journal: introduce sd_journal_wait() to simplify writing synchronous clients

[elogind.git] / src / shared / logs-show.c

diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index 4c59ca34cd55d8b132682b52ba8fe9024e130007..540b5a2a2cb3770416afea05745df470996c3846 100644 (file)
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -551,12 +551,12 @@ int show_journal_by_unit(
                 usec_t not_before,
                 unsigned how_many,
                 bool show_all,
-                bool follow) {
+                bool follow,
+                bool warn_cutoff) {
 
         char *m = NULL;
         sd_journal *j = NULL;
         int r;
-        int fd;
         unsigned line = 0;
         bool need_seek = false;
 
@@ -582,10 +582,6 @@ int show_journal_by_unit(
         if (r < 0)
                 goto finish;
 
-        fd = sd_journal_get_fd(j);
-        if (fd < 0)
-                goto finish;
-
         r = sd_journal_add_match(j, m, strlen(m));
         if (r < 0)
                 goto finish;
@@ -639,14 +635,30 @@ int show_journal_by_unit(
                                 goto finish;
                 }
 
+                if (warn_cutoff && line < how_many && not_before > 0) {
+                        sd_id128_t boot_id;
+                        usec_t cutoff;
+
+                        /* Check whether the cutoff line is too early */
+
+                        r = sd_id128_get_boot(&boot_id);
+                        if (r < 0)
+                                goto finish;
+
+                        r = sd_journal_get_cutoff_monotonic_usec(j, boot_id, &cutoff, NULL);
+                        if (r < 0)
+                                goto finish;
+
+                        if (not_before < cutoff)
+                                printf("Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.\n");
+
+                        warn_cutoff = false;
+                }
+
                 if (!follow)
                         break;
 
-                r = fd_wait_for_event(fd, POLLIN, (usec_t) -1);
-                if (r < 0)
-                        goto finish;
-
-                r = sd_journal_process(j);
+                r = sd_journal_wait(j, (usec_t) -1);
                 if (r < 0)
                         goto finish;