journal: add ability to filter by current user

This is the just the library part.

SD_JOURNAL_CURRENT_USER flags is added to sd_j_open(), to open
files from current user.

SD_JOURNAL_SYSTEM_ONLY is renamed to SD_JOURNAL_SYSTEM,
and changed to mean to (also) open system files. This way various
flags can be combined, which gives them nicer semantics, especially
if other ones are added later.

Backwards compatibility is kept, because SD_JOURNAL_SYSTEM_ONLY
is equivalent to SD_JOURNAL_SYSTEM if used alone, and before there
we no other flags.

2 files changed, 40 insertions, 7 deletions

diff --git a/src/journal/journal-gatewayd.c b/src/journal/journal-gatewayd.c
index 745f45f932..86338c66f3 100644
--- a/src/journal/journal-gatewayd.c
+++ b/src/journal/journal-gatewayd.c
@@ -109,7 +109,7 @@ static int open_journal(RequestMeta *m) {
         if (m->journal)
                 return 0;
 
-        return sd_journal_open(&m->journal, SD_JOURNAL_LOCAL_ONLY|SD_JOURNAL_SYSTEM_ONLY);
+        return sd_journal_open(&m->journal, SD_JOURNAL_LOCAL_ONLY|SD_JOURNAL_SYSTEM);
 }
 
 static int respond_oom_internal(struct MHD_Connection *connection) {
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 2bad243ea1..46511df6be 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1249,6 +1249,42 @@ static void check_network(sd_journal *j, int fd) {
                 F_TYPE_CMP(sfs.f_type, SMB_SUPER_MAGIC);
 }
 
+static bool file_has_type_prefix(const char *prefix, const char *filename) {
+        const char *full, *tilded, *atted;
+
+        full = strappend(prefix, ".journal");
+        tilded = strappenda(full, "~");
+        atted = strappenda(prefix, "@");
+
+        return streq(filename, full) ||
+               streq(filename, tilded) ||
+               startswith(filename, atted);
+}
+
+static bool file_type_wanted(int flags, const char *filename) {
+        if (!endswith(filename, ".journal") && !endswith(filename, ".journal~"))
+                return false;
+
+        /* no flags set → every type is OK */
+        if (!(flags & (SD_JOURNAL_SYSTEM | SD_JOURNAL_CURRENT_USER)))
+                return true;
+
+        if (flags & SD_JOURNAL_SYSTEM && file_has_type_prefix("system", filename))
+                return true;
+
+        if (flags & SD_JOURNAL_CURRENT_USER) {
+                char prefix[5 + DECIMAL_STR_MAX(uid_t) + 1];
+
+                assert_se(snprintf(prefix, sizeof(prefix), "user-%lu", (unsigned long) getuid())
+                          < (int) sizeof(prefix));
+
+                if (file_has_type_prefix(prefix, filename))
+                        return true;
+        }
+
+        return false;
+}
+
 static int add_file(sd_journal *j, const char *prefix, const char *filename) {
         _cleanup_free_ char *path = NULL;
         int r;
@@ -1258,11 +1294,7 @@ static int add_file(sd_journal *j, const char *prefix, const char *filename) {
         assert(prefix);
         assert(filename);
 
-        if ((j->flags & SD_JOURNAL_SYSTEM_ONLY) &&
-            !(streq(filename, "system.journal") ||
-              streq(filename, "system.journal~") ||
-              (startswith(filename, "system@") &&
-               (endswith(filename, ".journal") || endswith(filename, ".journal~")))))
+        if (!file_type_wanted(j->flags, filename))
                 return 0;
 
         path = strjoin(prefix, "/", filename, NULL);
@@ -1619,7 +1651,8 @@ _public_ int sd_journal_open(sd_journal **ret, int flags) {
 
         if (flags & ~(SD_JOURNAL_LOCAL_ONLY|
                       SD_JOURNAL_RUNTIME_ONLY|
-                      SD_JOURNAL_SYSTEM_ONLY))
+                      SD_JOURNAL_SYSTEM|
+                      SD_JOURNAL_CURRENT_USER))
                 return -EINVAL;
 
         j = journal_new(flags, NULL);