binfmt,tmpfiles,modules-load,sysctl: rework the various early-boot services that work on .d/ directories

This unifies much of the logic behind them:

- All four will now ofllow the rule that the earlier file and earlier
  assignment in the .d/ directories wins. Before, sysctl was the only
  outlier, where the later setting always won.

- All four now support getopt() and --help on the command line.

- All four can now handle specification of configuration file names on
  the command line to apply. The tools will automatically find them, and
  apply them. Previously only tmpfiles could do that. This is useful for
  %post scripts in RPMs and suchlike.

- This fixes various error path issues in conf_files_list()

1 files changed, 124 insertions, 57 deletions

diff --git a/src/modules-load/modules-load.c b/src/modules-load/modules-load.c
index 936aaed8e..88b126149 100644
--- a/src/modules-load/modules-load.c
+++ b/src/modules-load/modules-load.c
@@ -26,6 +26,7 @@
 #include <sys/stat.h>
 #include <limits.h>
 #include <dirent.h>
+#include <getopt.h>
 #include <libkmod.h>
 
 #include "log.h"
@@ -36,6 +37,16 @@
 
 static char **arg_proc_cmdline_modules = NULL;
 
+static const char conf_file_dirs[] =
+        "/etc/modules-load.d\0"
+        "/run/modules-load.d\0"
+        "/usr/local/lib/modules-load.d\0"
+        "/usr/lib/modules-load.d\0"
+#ifdef HAVE_SPLIT_USR
+        "/lib/modules-load.d\0"
+#endif
+        ;
+
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 static void systemd_kmod_log(void *data, int priority, const char *file, int line,
@@ -46,14 +57,14 @@ static void systemd_kmod_log(void *data, int priority, const char *file, int lin
 #pragma GCC diagnostic pop
 
 static int add_modules(const char *p) {
-        char **t, **k;
+        char **t;
+        _cleanup_strv_free_ char **k = NULL;
 
         k = strv_split(p, ",");
         if (!k)
                 return log_oom();
 
         t = strv_merge(arg_proc_cmdline_modules, k);
-        strv_free(k);
         if (!t)
                 return log_oom();
 
@@ -162,15 +173,98 @@ static int load_module(struct kmod_ctx *ctx, const char *m) {
         return r;
 }
 
+static int apply_file(struct kmod_ctx *ctx, const char *path, bool ignore_enoent) {
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(ctx);
+        assert(path);
+
+        r = search_and_fopen_nulstr(path, "re", conf_file_dirs, &f);
+        if (r < 0) {
+                if (ignore_enoent && r == -ENOENT)
+                        return 0;
+
+                log_error("Failed to open %s, ignoring: %s", path, strerror(-r));
+                return r;
+        }
+
+        log_debug("apply: %s\n", path);
+        for (;;) {
+                char line[LINE_MAX], *l;
+                int k;
+
+                if (!fgets(line, sizeof(line), f)) {
+                        if (feof(f))
+                                break;
+
+                        log_error("Failed to read file '%s', ignoring: %m", path);
+                        return -errno;
+                }
+
+                l = strstrip(line);
+                if (!*l)
+                        continue;
+                if (strchr(COMMENTS, *l))
+                        continue;
+
+                k = load_module(ctx, l);
+                if (k < 0 && r == 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int help(void) {
+
+        printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
+               "Loads statically configured kernel modules.\n\n"
+               "  -h --help             Show this help\n",
+               program_invocation_short_name);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        static const struct option options[] = {
+                { "help",      no_argument,       NULL, 'h'           },
+                { NULL,        0,                 NULL, 0             }
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
+
+                switch (c) {
+
+                case 'h':
+                        help();
+                        return 0;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        log_error("Unknown option code %c", c);
+                        return -EINVAL;
+                }
+        }
+
+        return 1;
+}
+
 int main(int argc, char *argv[]) {
-        int r = EXIT_FAILURE, k;
-        char **files = NULL, **fn, **i;
+        int r, k;
         struct kmod_ctx *ctx;
 
-        if (argc > 1) {
-                log_error("This program takes no argument.");
-                return EXIT_FAILURE;
-        }
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 
         log_set_target(LOG_TARGET_AUTO);
         log_parse_environment();
@@ -190,70 +284,43 @@ int main(int argc, char *argv[]) {
         kmod_load_resources(ctx);
         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 
-        r = EXIT_SUCCESS;
+        r = 0;
 
-        STRV_FOREACH(i, arg_proc_cmdline_modules) {
-                k = load_module(ctx, *i);
-                if (k < 0)
-                        r = EXIT_FAILURE;
-        }
-
-        k = conf_files_list(&files, ".conf", NULL,
-                            "/etc/modules-load.d",
-                            "/run/modules-load.d",
-                            "/usr/local/lib/modules-load.d",
-                            "/usr/lib/modules-load.d",
-#ifdef HAVE_SPLIT_USR
-                            "/lib/modules-load.d",
-#endif
-                            NULL);
-        if (k < 0) {
-                log_error("Failed to enumerate modules-load.d files: %s", strerror(-k));
-                r = EXIT_FAILURE;
-                goto finish;
-        }
-
-        STRV_FOREACH(fn, files) {
-                FILE *f;
+        if (argc > optind) {
+                int i;
 
-                f = fopen(*fn, "re");
-                if (!f) {
-                        if (errno == ENOENT)
-                                continue;
-
-                        log_error("Failed to open %s: %m", *fn);
-                        r = EXIT_FAILURE;
-                        continue;
+                for (i = optind; i < argc; i++) {
+                        k = apply_file(ctx, argv[i], false);
+                        if (k < 0 && r == 0)
+                                r = k;
                 }
 
-                log_debug("apply: %s\n", *fn);
-                for (;;) {
-                        char line[LINE_MAX], *l;
-
-                        if (!fgets(line, sizeof(line), f))
-                                break;
+        } else {
+                _cleanup_free_ char **files = NULL;
+                char **fn, **i;
 
-                        l = strstrip(line);
-                        if (*l == '#' || *l == 0)
-                                continue;
-
-                        k = load_module(ctx, l);
+                STRV_FOREACH(i, arg_proc_cmdline_modules) {
+                        k = load_module(ctx, *i);
                         if (k < 0)
                                 r = EXIT_FAILURE;
                 }
 
-                if (ferror(f)) {
-                        log_error("Failed to read from file: %m");
-                        r = EXIT_FAILURE;
+                r = conf_files_list_nulstr(&files, ".conf", NULL, conf_file_dirs);
+                if (r < 0) {
+                        log_error("Failed to enumerate modules-load.d files: %s", strerror(-r));
+                        goto finish;
                 }
 
-                fclose(f);
+                STRV_FOREACH(fn, files) {
+                        k = apply_file(ctx, *fn, true);
+                        if (k < 0 && r == 0)
+                                r = k;
+                }
         }
 
 finish:
-        strv_free(files);
         kmod_unref(ctx);
         strv_free(arg_proc_cmdline_modules);
 
-        return r;
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }