sd-journal: add logic to open journal files of a specific OS tree

With this change a new flag SD_JOURNAL_OS_ROOT is introduced. If specified
while opening the journal with the per-directory calls (specifically:
sd_journal_open_directory() and sd_journal_open_directory_fd()) the passed
directory is assumed to be the root directory of an OS tree, and the journal
files are searched for in /var/log/journal, /run/log/journal relative to it.

This is useful to allow usage of sd-journal on file descriptors returned by the
OpenRootDirectory() call of machined.

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 0798247..c1be1b5 100644 (file)
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1809,13 +1809,16 @@ _public_ int sd_journal_open_directory(sd_journal **ret, const char *path, int f
 
         assert_return(ret, -EINVAL);
         assert_return(path, -EINVAL);
-        assert_return(flags == 0, -EINVAL);
+        assert_return((flags & ~SD_JOURNAL_OS_ROOT) == 0, -EINVAL);
 
         j = journal_new(flags, path);
         if (!j)
                 return -ENOMEM;
 
-        r = add_root_directory(j, path, false);
+        if (flags & SD_JOURNAL_OS_ROOT)
+                r = add_search_paths(j);
+        else
+                r = add_root_directory(j, path, false);
         if (r < 0)
                 goto fail;
 
@@ -1862,7 +1865,7 @@ _public_ int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags) {
 
         assert_return(ret, -EINVAL);
         assert_return(fd >= 0, -EBADF);
-        assert_return(flags == 0, -EINVAL);
+        assert_return((flags & ~SD_JOURNAL_OS_ROOT) == 0, -EINVAL);
 
         if (fstat(fd, &st) < 0)
                 return -errno;
@@ -1876,7 +1879,10 @@ _public_ int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags) {
 
         j->toplevel_fd = fd;
 
-        r = add_root_directory(j, NULL, false);
+        if (flags & SD_JOURNAL_OS_ROOT)
+                r = add_search_paths(j);
+        else
+                r = add_root_directory(j, NULL, false);
         if (r < 0)
                 goto fail;
 

diff --git a/src/systemd/sd-journal.h b/src/systemd/sd-journal.h
index 06f0769..ac4a2f8 100644 (file)
--- a/src/systemd/sd-journal.h
+++ b/src/systemd/sd-journal.h
@@ -67,10 +67,11 @@ typedef struct sd_journal sd_journal;
 
 /* Open flags */
 enum {
-        SD_JOURNAL_LOCAL_ONLY = 1,
-        SD_JOURNAL_RUNTIME_ONLY = 2,
-        SD_JOURNAL_SYSTEM = 4,
-        SD_JOURNAL_CURRENT_USER = 8,
+        SD_JOURNAL_LOCAL_ONLY   = 1 << 0,
+        SD_JOURNAL_RUNTIME_ONLY = 1 << 1,
+        SD_JOURNAL_SYSTEM       = 1 << 2,
+        SD_JOURNAL_CURRENT_USER = 1 << 3,
+        SD_JOURNAL_OS_ROOT      = 1 << 4,
 
         SD_JOURNAL_SYSTEM_ONLY = SD_JOURNAL_SYSTEM /* deprecated name */
 };