dj(1), mm(1), npc(1), scrut(1), str(1): consistent argv[0] handling

src/dj.c

@@ -30,7 +30,7 @@
 
 extern int errno;
 
-char *program_name = "dj";
+static char *program_name = "dj";
 
 /* dj uses two structures that respectively correspond to the reading and
  * writing ends of its jockeyed "pipe". User-configurable members are noted
@@ -150,7 +150,7 @@ usage(char *s) {
 	fprintf(
 		stderr, "Usage: %s [-Hn] [-a byte] [-c count]\n"
 		"\t[-i file] [-b block_size] [-s offset]\n"
-		"\t[-o file] [-B block_size] [-S offset]\n", program_name
+		"\t[-o file] [-B block_size] [-S offset]\n", s
 	);
 
 	return EX_USAGE;
@@ -163,6 +163,7 @@ int main(int argc, char *argv[]) {
 	size_t i;     /* side of io being modified */
 	char noerror; /* 0=exits (default) 1=retries on partial reads or writes */
 	struct Io io[2 /* { in, out } */];
+	char *s = (argv[0] == NULL ? program_name : argv[0]);
 
 	/* Set defaults. */
 	align = -1;
@@ -233,7 +234,7 @@ int main(int argc, char *argv[]) {
 
 					/* FALLTHROUGH */
 				default:
-					return usage(program_name);
+					return usage(s);
 			}
 		}
 	}
@@ -241,7 +242,7 @@ int main(int argc, char *argv[]) {
 	assert(io->fd != STDIN_FILENO  || io->fl == read_flags);
 	assert(io->fd != STDOUT_FILENO || io->fl == write_flags);
 
-	if (argc > optind) { return usage(program_name); }
+	if (argc > optind) { return usage(s); }
 
 	for (i = 0; i < (sizeof io) / (sizeof *io); ++i) {
 		/* buffer allocation */

src/mm.c

@@ -48,7 +48,7 @@ struct Files{
 #endif
 
 /* pre-allocated strings */
-static char *program_name = "<no argv[0]>";
+static char *program_name = "mm";
 static char *stdin_name = "<stdin>";
 static char *stdout_name = "<stdout>";
 static char *stderr_name = "<stderr>";
@@ -125,6 +125,7 @@ int main(int argc, char *argv[]) {
 	size_t j;
 	size_t k; /* loop index but also unbuffer status */
 	int retval;
+	char *s = argv[0] == NULL ? program_name : argv[0];
 
 	/* Initializes the files structs with their default values, standard
 	 * input and standard output. If an input or an output is specified
@@ -149,7 +150,7 @@ int main(int argc, char *argv[]) {
 
 	k = 0;
 
-	if (argc > 0) { program_name = argv[0]; }
+	if (argc > 0) { program_name = s; }
 
 	if (argc > 1) {
 		while ((c = getopt(argc, argv, "aehi:no:u")) != -1) {
@@ -163,7 +164,7 @@ int main(int argc, char *argv[]) {
 						break;
 					}
 
-					retval = oserr(argv[0], "-e");
+					retval = oserr(s, "-e");
 					terminate;
 				case 'i':
 					if (
@@ -172,7 +173,7 @@ int main(int argc, char *argv[]) {
 						|| Files_open(&files[0], optarg) != NULL
 					) { break; }
 
-					retval = oserr(argv[0], optarg);
+					retval = oserr(s, optarg);
 					terminate;
 				case 'o':
 					if (
@@ -190,25 +191,25 @@ int main(int argc, char *argv[]) {
 						}
 					}
 
-					retval = oserr(argv[0], optarg);
+					retval = oserr(s, optarg);
 					terminate;
 				case 'n':
 					if (signal(SIGINT, SIG_IGN) != SIG_ERR) { break; }
 
-					retval = oserr(argv[0], "-n");
+					retval = oserr(s, "-n");
 					terminate;
 				case 'u':
 					k = 1;
 					break;
 				default:
-					retval = usage(argv[0]);
+					retval = usage(s);
 					terminate;
 			}
 		}
 	}
 
 	if (optind != argc) {
-		retval = usage(argv[0]);
+		retval = usage(s);
 		terminate;
 	}
 

src/npc.c

@@ -23,6 +23,8 @@
 #include <unistd.h> /* getopt(3) */
 #include <sysexits.h> /* EX_OK, EX_USAGE */
 
+static char *program_name = "dj";
+
 int usage(char *s) {
 	fprintf(stderr, "Usage: %s [-et]\n", s);
 	return EX_USAGE;
@@ -32,18 +34,19 @@ int main(int argc, char *argv[]) {
 	int c;
 	char showend = 0; /* print a dollar sign before each newline */
 	char showtab = 0; /* prints tab characters in caret notation */
+	char *s = (argv[0] == NULL ? program_name : argv[0]);
 
 	if (argc > 0) {
 		while ((c = getopt(argc, argv, "et")) != -1) {
 			switch (c){
 				case 'e': showend = 1; break;
 				case 't': showtab = 1; break;
-				default:  return usage(argv[0]);
+				default:  return usage(s);
 			}
 		}
 	}
 
-	if (argc > optind) { return usage(argv[0]); }
+	if (argc > optind) { return usage(s); }
 
 	while ((c = getc(stdin)) != EOF) {
 		if ((c & 0x80) != 0) { fputs("M-", stdout); }

src/scrut.c

@@ -26,7 +26,7 @@
                        * S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
                        * S_ISUID, S_ISVTX */
 
-char *program_name = "scrut";
+static char *program_name = "scrut";
 static char args[] = "bcdefgkprsuwxLS";
 
 int usage(char *s) {
@@ -36,15 +36,16 @@ int usage(char *s) {
 
 int main(int argc, char *argv[]) {
 	char sel[(sizeof args) / (sizeof *args)];
+	char *s = (argv[0] == NULL ? program_name : argv[0]);
 
-	if (argc < 2) { return usage(argv[0] == NULL ? program_name : argv[0]); }
+	if (argc < 2) { return usage(s); }
 
 	{ /* option parsing */
 		char *p;
 
 		memset(sel, '\0', sizeof sel);
 		for (int c; (c = getopt(argc, argv, args)) != -1;) {
-			if ((p = strchr(args, c)) == NULL) { return usage(argv[0]); }
+			if ((p = strchr(args, c)) == NULL) { return usage(s); }
 			else { sel[p - args] = c; }
 		}
 

src/str.c

@@ -53,8 +53,9 @@ int usage(char *s){
 int main(int argc, char *argv[]){
 	size_t ctype; /* selected from ctypes.h; index of ctype */
 	int retval;
+	char *s = (argv[0] == NULL ? program_name : argv[0]);
 
-	if (argc < 3) { return usage(argv[0] == NULL ? program_name : argv[0]); }
+	if (argc < 3) { return usage(s); }
 
 	for ( /* iterate ctypes */
 		ctype = 0;
@@ -63,15 +64,15 @@ int main(int argc, char *argv[]){
 		++ctype
 	);
 
-	if (ctypes[ctype].f == NULL) { return usage(argv[0]); }
+	if (ctypes[ctype].f == NULL) { return usage(s); }
 
 	/* iterate args */
 	for (argv += 2, retval = EXIT_FAILURE; *argv != NULL; ++argv) {
-		for (size_t i = 0; argv[0][i] != '\0'; ++i) { /* iterate arg bytes */
+		for (size_t i = 0; s[i] != '\0'; ++i) { /* iterate arg bytes */
-			/* First checks if argv[0][i] is valid ASCII; ctypes(3) don't
+			/* First checks if s[i] is valid ASCII; ctypes(3) don't
 			 * handle non-ASCII. This is bad. */
 			if(
-				(unsigned char)argv[0][i] < 0x80 && !ctypes[ctype].f(argv[0][i])
+				(unsigned char)s[i] < 0x80 && !ctypes[ctype].f(s[i])
 			) { return EXIT_FAILURE; }
 			else { retval = EXIT_SUCCESS; }
 		}