journalctl: allow the user to specify the file(s) to use

This is useful for debugging and feels pretty natural. For example
answering the question "is this big .journal file worth keeping?"
is made easier.

1 files changed, 30 insertions, 5 deletions

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index af0f4ba3c8..1a441dd0d6 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -74,6 +74,7 @@ static bool arg_this_boot = false;
 static bool arg_dmesg = false;
 static const char *arg_cursor = NULL;
 static const char *arg_directory = NULL;
+static char **arg_file = NULL;
 static int arg_priorities = 0xFF;
 static const char *arg_verify_key = NULL;
 #ifdef HAVE_GCRYPT
@@ -130,6 +131,7 @@ static int help(void) {
                "     --no-pager          Do not pipe output into a pager\n"
                "  -m --merge             Show entries from all available journals\n"
                "  -D --directory=PATH    Show journal files from directory\n"
+               "     --file=PATH         Show journal file\n"
                "     --root=ROOT         Operate on catalog files underneath the root ROOT\n"
 #ifdef HAVE_GCRYPT
                "     --interval=TIME     Time interval for changing the FSS sealing key\n"
@@ -167,6 +169,7 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_HEADER,
                 ARG_FULL,
                 ARG_SETUP_KEYS,
+                ARG_FILE,
                 ARG_INTERVAL,
                 ARG_VERIFY,
                 ARG_VERIFY_KEY,
@@ -198,6 +201,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "system",       no_argument,       NULL, ARG_SYSTEM       },
                 { "user",         no_argument,       NULL, ARG_USER         },
                 { "directory",    required_argument, NULL, 'D'              },
+                { "file",         required_argument, NULL, ARG_FILE         },
                 { "root",         required_argument, NULL, ARG_ROOT         },
                 { "header",       no_argument,       NULL, ARG_HEADER       },
                 { "priority",     required_argument, NULL, 'p'              },
@@ -343,6 +347,14 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_directory = optarg;
                         break;
 
+                case ARG_FILE:
+                        r = glob_extend(&arg_file, optarg);
+                        if (r < 0) {
+                                log_error("Failed to add paths: %s", strerror(-r));
+                                return r;
+                        };
+                        break;
+
                 case ARG_ROOT:
                         arg_root = optarg;
                         break;
@@ -506,6 +518,11 @@ static int parse_argv(int argc, char *argv[]) {
         if (arg_follow && !arg_no_tail && arg_lines < 0)
                 arg_lines = 10;
 
+        if (arg_directory && arg_file) {
+                log_error("Please specify either -D/--directory= or --file=, not both.");
+                return -EINVAL;
+        }
+
         if (arg_since_set && arg_until_set && arg_since > arg_until) {
                 log_error("--since= must be before --until=.");
                 return -EINVAL;
@@ -1110,10 +1127,14 @@ int main(int argc, char *argv[]) {
 
         if (arg_directory)
                 r = sd_journal_open_directory(&j, arg_directory, arg_journal_type);
+        else if (arg_file)
+                r = sd_journal_open_files(&j, (const char**) arg_file, 0);
         else
                 r = sd_journal_open(&j, !arg_merge*SD_JOURNAL_LOCAL_ONLY + arg_journal_type);
         if (r < 0) {
-                log_error("Failed to open journal: %s", strerror(-r));
+                log_error("Failed to open %s: %s",
+                          arg_directory ? arg_directory : arg_file ? "files" : "journal",
+                          strerror(-r));
                 return EXIT_FAILURE;
         }
 
@@ -1167,10 +1188,7 @@ int main(int argc, char *argv[]) {
         if (r < 0)
                 return EXIT_FAILURE;
 
-        /* Opening the fd now means the first sd_journal_wait() will actually wait */
-        r = sd_journal_get_fd(j);
-        if (r < 0)
-                return EXIT_FAILURE;
+        log_debug("Journal filter: %s", j->level0 ? journal_make_match_string(j) : "none");
 
         if (arg_field) {
                 const void *data;
@@ -1206,6 +1224,13 @@ int main(int argc, char *argv[]) {
                 return EXIT_SUCCESS;
         }
 
+        /* Opening the fd now means the first sd_journal_wait() will actually wait */
+        if (arg_follow) {
+                r = sd_journal_get_fd(j);
+                if (r < 0)
+                        return EXIT_FAILURE;
+        }
+
         if (arg_cursor) {
                 r = sd_journal_seek_cursor(j, arg_cursor);
                 if (r < 0) {