From: Florian Weimer <fweimer@redhat.com>

Date: Tue, 21 Jan 2020 15:52:33 +0000 (+0100)

Subject: resolv: Use <file_change_detection.h> in __resolv_conf_get_current

X-Git-Url: https://sourceware.org/git/?p=glibc.git;a=commitdiff_plain;h=9642b85fd0dfa5731020a3271c08e33e1dc05c85

resolv: Use <file_change_detection.h> in __resolv_conf_get_current

Only minor functional changes (i.e., regarding the handling of

directories, which are now treated as empty files).

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

---

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;

         }

     }