From: Ben Harris <bjh21@bjh21.me.uk>
Date: Sun, 31 Jan 2021 11:34:16 +0000 (+0000)
Subject: Add a usage message and trap various usage errors
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~bjharris/git?a=commitdiff_plain;h=6d3d8c42022bede059e0e031f97cdee02070a141;p=clunk.git

Add a usage message and trap various usage errors
---

diff --git a/clunk.c b/clunk.c
index 1616dbd..1bd3ecd 100644
--- a/clunk.c
+++ b/clunk.c
@@ -208,7 +208,8 @@ init_statefile(char const *statefilename)
 
 #ifdef WITH_LIBGPIOD
 static void
-init_libgpiod(char const *chip_name, char const *line_name, int line_num)
+init_libgpiod(char const *chip_name, char const *line_name,
+	      unsigned int line_num)
 {
 	struct gpiod_chip * chip;
 
@@ -247,6 +248,14 @@ init_sysfs(char const *path)
 	outfn = &sysfs_out;
 }
 
+static void
+usage()
+{
+
+	fprintf(stderr, "usage!\n");
+	exit(2);
+}
+
 static void
 init(int argc, char **argv)
 {
@@ -258,7 +267,9 @@ init(int argc, char **argv)
 	char *statefile = NULL, *statestr = NULL;
 #ifdef WITH_LIBGPIOD
 	char *gpiod_chip = NULL, *gpiod_line_name = NULL;
-	int gpiod_line_num = -1;
+	unsigned int gpiod_line_num;
+	char *endptr;
+	bool have_gpiod_line_num = false;
 #endif
 	int opt;
 
@@ -290,18 +301,35 @@ init(int argc, char **argv)
 			break;
 #ifdef WITH_LIBGPIOD
 		case 'G':
+			if (gpiod_line_name != NULL)
+				usage();
 			gpiod_line_name = optarg;
 			break;
 		case 'C':
+			if (gpiod_chip != NULL)
+				usage();
 			gpiod_chip = optarg;
 			break;
 		case 'L':
-			gpiod_line_num = atoi(optarg);
+			if (have_gpiod_line_num)
+				usage();
+			errno = 0;
+			gpiod_line_num = strtoul(optarg, &endptr, 0);
+			if (errno != 0) {
+				warn(NULL);
+				usage();
+			}
+			if (*endptr != '\0' || *optarg == '\0')
+				usage();
+			have_gpiod_line_num = true;
 			break;
 #endif /* WITH_LIBGPIOD */
 		case 'Y':
 			init_sysfs(optarg);
 			break;
+		case '?':
+			usage();
+			break;
 		}
 	}
 	/* Default startup state is to assume the dial is correct. */