From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 5 Jul 2023 00:49:45 +0000 (+0900)
Subject: sd-journal: introduce SD_JOURNAL_TAKE_DIRECTORY_FD flag for sd_journal_open_directory... 
X-Git-Tag: v254-rc1~31^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a45a2e0e3ac748bfe71be4ff32d1d85bfaeca1e;p=thirdparty%2Fsystemd.git

sd-journal: introduce SD_JOURNAL_TAKE_DIRECTORY_FD flag for sd_journal_open_directory_fd()

If it is called with the flag, then the provided file descriptor will be
owned by the sd_journal object, and will be closed in sd_journal_close().
---

diff --git a/man/sd_journal_open.xml b/man/sd_journal_open.xml
index 8f62c966eaf..8b7035fcc28 100644
--- a/man/sd_journal_open.xml
+++ b/man/sd_journal_open.xml
@@ -32,6 +32,7 @@
     <refname>SD_JOURNAL_OS_ROOT</refname>
     <refname>SD_JOURNAL_ALL_NAMESPACES</refname>
     <refname>SD_JOURNAL_INCLUDE_DEFAULT_NAMESPACE</refname>
+    <refname>SD_JOURNAL_TAKE_DIRECTORY_FD</refname>
     <refpurpose>Open the system journal for reading</refpurpose>
   </refnamediv>
 
@@ -136,7 +137,13 @@
 
     <para><function>sd_journal_open_directory_fd()</function> is similar to
     <function>sd_journal_open_directory()</function>, but takes a file descriptor referencing a directory in the file
-    system instead of an absolute file system path.</para>
+    system instead of an absolute file system path. In addtion to the flags accepted by
+    <function>sd_journal_open_directory()</function>, this function also accepts
+    <constant>SD_JOURNAL_TAKE_DIRECTORY_FD</constant>. If <constant>SD_JOURNAL_TAKE_DIRECTORY_FD</constant> is
+    specified, the function will take the ownership of the specified file descriptor on success, and it will be
+    closed by <function>sd_journal_close()</function>, hence the caller of the function must not close the file
+    descriptor. When the flag is not specified, <function>sd_journal_close()</function> will not close the file
+    descriptor, so the caller should close it after <function>sd_journal_close()</function>.</para>
 
     <para><function>sd_journal_open_files()</function> is similar to <function>sd_journal_open()</function> but takes a
     <constant>NULL</constant>-terminated list of file paths to open.  All files will be opened and interleaved
diff --git a/src/libsystemd/sd-journal/sd-journal.c b/src/libsystemd/sd-journal/sd-journal.c
index 0124900517c..d84b1177835 100644
--- a/src/libsystemd/sd-journal/sd-journal.c
+++ b/src/libsystemd/sd-journal/sd-journal.c
@@ -2177,13 +2177,16 @@ _public_ int sd_journal_open_files(sd_journal **ret, const char **paths, int fla
         return 0;
 }
 
-#define OPEN_DIRECTORY_FD_ALLOWED_FLAGS         \
+#define OPEN_DIRECTORY_FD_ALLOWED_FLAGS                 \
         (SD_JOURNAL_OS_ROOT |                           \
-         SD_JOURNAL_SYSTEM | SD_JOURNAL_CURRENT_USER )
+         SD_JOURNAL_SYSTEM |                            \
+         SD_JOURNAL_CURRENT_USER |                      \
+         SD_JOURNAL_TAKE_DIRECTORY_FD)
 
 _public_ int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags) {
         _cleanup_(sd_journal_closep) sd_journal *j = NULL;
         struct stat st;
+        bool take_fd;
         int r;
 
         assert_return(ret, -EINVAL);
@@ -2196,7 +2199,8 @@ _public_ int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags) {
         if (!S_ISDIR(st.st_mode))
                 return -EBADFD;
 
-        j = journal_new(flags, NULL, NULL);
+        take_fd = FLAGS_SET(flags, SD_JOURNAL_TAKE_DIRECTORY_FD);
+        j = journal_new(flags & ~SD_JOURNAL_TAKE_DIRECTORY_FD, NULL, NULL);
         if (!j)
                 return -ENOMEM;
 
@@ -2209,6 +2213,8 @@ _public_ int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags) {
         if (r < 0)
                 return r;
 
+        SET_FLAG(j->flags, SD_JOURNAL_TAKE_DIRECTORY_FD, take_fd);
+
         *ret = TAKE_PTR(j);
         return 0;
 }
@@ -2288,6 +2294,9 @@ _public_ void sd_journal_close(sd_journal *j) {
         hashmap_free(j->directories_by_path);
         hashmap_free(j->directories_by_wd);
 
+        if (FLAGS_SET(j->flags, SD_JOURNAL_TAKE_DIRECTORY_FD))
+                safe_close(j->toplevel_fd);
+
         safe_close(j->inotify_fd);
 
         if (j->mmap) {
diff --git a/src/systemd/sd-journal.h b/src/systemd/sd-journal.h
index 4af540400dc..7d2d75dd89a 100644
--- a/src/systemd/sd-journal.h
+++ b/src/systemd/sd-journal.h
@@ -71,6 +71,7 @@ enum {
         SD_JOURNAL_OS_ROOT                   = 1 << 4,
         SD_JOURNAL_ALL_NAMESPACES            = 1 << 5, /* Show all namespaces, not just the default or specified one */
         SD_JOURNAL_INCLUDE_DEFAULT_NAMESPACE = 1 << 6, /* Show default namespace in addition to specified one */
+        SD_JOURNAL_TAKE_DIRECTORY_FD         = 1 << 7, /* sd_journal_open_directory_fd() will take ownership of the provided file descriptor. */
 
         SD_JOURNAL_SYSTEM_ONLY _sd_deprecated_ = SD_JOURNAL_SYSTEM /* old name */
 };