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authorZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2015-01-08 20:47:25 -0500
committerZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2015-01-11 18:17:33 -0500
commite801700e9acdde60078eb1d41b41b06369b83541 (patch)
tree356c3165b7ad9b5203584ff3e802f539b9873fa0 /src/shared/util.c
parent4968105790c65af58d4ab42bffa2a4bedc0be8ee (diff)
Implement masking and overriding of generators
Sometimes it is necessary to stop a generator from running. Either because of a bug, or for testing, or some other reason. The only way to do that would be to rename or chmod the generator binary, which is inconvenient and does not survive upgrades. Allow masking and overriding generators similarly to units and other configuration files. For the systemd instance, masking would be more common, rather than overriding generators. For the user instances, it may also be useful for users to have generators in $XDG_CONFIG_HOME to augment or override system-wide generators. Directories are searched according to the usual scheme (/usr/lib, /usr/local/lib, /run, /etc), and files with the same name in higher priority directories override files with the same name in lower priority directories. Empty files and links to /dev/null mask a given name. https://bugs.freedesktop.org/show_bug.cgi?id=87230
Diffstat (limited to 'src/shared/util.c')
-rw-r--r--src/shared/util.c122
1 files changed, 76 insertions, 46 deletions
diff --git a/src/shared/util.c b/src/shared/util.c
index 06bd1b9f04..6520e511f0 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -4037,10 +4037,10 @@ bool dirent_is_file_with_suffix(const struct dirent *de, const char *suffix) {
return endswith(de->d_name, suffix);
}
-static int do_execute(const char *directory, usec_t timeout, char *argv[]) {
+static int do_execute(char **directories, usec_t timeout, char *argv[]) {
_cleanup_hashmap_free_free_ Hashmap *pids = NULL;
- _cleanup_closedir_ DIR *d;
- struct dirent *de;
+ _cleanup_set_free_free_ Set *seen = NULL;
+ char **directory;
/* We fork this all off from a child process so that we can
* somewhat cleanly make use of SIGALRM to set a time limit */
@@ -4050,57 +4050,80 @@ static int do_execute(const char *directory, usec_t timeout, char *argv[]) {
assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
- d = opendir(directory);
- if (!d) {
- if (errno == ENOENT)
- return 0;
-
- return log_error_errno(errno, "Failed to open directory %s: %m", directory);
- }
-
pids = hashmap_new(NULL);
if (!pids)
return log_oom();
- FOREACH_DIRENT(de, d, break) {
- _cleanup_free_ char *path = NULL;
- pid_t pid;
- int r;
+ seen = set_new(&string_hash_ops);
+ if (!seen)
+ return log_oom();
- if (!dirent_is_file(de))
- continue;
+ STRV_FOREACH(directory, directories) {
+ _cleanup_closedir_ DIR *d;
+ struct dirent *de;
- path = strjoin(directory, "/", de->d_name, NULL);
- if (!path)
- return log_oom();
+ d = opendir(*directory);
+ if (!d) {
+ if (errno == ENOENT)
+ continue;
- pid = fork();
- if (pid < 0) {
- log_error_errno(errno, "Failed to fork: %m");
- continue;
- } else if (pid == 0) {
- char *_argv[2];
+ return log_error_errno(errno, "Failed to open directory %s: %m", *directory);
+ }
- assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
+ FOREACH_DIRENT(de, d, break) {
+ _cleanup_free_ char *path = NULL;
+ pid_t pid;
+ int r;
- if (!argv) {
- _argv[0] = path;
- _argv[1] = NULL;
- argv = _argv;
+ if (!dirent_is_file(de))
+ continue;
+
+ if (set_contains(seen, de->d_name)) {
+ log_debug("%1$s/%2$s skipped (%2$s was already seen).", *directory, de->d_name);
+ continue;
+ }
+
+ r = set_put_strdup(seen, de->d_name);
+ if (r < 0)
+ return log_oom();
+
+ path = strjoin(*directory, "/", de->d_name, NULL);
+ if (!path)
+ return log_oom();
+
+ if (null_or_empty_path(path)) {
+ log_debug("%s is empty (a mask).", path);
+ continue;
} else
- argv[0] = path;
+ log_debug("%s will be executed.", path);
- execv(path, argv);
- return log_error_errno(errno, "Failed to execute %s: %m", path);
- }
+ pid = fork();
+ if (pid < 0) {
+ log_error_errno(errno, "Failed to fork: %m");
+ continue;
+ } else if (pid == 0) {
+ char *_argv[2];
- log_debug("Spawned %s as " PID_FMT ".", path, pid);
+ assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
- r = hashmap_put(pids, UINT_TO_PTR(pid), path);
- if (r < 0)
- return log_oom();
+ if (!argv) {
+ _argv[0] = path;
+ _argv[1] = NULL;
+ argv = _argv;
+ } else
+ argv[0] = path;
+
+ execv(path, argv);
+ return log_error_errno(errno, "Failed to execute %s: %m", path);
+ }
+
+ log_debug("Spawned %s as " PID_FMT ".", path, pid);
- path = NULL;
+ r = hashmap_put(pids, UINT_TO_PTR(pid), path);
+ if (r < 0)
+ return log_oom();
+ path = NULL;
+ }
}
/* Abort execution of this process after the timout. We simply
@@ -4126,14 +4149,21 @@ static int do_execute(const char *directory, usec_t timeout, char *argv[]) {
return 0;
}
-void execute_directory(const char *directory, usec_t timeout, char *argv[]) {
+void execute_directories(const char* const* directories, usec_t timeout, char *argv[]) {
pid_t executor_pid;
int r;
+ char *name;
+ char **dirs = (char**) directories;
+
+ assert(!strv_isempty(dirs));
- assert(directory);
+ name = basename(dirs[0]);
+ assert(!isempty(name));
- /* Executes all binaries in the directory in parallel and waits
- * for them to finish. Optionally a timeout is applied. */
+ /* Executes all binaries in the directories in parallel and waits
+ * for them to finish. Optionally a timeout is applied. If a file
+ * with the same name exists in more than one directory, the
+ * earliest one wins. */
executor_pid = fork();
if (executor_pid < 0) {
@@ -4141,11 +4171,11 @@ void execute_directory(const char *directory, usec_t timeout, char *argv[]) {
return;
} else if (executor_pid == 0) {
- r = do_execute(directory, timeout, argv);
+ r = do_execute(dirs, timeout, argv);
_exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
}
- wait_for_terminate_and_warn(directory, executor_pid, true);
+ wait_for_terminate_and_warn(name, executor_pid, true);
}
int kill_and_sigcont(pid_t pid, int sig) {