spool: support jobs with more than one file

We could do this already, by piping from cat. But this way is cleaner.

spool/spool.c

@@ -22,36 +22,11 @@
 #define BUF_SIZE	8192
 
 
-static void usage(const char *name)
+static void spool_file(FILE *file)
 {
-	fprintf(stderr, "usage: %s [file]\n", name);
-	exit(1);
-}
-
-
-int main(int argc, const char **argv)
-{
-	FILE *file;
 	char buf[BUF_SIZE+1];
 	size_t n;
-	char *port;
 
-	switch (argc) {
-	case 1:
-		file = stdin;
-		break;
-	case 2:
-		file = fopen(argv[1], "r");
-		if (!file) {
-			perror(argv[1]);
-			exit(1);
-		}
-		break;
-	default:
-		usage(*argv);
-	}
-	port = getenv("PORT");
-	serial_open(port ? port : DEFAULT_PORT);
 	while (1) {
 		n = fread(buf, 1, BUF_SIZE, file);
 		if (!n)
@@ -59,6 +34,51 @@ int main(int argc, const char **argv)
 		buf[n] = 0;
 		serial_printf("%s", buf);
 	}
+}
+
+
+static void usage(const char *name)
+{
+	fprintf(stderr, "usage: %s [file ...]\n", name);
+	exit(1);
+}
+
+
+int main(int argc, const char **argv)
+{
+	FILE **files;
+	char *port;
+	int n_files, i;
+
+	/*
+	 * Open all files before starting to spool, so that we don't risk
+	 * failing in the middle of the job.
+	 */
+	n_files = argc == 1 ? 1 : argc-1;
+	files = malloc(sizeof(FILE *));
+	if (!files) {
+		perror("malloc");
+		exit(1);
+	}
+
+	if (argc == 1) {
+		*files = stdin;
+	} else {
+		if (*argv[1] == '-')
+			usage(*argv);
+		for (i = 0; i != n_files; i++) {
+			files[i] = fopen(argv[i+1], "r");
+			if (!files[i]) {
+				perror(argv[i+1]);
+				exit(1);
+			}
+		}
+	}
+
+	port = getenv("PORT");
+	serial_open(port ? port : DEFAULT_PORT);
+	for (i = 0; i != n_files; i++)
+		spool_file(files[i]);
 sleep(3600);
 	serial_close();
 	return 0;