File 0119-Load-mechglue-config-files-from-etc-gss-mech.d.patch of Package krb5.37285

From 14a5b367c8f40b02ea9d5623e2208485e07a2c08 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCnther=20Deschner?= <gdeschner@redhat.com>
Date: Wed, 5 Mar 2014 15:25:43 +0100
Subject: [PATCH 1/3] Load mechglue config files from /etc/gss/mech.d

In addition to loading /etc/gss/mech, glob for *.conf files in
/etc/gss/mech.d.  Load only config files which have changed since the
highest mtime we saw in the previous scan.  Scan at most once per
second to avoid excessive numbers of filesystem syscalls for busy
GSSAPI applications.

[ghudson@mit.edu: rewrote commit message; style changes; added
once-per-second throttle on glob/stat calls]

ticket: 7882 (new)
(Cherry picked from commit 05cbef80d53f49d30a5d0563501226dc173734d4)
---
 src/lib/gssapi/mechglue/g_initialize.c | 65 +++++++++++++++++++++-----
 1 file changed, 54 insertions(+), 11 deletions(-)

diff --git a/src/lib/gssapi/mechglue/g_initialize.c b/src/lib/gssapi/mechglue/g_initialize.c
index ad12d1648..3aa978a97 100644
--- a/src/lib/gssapi/mechglue/g_initialize.c
+++ b/src/lib/gssapi/mechglue/g_initialize.c
@@ -41,6 +41,7 @@
 #include <string.h>
 #include <ctype.h>
 #include <errno.h>
+#include <glob.h>
 
 #define	M_DEFAULT	"default"
 
@@ -58,6 +59,7 @@
 #ifndef MECH_CONF
 #define	MECH_CONF "/etc/gss/mech"
 #endif
+#define MECH_CONF_PATTERN MECH_CONF ".d/*.conf"
 
 /* Local functions */
 static void addConfigEntry(const char *oidStr, const char *oid,
@@ -90,6 +92,7 @@ static gss_mech_info g_mechList = NULL;
 static gss_mech_info g_mechListTail = NULL;
 static k5_mutex_t g_mechListLock = K5_MUTEX_PARTIAL_INITIALIZER;
 static time_t g_confFileModTime = (time_t)0;
+static time_t g_confLastCall = (time_t)0;
 
 static time_t g_mechSetTime = (time_t)0;
 static gss_OID_set_desc g_mechSet = { 0, NULL };
@@ -457,6 +460,56 @@ const gss_OID oid;
 	return (modOptions);
 } /* gssint_get_modOptions */
 
+/* Return the mtime of filename or its eventual symlink target (if it is a
+ * symlink), whichever is larger.  Return (time_t)-1 if lstat or stat fails. */
+static time_t
+check_link_mtime(const char *filename, time_t *mtime_out)
+{
+	struct stat st1, st2;
+
+	if (lstat(filename, &st1) != 0)
+		return (time_t)-1;
+	if (!S_ISLNK(st1.st_mode))
+		return st1.st_mtime;
+	if (stat(filename, &st2) != 0)
+		return (time_t)-1;
+	return (st1.st_mtime > st2.st_mtime) ? st1.st_mtime : st2.st_mtime;
+}
+
+/* Try to load any config files which have changed since the last call.  Config
+ * files are MECH_CONF and any files matching MECH_CONF_PATTERN. */
+static void
+loadConfigFiles()
+{
+	glob_t globbuf;
+	time_t highest_mtime = 0, mtime, now;
+	char **pathptr;
+
+	/* Don't glob and stat more than once per second. */
+	if (time(&now) == (time_t)-1 || now == g_confLastCall)
+		return;
+	g_confLastCall = now;
+
+	globbuf.gl_offs = 1;
+	if (glob(MECH_CONF_PATTERN, GLOB_DOOFFS, NULL, &globbuf) != 0)
+		return;
+	globbuf.gl_pathv[0] = MECH_CONF;
+
+	for (pathptr = globbuf.gl_pathv; *pathptr != NULL; pathptr++) {
+		mtime = check_link_mtime(*pathptr, &mtime);
+		if (mtime == (time_t)-1)
+			continue;
+		if (mtime > highest_mtime)
+			highest_mtime = mtime;
+		if (mtime > g_confFileModTime)
+			loadConfigFile(*pathptr);
+	}
+	g_confFileModTime = highest_mtime;
+
+	globbuf.gl_pathv[0] = NULL;
+	globfree(&globbuf);
+}
+
 /*
  * determines if the mechList needs to be updated from file
  * and performs the update.
@@ -475,17 +528,7 @@ updateMechList(void)
 	loadConfigFromRegistry(HKEY_CURRENT_USER, MECH_KEY);
 	loadConfigFromRegistry(HKEY_LOCAL_MACHINE, MECH_KEY);
 #else /* _WIN32 */
-	char *fileName;
-	struct stat fileInfo;
-
-	fileName = MECH_CONF;
-
-	/* check if mechList needs updating */
-	if (stat(fileName, &fileInfo) != 0 ||
-	    g_confFileModTime >= fileInfo.st_mtime)
-		return;
-	g_confFileModTime = fileInfo.st_mtime;
-	loadConfigFile(fileName);
+	loadConfigFiles();
 #endif /* !_WIN32 */
 
 	/* Load any unloaded interposer mechanisms immediately, to make sure we
-- 
2.22.0