xref: /freebsd/lib/libcasper/services/cap_syslog/cap_syslog.c (revision f7c32ed617858bcd22f8d1b03199099d50125721)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2017 Mariusz Zaborski <oshogbo@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/dnv.h>
33 #include <sys/nv.h>
34 
35 #include <assert.h>
36 #include <errno.h>
37 #include <stdarg.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <syslog.h>
42 
43 #include <libcasper.h>
44 #include <libcasper_service.h>
45 
46 #include "cap_syslog.h"
47 
48 #define	CAP_SYSLOG_LIMIT	2048
49 
50 void
51 cap_syslog(cap_channel_t *chan, int pri, const char *fmt, ...)
52 {
53 	va_list ap;
54 
55 	va_start(ap, fmt);
56 	cap_vsyslog(chan, pri, fmt, ap);
57 	va_end(ap);
58 }
59 
60 void
61 cap_vsyslog(cap_channel_t *chan, int priority, const char *fmt, va_list ap)
62 {
63 	nvlist_t *nvl;
64 	char message[CAP_SYSLOG_LIMIT];
65 
66 	(void)vsnprintf(message, sizeof(message), fmt, ap);
67 
68 	nvl = nvlist_create(0);
69 	nvlist_add_string(nvl, "cmd", "vsyslog");
70 	nvlist_add_number(nvl, "priority", priority);
71 	nvlist_add_string(nvl, "message", message);
72 	nvl = cap_xfer_nvlist(chan, nvl);
73 	if (nvl == NULL) {
74 		return;
75 	}
76 	nvlist_destroy(nvl);
77 }
78 
79 void
80 cap_openlog(cap_channel_t *chan, const char *ident, int logopt, int facility)
81 {
82 	nvlist_t *nvl;
83 
84 	nvl = nvlist_create(0);
85 	nvlist_add_string(nvl, "cmd", "openlog");
86 	if (ident != NULL) {
87 		nvlist_add_string(nvl, "ident", ident);
88 	}
89 	nvlist_add_number(nvl, "logopt", logopt);
90 	nvlist_add_number(nvl, "facility", facility);
91 	if (logopt & LOG_PERROR) {
92 		nvlist_add_descriptor(nvl, "stderr", STDERR_FILENO);
93 	}
94 	nvl = cap_xfer_nvlist(chan, nvl);
95 	if (nvl == NULL) {
96 		return;
97 	}
98 	nvlist_destroy(nvl);
99 }
100 
101 void
102 cap_closelog(cap_channel_t *chan)
103 {
104 	nvlist_t *nvl;
105 
106 	nvl = nvlist_create(0);
107 	nvlist_add_string(nvl, "cmd", "closelog");
108 	nvl = cap_xfer_nvlist(chan, nvl);
109 	if (nvl == NULL) {
110 		return;
111 	}
112 	nvlist_destroy(nvl);
113 }
114 
115 int
116 cap_setlogmask(cap_channel_t *chan, int maskpri)
117 {
118 	nvlist_t *nvl;
119 	int omask;
120 
121 	nvl = nvlist_create(0);
122 	nvlist_add_string(nvl, "cmd", "setlogmask");
123 	nvlist_add_number(nvl, "maskpri", maskpri);
124 	nvl = cap_xfer_nvlist(chan, nvl);
125 	omask = nvlist_get_number(nvl, "omask");
126 
127 	nvlist_destroy(nvl);
128 
129 	return (omask);
130 }
131 
132 /*
133  * Service functions.
134  */
135 
136 static char *LogTag;
137 static int prev_stderr = -1;
138 
139 static void
140 slog_vsyslog(const nvlist_t *limits __unused, const nvlist_t *nvlin,
141     nvlist_t *nvlout __unused)
142 {
143 
144 	syslog(nvlist_get_number(nvlin, "priority"), "%s",
145 	    nvlist_get_string(nvlin, "message"));
146 }
147 
148 static void
149 slog_openlog(const nvlist_t *limits __unused, const nvlist_t *nvlin,
150     nvlist_t *nvlout __unused)
151 {
152 	const char *ident;
153 	uint64_t logopt;
154 	int stderr_fd;
155 
156 	ident = dnvlist_get_string(nvlin, "ident", NULL);
157 	if (ident != NULL) {
158 		free(LogTag);
159 		LogTag = strdup(ident);
160 	}
161 
162 	logopt = nvlist_get_number(nvlin, "logopt");
163 	if (logopt & LOG_PERROR) {
164 		stderr_fd = dnvlist_get_descriptor(nvlin, "stderr", -1);
165 		if (prev_stderr == -1)
166 			prev_stderr = dup(STDERR_FILENO);
167 		if (prev_stderr != -1)
168 			(void)dup2(stderr_fd, STDERR_FILENO);
169 	} else if (prev_stderr != -1) {
170 		(void)dup2(prev_stderr, STDERR_FILENO);
171 		close(prev_stderr);
172 		prev_stderr = -1;
173 	}
174 	openlog(LogTag, logopt, nvlist_get_number(nvlin, "facility"));
175 }
176 
177 static void
178 slog_closelog(const nvlist_t *limits __unused, const nvlist_t *nvlin __unused,
179     nvlist_t *nvlout __unused)
180 {
181 
182 	closelog();
183 
184 	free(LogTag);
185 	LogTag = NULL;
186 
187 	if (prev_stderr != -1) {
188 		(void)dup2(prev_stderr, STDERR_FILENO);
189 		close(prev_stderr);
190 		prev_stderr = -1;
191 	}
192 }
193 
194 static void
195 slog_setlogmask(const nvlist_t *limits __unused, const nvlist_t *nvlin,
196     nvlist_t *nvlout)
197 {
198 	int omask;
199 
200 	omask = setlogmask(nvlist_get_number(nvlin, "maskpri"));
201 	nvlist_add_number(nvlout, "omask", omask);
202 }
203 
204 static int
205 syslog_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin,
206     nvlist_t *nvlout)
207 {
208 
209 	if (strcmp(cmd, "vsyslog") == 0) {
210 		slog_vsyslog(limits, nvlin, nvlout);
211 	} else if (strcmp(cmd, "openlog") == 0) {
212 		slog_openlog(limits, nvlin, nvlout);
213 	} else if (strcmp(cmd, "closelog") == 0) {
214 		slog_closelog(limits, nvlin, nvlout);
215 	} else if (strcmp(cmd, "setlogmask") == 0) {
216 		slog_setlogmask(limits, nvlin, nvlout);
217 	} else {
218 		return (EINVAL);
219 	}
220 
221 	return (0);
222 }
223 
224 CREATE_SERVICE("system.syslog", NULL, syslog_command, 0);
225