Make kill(1) POSIX conformant

* XSI extensions support is missing, -signal_name and -signal_number.

kill.1

@@ -4,25 +4,26 @@ KILL \- signal processes
 .SH SYNOPSIS
 .B kill
 .RB [ \-s
-.IR signal ]
-.RI [ pid ...]
+.IR signal_name ]
+.IR pid
+.IR ...
 .P
 .B kill
 .B -l
-.RI [ signum ]
+.RI [ exit_status ]
 .SH DESCRIPTION
 .B kill
-sends a
+by default sends a
 .I TERM
 signal to the given processes.
 .SH OPTIONS
 .TP
-.BI \-s " signal"
-sends the named signal.
+.BI \-s " signal_name"
+Sends the named signal.
 .TP
 .B \-l
-lists available signals.  If a
-.I signum
+Lists available signals.  If an
+.I exit_status
 is given, only the corresponding signal name will be printed.
 .SH SEE ALSO
 .IR kill (2),

kill.c

@@ -1,11 +1,13 @@
 /* See LICENSE file for copyright and license details. */
+#include <sys/wait.h>
+#include <errno.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <strings.h>
 #include <unistd.h>
-#include <sys/wait.h>
 #include "util.h"
 
 struct {
@@ -19,60 +21,110 @@ struct {
 #undef SIG
 };
 
+const char *sig2name(int);
+
 static void
 usage(void)
 {
-	eprintf("usage: %s [-s signal] [pid...]\n"
-	        "       %s -l [signum]\n", argv0, argv0);
+	weprintf("usage: %s -s signal_name pid...\n", argv0);
+	weprintf("       %s -l [exit_status]\n", argv0);
+	exit(1);
 }
 
 int
 main(int argc, char *argv[])
 {
-	bool lflag = false;
-	char *end, *v;
+	char *end;
+	const char *name;
+	int ret = 0;
 	int sig = SIGTERM;
 	pid_t pid;
 	size_t i;
 
-	ARGBEGIN {
-	case 'l':
-		lflag = true;
-		break;
-	case 's':
-		v = EARGF(usage());
-		sig = strtol(v, &end, 0);
-		if(*end == '\0')
-			break;
-		for(i = 0; i < LEN(sigs); i++) {
-			if(!strcasecmp(v, sigs[i].name)) {
-				sig = sigs[i].sig;
-				break;
+	argv0 = argv[0];
+	if (argc < 2)
+		usage();
+
+	argc--;
+	argv++;
+	if (strcmp(argv[0], "-l") == 0) {
+		argc--;
+		argv++;
+		if (argc == 0) {
+			for (i = 0; i < LEN(sigs); i++)
+				puts(sigs[i].name);
+			exit(0);
+		}
+		for (; argc; argc--, argv++) {
+			errno = 0;
+			sig = strtol(argv[0], &end, 0);
+			if (*end == '\0' && errno == 0) {
+				name = sig2name(sig);
+				if (!name)
+					printf("%d\n", sig);
+				else
+					puts(name);
+			} else {
+				weprintf("%s: bad signal number\n", argv[0]);
+				ret = 1;
 			}
 		}
-		if(i == LEN(sigs))
-			eprintf("%s: unknown signal\n", v);
-		break;
-	default:
-		usage();
-	} ARGEND;
-
-	if(argc < 1 && !lflag)
-		usage();
-
-	if(lflag) {
-		sig = (argc > 0) ? estrtol(argv[0], 0) : 0;
-		if(sig > 128)
-			sig = WTERMSIG(sig);
-		for(i = 0; i < LEN(sigs); i++)
-			if(sigs[i].sig == sig || sig == 0)
-				putword(sigs[i].name);
-		putchar('\n');
-	} else for(; argc > 0; argc--, argv++) {
-		pid = estrtol(argv[0], 0);
-		if(kill(pid, sig) == -1)
-			eprintf("kill %d:", pid);
+		exit(0);
+	} else if (strcmp(argv[0], "-s") == 0) {
+		argc--;
+		argv++;
+		if (argc == 0)
+			usage();
+		if (strcmp(argv[0], "0") == 0) {
+			sig = 0;
+		} else {
+			for (i = 0; i < LEN(sigs); i++) {
+				if (strcasecmp(sigs[i].name, argv[0]) == 0) {
+					sig = sigs[i].sig;
+					break;
+				}
+			}
+			if (i == LEN(sigs))
+				eprintf("%s: bad signal number\n", argv[0]);
+		}
+		argc--;
+		argv++;
+	} else if (strcmp(argv[0], "--") == 0) {
+		argc--;
+		argv++;
+		if (argc == 0)
+			usage();
 	}
 
-	return 0;
+	if (argc == 0)
+		usage();
+
+	for (; argc; argc--, argv++) {
+		errno = 0;
+		pid = strtol(argv[0], &end, 0);
+		if (*end == '\0' && errno == 0) {
+			if (kill(pid, sig) < 0) {
+				weprintf("kill %d:", pid);
+				ret = 1;
+			}
+		} else {
+			weprintf("%s: bad pid\n", argv[0]);
+			ret = 1;
+		}
+	}
+
+	exit(ret);
+}
+
+const char *
+sig2name(int sig)
+{
+	size_t i;
+
+	if (sig > 128)
+		sig = WTERMSIG(sig);
+	for (i = 0; i < LEN(sigs); i++)
+		if (sigs[i].sig == sig)
+			return sigs[i].name;
+	return NULL;
 }