it is finished

wip/peek/peek.c

@@ -1,4 +1,4 @@
-/* #include <errno.h> /* errno */
+#include <errno.h> /* errno */
 #include <stdio.h> /* fprintf(3), getc(3), putc(3), EOF */
 #include <stdlib.h> /* size_t */
 #include <string.h> /* strerror(3) */
@@ -6,8 +6,8 @@
 #	include <sysexits.h>
 #endif
 #include <termios.h> /* tcgetattr(3), tcsetattr(3), struct termios, ECHO */
-#include <unistd.h> /* fork(2), getopt(3), pipe(2), write(2), STDERR_FILENO,
-                     * STDOUT_FILENO */
+#include <unistd.h> /* dup(2), execvp(3), fork(2), getopt(3), pipe(2),
+                     * write(2), STDERR_FILENO, STDOUT_FILENO */
 
 static char *program_name = "peek";
 
@@ -26,58 +26,58 @@ int main(int argc, char *argv[]){
 	tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);
 
 	if(argc < 1)
-		argv[0] = program_name;
+		goto usage;
 
 	eof = EOF;
 	include_eof = 0;
-	while((c = getopt(argc, argv, "1enop:")) != -1)
+	while((c = getopt(argc, argv, "1enop")) != -1)
 		switch(c){
 		case '1': eof = '\n';                 break;
 		case 'n': include_eof = 1;            break;
 		case 'o': outputs[0] = STDOUT_FILENO; break;
 		case 'e': outputs[1] = STDERR_FILENO; break;
 		case 'p':
-			printf("not implemented\n"); return;
 			if(pipe(p) != 0){
 				fprintf(stderr, "%s: %s\n",
-					argv[0] == NULL
-						? program_name
-						: argv[0],
-					strerror(errno));
+					argv[0], strerror(errno));
 				return EX_OSERR;
 			}else
 				outputs[2] = p[1];
 			break;
-		default:
-			fprintf(stderr, "Usage: %s (-1eno) (-p [program])\n",
-				argv[0] == NULL ? program_name : argv[0]);
-			return EX_USAGE;
+		default:  goto usage;
 		}
 
-	if(outputs[2] != 0){
-		switch(fork()){
-		case -1:
-			fprintf(stderr, "%s: %s\n", argv[0], strerror(errno));
-			return EX_OSERR;
-		case 0:
-			if(dup2(p[0], STDIN_FILENO) != STDIN_FILENO){
-				fprintf(stderr, "%s: %s\n",
-					argv[0] == NULL
-						? program_name
-						: argv[0],
-					strerror(errno));
-				return EX_OSERR;
-			}
-			/* exec */
-		}
+	if((argc > optind && outputs[2] == 0)
+			|| (!(argc > optind) && outputs[2] != 0)){
+usage:		fprintf(stderr, "Usage: %s (-1eno)"
+			" (-p [program [arguments...]])\n",
+			argv[0] == NULL ? program_name : argv[0]);
+		return EX_USAGE;
 	}
 
+	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);
+		case -1:
+			goto die;
+		default:
+			if(close(p[0]) != 0)
+				goto die;
+		}
+
 	do{	if((c = getc(stdin)) != eof || include_eof)
 			for(i = 0; i < (sizeof outputs)/(sizeof *outputs); ++i)
 				if(outputs[i] != 0
 						&& write(outputs[i], &c, 1)
-							!= 1)
-					{/* errno */}
+							== -1){
+					if(i == 2)
+						close(outputs[i]);
+					outputs[i] = 0;
+				}
 	}while(c != eof);
 
 	tcgetattr(STDIN_FILENO, &t);
@@ -85,4 +85,7 @@ int main(int argc, char *argv[]){
 	tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);
 
 	return EX_OK;
+
+die:	fprintf(stderr, "%s: %s\n", argv[0], strerror(errno));
+	return EX_USAGE;
 }