journal: add inotify watches by-fd instead of by-path

This is slightly nicer, since we actually watch the directories we opened and
enumerate. However, primarily this is preparation for adding support for
opening journal files by fd without specifying any path, to be added in a later
commit.

diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index 51268828af4f07ea2ee4f0e6451d67d2c0877081..e24e7036f751a88056836b8352127cfd3a4a2847 100644 (file)
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -38,6 +38,7 @@
 #include "mkdir.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "time-util.h"
@@ -493,3 +494,17 @@ int get_files_in_directory(const char *path, char ***list) {
 
         return n;
 }
+
+int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
+        char path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
+        int r;
+
+        /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
+        xsprintf(path, "/proc/self/fd/%i", what);
+
+        r = inotify_add_watch(fd, path, mask);
+        if (r < 0)
+                return -errno;
+
+        return r;
+}

diff --git a/src/basic/fs-util.h b/src/basic/fs-util.h
index 0d23f8635fe6b14a729f83dc32d7558bb7245748..517b599d6f09751b9128612572e904f56513ba42 100644 (file)
--- a/src/basic/fs-util.h
+++ b/src/basic/fs-util.h
@@ -72,3 +72,5 @@ union inotify_event_buffer {
         struct inotify_event ev;
         uint8_t raw[INOTIFY_EVENT_MAX];
 };
+
+int inotify_add_watch_fd(int fd, int what, uint32_t mask);

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 3c21d4129e474518af3af33096a3e2fa9ab911ab..7ae8941a5e7b95a456a63684656a2df0426bd158 100644 (file)
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1420,10 +1420,10 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
 
         if (m->wd <= 0 && j->inotify_fd >= 0) {
 
-                m->wd = inotify_add_watch(j->inotify_fd, m->path,
-                                          IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
-                                          IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_MOVED_FROM|
-                                          IN_ONLYDIR);
+                m->wd = inotify_add_watch_fd(j->inotify_fd, dirfd(d),
+                                             IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
+                                             IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_MOVED_FROM|
+                                             IN_ONLYDIR);
 
                 if (m->wd > 0 && hashmap_put(j->directories_by_wd, INT_TO_PTR(m->wd), m) < 0)
                         inotify_rm_watch(j->inotify_fd, m->wd);
@@ -1505,7 +1505,7 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
 
         if (m->wd <= 0 && j->inotify_fd >= 0) {
 
-                m->wd = inotify_add_watch(j->inotify_fd, m->path,
+                m->wd = inotify_add_watch_fd(j->inotify_fd, dirfd(d),
                                           IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
                                           IN_ONLYDIR);