* 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.
*
*/
+#include <config.h>
+
#include <stdio.h>
#include <stdbool.h>
#include <sys/types.h>
#include "shmlog.h"
#include <i3/ipc.h>
+#if !defined(__OpenBSD__)
+static uint32_t offset_next_write;
+#endif
+static uint32_t 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;
+#if !defined(__OpenBSD__)
+ bool follow = false;
+#endif
static struct option long_options[] = {
{"version", no_argument, 0, 'v'},
{"verbose", no_argument, 0, 'V'},
+#if !defined(__OpenBSD__)
+ {"follow", no_argument, 0, 'f'},
+#endif
{"help", no_argument, 0, 'h'},
{0, 0, 0, 0}
};
- char *options_string = "s:vVh";
+#if !defined(__OpenBSD__)
+ char *options_string = "s:vfVh";
+#else
+ char *options_string = "vVh";
+#endif
while ((o = getopt_long(argc, argv, options_string, long_options, &option_index)) != -1) {
if (o == 'v') {
return 0;
} else if (o == 'V') {
verbose = true;
+#if !defined(__OpenBSD__)
+ } else if (o == 'f') {
+ follow = true;
+#endif
} else if (o == 'h') {
printf("i3-dump-log " I3_VERSION "\n");
- printf("i3-dump-log [-s <socket>]\n");
+#if !defined(__OpenBSD__)
+ printf("i3-dump-log [-fhVv]\n");
+#else
+ printf("i3-dump-log [-hVv]\n");
+#endif
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')
+ free(shmname);
+ walk = logbuffer + header->offset_next_write;
+
+ /* 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++;
-
- /* 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);
}
+ /* 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 !defined(__OpenBSD__)
+ 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();
+ }
+ }
}
+#endif
return 0;
}