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Implement logging to a SHM ringbuffer 

This feature is automatically enabled when running a debug version of i3.
The logfile will use 1% of your physical RAM size, but at max 25 MiB.
This commit is contained in:
Michael Stapelberg 2011-12-09 22:27:35 +00:00
parent 4cd5bf94cf
commit e65ee63763
3 changed files with 146 additions and 23 deletions
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1
common.mk
View File

@ -68,6 +68,7 @@ CPPFLAGS += -DPCRE_HAS_UCP=1
endif
LIBS += -lm
LIBS += -lrt
LIBS += -L $(TOPDIR)/libi3 -li3
LIBS += $(call ldflags_for_lib, xcb-event,xcb-event)
LIBS += $(call ldflags_for_lib, xcb-keysyms,xcb-keysyms)

9
include/log.h
View File

@ -21,6 +21,8 @@
extern char *loglevels[];
extern char *errorfilename;
extern char *shmlogname;
extern int shmlog_size;
/**
* Initializes logging by creating an error logfile in /tmp (or
@ -35,6 +37,13 @@ void init_logging();
*/
void add_loglevel(const char *level);
/**
* Returns the offsets for the next write and for the last wrap.
* Necessary to print the i3 SHM log in the correct order.
*
*/
void get_log_markers(int *offset_next_write, int *offset_last_wrap, int *size);
/**
* Set verbosity of i3. If verbose is set to true, informative messages will
* be printed to stdout. If verbose is set to false, only errors will be

159
src/log.c
View File

@ -15,9 +15,14 @@
#include <sys/time.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include "util.h"
#include "log.h"
#include "i3.h"
#include "libi3.h"
/* loglevels.h is autogenerated at make time */
#include "loglevels.h"
@ -27,21 +32,79 @@ static bool verbose = false;
static FILE *errorfile;
char *errorfilename;
/* SHM logging variables */
/* The name for the SHM (/i3-log-%pid). Will end up on /dev/shm on most
* systems. Global so that we can clean up at exit. */
char *shmlogname = "";
/* Size limit for the SHM log, by default 25 MiB. Can be overwritten using the
* flag --shmlog-size. */
int shmlog_size = 25 * 1024 * 1024;
/* If enabled, logbuffer will point to a memory mapping of the i3 SHM log. */
static char *logbuffer;
/* A pointer (within logbuffer) where data will be written to next. */
static char *logwalk;
/* A pointer to the byte where we last wrapped. Necessary to not print the
* left-overs at the end of the ringbuffer. */
static char *loglastwrap;
/* Size (in bytes) of the i3 SHM log. */
static int logbuffer_size;
/* File descriptor for shm_open. */
static int logbuffer_shm;
/*
* Initializes logging by creating an error logfile in /tmp (or
* XDG_RUNTIME_DIR, see get_process_filename()).
*
* Will be called twice if --shmlog-size is specified.
*
*/
void init_logging() {
errorfilename = get_process_filename("errorlog");
if (errorfilename == NULL) {
ELOG("Could not initialize errorlog\n");
return;
if (!errorfilename) {
if (!(errorfilename = get_process_filename("errorlog")))
ELOG("Could not initialize errorlog\n");
else {
errorfile = fopen(errorfilename, "w");
if (fcntl(fileno(errorfile), F_SETFD, FD_CLOEXEC)) {
ELOG("Could not set close-on-exec flag\n");
}
}
}
errorfile = fopen(errorfilename, "w");
if (fcntl(fileno(errorfile), F_SETFD, FD_CLOEXEC)) {
ELOG("Could not set close-on-exec flag\n");
/* If this is a debug build (not a release version), we will enable SHM
* logging by default, unless the user turned it off explicitly. */
if (logbuffer == NULL && shmlog_size > 0) {
/* Reserve 1% of the RAM for the logfile, but at max 25 MiB.
* For 512 MiB of RAM this will lead to a 5 MiB log buffer.
* At the moment (2011-12-10), no testcase leads to an i3 log
* of more than ~ 600 KiB. */
long long physical_mem_bytes = (long long)sysconf(_SC_PHYS_PAGES) *
sysconf(_SC_PAGESIZE);
logbuffer_size = min(physical_mem_bytes * 0.01, shmlog_size);
sasprintf(&shmlogname, "/i3-log-%d", getpid());
logbuffer_shm = shm_open(shmlogname, O_RDWR | O_CREAT | O_TRUNC, S_IREAD | S_IWRITE);
if (logbuffer_shm == -1) {
ELOG("Could not shm_open SHM segment for the i3 log: %s\n", strerror(errno));
return;
}
if (ftruncate(logbuffer_shm, logbuffer_size) == -1) {
close(logbuffer_shm);
shm_unlink("/i3-log-");
ELOG("Could not ftruncate SHM segment for the i3 log: %s\n", strerror(errno));
return;
}
logbuffer = mmap(NULL, logbuffer_size, PROT_READ | PROT_WRITE, MAP_SHARED, logbuffer_shm, 0);
if (logbuffer == MAP_FAILED) {
close(logbuffer_shm);
shm_unlink("/i3-log-");
ELOG("Could not mmap SHM segment for the i3 log: %s\n", strerror(errno));
logbuffer = NULL;
return;
}
logwalk = logbuffer;
loglastwrap = logbuffer + logbuffer_size;
}
}
@ -79,28 +142,78 @@ void add_loglevel(const char *level) {
}
/*
* Logs the given message to stdout while prefixing the current time to it.
* Returns the offsets for the next write and for the last wrap.
* Necessary to print the i3 SHM log in the correct order.
*
*/
void get_log_markers(int *offset_next_write, int *offset_last_wrap, int *size) {
*offset_next_write = (logwalk - logbuffer);
*offset_last_wrap = (loglastwrap - logbuffer);
*size = logbuffer_size;
}
/*
* Logs the given message to stdout (if print is true) while prefixing the
* current time to it. Additionally, the message will be saved in the i3 SHM
* log if enabled.
* This is to be called by *LOG() which includes filename/linenumber/function.
*
*/
void vlog(char *fmt, va_list args) {
static char timebuf[64];
static void vlog(const bool print, const char *fmt, va_list args) {
/* Precisely one page to not consume too much memory but to hold enough
* data to be useful. */
static char message[4096];
static struct tm result;
static time_t t;
static struct tm *tmp;
static size_t len;
/* Get current time */
time_t t = time(NULL);
t = time(NULL);
/* Convert time to local time (determined by the locale) */
struct tm *tmp = localtime_r(&t, &result);
tmp = localtime_r(&t, &result);
/* Generate time prefix */
strftime(timebuf, sizeof(timebuf), "%x %X - ", tmp);
len = strftime(message, sizeof(message), "%x %X - ", tmp);
/*
* logbuffer print
* ----------------
* true true format message, save, print
* true false format message, save
* false true print message only
* false false INVALID, never called
*/
if (!logbuffer) {
#ifdef DEBUG_TIMING
struct timeval tv;
gettimeofday(&tv, NULL);
printf("%s%d.%d - ", timebuf, tv.tv_sec, tv.tv_usec);
struct timeval tv;
gettimeofday(&tv, NULL);
printf("%s%d.%d - ", message, tv.tv_sec, tv.tv_usec);
#else
printf("%s", timebuf);
printf("%s", message);
#endif
vprintf(fmt, args);
vprintf(fmt, args);
} else {
len += vsnprintf(message + len, sizeof(message) - len, fmt, args);
if (len == sizeof(message)) {
fprintf(stderr, "BUG: single log message > 4k\n");
}
/* If there is no space for the current message (plus trailing
* nullbyte) in the ringbuffer, we need to wrap and write to the
* beginning again. */
if ((len+1) >= (logbuffer_size - (logwalk - logbuffer))) {
loglastwrap = logwalk;
logwalk = logbuffer;
}
/* Copy the buffer, terminate it, move the write pointer to the byte after
* our current message. */
strncpy(logwalk, message, len);
logwalk[len] = '\0';
logwalk += len + 1;
if (print)
fwrite(message, len, 1, stdout);
}
}
/*
@ -111,11 +224,11 @@ void vlog(char *fmt, va_list args) {
void verboselog(char *fmt, ...) {
va_list args;
if (!verbose)
if (!logbuffer && !verbose)
return;
va_start(args, fmt);
vlog(fmt, args);
vlog(verbose, fmt, args);
va_end(args);
}
@ -127,7 +240,7 @@ void errorlog(char *fmt, ...) {
va_list args;
va_start(args, fmt);
vlog(fmt, args);
vlog(true, fmt, args);
va_end(args);
/* also log to the error logfile, if opened */
@ -146,10 +259,10 @@ void errorlog(char *fmt, ...) {
void debuglog(uint64_t lev, char *fmt, ...) {
va_list args;
if ((loglevel & lev) == 0)
if (!logbuffer && !(loglevel & lev))
return;
va_start(args, fmt);
vlog(fmt, args);
vlog((loglevel & lev), fmt, args);
va_end(args);
}