move peek out of wip

peek/Makefile

@@ -0,0 +1 @@
+peek: peek.c

peek/peek.c

@@ -0,0 +1,91 @@
+#include <errno.h> /* errno */
+#include <stdio.h> /* fprintf(3), getc(3), putc(3), EOF */
+#include <stdlib.h> /* size_t */
+#include <string.h> /* strerror(3) */
+#if !defined EX_OK || !defined EX_OSERR || !defined EX_USAGE
+#	include <sysexits.h>
+#endif
+#include <termios.h> /* tcgetattr(3), tcsetattr(3), struct termios, ECHO */
+#include <unistd.h> /* dup(2), execvp(3), fork(2), getopt(3), pipe(2),
+                     * write(2), STDERR_FILENO, STDOUT_FILENO */
+
+static char *program_name = "peek";
+
+int main(int argc, char *argv[]){
+	int c;
+	int eof;
+	size_t i;
+	char include_eof;
+	int outputs[] = {0 /* stdout */, 0 /* stderr */, 0 /* -p */};
+	int p[2] = {0, 0};
+	struct termios t;
+
+	/* terminal echo */
+	tcgetattr(STDIN_FILENO, &t);
+	t.c_lflag ^= ECHO;
+	tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);
+
+	if(argc < 1)
+		goto usage;
+
+	eof = EOF;
+	include_eof = 0;
+	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':
+			if(pipe(p) != 0){
+				fprintf(stderr, "%s: %s\n",
+					argv[0], strerror(errno));
+				return EX_OSERR;
+			}else
+				outputs[2] = p[1];
+			break;
+		default:  goto usage;
+		}
+
+	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){
+					if(i == 2)
+						close(outputs[i]);
+					outputs[i] = 0;
+				}
+	}while(c != eof);
+
+	tcgetattr(STDIN_FILENO, &t);
+	t.c_lflag |= ECHO;
+	tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);
+
+	return EX_OK;
+
+die:	fprintf(stderr, "%s: %s\n", argv[0], strerror(errno));
+	return EX_USAGE;
+}