headpats

cat/Makefile

@@ -1,7 +1,2 @@
 cat: cat.c
 	$(CC) -g -o cat cat.c
-
-clean:
-	rm -f cat
-
-.PHONY: clean

cat/cat.c

@@ -2,34 +2,31 @@
                     * ENOENT, ENOMEM, ENOTDIR, EOVERFLOW */
 #include <stdio.h> /* fprintf(3), getc(3), putc(3), setvbuf(3), stderr, stdin,
                     * stdout */
+#include <string.h> /* strerror(3) */
 #include <sysexits.h> /* EX_DATAERR, EX_NOINPUT, EX_OK, EX_OSERR,
                        * EX_UNAVAILABLE, EX_USAGE */
 #include <unistd.h> /* getopt(3) */
 #include <sys/stat.h> /* stat(2), struct stat, S_ISDIR */
 
+static char *program_name = "cat";
+
 /* NetBSD's default size according to an strace */
 static unsigned char buf[4096];
-static char *default_argv[] = {
-	"cat",
-	"-",
-	(char *)NULL
-};
-static char *stdin_name = "/dev/stdin";
 
 int main(int argc, char *argv[]){
 	char *argv0;
 	int c;
-	extern int errno;
 	struct stat fi; /* info */
 	char *fn; /* name */
 	FILE *fo; /* object */
 
-	setvbuf(stdout, buf, _IOFBF, (sizeof buf)/(sizeof *buf));
+	setvbuf(stdout, (char *)buf, _IOFBF, (sizeof buf)/(sizeof *buf));
 	if(argc < 2){
-		argc = 2;
-		if(argc > 0)
-			default_argv[0] = argv[0];
-		argv = default_argv;
+		argv0 = argc > 0
+			? argv[0]
+			: program_name;
+		argv -= argv[0] == NULL;
+		goto simple;
 	}
 
 	while((c = getopt(argc, argv, "hu")) != -1)
@@ -37,52 +34,42 @@ int main(int argc, char *argv[]){
 			case 'u':
 				setvbuf(stdout, NULL, _IONBF, 0);
 				continue;
-			case 'h': default: usage:
+			default:
 				fprintf(stderr, "Usage: %s (-h) (file...)\n",
 					argv[0]);
 				return EX_USAGE;
 		}
+
 	argv0 = argv[0];
-	argc -= optind;
 	argv += optind;
 
-	while(argc --> 0){
-		if(argv[0][0] == '-' && argv[0][1] == '\0'){ /* "-" */
-			fn = stdin_name;
-			fo = stdin;
-		}else{
+	while(*argv != NULL){
+		if(argv[0][0] == '-' && argv[0][1] == '\0') /* "-" */
+simple:			fo = stdin;
+		else{
 			fn = argv[0];
 			if(stat(fn, &fi) == -1){
+				fprintf(stderr, "%s: %s: %s\n", argv0, fn,
+					strerror(errno));
 				switch(errno){
 				case EFAULT: case ENOENT: case ENOTDIR:
-					fprintf(stderr,
-						"%s: %s: Unable to open file."
-						"  Does it exist?\n",
-						argv[0], fn);
 					return EX_NOINPUT;
 				case EBADF: case EINVAL: case ENOMEM:
 				case EOVERFLOW:
-					fprintf(stderr,
-						"%s: %s: System error"
-						" (errno=%d),\n",
-						argv[0], fn, errno);
 					return EX_OSERR;
 				case ELOOP: case ENAMETOOLONG:
-					fprintf(stderr,
-						"%s: %s: Unable to open file.",
-						argv[0], fn);
 					return EX_DATAERR;
 				}
 			}
 			if(S_ISDIR(fi.st_mode)){
-				fprintf(stderr, "%s: %s: Is a directory.\n",
+				fprintf(stderr, "%s: %s: Is a directory\n",
 					argv[0], fn);
 				return EX_DATAERR;
 			}
 			if((fo = fopen(fn, "r")) == NULL){
 				fprintf(stderr,
-					"%s: %s: Error opening file.\n",
-					argv[0], fn);
+					"%s: %s: %s\n",
+					argv0, fn, strerror(errno));
 				return EX_OSERR;
 			}
 		}
@@ -92,13 +79,15 @@ int main(int argc, char *argv[]){
 				fprintf(stderr,
 					"%s: Exiting due to error writing to"
 					" output...\n",
-					argv[0]);
+					argv0);
 				fclose(fo);
 				return EX_UNAVAILABLE;
 			}
 
 		if(fo != stdin)
 			fclose(fo);
+
+		++argv;
 	}
 
 	return EX_OK;