peek(1): remove gotos, fix style to fit bonsai/coreutils

peek/peek.c

@@ -1,6 +1,5 @@
-#include <errno.h> /* errno */
-#include <stdio.h> /* fprintf(3), getc(3), putc(3), stderr, stdin, stdout, EOF,
-                    * NULL */
+#include <stdio.h> /* fprintf(3), getc(3), perror(3), putc(3), stderr, stdin,
+                    * stdout, EOF, NULL */
 #include <stdlib.h> /* size_t */
 #include <string.h> /* strerror(3) */
 #if !defined EX_OK || !defined EX_OSERR || !defined EX_USAGE
@@ -10,7 +9,14 @@
 #include <unistd.h> /* dup(2), execvp(3), fork(2), getopt(3), isatty(3),
                      * pipe(2), STDIN_FILENO */
 
+static int oserr(char *s){ perror(s); return EX_OSERR; }
+
 static char *program_name = "peek";
+static int usage(char *s){
+	fprintf(stderr, "Usage: %s (-1enot) (-p [program [arguments...]])\n",
+		s == NULL ? program_name : s);
+	return EX_USAGE;
+}
 
 int main(int argc, char *argv[]){
 	int c;
@@ -26,7 +32,7 @@ int main(int argc, char *argv[]){
 	struct termios t;
 
 	if(argc < 1)
-		goto usage;
+		usage(argv[0]);
 
 	eof = EOF;
 	include_eof = 0;
@@ -37,10 +43,8 @@ int main(int argc, char *argv[]){
 		case 'o':	outputs[0] = stdout; break;
 		case 'e':	outputs[1] = stderr; break;
 		case 'p':
-			if(pipe(p) != 0)
-				goto die;
-			else if((outputs[2] = fdopen(p[1], "ab")) == NULL)
-				goto die;
+			if(pipe(p) != 0 || (outputs[2] = fdopen(p[1], "ab")) == NULL)
+				return oserr(argv[0]);
 			break;
 		case 't':
 			if(isatty(STDIN_FILENO) != 1){
@@ -48,33 +52,27 @@ int main(int argc, char *argv[]){
 					" (option -t specified)\n", argv[0]);
 				return EX_USAGE;
 			}
-		default:  goto usage;
+		default:	return usage(argv[0]);
 		}
 
-	/* If -p is used there must be additional arguments. Getopt(3) wouldn't
+	/* If -p is used there must be additional arguments. getopt(3) wouldn't
 	 * work for this because optarg would have to be one string to give to
 	 * system(3) or an equivalent and it would be a mess of parsing and
 	 * security issues. Any intended usage works with this slightly funkier
 	 * argument parsing, unintended usages work as happy coincidence. */
-	if((argc > optind) == (outputs[2] == 0)){
-usage:		fprintf(stderr, "Usage: %s (-1enot)"
-			" (-p [program [arguments...]])\n",
-			argv[0] == NULL ? program_name : argv[0]);
-		return EX_USAGE;
-	}
+	if((argc > optind) == (outputs[2] == 0))
+		return usage(argv[0]);
 
 	if(outputs[2] != 0)
 		switch(fork()){
 		case 0:
-			if(close(p[1]) == 0
-					&& dup2(p[0], STDIN_FILENO)
-						== STDIN_FILENO)
-				execvp(argv[optind], argv + optind);
+			if(close(p[1]) == 0 && dup2(p[0], STDIN_FILENO) == STDIN_FILENO)
+				execvp(argv[optind], &argv[optind]);
 		case -1:
-			goto die;
+			return oserr(argv[0]);
 		default:
 			if(close(p[0]) != 0)
-				goto die;
+				return oserr(argv[0]);
 		}
 
 	/* terminal echo */
@@ -84,11 +82,10 @@ usage:		fprintf(stderr, "Usage: %s (-1enot)"
 
 	do{	if((c = getc(stdin)) != eof || include_eof)
 			for(i = 0; i < (sizeof outputs)/(sizeof *outputs); ++i)
-				if(outputs[i] != NULL
-						&& putc(c, outputs[i]) == EOF){
-					if(i == 2)
+				if(outputs[i] != NULL && putc(c, outputs[i]) == EOF){
+					if(outputs[i] != stdout && outputs[i] != stderr)
 						fclose(outputs[i]);
-					outputs[i] = 0;
+					outputs[i] = NULL;
 				}
 	}while(c != eof);
 
@@ -97,7 +94,4 @@ usage:		fprintf(stderr, "Usage: %s (-1enot)"
 	tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);
 
 	return EX_OK;
-
-die:	fprintf(stderr, "%s: %s\n", argv[0], strerror(errno));
-	return EX_OSERR;
 }