flash_{un,}lock: abstract the argument positions

Previously, there were no options (besides stand-alone --help and
--version), so we just used fixed-position argv indexes. Let's change
that.

Also clean up the sanity checks a bit to make them more verbose and
specific.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/flash_unlock.c b/flash_unlock.c
index 27e7df1eac3fc4630e7629f7ca2e42b333ffa22f..ce72e49d4ba6912437822fa9847ed124bfba8381 100644 (file)
--- a/flash_unlock.c
+++ b/flash_unlock.c
@@ -54,7 +54,8 @@ int main(int argc, char *argv[])
        struct mtd_info_user mtdInfo;
        struct erase_info_user mtdLockInfo;
        int count;
-       const char *dev;
+       const char *dev, *offs_s, *count_s;
+       int arg_idx;
 
        for (;;) {
                int c;
@@ -76,11 +77,31 @@ int main(int argc, char *argv[])
                }
        }
 
-       /* Parse command line options */
-       if (argc < 2 || argc > 4)
+       arg_idx = optind;
+
+       /* Sanity checks */
+       if (argc - arg_idx < 1) {
+               errmsg("too few arguments");
+               usage(1);
+       } else if (argc - arg_idx > 3) {
+               errmsg("too many arguments");
                usage(1);
+       }
+
+       /* First non-option argument */
+       dev = argv[arg_idx++];
 
-       dev = argv[1];
+       /* Second non-option argument */
+       if (arg_idx < argc)
+               offs_s = argv[arg_idx++];
+       else
+               offs_s = NULL;
+
+       /* Third non-option argument */
+       if (arg_idx < argc)
+               count_s = argv[arg_idx++];
+       else
+               count_s = NULL;
 
        /* Get the device info to compare to command line sizes */
        fd = open(dev, O_RDWR);
@@ -91,16 +112,16 @@ int main(int argc, char *argv[])
                sys_errmsg_die("could not get mtd info: %s", dev);
 
        /* Make sure user options are valid */
-       if (argc > 2)
-               mtdLockInfo.start = strtol(argv[2], NULL, 0);
+       if (offs_s)
+               mtdLockInfo.start = strtol(offs_s, NULL, 0);
        else
                mtdLockInfo.start = 0;
        if (mtdLockInfo.start > mtdInfo.size)
                errmsg_die("%#x is beyond device size %#x",
                        mtdLockInfo.start, mtdInfo.size);
 
-       if (argc > 3) {
-               count = strtol(argv[3], NULL, 0);
+       if (count_s) {
+               count = strtol(count_s, NULL, 0);
                if (count == -1)
                        mtdLockInfo.length = mtdInfo.size;
                else