utils-std

commit: 5b886a7ee7e64856e30b69332f63773703cdf768
parent 3d699fc33f744ab5ef71b3f1b0730338aeee5064
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Mon,  1 Apr 2024 10:50:41 +0200

cmd/cat.c: Use getopt instead of hacks

Diffstat:
M
cmd/cat.c
54
+++++++++++++++++++++++++++++++++++++-----------------
M
test-cmd/cat
2
+-

2 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/cmd/cat.c b/cmd/cat.c
@@ -3,14 +3,15 @@
 // SPDX-License-Identifier: MPL-2.0
 
 #define _POSIX_C_SOURCE 200809L
-#define _GNU_SOURCE /* splice(2) */
+#define _GNU_SOURCE // splice
 #include <assert.h>
 #include <errno.h>
-#include <fcntl.h>  /* open(), O_RDONLY, splice(2) */
-#include <stdint.h> /* SIZE_MAX */
-#include <stdio.h>  /* fprintf(), BUFSIZ */
-#include <string.h> /* strerror(), strncmp() */
-#include <unistd.h> /* read(), write(), close() */
+#include <fcntl.h>  // open, O_RDONLY, splice
+#include <stdint.h> // SIZE_MAX
+#include <stdio.h>  // fprintf, BUFSIZ
+#include <stdlib.h> // abort
+#include <string.h> // strerror, strncmp
+#include <unistd.h> // read, write, close, getopt
 
 static int
 concat(int fd, const char *fdname)
@@ -75,22 +76,45 @@ again:
 #define fd_copy concat
 #endif // HAS_SPLICE
 
+static void
+usage()
+{
+	fprintf(stderr, "Usage: cat [-u] [files ...]\n");
+}
+
 int
 main(int argc, char *argv[])
 {
-	if(argc <= 1)
+	int c = -1;
+	while((c = getopt(argc, argv, ":u")) != -1)
 	{
-		return fd_copy(0, "<stdin>");
+		switch(c)
+		{
+		case 'u':
+			// POSIX: Ignored, buffered streams aren't used
+			break;
+		case ':':
+			fprintf(stderr, "cat: Error: Missing operand for option: '-%c'\n", optopt);
+			usage();
+			return 1;
+		case '?':
+			fprintf(stderr, "cat: Error: Unrecognised option: '-%c'\n", optopt);
+			usage();
+			return 1;
+		default:
+			abort();
+		}
 	}
 
-	// For POSIX compatibility
-	if(strncmp(argv[1], "-u", 3) == 0)
+	argc -= optind;
+	argv += optind;
+
+	if(argc < 1)
 	{
-		argc--;
-		argv++;
+		return fd_copy(0, "<stdin>");
 	}
 
-	for(int argi = 1; argi < argc; argi++)
+	for(int argi = 0; argi < argc; argi++)
 	{
 		if(strncmp(argv[argi], "-", 2) == 0)
 		{
@@ -99,10 +123,6 @@ main(int argc, char *argv[])
 				return 1;
 			}
 		}
-		else if(strncmp(argv[argi], "--", 3) == 0)
-		{
-			continue;
-		}
 		else
 		{
 			assert(errno == 0);
diff --git a/test-cmd/cat b/test-cmd/cat
@@ -61,7 +61,7 @@ atf_test_case doubledash
 doubledash_body() {
 	atf_check -o file:inputs/all_bytes -- ../cmd/cat -- inputs/all_bytes
 	# shellcheck disable=SC1112
-	atf_check -s exit:1 -e 'inline:cat: Error opening ‘---’: No such file or directory\n' -o empty -- ../cmd/cat --- inputs/all_bytes
+	atf_check -s exit:1 -e "inline:cat: Error: Unrecognised option: '--'\nUsage: cat [-u] [files ...]\n" -o empty -- ../cmd/cat --- inputs/all_bytes
 }
 
 atf_init_test_cases() {