journal: add ability to browse journals of running OS containers

This adds the new library call sd_journal_open_container() and a new
"-M" switch to journalctl. Particular care is taken that journalctl's
"-b" switch resolves to the current boot ID of the container, not the
host.

1 files changed, 13 insertions, 4 deletions

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index f74dde9c48..5d12c2b162 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -93,6 +93,7 @@ static bool arg_catalog = false;
 static bool arg_reverse = false;
 static int arg_journal_type = 0;
 static const char *arg_root = NULL;
+static const char *arg_machine = NULL;
 
 static enum {
         ACTION_SHOW,
@@ -120,6 +121,7 @@ static int help(void) {
                "Flags:\n"
                "     --system              Show only the system journal\n"
                "     --user                Show only the user journal for current user\n"
+               "  -M --machine=CONTAINER   Operate on local container\n"
                "     --since=DATE          Start showing entries newer or of the specified date\n"
                "     --until=DATE          Stop showing entries older or of the specified date\n"
                "  -c --cursor=CURSOR       Start showing entries from specified cursor\n"
@@ -247,6 +249,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "dump-catalog",   no_argument,       NULL, ARG_DUMP_CATALOG   },
                 { "update-catalog", no_argument,       NULL, ARG_UPDATE_CATALOG },
                 { "reverse",        no_argument,       NULL, 'r'                },
+                { "machine",        required_argument, NULL, 'M'                },
                 {}
         };
 
@@ -255,7 +258,7 @@ static int parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "hefo:aln::qmb::kD:p:c:u:F:xr", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "hefo:aln::qmb::kD:p:c:u:F:xrM:", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -389,6 +392,10 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_journal_type |= SD_JOURNAL_CURRENT_USER;
                         break;
 
+                case 'M':
+                        arg_machine = optarg;
+                        break;
+
                 case 'D':
                         arg_directory = optarg;
                         break;
@@ -576,8 +583,8 @@ 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.");
+        if (!!arg_directory + !!arg_file + !!arg_machine > 1) {
+                log_error("Please specify either -D/--directory= or --file= or -M/--machine=, not more than one.");
                 return -EINVAL;
         }
 
@@ -881,7 +888,7 @@ static int add_boot(sd_journal *j) {
                 return 0;
 
         if (!arg_boot_descriptor)
-                return add_match_this_boot(j);
+                return add_match_this_boot(j, arg_machine);
 
         if (strlen(arg_boot_descriptor) >= 32) {
                 char tmp = arg_boot_descriptor[32];
@@ -1460,6 +1467,8 @@ int main(int argc, char *argv[]) {
                 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 if (arg_machine)
+                r = sd_journal_open_container(&j, arg_machine, 0);
         else
                 r = sd_journal_open(&j, !arg_merge*SD_JOURNAL_LOCAL_ONLY + arg_journal_type);
         if (r < 0) {