From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Subject: [PATCH 2/5] resolv: Use <file_change_detection.h> in __resolv_conf_get_current
Date: Tue, 21 Jan 2020 18:42:00 -0000 [thread overview]
Message-ID: <c657cfe9aedbc48a368f11442f453190ed1cf1e9.1579631655.git.fweimer@redhat.com> (raw)
In-Reply-To: <cover.1579631655.git.fweimer@redhat.com>
Only minor functional changes (i.e., regarding the handling of
directories, which are now treated as empty files).
---
resolv/resolv_conf.c | 43 ++++++++-----------------------------------
1 file changed, 8 insertions(+), 35 deletions(-)
diff --git a/resolv/resolv_conf.c b/resolv/resolv_conf.c
index 08c50ef19e..d954ba9a5a 100644
--- a/resolv/resolv_conf.c
+++ b/resolv/resolv_conf.c
@@ -24,6 +24,7 @@
#include <resolv-internal.h>
#include <sys/stat.h>
#include <libc-symbols.h>
+#include <file_change_detection.h>
/* _res._u._ext.__glibc_extension_index is used as an index into a
struct resolv_conf_array object. The intent of this construction
@@ -68,12 +69,8 @@ struct resolv_conf_global
/* Cached current configuration object for /etc/resolv.conf. */
struct resolv_conf *conf_current;
- /* These properties of /etc/resolv.conf are used to check if the
- configuration needs reloading. */
- struct timespec conf_mtime;
- struct timespec conf_ctime;
- off64_t conf_size;
- ino64_t conf_ino;
+ /* File system identification for /etc/resolv.conf. */
+ struct file_change_detection file_resolve_conf;
};
/* Lazily allocated storage for struct resolv_conf_global. */
@@ -123,37 +120,16 @@ conf_decrement (struct resolv_conf *conf)
struct resolv_conf *
__resolv_conf_get_current (void)
{
- struct stat64 st;
- if (stat64 (_PATH_RESCONF, &st) != 0)
- {
- switch (errno)
- {
- case EACCES:
- case EISDIR:
- case ELOOP:
- case ENOENT:
- case ENOTDIR:
- case EPERM:
- /* Ignore errors due to file system contents. */
- memset (&st, 0, sizeof (st));
- break;
- default:
- /* Other errors are fatal. */
- return NULL;
- }
- }
+ struct file_change_detection initial;
+ if (!file_change_detection_for_path (&initial, _PATH_RESCONF))
+ return NULL;
struct resolv_conf_global *global_copy = get_locked_global ();
if (global_copy == NULL)
return NULL;
struct resolv_conf *conf;
if (global_copy->conf_current != NULL
- && (global_copy->conf_mtime.tv_sec == st.st_mtim.tv_sec
- && global_copy->conf_mtime.tv_nsec == st.st_mtim.tv_nsec
- && global_copy->conf_ctime.tv_sec == st.st_ctim.tv_sec
- && global_copy->conf_ctime.tv_nsec == st.st_ctim.tv_nsec
- && global_copy->conf_ino == st.st_ino
- && global_copy->conf_size == st.st_size))
+ && file_is_unchanged (&initial, &global_copy->file_resolve_conf))
/* We can reuse the cached configuration object. */
conf = global_copy->conf_current;
else
@@ -171,10 +147,7 @@ __resolv_conf_get_current (void)
read could be a newer version of the file, but this does
not matter because this will lead to an extraneous reload
later. */
- global_copy->conf_mtime = st.st_mtim;
- global_copy->conf_ctime = st.st_ctim;
- global_copy->conf_ino = st.st_ino;
- global_copy->conf_size = st.st_size;
+ global_copy->file_resolve_conf = initial;
}
}
--
2.24.1
next prev parent reply other threads:[~2020-01-21 18:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 18:41 [PATCH 0/5] Race condition in /etc/resolv.conf reloading (bug 25420) Florian Weimer
2020-01-21 18:41 ` [PATCH 1/5] Add internal <file_change_detection.h> header file Florian Weimer
2020-02-10 19:47 ` Adhemerval Zanella
2020-02-10 19:58 ` Florian Weimer
2020-02-10 20:57 ` Adhemerval Zanella
2020-01-21 18:42 ` [PATCH 3/5] resolv: Fix file handle leak in __resolv_conf_load [BZ #25429] Florian Weimer
2020-02-13 21:01 ` Adhemerval Zanella
2020-02-13 21:08 ` Florian Weimer
2020-02-13 21:30 ` Adhemerval Zanella
2020-01-21 18:42 ` Florian Weimer [this message]
2020-02-13 20:53 ` [PATCH 2/5] resolv: Use <file_change_detection.h> in __resolv_conf_get_current Adhemerval Zanella
2020-01-21 18:42 ` [PATCH 4/5] resolv: Enhance __resolv_conf_load to capture file change data Florian Weimer
2020-02-13 21:33 ` Adhemerval Zanella
2020-01-21 21:28 ` [PATCH 5/5] resolv: Fix ABA race in /etc/resolv.conf change detection [BZ #25420] Florian Weimer
2020-02-13 21:59 ` Adhemerval Zanella
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c657cfe9aedbc48a368f11442f453190ed1cf1e9.1579631655.git.fweimer@redhat.com \
--to=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).