Import syslog utility program

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>

.gitignore

@@ -17,3 +17,4 @@ config.h
 *~
 klogd
 usyslogd
+syslog

Makefile.am

@@ -5,7 +5,9 @@ AM_CFLAGS = $(WARN_CFLAGS)
 
 usyslogd_SOURCES = syslogd.c syslogd.h proto.c logfile.c mksock.c protomap.c
 klogd_SOURCES = klogd.c
+syslog_SOURCES = syslog.c protomap.c
 
-bin_PROGRAMS =
+dist_man1_MANS = syslog.1
+bin_PROGRAMS = syslog
 sbin_PROGRAMS = usyslogd klogd
 EXTRA_DIST = LICENSE

protomap.c

@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: ISC */
 #include "syslogd.h"
 
+#include <string.h>
+
 typedef struct {
 	const char *name;
 	int id;
@@ -54,12 +56,30 @@ static const char *enum_to_name(const enum_map_t *map, int id)
 	return map->name;
 }
 
+static int enum_by_name(const enum_map_t *map, const char *name)
+{
+	while (map->name != NULL && strcmp(map->name, name) != 0)
+		++map;
+
+	return map->name == NULL ? -1 : map->id;
+}
+
 const char *level_id_to_string(int level)
 {
 	return enum_to_name(levels, level);
 }
 
-const char *facility_id_to_string(int level)
+const char *facility_id_to_string(int id)
 {
-	return enum_to_name(facilities, level);
+	return enum_to_name(facilities, id);
+}
+
+int level_id_from_string(const char *level)
+{
+	return enum_by_name(levels, level);
+}
+
+int facility_id_from_string(const char *fac)
+{
+	return enum_by_name(facilities, fac);
 }

syslog.1

@@ -0,0 +1,45 @@
+.TH syslog 1 "August 2018" "usyslog"
+.SH NAME
+syslog \- send a log message to the syslog daemon
+.SH SYNOPSIS
+.B syslog
+[options] message..
+.SH DESCRIPTION
+The syslog command concatenates all non option arguments to a single message
+that it sends to the syslog daemon.
+.SH OPTIONS
+.TP
+.BR \-h , " \-\-help"
+Display a brief help text, a list of available facilities, log levels, all the
+default setting and exit.
+.TP
+.BR \-V , " \-\-version"
+Print version information and exit.
+.TP
+.BR \-f , " \-\-facility " \fIfacility\fP
+Logging facility name or numeric identifier. Use
+.B \-\-help
+to get a list of all available facility names.
+.TP
+.BR \-l , " \-\-level " \fIlevel\fP
+A log level number from 0 to 8 with 8 being most severe, or a name from
+.I debug
+to
+.I emergency.
+Use
+.B \-\-help
+to get a list of all available log level names.
+.TP
+.BR \-i , " \-\-ident " \fIname\fP
+Program name to specify to syslog. If not set, "(shell)" is used as sensible
+default to indicate that the message came from the command line.
+.TP
+.BR \-c , " \-\-console"
+Try to write directly to the console if opening the syslog socket fails.
+.SH AVAILABILITY
+This program is part of the Pygos init system.
+.SH COPYRIGHT
+Copyright \(co 2018 David Oberhollenzer
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.

syslog.c

@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: ISC */
+#include <getopt.h>
+#include <syslog.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+
+#include "syslogd.h"
+
+static int facility = 1;
+static int level = LOG_INFO;
+static int flags = LOG_NDELAY | LOG_NOWAIT;
+static const char *ident = "(shell)";
+
+static const struct option options[] = {
+	{ "help", no_argument, NULL, 'h' },
+	{ "version", no_argument, NULL, 'V' },
+	{ "console", required_argument, NULL, 'c' },
+	{ "facility", required_argument, NULL, 'f' },
+	{ "level", required_argument, NULL, 'l' },
+	{ "ident", required_argument, NULL, 'i' },
+	{ NULL, 0, NULL, 0 },
+};
+
+static const char *shortopt = "hVcf:l:i:";
+
+static const char *helptext =
+"Usage: syslog [OPTION]... [STRING]...\n\n"
+"Concatenate the given STRINGs and send a log message to the syslog daemon.\n"
+"\n"
+"The following OPTIONSs can be used:\n"
+"  -f, --facility <facility>  Logging facilty name or numeric identifier.\n"
+"  -l, --level <level>        Log level name or numeric identifier.\n"
+"  -i, --ident <name>         Program name for log syslog message.\n"
+"                             Default is \"%s\".\n\n"
+"  -c, --console              Write to the console if opening the syslog\n"
+"                             socket fails.\n\n"
+"  -h, --help                 Print this help text and exit\n"
+"  -V, --version              Print version information and exit\n\n";
+
+static const char *version_string =
+"syslog (usyslog) " PACKAGE_VERSION "\n"
+"Copyright (C) 2018 David Oberhollenzer\n\n"
+"This is free software: you are free to change and redistribute it.\n"
+"There is NO WARRANTY, to the extent permitted by law.\n";
+
+static void usage(int status)
+{
+	const char *str;
+	int i;
+
+	if (status != EXIT_SUCCESS) {
+		fputs("Try `syslog --help' for more information\n", stderr);
+	} else {
+		printf(helptext, ident);
+
+		fputs("The following values can be used for --level:\n",
+		      stdout);
+
+		i = 0;
+		while ((str = level_id_to_string(i)) != NULL) {
+			printf("  %s (=%d)%s\n", str, i,
+			       i == level ? ", set as default" : "");
+			++i;
+		}
+
+		fputs("\nThe following values can be used for --facility:\n",
+		      stdout);
+
+		i = 0;
+		while ((str = facility_id_to_string(i)) != NULL) {
+			printf("  %s (=%d)%s\n", str, i,
+			       i == facility ? ", set as default" : "");
+			++i;
+		}
+	}
+
+	exit(status);
+}
+
+static int readint(const char *str)
+{
+	int x = 0;
+
+	if (!isdigit(*str))
+		return -1;
+
+	while (isdigit(*str))
+		x = x * 10 + (*(str++)) - '0';
+
+	return (*str == '\0') ? x : -1;
+}
+
+static void process_options(int argc, char **argv)
+{
+	int c;
+
+	for (;;) {
+		c = getopt_long(argc, argv, shortopt, options, NULL);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'f':
+			facility = readint(optarg);
+			if (facility >= 0)
+				break;
+			facility = facility_id_from_string(optarg);
+			if (facility < 0) {
+				fprintf(stderr, "Unknown facility name '%s'\n",
+					optarg);
+				usage(EXIT_FAILURE);
+			}
+			break;
+		case 'l':
+			level = readint(optarg);
+			if (level >= 0)
+				break;
+			level = level_id_from_string(optarg);
+			if (level < 0) {
+				fprintf(stderr, "Unknown log level '%s'\n",
+					optarg);
+				usage(EXIT_FAILURE);
+			}
+			break;
+		case 'i':
+			ident = optarg;
+			break;
+		case 'c':
+			flags |= LOG_CONS;
+			break;
+		case 'V':
+			fputs(version_string, stdout);
+			exit(EXIT_SUCCESS);
+			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
+			break;
+		default:
+			usage(EXIT_FAILURE);
+			break;
+		}
+	}
+}
+
+
+int main(int argc, char **argv)
+{
+	size_t len = 0;
+	char *str;
+	int i;
+
+	process_options(argc, argv);
+
+	if (optind >= argc) {
+		fputs("Error: no log string provided.\n", stderr);
+		usage(EXIT_FAILURE);
+	}
+
+	for (i = optind; i < argc; ++i)
+		len += strlen(argv[i]);
+
+	len += argc - optind - 1;
+
+	str = calloc(1, len + 1);
+	if (str == NULL) {
+		fputs("syslog: out of memory\n", stderr);
+		return EXIT_FAILURE;
+	}
+
+	for (i = optind; i < argc; ++i) {
+		if (i > optind)
+			strcat(str, " ");
+		strcat(str, argv[i]);
+	}
+
+	openlog(ident, flags, facility << 3);
+	syslog(level, "%s", str);
+	closelog();
+
+	free(str);
+	return EXIT_SUCCESS;
+}

syslogd.h

@@ -76,6 +76,10 @@ int mksock(const char *path);
 
 const char *level_id_to_string(int level);
 
-const char *facility_id_to_string(int level);
+const char *facility_id_to_string(int id);
+
+int level_id_from_string(const char *level);
+
+int facility_id_from_string(const char *fac);
 
 #endif /* LOGFILE_H */