i3
log.c
Go to the documentation of this file.
1 #undef I3__FILE__
2 #define I3__FILE__ "log.c"
3 /*
4  * vim:ts=4:sw=4:expandtab
5  *
6  * i3 - an improved dynamic tiling window manager
7  * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
8  *
9  * log.c: Logging functions.
10  *
11  */
12 #include <stdarg.h>
13 #include <stdio.h>
14 #include <string.h>
15 #include <stdbool.h>
16 #include <stdlib.h>
17 #include <sys/time.h>
18 #include <unistd.h>
19 #include <fcntl.h>
20 #include <sys/mman.h>
21 #include <sys/stat.h>
22 #include <errno.h>
23 #include <pthread.h>
24 #if defined(__APPLE__)
25 #include <sys/types.h>
26 #include <sys/sysctl.h>
27 #endif
28 
29 #include "util.h"
30 #include "log.h"
31 #include "i3.h"
32 #include "libi3.h"
33 #include "shmlog.h"
34 
35 static bool debug_logging = false;
36 static bool verbose = false;
37 static FILE *errorfile;
39 
40 /* SHM logging variables */
41 
42 /* The name for the SHM (/i3-log-%pid). Will end up on /dev/shm on most
43  * systems. Global so that we can clean up at exit. */
44 char *shmlogname = "";
45 /* Size limit for the SHM log, by default 25 MiB. Can be overwritten using the
46  * flag --shmlog-size. */
47 int shmlog_size = 0;
48 /* If enabled, logbuffer will point to a memory mapping of the i3 SHM log. */
49 static char *logbuffer;
50 /* A pointer (within logbuffer) where data will be written to next. */
51 static char *logwalk;
52 /* A pointer to the shmlog header */
54 /* A pointer to the byte where we last wrapped. Necessary to not print the
55  * left-overs at the end of the ringbuffer. */
56 static char *loglastwrap;
57 /* Size (in bytes) of the i3 SHM log. */
58 static int logbuffer_size;
59 /* File descriptor for shm_open. */
60 static int logbuffer_shm;
61 
62 /*
63  * Writes the offsets for the next write and for the last wrap to the
64  * shmlog_header.
65  * Necessary to print the i3 SHM log in the correct order.
66  *
67  */
68 static void store_log_markers(void) {
69  header->offset_next_write = (logwalk - logbuffer);
71  header->size = logbuffer_size;
72 }
73 
74 /*
75  * Initializes logging by creating an error logfile in /tmp (or
76  * XDG_RUNTIME_DIR, see get_process_filename()).
77  *
78  * Will be called twice if --shmlog-size is specified.
79  *
80  */
81 void init_logging(void) {
82  if (!errorfilename) {
83  if (!(errorfilename = get_process_filename("errorlog")))
84  fprintf(stderr, "Could not initialize errorlog\n");
85  else {
86  errorfile = fopen(errorfilename, "w");
87  if (fcntl(fileno(errorfile), F_SETFD, FD_CLOEXEC)) {
88  fprintf(stderr, "Could not set close-on-exec flag\n");
89  }
90  }
91  }
92  /* Start SHM logging if shmlog_size is > 0. shmlog_size is SHMLOG_SIZE by
93  * default on development versions, and 0 on release versions. If it is
94  * not > 0, the user has turned it off, so let's close the logbuffer. */
95  if (shmlog_size > 0 && logbuffer == NULL)
97  else if (shmlog_size <= 0 && logbuffer)
99  atexit(purge_zerobyte_logfile);
100 }
101 
102 /*
103  * Opens the logbuffer.
104  *
105  */
106 void open_logbuffer(void) {
107  /* Reserve 1% of the RAM for the logfile, but at max 25 MiB.
108  * For 512 MiB of RAM this will lead to a 5 MiB log buffer.
109  * At the moment (2011-12-10), no testcase leads to an i3 log
110  * of more than ~ 600 KiB. */
111  long long physical_mem_bytes;
112 #if defined(__APPLE__)
113  int mib[2] = { CTL_HW, HW_MEMSIZE };
114  size_t length = sizeof(long long);
115  sysctl(mib, 2, &physical_mem_bytes, &length, NULL, 0);
116 #else
117  physical_mem_bytes = (long long)sysconf(_SC_PHYS_PAGES) *
118  sysconf(_SC_PAGESIZE);
119 #endif
120  logbuffer_size = min(physical_mem_bytes * 0.01, shmlog_size);
121 #if defined(__FreeBSD__)
122  sasprintf(&shmlogname, "/tmp/i3-log-%d", getpid());
123 #else
124  sasprintf(&shmlogname, "/i3-log-%d", getpid());
125 #endif
126  logbuffer_shm = shm_open(shmlogname, O_RDWR | O_CREAT, S_IREAD | S_IWRITE);
127  if (logbuffer_shm == -1) {
128  fprintf(stderr, "Could not shm_open SHM segment for the i3 log: %s\n", strerror(errno));
129  return;
130  }
131 
132  if (ftruncate(logbuffer_shm, logbuffer_size) == -1) {
133  close(logbuffer_shm);
134  shm_unlink(shmlogname);
135  fprintf(stderr, "Could not ftruncate SHM segment for the i3 log: %s\n", strerror(errno));
136  return;
137  }
138 
139  logbuffer = mmap(NULL, logbuffer_size, PROT_READ | PROT_WRITE, MAP_SHARED, logbuffer_shm, 0);
140  if (logbuffer == MAP_FAILED) {
141  close_logbuffer();
142  fprintf(stderr, "Could not mmap SHM segment for the i3 log: %s\n", strerror(errno));
143  return;
144  }
145 
146  /* Initialize with 0-bytes, just to be sure… */
147  memset(logbuffer, '\0', logbuffer_size);
148 
149  header = (i3_shmlog_header*)logbuffer;
150 
151  pthread_condattr_t cond_attr;
152  pthread_condattr_init(&cond_attr);
153  if (pthread_condattr_setpshared(&cond_attr, PTHREAD_PROCESS_SHARED) != 0)
154  fprintf(stderr, "pthread_condattr_setpshared() failed, i3-dump-log -f will not work!\n");
155  pthread_cond_init(&(header->condvar), &cond_attr);
156 
157  logwalk = logbuffer + sizeof(i3_shmlog_header);
160 }
161 
162 /*
163  * Closes the logbuffer.
164  *
165  */
166 void close_logbuffer(void) {
167  close(logbuffer_shm);
168  shm_unlink(shmlogname);
169  logbuffer = NULL;
170  shmlogname = "";
171 }
172 
173 /*
174  * Set verbosity of i3. If verbose is set to true, informative messages will
175  * be printed to stdout. If verbose is set to false, only errors will be
176  * printed.
177  *
178  */
179 void set_verbosity(bool _verbose) {
180  verbose = _verbose;
181 }
182 
183 /*
184  * Get debug logging.
185  *
186  */
187 bool get_debug_logging(void) {
188  return debug_logging;
189 }
190 
191 /*
192  * Set debug logging.
193  *
194  */
195 void set_debug_logging(const bool _debug_logging) {
196  debug_logging = _debug_logging;
197 }
198 
199 /*
200  * Logs the given message to stdout (if print is true) while prefixing the
201  * current time to it. Additionally, the message will be saved in the i3 SHM
202  * log if enabled.
203  * This is to be called by *LOG() which includes filename/linenumber/function.
204  *
205  */
206 static void vlog(const bool print, const char *fmt, va_list args) {
207  /* Precisely one page to not consume too much memory but to hold enough
208  * data to be useful. */
209  static char message[4096];
210  static struct tm result;
211  static time_t t;
212  static struct tm *tmp;
213  static size_t len;
214 
215  /* Get current time */
216  t = time(NULL);
217  /* Convert time to local time (determined by the locale) */
218  tmp = localtime_r(&t, &result);
219  /* Generate time prefix */
220  len = strftime(message, sizeof(message), "%x %X - ", tmp);
221 
222  /*
223  * logbuffer print
224  * ----------------
225  * true true format message, save, print
226  * true false format message, save
227  * false true print message only
228  * false false INVALID, never called
229  */
230  if (!logbuffer) {
231 #ifdef DEBUG_TIMING
232  struct timeval tv;
233  gettimeofday(&tv, NULL);
234  printf("%s%d.%d - ", message, tv.tv_sec, tv.tv_usec);
235 #else
236  printf("%s", message);
237 #endif
238  vprintf(fmt, args);
239  } else {
240  len += vsnprintf(message + len, sizeof(message) - len, fmt, args);
241  if (len >= sizeof(message)) {
242  fprintf(stderr, "BUG: single log message > 4k\n");
243  }
244 
245  /* If there is no space for the current message in the ringbuffer, we
246  * need to wrap and write to the beginning again. */
247  if (len >= (logbuffer_size - (logwalk - logbuffer))) {
249  logwalk = logbuffer + sizeof(i3_shmlog_header);
251  header->wrap_count++;
252  }
253 
254  /* Copy the buffer, move the write pointer to the byte after our
255  * current message. */
256  strncpy(logwalk, message, len);
257  logwalk += len;
258 
260 
261  /* Wake up all (i3-dump-log) processes waiting for condvar. */
262  pthread_cond_broadcast(&(header->condvar));
263 
264  if (print)
265  fwrite(message, len, 1, stdout);
266  }
267 }
268 
269 /*
270  * Logs the given message to stdout while prefixing the current time to it,
271  * but only if verbose mode is activated.
272  *
273  */
274 void verboselog(char *fmt, ...) {
275  va_list args;
276 
277  if (!logbuffer && !verbose)
278  return;
279 
280  va_start(args, fmt);
281  vlog(verbose, fmt, args);
282  va_end(args);
283 }
284 
285 /*
286  * Logs the given message to stdout while prefixing the current time to it.
287  *
288  */
289 void errorlog(char *fmt, ...) {
290  va_list args;
291 
292  va_start(args, fmt);
293  vlog(true, fmt, args);
294  va_end(args);
295 
296  /* also log to the error logfile, if opened */
297  va_start(args, fmt);
298  vfprintf(errorfile, fmt, args);
299  fflush(errorfile);
300  va_end(args);
301 }
302 
303 /*
304  * Logs the given message to stdout while prefixing the current time to it,
305  * but only if debug logging was activated.
306  * This is to be called by DLOG() which includes filename/linenumber
307  *
308  */
309 void debuglog(char *fmt, ...) {
310  va_list args;
311 
312  if (!logbuffer && !(debug_logging))
313  return;
314 
315  va_start(args, fmt);
316  vlog(debug_logging, fmt, args);
317  va_end(args);
318 }
319 
320 /*
321  * Deletes the unused log files. Useful if i3 exits immediately, eg.
322  * because --get-socketpath was called. We don't care for syscall
323  * failures. This function is invoked automatically when exiting.
324  */
326  struct stat st;
327  char *slash;
328 
329  if (!errorfilename)
330  return;
331 
332  /* don't delete the log file if it contains something */
333  if ((stat(errorfilename, &st)) == -1 || st.st_size > 0)
334  return;
335 
336  if (unlink(errorfilename) == -1)
337  return;
338 
339  if ((slash = strrchr(errorfilename, '/')) != NULL) {
340  *slash = '\0';
341  /* possibly fails with ENOTEMPTY if there are files (or
342  * sockets) left. */
343  rmdir(errorfilename);
344  }
345 }