Add alternative main() for a simple `cat' program
diff --git a/src/cat.c b/src/cat.c
new file mode 100644
index 0000000..dfe7196
--- /dev/null
+++ b/src/cat.c
@@ -0,0 +1,116 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <getopt.h>
+#include <ctype.h>
+
+#include "blockdev.h"
+#include "vfs.h"
+
+extern void adainit (void);
+extern void adafinal (void);
+
+struct program_options {
+ char *devname;
+};
+
+static int get_options(int argc, char* argv[], struct program_options* opt);
+static void cat(int argc, char *argv[]);
+static void cat_file(const char *path);
+
+int main(int argc, char* argv[])
+{
+ struct program_options opt = { 0, };
+ int ret = -1;
+
+ adainit();
+
+ if (get_options(argc, argv, &opt)) {
+ goto final;
+ }
+
+ if (devopen(opt.devname, NULL) != 1) {
+ goto final;
+ }
+
+ cat(argc - optind, argv + optind);
+
+ devclose();
+ ret = 0;
+
+final:
+ adafinal();
+ return ret;
+}
+
+static void fprint_help(FILE* to, char * pname)
+{
+ fprintf(to, "Usage: %s\n"
+ " -d | --dev <path> \t File to use as block device\n"
+ , pname);
+}
+
+static int get_options(int argc, char* argv[], struct program_options *opt){
+ const struct option long_options[] = {
+ {"dev", required_argument, NULL, 'd'},
+ {NULL, 0, NULL, 0},
+ };
+
+ int c, option_index = 0;
+ while ((c = getopt_long(argc, argv, "d:", long_options, &option_index)) != -1) {
+ switch (c) {
+ case 'd':
+ opt->devname = optarg;
+ break;
+ default:
+ fprint_help(stderr, argv[0]);
+ return -1;
+ }
+ }
+
+ if (argc == 1) {
+ fprintf(stderr, "%s needs arguments.\n", argv[0]);
+ fprint_help(stderr, argv[0]);
+ return -1;
+ }
+
+ if (opt->devname == NULL) {
+ fprintf(stderr, "Argument \"--dev/-d\" missing.\n");
+ return -1;
+ }
+ return 0;
+}
+
+static void cat(int argc, char *argv[])
+{
+ if (!mount_fs(NULL)) {
+ fprintf(stderr, "ERROR: Failed to mount FS.\n");
+ return;
+ }
+
+ for (; argc; --argc, ++argv)
+ cat_file(*argv);
+}
+
+static void cat_file(const char *path)
+{
+ if (!file_open(path)) {
+ fprintf(stderr, "ERROR: Failed to open `%s'.\n", path);
+ return;
+ }
+
+ unsigned char motd[1024];
+ int read;
+
+ do {
+ read = file_read(motd, sizeof(motd));
+ if (read > 0)
+ fwrite(motd, 1, read, stdout);
+ } while (read == sizeof(motd));
+ fflush(stdout);
+ file_close();
+
+ if (read < 0) {
+ fprintf(stderr, "ERROR: Failed to read from `%s'.\n", path);
+ return;
+ }
+}