microcom: tiny shrink, adding comments

1 files changed, 8 insertions, 7 deletions

diff --git a/miscutils/microcom.c b/miscutils/microcom.c
index ea48291ae..3c573eaa9 100644
--- a/miscutils/microcom.c
+++ b/miscutils/microcom.c
@@ -51,18 +51,17 @@ int microcom_main(int argc, char **argv)
         enum {
                 OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@
                 OPT_s = 1 << 1, // baudrate
-                OPT_d = 1 << 2, // wait for device response, msecs
+                OPT_d = 1 << 2, // wait for device response, ms
                 OPT_t = 1 << 3, // timeout, ms
         };
         speed_t speed = 9600;
         int delay = -1;
         int timeout = -1;
+        unsigned opts;
 
         // fetch options
-        unsigned opts;
-        opt_complementary = "=1:s+:d+:t+"; // exactly one arg should be there
+        opt_complementary = "=1:s+:d+:t+"; // exactly one arg, numeric options
         opts = getopt32(argv, "Xs:d:t:", &speed, &delay, &timeout);
-
 //      argc -= optind;
         argv += optind;
 
@@ -71,14 +70,16 @@ int microcom_main(int argc, char **argv)
         device_lock_file = xasprintf("/var/lock/LCK..%s", device_lock_file);
         sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
         if (sfd < 0) {
+                // device already locked -> bail out
                 if (errno == EEXIST)
                         bb_perror_msg_and_die("can't create %s", device_lock_file);
+                // can't create lock -> don't care
                 if (ENABLE_FEATURE_CLEAN_UP)
                         free(device_lock_file);
                 device_lock_file = NULL;
-        }
-        if (sfd > 0) {
-                // %4d to make mgetty happy. It treats 4-bytes lock files as binary,
+        } else {
+                // %4d to make concurrent mgetty (if any) happy.
+                // Mgetty treats 4-bytes lock files as binary,
                 // not text, PID. Making 5+ char file. Brrr...
                 char *s = xasprintf("%4d\n", getpid());
                 write(sfd, s, strlen(s));