aboutgitcodebugslistschat
path: root/log.c
blob: 9ed6bc1fbf1617a8002b7478d411ba1264bc1b7b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
// SPDX-License-Identifier: GPL-2.0-or-later

/* PASST - Plug A Simple Socket Transport
 *  for qemu/UNIX domain socket mode
 *
 * PASTA - Pack A Subtle Tap Abstraction
 *  for network namespace/tap device mode
 *
 * log.c - Logging functions
 *
 * Copyright (c) 2020-2022 Red Hat GmbH
 * Author: Stefano Brivio <sbrivio@redhat.com>
 */

#include <arpa/inet.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <syslog.h>
#include <stdarg.h>
#include <sys/socket.h>

#include "log.h"
#include "util.h"
#include "passt.h"

static int	log_sock = -1;		/* Optional socket to system logger */
static char	log_ident[BUFSIZ];	/* Identifier string for openlog() */
static int	log_mask;		/* Current log priority mask */

static int	log_file = -1;		/* Optional log file descriptor */
static size_t	log_size;		/* Maximum log file size in bytes */
static size_t	log_written;		/* Currently used bytes in log file */
static size_t	log_cut_size;		/* Bytes to cut at start on rotation */
static char	log_header[BUFSIZ];	/* File header, written back on cuts */

static time_t	log_start;		/* Start timestamp */

int		log_trace;		/* --trace mode enabled */
bool		log_conf_parsed;	/* Logging options already parsed */
bool		log_runtime;		/* Daemonised, or ready in foreground */

void vlogmsg(int pri, const char *format, va_list ap)
{
	bool debug_print = (log_mask & LOG_MASK(LOG_DEBUG)) && log_file == -1;
	struct timespec tp;

	if (debug_print) {
		clock_gettime(CLOCK_REALTIME, &tp);
		fprintf(stderr, "%lli.%04lli: ",
			(long long int)tp.tv_sec - log_start,
			(long long int)tp.tv_nsec / (100L * 1000));
	}

	if ((log_mask & LOG_MASK(LOG_PRI(pri))) || !log_conf_parsed) {
		va_list ap2;

		va_copy(ap2, ap); /* Don't clobber ap, we need it again */
		if (log_file != -1)
			logfile_write(pri, format, ap2);
		else if (!(log_mask & LOG_MASK(LOG_DEBUG)))
			passt_vsyslog(pri, format, ap2);

		va_end(ap2);
	}

	if (debug_print || !log_conf_parsed ||
	    (!log_runtime && (log_mask & LOG_MASK(LOG_PRI(pri))))) {
		(void)vfprintf(stderr, format, ap);
		if (format[strlen(format)] != '\n')
			fprintf(stderr, "\n");
	}
}

/**
 * logmsg() - vlogmsg() wrapper for variable argument lists
 * @pri:	Facility and level map, same as priority for vsyslog()
 * @format:	Message
 */
void logmsg(int pri, const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	vlogmsg(pri, format, ap);
	va_end(ap);
}

/**
 * logmsg_perror() - vlogmsg() wrapper with perror()-like functionality
 * @pri:	Facility and level map, same as priority for vsyslog()
 * @format:	Message
 */
void logmsg_perror(int pri, const char *format, ...)
{
	int errno_copy = errno;
	va_list ap;

	va_start(ap, format);
	vlogmsg(pri, format, ap);
	va_end(ap);

	logmsg(pri, ": %s", strerror(errno_copy));
}

/* Prefixes for log file messages, indexed by priority */
const char *logfile_prefix[] = {
	NULL, NULL, NULL,	/* Unused: LOG_EMERG, LOG_ALERT, LOG_CRIT */
	"ERROR:   ",
	"WARNING: ",
	NULL,			/* Unused: LOG_NOTICE */
	"info:    ",
	"         ",		/* LOG_DEBUG */
};

/**
 * trace_init() - Set log_trace depending on trace (debug) mode
 * @enable:	Tracing debug mode enabled if non-zero
 */
void trace_init(int enable)
{
	log_trace = enable;
}

/**
 * __openlog() - Non-optional openlog() implementation, for custom vsyslog()
 * @ident:	openlog() identity (program name)
 * @option:	openlog() options, unused
 * @facility:	openlog() facility (LOG_DAEMON)
 */
void __openlog(const char *ident, int option, int facility)
{
	struct timespec tp;

	(void)option;

	clock_gettime(CLOCK_REALTIME, &tp);
	log_start = tp.tv_sec;

	if (log_sock < 0) {
		struct sockaddr_un a = { .sun_family = AF_UNIX, };

		log_sock = socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);
		if (log_sock < 0)
			return;

		strncpy(a.sun_path, _PATH_LOG, sizeof(a.sun_path));
		if (connect(log_sock, (const struct sockaddr *)&a, sizeof(a))) {
			close(log_sock);
			log_sock = -1;
			return;
		}
	}

	log_mask |= facility;
	strncpy(log_ident, ident, sizeof(log_ident) - 1);
}

/**
 * __setlogmask() - setlogmask() wrapper, to allow custom vsyslog()
 * @mask:	Same as setlogmask() mask
 */
void __setlogmask(int mask)
{
	log_mask = mask;
	setlogmask(mask);
}

/**
 * passt_vsyslog() - vsyslog() implementation not using heap memory
 * @pri:	Facility and level map, same as priority for vsyslog()
 * @format:	Same as vsyslog() format
 * @ap:		Same as vsyslog() ap
 */
void passt_vsyslog(int pri, const char *format, va_list ap)
{
	char buf[BUFSIZ];
	int n;

	/* Send without timestamp, the system logger should add it */
	n = snprintf(buf, BUFSIZ, "<%i> %s: ", pri, log_ident);

	n += vsnprintf(buf + n, BUFSIZ - n, format, ap);

	if (format[strlen(format)] != '\n')
		n += snprintf(buf + n, BUFSIZ - n, "\n");

	if (log_sock >= 0 && send(log_sock, buf, n, 0) != n && !log_runtime)
		fprintf(stderr, "Failed to send %i bytes to syslog\n", n);
}

/**
 * logfile_init() - Open log file and write header with PID, version, path
 * @name:	Identifier for header: passt or pasta
 * @path:	Path to log file
 * @size:	Maximum size of log file: log_cut_size is calculatd here
 */
void logfile_init(const char *name, const char *path, size_t size)
{
	char nl = '\n', exe[PATH_MAX] = { 0 };
	int n;

	if (readlink("/proc/self/exe", exe, PATH_MAX - 1) < 0)
		die_perror("Failed to read own /proc/self/exe link");

	log_file = open(path, O_CREAT | O_TRUNC | O_APPEND | O_RDWR | O_CLOEXEC,
			S_IRUSR | S_IWUSR);
	if (log_file == -1)
		die_perror("Couldn't open log file %s", path);

	log_size = size ? size : LOGFILE_SIZE_DEFAULT;

	n = snprintf(log_header, sizeof(log_header), "%s " VERSION ": %s (%i)",
		     name, exe, getpid());

	if (write(log_file, log_header, n) <= 0 ||
	    write(log_file, &nl, 1) <= 0)
		die_perror("Couldn't write to log file");

	/* For FALLOC_FL_COLLAPSE_RANGE: VFS block size can be up to one page */
	log_cut_size = ROUND_UP(log_size * LOGFILE_CUT_RATIO / 100, PAGE_SIZE);
}

#ifdef FALLOC_FL_COLLAPSE_RANGE
/**
 * logfile_rotate_fallocate() - Write header, set log_written after fallocate()
 * @fd:		Log file descriptor
 * @now:	Current timestamp
 *
 * #syscalls lseek ppc64le:_llseek ppc64:_llseek arm:_llseek
 */
static void logfile_rotate_fallocate(int fd, const struct timespec *now)
{
	char buf[BUFSIZ];
	const char *nl;
	int n;

	if (lseek(fd, 0, SEEK_SET) == -1)
		return;
	if (read(fd, buf, BUFSIZ) == -1)
		return;

	n = snprintf(buf, BUFSIZ,
		     "%s - log truncated at %lli.%04lli", log_header,
		     (long long int)(now->tv_sec - log_start),
		     (long long int)(now->tv_nsec / (100L * 1000)));

	/* Avoid partial lines by padding the header with spaces */
	nl = memchr(buf + n + 1, '\n', BUFSIZ - n - 1);
	if (nl)
		memset(buf + n, ' ', nl - (buf + n));

	if (lseek(fd, 0, SEEK_SET) == -1)
		return;
	if (write(fd, buf, BUFSIZ) == -1)
		return;

	log_written -= log_cut_size;
}
#endif /* FALLOC_FL_COLLAPSE_RANGE */

/**
 * logfile_rotate_move() - Fallback: move recent entries toward start, then cut
 * @fd:		Log file descriptor
 * @now:	Current timestamp
 *
 * #syscalls lseek ppc64le:_llseek ppc64:_llseek arm:_llseek
 * #syscalls ftruncate
 */
static void logfile_rotate_move(int fd, const struct timespec *now)
{
	int header_len, write_offset, end, discard, n;
	char buf[BUFSIZ];
	const char *nl;

	header_len = snprintf(buf, BUFSIZ,
			      "%s - log truncated at %lli.%04lli\n", log_header,
			      (long long int)(now->tv_sec - log_start),
			      (long long int)(now->tv_nsec / (100L * 1000)));
	if (lseek(fd, 0, SEEK_SET) == -1)
		return;
	if (write(fd, buf, header_len) == -1)
		return;

	end = write_offset = header_len;
	discard = log_cut_size + header_len;

	/* Try to cut cleanly at newline */
	if (lseek(fd, discard, SEEK_SET) == -1)
		goto out;
	if ((n = read(fd, buf, BUFSIZ)) <= 0)
		goto out;
	if ((nl = memchr(buf, '\n', n)))
		discard += (nl - buf) + 1;

	/* Go to first block to be moved */
	if (lseek(fd, discard, SEEK_SET) == -1)
		goto out;

	while ((n = read(fd, buf, BUFSIZ)) > 0) {
		end = header_len;

		if (lseek(fd, write_offset, SEEK_SET) == -1)
			goto out;
		if ((n = write(fd, buf, n)) == -1)
			goto out;
		write_offset += n;

		if ((n = lseek(fd, 0, SEEK_CUR)) == -1)
			goto out;

		if (lseek(fd, discard - header_len, SEEK_CUR) == -1)
			goto out;

		end = n;
	}

out:
	if (ftruncate(fd, end))
		return;

	log_written = end;
}

/**
 * logfile_rotate() - "Rotate" log file once it's full
 * @fd:		Log file descriptor
 * @now:	Current timestamp
 *
 * Return: 0 on success, negative error code on failure
 *
 * #syscalls fcntl
 *
 * fallocate() passed as EXTRA_SYSCALL only if FALLOC_FL_COLLAPSE_RANGE is there
 */
static int logfile_rotate(int fd, const struct timespec *now)
{
	if (fcntl(fd, F_SETFL, O_RDWR /* Drop O_APPEND: explicit lseek() */))
		return -errno;

#ifdef FALLOC_FL_COLLAPSE_RANGE
	/* Only for Linux >= 3.15, extent-based ext4 or XFS, glibc >= 2.18 */
	if (!fallocate(fd, FALLOC_FL_COLLAPSE_RANGE, 0, log_cut_size))
		logfile_rotate_fallocate(fd, now);
	else
#endif
		logfile_rotate_move(fd, now);

	if (fcntl(fd, F_SETFL, O_RDWR | O_APPEND))
		return -errno;

	return 0;
}

/**
 * logfile_write() - Write entry to log file, trigger rotation if full
 * @pri:	Facility and level map, same as priority for vsyslog()
 * @format:	Same as vsyslog() format
 * @ap:		Same as vsyslog() ap
 */
void logfile_write(int pri, const char *format, va_list ap)
{
	struct timespec now;
	char buf[BUFSIZ];
	int n;

	if (clock_gettime(CLOCK_REALTIME, &now))
		return;

	n = snprintf(buf, BUFSIZ, "%lli.%04lli: %s",
		     (long long int)(now.tv_sec - log_start),
		     (long long int)(now.tv_nsec / (100L * 1000)),
		     logfile_prefix[pri]);

	n += vsnprintf(buf + n, BUFSIZ - n, format, ap);

	if (format[strlen(format)] != '\n')
		n += snprintf(buf + n, BUFSIZ - n, "\n");

	if ((log_written + n >= log_size) && logfile_rotate(log_file, &now))
		return;

	if ((n = write(log_file, buf, n)) >= 0)
		log_written += n;
}