From: Lennart Poettering <lennart@poettering.net>
Date: Sun, 24 Apr 2016 22:18:27 +0000 (+0200)
Subject: journal: add inotify watches by-fd instead of by-path
X-Git-Tag: v230~133^2~11
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=430fbf8e7ff4368f6d43a8f86e0bc6494b0a979c;p=thirdparty%2Fsystemd.git

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 51268828af4..e24e7036f75 100644
--- 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 0d23f8635fe..517b599d6f0 100644
--- 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 3c21d4129e4..7ae8941a5e7 100644
--- 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);