chiark / gitweb /
journalctl: add --reverse option to show the newest lines first
[elogind.git] / src / journal / journalctl.c
index 45543a50130a4aada7dcc7db2102533434096183..4c9862fa6ce5a83c080c189bcae6febf09feb753 100644 (file)
@@ -60,7 +60,7 @@ static bool arg_follow = false;
 static bool arg_full = false;
 static bool arg_all = false;
 static bool arg_no_pager = false;
-static unsigned arg_lines = 0;
+static int arg_lines = -1;
 static bool arg_no_tail = false;
 static bool arg_quiet = false;
 static bool arg_merge = false;
@@ -77,6 +77,7 @@ static bool arg_since_set = false, arg_until_set = false;
 static const char *arg_unit = NULL;
 static const char *arg_field = NULL;
 static bool arg_catalog = false;
+static bool arg_reverse = false;
 
 static enum {
         ACTION_SHOW,
@@ -103,6 +104,7 @@ static int help(void) {
                "  -f --follow            Follow journal\n"
                "  -n --lines[=INTEGER]   Number of journal entries to show\n"
                "     --no-tail           Show all lines, even in follow mode\n"
+               "  -r --reverse           Show the newest entries first\n"
                "  -o --output=STRING     Change journal output mode (short, short-monotonic,\n"
                "                         verbose, export, json, json-pretty, json-sse, cat)\n"
                "  -x --catalog           Add message explanations where available\n"
@@ -184,6 +186,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "catalog",      no_argument,       NULL, 'x'              },
                 { "list-catalog", no_argument,       NULL, ARG_LIST_CATALOG },
                 { "update-catalog",no_argument,      NULL, ARG_UPDATE_CATALOG },
+                { "reverse",      no_argument,       NULL, 'r'              },
                 { NULL,           0,                 NULL, 0                }
         };
 
@@ -192,7 +195,7 @@ static int parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "hfo:an::qmbD:p:c:u:F:x", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "hfo:an::qmbD:p:c:u:F:xr", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -239,13 +242,30 @@ static int parse_argv(int argc, char *argv[]) {
 
                 case 'n':
                         if (optarg) {
-                                r = safe_atou(optarg, &arg_lines);
-                                if (r < 0 || arg_lines <= 0) {
+                                r = safe_atoi(optarg, &arg_lines);
+                                if (r < 0 || arg_lines < 0) {
                                         log_error("Failed to parse lines '%s'", optarg);
                                         return -EINVAL;
                                 }
-                        } else
-                                arg_lines = 10;
+                        } else {
+                                int n;
+
+                                /* Hmm, no argument? Maybe the next
+                                 * word on the command line is
+                                 * supposed to be the argument? Let's
+                                 * see if there is one, and is
+                                 * parsable as a positive
+                                 * integer... */
+
+                                if (optind < argc &&
+                                    safe_atoi(argv[optind], &n) >= 0 &&
+                                    n >= 0) {
+
+                                        arg_lines = n;
+                                        optind++;
+                                } else
+                                        arg_lines = 10;
+                        }
 
                         break;
 
@@ -407,16 +427,20 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_action = ACTION_UPDATE_CATALOG;
                         break;
 
+                case 'r':
+                        arg_reverse = true;
+                        break;
+
                 default:
                         log_error("Unknown option code %c", c);
                         return -EINVAL;
                 }
         }
 
-        if (arg_follow && !arg_no_tail && arg_lines <= 0)
+        if (arg_follow && !arg_no_tail && arg_lines < 0)
                 arg_lines = 10;
 
-        if (arg_since_set && arg_until_set && arg_since_set > arg_until_set) {
+        if (arg_since_set && arg_until_set && arg_since > arg_until) {
                 log_error("--since= must be before --until=.");
                 return -EINVAL;
         }
@@ -426,6 +450,11 @@ static int parse_argv(int argc, char *argv[]) {
                 return -EINVAL;
         }
 
+        if (arg_follow && arg_reverse) {
+                log_error("Please specify either --reverse= or --follow=, not both.");
+                return -EINVAL;
+        }
+
         return 1;
 }
 
@@ -445,14 +474,17 @@ static int generate_new_id128(void) {
                "As UUID:\n"
                "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x\n\n"
                "As macro:\n"
-              "#define MESSAGE_XYZ SD_ID128_MAKE(",
+               "#define MESSAGE_XYZ SD_ID128_MAKE(",
                SD_ID128_FORMAT_VAL(id),
                SD_ID128_FORMAT_VAL(id));
-
         for (i = 0; i < 16; i++)
                 printf("%02x%s", id.bytes[i], i != 15 ? "," : "");
+        fputs(")\n\n", stdout);
 
-        fputs(")\n", stdout);
+        printf("As Python constant:\n"
+               ">>> import uuid\n"
+               ">>> MESSAGE_XYZ = uuid.UUID('" SD_ID128_FORMAT_STR "')\n",
+               SD_ID128_FORMAT_VAL(id));
 
         return 0;
 }
@@ -849,8 +881,8 @@ int main(int argc, char *argv[]) {
         sd_journal *j = NULL;
         bool need_seek = false;
         sd_id128_t previous_boot_id;
-        bool previous_boot_id_valid = false;
-        unsigned n_shown = 0;
+        bool previous_boot_id_valid = false, first_line = true;
+        int n_shown = 0;
 
         setlocale(LC_ALL, "");
         log_parse_environment();
@@ -937,6 +969,11 @@ int main(int argc, char *argv[]) {
         if (r < 0)
                 goto finish;
 
+        /* Opening the fd now means the first sd_journal_wait() will actually wait */
+        r = sd_journal_get_fd(j);
+        if (r < 0)
+                goto finish;
+
         if (arg_field) {
                 const void *data;
                 size_t size;
@@ -950,7 +987,7 @@ int main(int argc, char *argv[]) {
                 SD_JOURNAL_FOREACH_UNIQUE(j, data, size) {
                         const void *eq;
 
-                        if (arg_lines > 0 && n_shown >= arg_lines)
+                        if (arg_lines >= 0 && n_shown >= arg_lines)
                                 break;
 
                         eq = memchr(data, '=', size);
@@ -972,10 +1009,12 @@ int main(int argc, char *argv[]) {
                         log_error("Failed to seek to cursor: %s", strerror(-r));
                         goto finish;
                 }
+                if (!arg_reverse)
+                        r = sd_journal_next(j);
+                else
+                        r = sd_journal_previous(j);
 
-                r = sd_journal_next(j);
-
-        } else if (arg_since_set) {
+        } else if (arg_since_set && !arg_reverse) {
                 r = sd_journal_seek_realtime_usec(j, arg_since);
                 if (r < 0) {
                         log_error("Failed to seek to date: %s", strerror(-r));
@@ -983,7 +1022,15 @@ int main(int argc, char *argv[]) {
                 }
                 r = sd_journal_next(j);
 
-        } else if (arg_lines > 0) {
+        } else if (arg_until_set && arg_reverse) {
+                r = sd_journal_seek_realtime_usec(j, arg_until);
+                if (r < 0) {
+                        log_error("Failed to seek to date: %s", strerror(-r));
+                        goto finish;
+                }
+                r = sd_journal_previous(j);
+
+        } else if (arg_lines >= 0) {
                 r = sd_journal_seek_tail(j);
                 if (r < 0) {
                         log_error("Failed to seek to tail: %s", strerror(-r));
@@ -992,6 +1039,15 @@ int main(int argc, char *argv[]) {
 
                 r = sd_journal_previous_skip(j, arg_lines);
 
+        } else if (arg_reverse) {
+                r = sd_journal_seek_tail(j);
+                if (r < 0) {
+                        log_error("Failed to seek to tail: %s", strerror(-r));
+                        goto finish;
+                }
+
+                r = sd_journal_previous(j);
+
         } else {
                 r = sd_journal_seek_head(j);
                 if (r < 0) {
@@ -1032,11 +1088,14 @@ int main(int argc, char *argv[]) {
         }
 
         for (;;) {
-                while (arg_lines == 0 || arg_follow || n_shown < arg_lines) {
+                while (arg_lines < 0 || n_shown < arg_lines || (arg_follow && !first_line)) {
                         int flags;
 
                         if (need_seek) {
-                                r = sd_journal_next(j);
+                                if(!arg_reverse)
+                                        r = sd_journal_next(j);
+                                else
+                                        r = sd_journal_previous(j);
                                 if (r < 0) {
                                         log_error("Failed to iterate through journal: %s", strerror(-r));
                                         goto finish;
@@ -1046,7 +1105,7 @@ int main(int argc, char *argv[]) {
                         if (r == 0)
                                 break;
 
-                        if (arg_until_set) {
+                        if (arg_until_set && !arg_reverse) {
                                 usec_t usec;
 
                                 r = sd_journal_get_realtime_usec(j, &usec);
@@ -1054,6 +1113,20 @@ int main(int argc, char *argv[]) {
                                         log_error("Failed to determine timestamp: %s", strerror(-r));
                                         goto finish;
                                 }
+                                if (usec > arg_until)
+                                        goto finish;
+                        }
+
+                        if (arg_since_set && arg_reverse) {
+                                usec_t usec;
+
+                                r = sd_journal_get_realtime_usec(j, &usec);
+                                if (r < 0) {
+                                        log_error("Failed to determine timestamp: %s", strerror(-r));
+                                        goto finish;
+                                }
+                                if (usec < arg_since)
+                                        goto finish;
                         }
 
                         if (!arg_merge) {
@@ -1092,6 +1165,8 @@ int main(int argc, char *argv[]) {
                         log_error("Couldn't wait for journal event: %s", strerror(-r));
                         goto finish;
                 }
+
+                first_line = false;
         }
 
 finish: