ char *unit_file;
+
+ if (i->path) {
+ unit_file = path_get_file_name(i->path);
+
+ if (unit_name_is_instance(unit_file))
+ /* unit file named as instance exists, thus all symlinks
+ * pointing to it will be removed */
+ q = mark_symlink_for_removal(remove_symlinks_to, i->name);
+ else
+ /* does not exist, thus we will mark for removal symlinks
+ * to template unit file */
+ q = mark_symlink_for_removal(remove_symlinks_to, unit_file);
+ } else {
+ /* If i->path is not set, it means that we didn't actually find
+ * the unit file. But we can still remove symlinks to the
+ * nonexistent template. */
+ unit_file = unit_name_template(i->name);
+ if (!unit_file)
+ return log_oom();
- unit_file = path_get_file_name(i->path);
-
- if (unit_name_is_instance(unit_file))
- /* unit file named as instance exists, thus all symlinks pointing to it, will be removed */
- q = mark_symlink_for_removal(remove_symlinks_to, i->name);
- else
- /* does not exist, thus we will mark for removal symlinks to template unit file */
q = mark_symlink_for_removal(remove_symlinks_to, unit_file);
+ free(unit_file);
+ }
} else
q = mark_symlink_for_removal(remove_symlinks_to, i->name);