1 /* $OpenBSD: syslogc.c,v 1.19 2021/11/15 15:14:24 millert Exp $ */
2
3 /*
4 * Copyright (c) 2004 Damien Miller
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 #include <sys/un.h>
22
23 #include <err.h>
24 #include <stdio.h>
25 #include <stdint.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29
30 #define DEFAULT_CTLSOCK "/var/run/syslogd.sock"
31
32 #define MAX_MEMBUF_NAME 64 /* Max length of membuf log name */
33
34 /*
35 * Client protocol NB. all numeric fields in network byte order
36 */
37 #define CTL_VERSION 2
38
39 /* Request */
40 struct ctl_cmd {
41 u_int32_t version;
42 #define CMD_READ 1 /* Read out log */
43 #define CMD_READ_CLEAR 2 /* Read and clear log */
44 #define CMD_CLEAR 3 /* Clear log */
45 #define CMD_LIST 4 /* List available logs */
46 #define CMD_FLAGS 5 /* Query flags only */
47 #define CMD_READ_CONT 6 /* Read out log continuously */
48 u_int32_t cmd;
49 u_int32_t lines;
50 char logname[MAX_MEMBUF_NAME];
51 };
52
53 /* Reply */
54 struct ctl_reply_hdr {
55 u_int32_t version;
56 #define CTL_HDR_FLAG_OVERFLOW 0x01
57 u_int32_t flags;
58 /* Reply text follows, up to MAX_MEMBUF long */
59 };
60
61 static void
usage(void)62 usage(void)
63 {
64 extern char *__progname;
65
66 fprintf(stderr,
67 "usage: %s [-Ccfo] [-n lines] [-s reporting_socket] logname\n"
68 " %s -q\n", __progname, __progname);
69 exit(1);
70 }
71
72 int
main(int argc,char ** argv)73 main(int argc, char **argv)
74 {
75 const char *ctlsock_path;
76 char buf[8192];
77 struct sockaddr_un ctl;
78 int ctlsock, ch, oflag, rval;
79 FILE *ctlf;
80 struct ctl_cmd cc;
81 struct ctl_reply_hdr rr;
82 const char *errstr;
83
84 memset(&cc, '\0', sizeof(cc));
85
86 ctlsock_path = DEFAULT_CTLSOCK;
87 rval = oflag = 0;
88 while ((ch = getopt(argc, argv, "Ccfhon:qs:")) != -1) {
89 switch (ch) {
90 case 'C':
91 cc.cmd = CMD_CLEAR;
92 break;
93 case 'c':
94 cc.cmd = CMD_READ_CLEAR;
95 break;
96 case 'h':
97 usage();
98 break;
99 case 'f':
100 cc.cmd = CMD_READ_CONT;
101 break;
102 case 'n':
103 cc.lines = strtonum(optarg, 1, UINT32_MAX, &errstr);
104 if (errstr)
105 errx(1, "number of lines is %s: %s",
106 errstr, optarg);
107 break;
108 case 'o':
109 cc.cmd = CMD_FLAGS;
110 oflag = 1;
111 break;
112 case 'q':
113 cc.cmd = CMD_LIST;
114 break;
115 case 's':
116 ctlsock_path = optarg;
117 break;
118 default:
119 usage();
120 break;
121 }
122 }
123
124 if (cc.cmd == 0)
125 cc.cmd = CMD_READ;
126
127 if ((cc.cmd != CMD_LIST && optind != argc - 1) ||
128 (cc.cmd == CMD_LIST && optind != argc))
129 usage();
130
131 if (cc.cmd != CMD_LIST) {
132 if (strlcpy(cc.logname, argv[optind], sizeof(cc.logname)) >=
133 sizeof(cc.logname))
134 errx(1, "Specified log name is too long");
135 }
136
137 memset(&ctl, '\0', sizeof(ctl));
138 strlcpy(ctl.sun_path, ctlsock_path, sizeof(ctl.sun_path));
139 ctl.sun_family = AF_UNIX;
140
141 if ((ctlsock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
142 err(1, "socket");
143 if (connect(ctlsock, (struct sockaddr *)&ctl, sizeof(ctl)) == -1)
144 err(1, "connect: %s", ctl.sun_path);
145 if ((ctlf = fdopen(ctlsock, "r+")) == NULL)
146 err(1, "fdopen");
147
148 if (pledge("stdio", NULL) == -1)
149 err(1, "stdio");
150
151 cc.version = htonl(CTL_VERSION);
152 cc.cmd = htonl(cc.cmd);
153 /* Send command */
154 if (fwrite(&cc, sizeof(cc), 1, ctlf) != 1)
155 err(1, "fwrite");
156
157 fflush(ctlf);
158 setvbuf(ctlf, NULL, _IOLBF, 0);
159 setvbuf(stdout, NULL, _IOLBF, 0);
160
161 /* Fetch header */
162 if (fread(&rr, sizeof(rr), 1, ctlf) != 1)
163 err(1, "fread header");
164
165 if (ntohl(rr.version) != CTL_VERSION)
166 errx(1, "unsupported syslogd version");
167
168 /* Write out reply */
169 while ((fgets(buf, sizeof(buf), ctlf)) != NULL) {
170 if (!strcmp(buf, "<ENOBUFS>\n"))
171 fprintf(stderr, "syslogc [%s]: Lines were dropped!\n",
172 cc.logname);
173 else
174 fputs(buf, stdout);
175 }
176
177 if (oflag && (ntohl(rr.flags) & CTL_HDR_FLAG_OVERFLOW)) {
178 printf("%s has overflowed\n", cc.logname);
179 rval = 1;
180 }
181
182 fclose(ctlf);
183 close(ctlsock);
184
185 exit(rval);
186 }
187