dss.ggo: Minor documentation improvements.
[dss.git] / dss.c
diff --git a/dss.c b/dss.c
index d77fef2f8cb31704c619d6cda61fd68570bbbe35..1bab9aef5f2dce9c92c5416e0d266a1bd1df35cc 100644 (file)
--- a/dss.c
+++ b/dss.c
@@ -42,9 +42,26 @@ static int rsync_stopped;
 static pid_t rm_pid;
 /** When the next snapshot is due. */
 struct timeval next_snapshot_time;
+
+pid_t pre_create_hook_pid;
+pid_t post_create_hook_pid;
+
 /* Creation time of the snapshot currently being created. */
 int64_t current_snapshot_creation_time;
 
+static char *path_to_last_complete_snapshot;
+
+enum {
+       SCS_READY,
+       SCS_PRE_HOOK_RUNNING,
+       SCS_PRE_HOOK_SUCCESS,
+       SCS_RSYNC_RUNNING,
+       SCS_RSYNC_SUCCESS,
+       SCS_POST_HOOK_RUNNING,
+};
+
+static unsigned snapshot_creation_status;
+
 
 DEFINE_DSS_ERRLIST;
 
@@ -383,10 +400,14 @@ int wait_for_process(pid_t pid, int *status)
 
        DSS_DEBUG_LOG("Waiting for process %d to terminate\n", (int)pid);
        for (;;) {
-               pause();
-               ret = next_signal();
+               fd_set rfds;
+
+               FD_ZERO(&rfds);
+               FD_SET(signal_pipe, &rfds);
+               ret = dss_select(signal_pipe + 1, &rfds, NULL, NULL);
                if (ret < 0)
                        break;
+               ret = next_signal();
                if (!ret)
                        continue;
                if (ret == SIGCHLD) {
@@ -445,8 +466,8 @@ int remove_redundant_snapshot(struct snapshot_list *sl)
 
                if (keep >= num)
                        missing += keep - num;
-               DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
-                       interval, keep, num, missing);
+//             DSS_DEBUG_LOG("interval %i: keep: %u, have: %u, missing: %u\n",
+//                     interval, keep, num, missing);
                if (keep + missing >= num)
                        continue;
                /* redundant snapshot in this interval, pick snapshot with lowest score */
@@ -620,6 +641,8 @@ void parse_config_file(int override)
                logfile = open_log(conf.logfile_arg);
                log_welcome(conf.loglevel_arg);
        }
+       DSS_EMERG_LOG("loglevel: %d\n", conf.loglevel_arg);
+//     cmdline_parser_dump(logfile? logfile : stdout, &conf);
        ret = dss_chdir(conf.dest_dir_arg);
 out:
        free(config_file);
@@ -637,21 +660,65 @@ void handle_sighup(void)
 
 int rename_incomplete_snapshot(int64_t start)
 {
-       char *old_name, *new_name;
+       char *old_name;
        int ret;
 
-       ret = complete_name(start, get_current_time(), &new_name);
+       free(path_to_last_complete_snapshot);
+       ret = complete_name(start, get_current_time(),
+               &path_to_last_complete_snapshot);
        if (ret < 0)
                return ret;
        old_name = incomplete_name(start);
-       ret = dss_rename(old_name, new_name);
+       ret = dss_rename(old_name, path_to_last_complete_snapshot);
        if (ret >= 0)
-               DSS_NOTICE_LOG("%s -> %s\n", old_name, new_name);
+               DSS_NOTICE_LOG("%s -> %s\n", old_name,
+                       path_to_last_complete_snapshot);
        free(old_name);
-       free(new_name);
        return ret;
 }
 
+void compute_next_snapshot_time(void)
+{
+       struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
+               tmp, diff;
+       int64_t x = 0;
+       unsigned wanted = num_snapshots(0), num_complete_snapshots = 0;
+       int i, ret;
+       struct snapshot *s = NULL;
+       struct snapshot_list sl;
+
+       assert(snapshot_creation_status == SCS_READY);
+       current_snapshot_creation_time = 0;
+       get_snapshot_list(&sl);
+       FOR_EACH_SNAPSHOT(s, i, &sl) {
+               if (!(s->flags & SS_COMPLETE))
+                       continue;
+               num_complete_snapshots++;
+               x += s->completion_time - s->creation_time;
+       }
+       assert(x >= 0);
+       if (num_complete_snapshots)
+               x /= num_complete_snapshots; /* avg time to create one snapshot */
+       x *= wanted; /* time to create all snapshots in interval 0 */
+       tmp.tv_sec = x;
+       tmp.tv_usec = 0;
+       ret = tv_diff(&unit_interval, &tmp, &diff); /* total sleep time per unit interval */
+       gettimeofday(&now, NULL);
+       if (ret < 0 || !s)
+               goto min_sleep;
+       tv_divide(wanted, &diff, &tmp); /* sleep time betweeen two snapshots */
+       diff.tv_sec = s->completion_time;
+       diff.tv_usec = 0;
+       tv_add(&diff, &tmp, &next_snapshot_time);
+       if (tv_diff(&now, &next_snapshot_time, NULL) < 0)
+               goto out;
+min_sleep:
+       next_snapshot_time = now;
+       next_snapshot_time.tv_sec += 60;
+out:
+       free_snapshot_list(&sl);
+}
+
 int handle_rsync_exit(int status)
 {
        int es, ret;
@@ -659,18 +726,24 @@ int handle_rsync_exit(int status)
        if (!WIFEXITED(status)) {
                make_err_msg("rsync process %d died involuntary", (int)rsync_pid);
                ret = -E_INVOLUNTARY_EXIT;
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
                goto out;
        }
        es = WEXITSTATUS(status);
        if (es != 0 && es != 23 && es != 24) {
                make_err_msg("rsync process %d returned %d", (int)rsync_pid, es);
                ret = -E_BAD_EXIT_CODE;
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
                goto out;
        }
        ret = rename_incomplete_snapshot(current_snapshot_creation_time);
+       if (ret < 0)
+               goto out;
+       snapshot_creation_status = SCS_RSYNC_SUCCESS;
 out:
        rsync_pid = 0;
-       current_snapshot_creation_time = 0;
        rsync_stopped = 0;
        return ret;
 }
@@ -747,45 +820,107 @@ void free_rsync_argv(char **argv)
        free(argv);
 }
 
+int pre_create_hook(void)
+{
+       int ret, fds[3] = {0, 0, 0};
+
+       if (!conf.pre_create_hook_given) {
+               snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
+               return 0;
+       }
+       DSS_NOTICE_LOG("executing %s\n", conf.pre_create_hook_arg);
+       ret = dss_exec_cmdline_pid(&pre_create_hook_pid,
+               conf.pre_create_hook_arg, fds);
+       if (ret < 0)
+               return ret;
+       snapshot_creation_status = SCS_PRE_HOOK_RUNNING;
+       return ret;
+}
+
+int post_create_hook(void)
+{
+       int ret, fds[3] = {0, 0, 0};
+       char *cmd;
+
+       if (!conf.post_create_hook_given) {
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
+               return 0;
+       }
+       cmd = make_message("%s %s", conf.post_create_hook_arg,
+               path_to_last_complete_snapshot);
+       DSS_NOTICE_LOG("executing %s\n", cmd);
+       ret = dss_exec_cmdline_pid(&post_create_hook_pid, cmd, fds);
+       free(cmd);
+       if (ret < 0)
+               return ret;
+       snapshot_creation_status = SCS_POST_HOOK_RUNNING;
+       return ret;
+}
+
 int create_snapshot(char **argv)
 {
-       int fds[3] = {0, 0, 0};
-       char *name = incomplete_name(current_snapshot_creation_time);
+       int ret, fds[3] = {0, 0, 0};
+       char *name;
 
+       name = incomplete_name(current_snapshot_creation_time);
        DSS_NOTICE_LOG("creating new snapshot %s\n", name);
        free(name);
-       return dss_exec(&rsync_pid, argv[0], argv, fds);
+       ret = dss_exec(&rsync_pid, argv[0], argv, fds);
+       if (ret < 0)
+               return ret;
+       snapshot_creation_status = SCS_RSYNC_RUNNING;
+       return ret;
 }
 
-void compute_next_snapshot_time(struct snapshot_list *sl)
+int handle_pre_create_hook_exit(int status)
 {
-       struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg},
-               tmp, diff;
-       int64_t x = 0;
-       unsigned wanted = num_snapshots(0), num_complete_snapshots = 0;
-       int i, ret;
-       struct snapshot *s;
+       int es, ret;
 
-       gettimeofday(&now, NULL);
-       FOR_EACH_SNAPSHOT(s, i, sl) {
-               if (!(s->flags & SS_COMPLETE))
-                       continue;
-               num_complete_snapshots++;
-               x += s->completion_time - s->creation_time;
+       if (!WIFEXITED(status)) {
+               make_err_msg("pre-create-hook %d died involuntary",
+                       (int)pre_create_hook_pid);
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
+               ret = -E_INVOLUNTARY_EXIT;
+               goto out;
        }
-       assert(x >= 0);
-       if (num_complete_snapshots)
-               x /= num_complete_snapshots; /* avg time to create one snapshot */
-       x *= wanted; /* time to create all snapshots in interval 0 */
-       tmp.tv_sec = x;
-       tmp.tv_usec = 0;
-       ret = tv_diff(&unit_interval, &tmp, &diff); /* time between creation */
-       if (ret < 0) {
-               next_snapshot_time = now;
-               return;
+       es = WEXITSTATUS(status);
+       if (es) {
+               make_err_msg("pre-create-hook %d returned %d",
+                       (int)pre_create_hook_pid, es);
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
+               ret = -E_BAD_EXIT_CODE;
+               goto out;
        }
-       tv_divide(wanted, &diff, &tmp);
-       tv_add(&now, &tmp, &next_snapshot_time);
+       snapshot_creation_status = SCS_PRE_HOOK_SUCCESS;
+       ret = 1;
+out:
+       pre_create_hook_pid = 0;
+       return ret;
+}
+
+int handle_sigchld()
+{
+       pid_t pid;
+       int status, ret = reap_child(&pid, &status);
+
+       if (ret <= 0)
+               return ret;
+       if (pid == rsync_pid)
+               return handle_rsync_exit(status);
+       if (pid == rm_pid)
+               return handle_rm_exit(status);
+       if (pid == pre_create_hook_pid)
+               return handle_pre_create_hook_exit(status);
+       if (pid == post_create_hook_pid) {
+               snapshot_creation_status = SCS_READY;
+               compute_next_snapshot_time();
+               return 1;
+       }
+       DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
+       exit(EXIT_FAILURE);
 }
 
 void handle_signal(void)
@@ -796,8 +931,6 @@ void handle_signal(void)
                goto out;
        sig = ret;
        switch (sig) {
-               int status;
-               pid_t pid;
        case SIGINT:
        case SIGTERM:
                restart_rsync_process();
@@ -809,14 +942,8 @@ void handle_signal(void)
                ret = 1;
                break;
        case SIGCHLD:
-               ret = reap_child(&pid, &status);
-               if (ret <= 0)
-                       break;
-               assert(pid == rsync_pid || pid == rm_pid);
-               if (pid == rsync_pid)
-                       ret = handle_rsync_exit(status);
-               else
-                       ret = handle_rm_exit(status);
+               ret = handle_sigchld();
+               break;
        }
 out:
        if (ret < 0)
@@ -875,55 +1002,56 @@ int disk_space_low(void)
        return 0;
 }
 
-int try_to_free_disk_space(int low_disk_space, struct snapshot_list *sl)
+int try_to_free_disk_space(int low_disk_space)
 {
        int ret;
+       struct snapshot_list sl;
 
-       ret = remove_outdated_snapshot(sl);
+       get_snapshot_list(&sl);
+       ret = remove_outdated_snapshot(&sl);
        if (ret) /* error, or we are removing something */
-               return ret;
+               goto out;
        /* no outdated snapshot */
-       ret = remove_redundant_snapshot(sl);
+       ret = remove_redundant_snapshot(&sl);
        if (ret)
-               return ret;
+               goto out;
+       ret = 0;
        if (!low_disk_space)
-               return 0;
+               goto out;
        DSS_WARNING_LOG("disk space low and nothing obvious to remove\n");
        ret = remove_oldest_snapshot();
        if (ret)
-               return ret;
+               goto out;
        make_err_msg("uhuhu: not enough disk space for a single snapshot");
-       return  -ENOSPC;
+       ret= -ENOSPC;
+out:
+       free_snapshot_list(&sl);
+       return ret;
 }
 
 int select_loop(void)
 {
        int ret;
        struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
-       struct snapshot_list sl = {.num_snapshots = 0};
 
        for (;;) {
-               struct timeval now, *tvp = &tv;
                fd_set rfds;
                int low_disk_space;
                char **rsync_argv;
+               struct timeval now, *tvp = &tv;
 
-               free_snapshot_list(&sl);
-               get_snapshot_list(&sl);
-               compute_next_snapshot_time(&sl);
-               FD_ZERO(&rfds);
-               FD_SET(signal_pipe, &rfds);
                if (rsync_pid)
-                       tv.tv_sec = 60;
+                       tv.tv_sec = 60; /* check every 60 seconds for free disk space */
                else if (rm_pid)
-                       tvp = NULL;
+                       tvp = NULL; /* sleep until rm process dies */
+               FD_ZERO(&rfds);
+               FD_SET(signal_pipe, &rfds);
+               DSS_DEBUG_LOG("tvp: %p, tv_sec: %lu\n", tvp, (long unsigned) tv.tv_sec);
                ret = dss_select(signal_pipe + 1, &rfds, NULL, tvp);
                if (ret < 0)
                        return ret;
-               if (FD_ISSET(signal_pipe, &rfds)) {
+               if (FD_ISSET(signal_pipe, &rfds))
                        handle_signal();
-                       continue;
-               }
                if (rm_pid)
                        continue;
                ret = disk_space_low();
@@ -932,26 +1060,42 @@ int select_loop(void)
                low_disk_space = ret;
                if (low_disk_space)
                        stop_rsync_process();
-               ret = try_to_free_disk_space(low_disk_space, &sl);
+               ret = try_to_free_disk_space(low_disk_space);
                if (ret < 0)
                        break;
                if (rm_pid)
                        continue;
-               if (rsync_pid) {
-                       restart_rsync_process();
-                       continue;
-               }
-               /* neither rsync nor rm are running. Start rsync? */
+               restart_rsync_process();
                gettimeofday(&now, NULL);
                if (tv_diff(&next_snapshot_time, &now, &tv) > 0)
                        continue;
-               create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
-               ret = create_snapshot(rsync_argv);
-               free_rsync_argv(rsync_argv);
-               if (ret < 0)
-                       break;
+               switch (snapshot_creation_status) {
+               case SCS_READY:
+                       ret = pre_create_hook();
+                       if (ret < 0)
+                               goto out;
+                       continue;
+               case SCS_PRE_HOOK_RUNNING:
+                       continue;
+               case SCS_PRE_HOOK_SUCCESS:
+                       create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
+                       ret = create_snapshot(rsync_argv);
+                       free_rsync_argv(rsync_argv);
+                       if (ret < 0)
+                               goto out;
+                       continue;
+               case SCS_RSYNC_RUNNING:
+                       continue;
+               case SCS_RSYNC_SUCCESS:
+                       ret = post_create_hook();
+                       if (ret < 0)
+                               goto out;
+                       continue;
+               case SCS_POST_HOOK_RUNNING:
+                       continue;
+               }
        }
-       free_snapshot_list(&sl);
+out:
        return ret;
 }
 
@@ -966,6 +1110,7 @@ int com_run(void)
        ret = install_sighandler(SIGHUP);
        if (ret < 0)
                return ret;
+       compute_next_snapshot_time();
        return select_loop();
 }
 
@@ -1020,20 +1165,33 @@ int com_create(void)
        int ret, status;
        char **rsync_argv;
 
-       create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
        if (conf.dry_run_given) {
                int i;
                char *msg = NULL;
+               create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
                for (i = 0; rsync_argv[i]; i++) {
                        char *tmp = msg;
                        msg = make_message("%s%s%s", tmp? tmp : "",
                                tmp? " " : "", rsync_argv[i]);
                        free(tmp);
                }
+               free_rsync_argv(rsync_argv);
                dss_msg("%s\n", msg);
                free(msg);
                return 1;
        }
+       ret = pre_create_hook();
+       if (ret < 0)
+               return ret;
+       if (pre_create_hook_pid) {
+               ret = wait_for_process(pre_create_hook_pid, &status);
+               if (ret < 0)
+                       return ret;
+               ret = handle_pre_create_hook_exit(status);
+               if (ret < 0)
+                       return ret;
+       }
+       create_rsync_argv(&rsync_argv, &current_snapshot_creation_time);
        ret = create_snapshot(rsync_argv);
        if (ret < 0)
                goto out;
@@ -1041,6 +1199,11 @@ int com_create(void)
        if (ret < 0)
                goto out;
        ret = handle_rsync_exit(status);
+       if (ret < 0)
+               goto out;
+       post_create_hook();
+       if (post_create_hook_pid)
+               ret = wait_for_process(post_create_hook_pid, &status);
 out:
        free_rsync_argv(rsync_argv);
        return ret;
@@ -1096,6 +1259,7 @@ int main(int argc, char **argv)
 
        cmdline_parser_ext(argc, argv, &conf, &params); /* aborts on errors */
        parse_config_file(0);
+
        if (conf.daemon_given)
                daemon_init();
        setup_signal_handling();