More helpful error messages. Closes #3.

db.c

@@ -970,7 +970,10 @@ void db_read_cfg(const char *filename)
 
 	MD5_Init(&ctx);
 	fh = fopen(filename, "r");
-	assert(fh);
+	if (!fh) {
+		fprintf(stderr, "Failed to open config (%s)\n", filename);
+		exit(1);
+	}
 	while (fgets(buf, sizeof(buf), fh)) {
 		int len = strlen(buf);
 		assert(len && buf[len - 1] == '\n');

mm.c

@@ -293,6 +293,19 @@ static int mm_init_old(void)
 	return 0;
 }
 
+static void assertdir(const char *name)
+{
+	char fn[1024];
+	struct stat sb;
+	int len = snprintf(fn, sizeof(fn), "%s/%s", basedir, name);
+	assert(len < (int)sizeof(fn));
+	int r = stat(fn, &sb);
+	if (r || !S_ISDIR(sb.st_mode)) {
+		fprintf(stderr, "Directory %s doesn't exist\n", fn);
+		exit(1);
+	}
+}
+
 /* Note that this returns 1 for a new cache, not failure as such. */
 int mm_init(void)
 {
@@ -321,7 +334,15 @@ int mm_init(void)
 	len = snprintf(fn, sizeof(fn), "%s/LOCK", basedir);
 	assert(len < (int)sizeof(fn));
 	mm_lock_fd = open(fn, O_RDWR | O_CREAT | O_EXLOCK, 0600);
-	assert(mm_lock_fd != -1);
+	if (mm_lock_fd == -1) {
+		char buf[len + 28];
+		snprintf(buf, sizeof(buf), "Failed to open lockfile (%s)", fn);
+		perror(buf);
+		exit(1);
+	}
+	assertdir("dump");
+	assertdir("log");
+	assertdir("mm_cache");
 	len = read(mm_lock_fd, &clean, 1);
 	if (len != 1) clean = 'U';
 	pos = lseek(mm_lock_fd, 0, SEEK_SET);

server.c

@@ -104,12 +104,15 @@ int main(int argc, char **argv)
 	logconn->flags = CONNFLAG_LOG;
 	logconn->trans.conn = logconn;
 
-	assert(argc == 2);
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s configfile\n", argv[0]);
+		return 1;
+	}
 	db_read_cfg(argv[1]);
 	printf("initing mm..\n");
 	if (mm_init()) populate_from_dump();
 	if (!*logdumpindex && blacklisted_guid()) {
-		printf("Don't use the example GUID\n");
+		fprintf(stderr, "Don't use the example GUID\n");
 		return 1;
 	}
 	mm_print();