chiark / gitweb /
avoid crashes on log client teardown
[disorder] / lib / log.c
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460b9539 1/*
2 * This file is part of DisOrder.
3 * Copyright (C) 2004, 2005, 2006 Richard Kettlewell
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
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20/** @file lib/log.c @brief Errors and logging
21 *
22 * All messages are initially emitted by one of the four functions below.
23 * debug() is generally invoked via D() so that mostly you just do a test
24 * rather than a complete subroutine call.
25 *
26 * Messages are dispatched via @ref log_default. This defaults to @ref
27 * log_stderr. daemonize() will turn off @ref log_stderr and use @ref
28 * log_syslog instead.
29 *
30 * fatal() will call exitfn() with a nonzero status. The default value is
31 * exit(), but it should be set to _exit() anywhere but the 'main line' of the
32 * program, to guarantee that exit() gets called at most once.
33 */
460b9539 34
35#define NO_MEMORY_ALLOCATION
36/* because the memory allocation functions report errors */
37
38#include <config.h>
39
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <errno.h>
44#include <syslog.h>
45#include <sys/time.h>
46
47#include "log.h"
48#include "disorder.h"
49#include "printf.h"
50
14ad73b9 51/** @brief Definition of a log output */
460b9539 52struct log_output {
14ad73b9 53 /** @brief Function to call */
460b9539 54 void (*fn)(int pri, const char *msg, void *user);
14ad73b9 55 /** @brief User data */
460b9539 56 void *user;
57};
58
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59/** @brief Function to call on a fatal error
60 *
61 * This is normally @c exit() but in the presence of @c fork() it
62 * sometimes gets set to @c _exit(). */
460b9539 63void (*exitfn)(int) attribute((noreturn)) = exit;
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64
65/** @brief Debug flag */
460b9539 66int debugging;
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67
68/** @brief Program name */
460b9539 69const char *progname;
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70
71/** @brief Filename for debug messages */
460b9539 72const char *debug_filename;
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73
74/** @brief Line number for debug messages */
460b9539 75int debug_lineno;
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76
77/** @brief Pointer to chosen log output structure */
460b9539 78struct log_output *log_default = &log_stderr;
79
14ad73b9 80/** @brief Filename to debug for */
460b9539 81static const char *debug_only;
82
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83/** @brief Construct log line, encoding special characters
84 *
85 * We might be receiving things in any old encoding, or binary rubbish
86 * in no encoding at all, so escape anything we don't like the look
87 * of. We limit the log message to a kilobyte.
88 */
460b9539 89static void format(char buffer[], size_t bufsize, const char *fmt, va_list ap) {
90 char t[1024];
91 const char *p;
92 int ch;
93 size_t n = 0;
94
95 if(byte_vsnprintf(t, sizeof t, fmt, ap) < 0)
96 strcpy(t, "[byte_vsnprintf failed]");
97 p = t;
98 while((ch = (unsigned char)*p++)) {
99 if(ch >= ' ' && ch <= 126) {
100 if(n < bufsize) buffer[n++] = ch;
101 } else {
102 if(n < bufsize) buffer[n++] = '\\';
103 if(n < bufsize) buffer[n++] = '0' + ((ch >> 6) & 7);
104 if(n < bufsize) buffer[n++] = '0' + ((ch >> 3) & 7);
105 if(n < bufsize) buffer[n++] = '0' + ((ch >> 0) & 7);
106 }
107 }
108 if(n >= bufsize)
109 n = bufsize - 1;
110 buffer[n] = 0;
111}
112
14ad73b9 113/** @brief Log to a file
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114 * @param pri Message priority (as per syslog)
115 * @param msg Messagge to log
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116 * @param user The @c FILE @c * to log to or NULL for @c stderr
117 */
460b9539 118static void logfp(int pri, const char *msg, void *user) {
119 struct timeval tv;
120 FILE *fp = user ? user : stderr;
121 /* ...because stderr is not a constant so we can't initialize log_stderr
122 * sanely */
123 const char *p;
124
125 if(progname)
126 fprintf(fp, "%s: ", progname);
127 if(pri <= LOG_ERR)
128 fputs("ERROR: ", fp);
129 else if(pri < LOG_DEBUG)
130 fputs("INFO: ", fp);
131 else {
132 if(!debug_only) {
133 if(!(debug_only = getenv("DISORDER_DEBUG_ONLY")))
134 debug_only = "";
135 }
136 gettimeofday(&tv, 0);
137 p = debug_filename;
138 while(!strncmp(p, "../", 3)) p += 3;
139 if(*debug_only && strcmp(p, debug_only))
140 return;
141 fprintf(fp, "%llu.%06lu: %s:%d: ",
142 (unsigned long long)tv.tv_sec, (unsigned long)tv.tv_usec,
143 p, debug_lineno);
144 }
145 fputs(msg, fp);
146 fputc('\n', fp);
147}
148
14ad73b9 149/** @brief Log to syslog */
460b9539 150static void logsyslog(int pri, const char *msg,
151 void attribute((unused)) *user) {
152 if(pri < LOG_DEBUG)
153 syslog(pri, "%s", msg);
154 else
155 syslog(pri, "%s:%d: %s", debug_filename, debug_lineno, msg);
156}
157
14ad73b9 158/** @brief Log output that writes to @c stderr */
460b9539 159struct log_output log_stderr = { logfp, 0 };
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160
161/** @brief Log output that sends to syslog */
460b9539 162struct log_output log_syslog = { logsyslog, 0 };
163
14ad73b9 164/** @brief Format and log a message */
460b9539 165static void vlogger(int pri, const char *fmt, va_list ap) {
166 char buffer[1024];
167
168 format(buffer, sizeof buffer, fmt, ap);
169 log_default->fn(pri, buffer, log_default->user);
170}
171
14ad73b9 172/** @brief Format and log a message */
460b9539 173static void logger(int pri, const char *fmt, ...) {
174 va_list ap;
175
176 va_start(ap, fmt);
177 vlogger(pri, fmt, ap);
178 va_end(ap);
179}
180
14ad73b9 181/** @brief Format and log a message
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182 * @param pri Message priority (as per syslog)
183 * @param fmt Format string
14ad73b9 184 * @param errno_value Errno value to include as a string, or 0
840f3008 185 * @param ap Argument list
14ad73b9 186 */
460b9539 187void elog(int pri, int errno_value, const char *fmt, va_list ap) {
188 char buffer[1024];
189
190 if(errno_value == 0)
191 vlogger(pri, fmt, ap);
192 else {
193 memset(buffer, 0, sizeof buffer);
194 byte_vsnprintf(buffer, sizeof buffer, fmt, ap);
195 buffer[sizeof buffer - 1] = 0;
196 logger(pri, "%s: %s", buffer, strerror(errno_value));
197 }
198}
199
200#define disorder_fatal fatal
201#define disorder_error error
202#define disorder_info info
203
204/* shared implementation of vararg functions */
205#include "log-impl.h"
206
14ad73b9 207/** @brief Log a debug message */
460b9539 208void debug(const char *msg, ...) {
209 va_list ap;
210
211 va_start(ap, msg);
212 vlogger(LOG_DEBUG, msg, ap);
213 va_end(ap);
214}
215
14ad73b9 216/** @brief Set the program name from @c argc */
460b9539 217void set_progname(char **argv) {
218 if((progname = strrchr(argv[0], '/')))
219 ++progname;
220 else
221 progname = argv[0];
222}
223
224/*
225Local Variables:
226c-basic-offset:2
227comment-column:40
228End:
229*/