X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=i3-dump-log%2Fmain.c;h=137554a4f1fefc36539c5ca8c40b5357b32a7e2a;hb=96e1b80371b985d4f67b36e6cb48e61b5fb83995;hp=30dd514f6d143d927d7776139faac84c33701e12;hpb=8d72a77c7a56fa788d29a54455c806f18e2a3fd5;p=i3%2Fi3 diff --git a/i3-dump-log/main.c b/i3-dump-log/main.c index 30dd514f..137554a4 100644 --- a/i3-dump-log/main.c +++ b/i3-dump-log/main.c @@ -2,7 +2,7 @@ * vim:ts=4:sw=4:expandtab * * i3 - an improved dynamic tiling window manager - * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE) + * © 2009 Michael Stapelberg and contributors (see also: LICENSE) * * i3-dump-log/main.c: Dumps the i3 SHM log to stdout. * @@ -28,18 +28,46 @@ #include "shmlog.h" #include +static uint32_t offset_next_write, + wrap_count; + +static i3_shmlog_header *header; +static char *logbuffer, + *walk; + +static int check_for_wrap(void) { + if (wrap_count == header->wrap_count) + return 0; + + /* The log wrapped. Print the remaining content and reset walk to the top + * of the log. */ + wrap_count = header->wrap_count; + const int len = (logbuffer + header->offset_last_wrap) - walk; + swrite(STDOUT_FILENO, walk, len); + walk = logbuffer + sizeof(i3_shmlog_header); + return 1; +} + +static void print_till_end(void) { + check_for_wrap(); + const int len = (logbuffer + header->offset_next_write) - walk; + swrite(STDOUT_FILENO, walk, len); + walk += len; +} + int main(int argc, char *argv[]) { int o, option_index = 0; - bool verbose = false; + bool verbose = false, + follow = false; static struct option long_options[] = { {"version", no_argument, 0, 'v'}, {"verbose", no_argument, 0, 'V'}, + {"follow", no_argument, 0, 'f'}, {"help", no_argument, 0, 'h'}, - {0, 0, 0, 0} - }; + {0, 0, 0, 0}}; - char *options_string = "s:vVh"; + char *options_string = "s:vfVh"; while ((o = getopt_long(argc, argv, options_string, long_options, &option_index)) != -1) { if (o == 'v') { @@ -47,61 +75,106 @@ int main(int argc, char *argv[]) { return 0; } else if (o == 'V') { verbose = true; + } else if (o == 'f') { + follow = true; } else if (o == 'h') { printf("i3-dump-log " I3_VERSION "\n"); - printf("i3-dump-log [-s ]\n"); + printf("i3-dump-log [-f] [-s ]\n"); return 0; } } - char *shmname = root_atom_contents("I3_SHMLOG_PATH"); - if (shmname == NULL) + char *shmname = root_atom_contents("I3_SHMLOG_PATH", NULL, 0); + if (shmname == NULL) { + /* Something failed. Let’s invest a little effort to find out what it + * is. This is hugely helpful for users who want to debug i3 but are + * not used to the procedure yet. */ + xcb_connection_t *conn; + int screen; + if ((conn = xcb_connect(NULL, &screen)) == NULL || + xcb_connection_has_error(conn)) { + fprintf(stderr, "i3-dump-log: ERROR: Cannot connect to X11.\n\n"); + if (getenv("DISPLAY") == NULL) { + fprintf(stderr, "Your DISPLAY environment variable is not set.\n"); + fprintf(stderr, "Are you running i3-dump-log via SSH or on a virtual console?\n"); + fprintf(stderr, "Try DISPLAY=:0 i3-dump-log\n"); + exit(1); + } + fprintf(stderr, "FYI: The DISPLAY environment variable is set to \"%s\".\n", getenv("DISPLAY")); + exit(1); + } + if (root_atom_contents("I3_CONFIG_PATH", conn, screen) != NULL) { + fprintf(stderr, "i3-dump-log: ERROR: i3 is running, but SHM logging is not enabled.\n\n"); + if (!is_debug_build()) { + fprintf(stderr, "You seem to be using a release version of i3:\n %s\n\n", I3_VERSION); + fprintf(stderr, "Release versions do not use SHM logging by default,\ntherefore i3-dump-log does not work.\n\n"); + fprintf(stderr, "Please follow this guide instead:\nhttp://i3wm.org/docs/debugging-release-version.html\n"); + exit(1); + } + } errx(EXIT_FAILURE, "Cannot get I3_SHMLOG_PATH atom contents. Is i3 running on this display?"); + } if (*shmname == '\0') errx(EXIT_FAILURE, "Cannot dump log: SHM logging is disabled in i3."); struct stat statbuf; - int logbuffer_shm = shm_open(shmname, O_RDONLY, 0); + /* NB: While we must never write, we need O_RDWR for the pthread condvar. */ + int logbuffer_shm = shm_open(shmname, O_RDWR, 0); if (logbuffer_shm == -1) err(EXIT_FAILURE, "Could not shm_open SHM segment for the i3 log (%s)", shmname); if (fstat(logbuffer_shm, &statbuf) != 0) err(EXIT_FAILURE, "stat(%s)", shmname); - char *logbuffer = mmap(NULL, statbuf.st_size, PROT_READ, MAP_SHARED, logbuffer_shm, 0); + /* NB: While we must never write, we need PROT_WRITE for the pthread condvar. */ + logbuffer = mmap(NULL, statbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, logbuffer_shm, 0); if (logbuffer == MAP_FAILED) err(EXIT_FAILURE, "Could not mmap SHM segment for the i3 log"); - i3_shmlog_header *header = (i3_shmlog_header*)logbuffer; + header = (i3_shmlog_header *)logbuffer; if (verbose) printf("next_write = %d, last_wrap = %d, logbuffer_size = %d, shmname = %s\n", header->offset_next_write, header->offset_last_wrap, header->size, shmname); - int chars; - char *walk = logbuffer + header->offset_next_write; - /* Skip the first line, it very likely is mangled. Not a problem, though, - * the log is chatty enough to have plenty lines left. */ - while (*walk != '\0') - walk++; + walk = logbuffer + header->offset_next_write; - /* Print the oldest log lines. We use printf("%s") to stop on \0. */ - while (walk < (logbuffer + header->offset_last_wrap)) { - chars = printf("%s", walk); - /* Shortcut: If there are two consecutive \0 bytes, this part of the - * buffer was never touched. To not call printf() for every byte of the - * buffer, we directly exit the loop. */ - if (*walk == '\0' && *(walk+1) == '\0') - break; - walk += (chars > 0 ? chars : 1); + /* We first need to print old content in case there was at least one + * wrapping already. */ + + if (*walk != '\0') { + /* In case there was a write to the buffer already, skip the first + * old line, it very likely is mangled. Not a problem, though, the log + * is chatty enough to have plenty lines left. */ + while (*walk != '\n') + walk++; + walk++; } + /* In case there was no wrapping, this is a no-op, otherwise it prints the + * old lines. */ + wrap_count = 0; + check_for_wrap(); + /* Then start from the beginning and print the newer lines */ walk = logbuffer + sizeof(i3_shmlog_header); - while (walk < (logbuffer + header->offset_next_write)) { - chars = printf("%s", walk); - walk += (chars > 0 ? chars : 1); + print_till_end(); + + if (follow) { + /* Since pthread_cond_wait() expects a mutex, we need to provide one. + * To not lock i3 (that’s bad, mhkay?) we just define one outside of + * the shared memory. */ + pthread_mutex_t dummy_mutex = PTHREAD_MUTEX_INITIALIZER; + pthread_mutex_lock(&dummy_mutex); + while (1) { + pthread_cond_wait(&(header->condvar), &dummy_mutex); + /* If this was not a spurious wakeup, print the new lines. */ + if (header->offset_next_write != offset_next_write) { + offset_next_write = header->offset_next_write; + print_till_end(); + } + } } return 0;