From: Alan T. DeKok <aland@freeradius.org>
Date: Mon, 26 Feb 2018 19:41:41 +0000 (-0500)
Subject: don't lock the file if it has been renamed
X-Git-Tag: release_3_0_17~55
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=abbbf09df831;p=thirdparty%2Ffreeradius-server.git

don't lock the file if it has been renamed
---

diff --git a/src/main/exfile.c b/src/main/exfile.c
index 5a3953753ee..4802d94cbad 100644
--- a/src/main/exfile.c
+++ b/src/main/exfile.c
@@ -33,6 +33,8 @@ typedef struct exfile_entry_t {
 	int		fd;		//!< File descriptor associated with an entry.
 	uint32_t	hash;		//!< Hash for cheap comparison.
 	time_t		last_used;	//!< Last time the entry was used.
+	dev_t		st_dev;		//!< device inode
+	ino_t		st_ino;		//!< inode number
 	char		*filename;	//!< Filename.
 } exfile_entry_t;
 
@@ -325,6 +327,16 @@ int exfile_open(exfile_t *ef, char const *filename, mode_t permissions)
 			PTHREAD_MUTEX_UNLOCK(&(ef->mutex));
 			return -1;
 		}
+
+		if (fstat(ef->entries[i].fd, &st) < 0) goto error;
+
+		/*
+		 *	Remember which device and inode this file is
+		 *	for.
+		 */
+		ef->entries[i].st_dev = st.st_dev;
+		ef->entries[i].st_ino = st.st_ino;
+
 	} else {
 		i = found;
 	}
@@ -378,8 +390,7 @@ int exfile_open(exfile_t *ef, char const *filename, mode_t permissions)
 	}
 
 	/*
-	 *	Maybe someone deleted the file while we were waiting
-	 *	for the lock.  If so, re-open it.
+	 *	See which file it really is.
 	 */
 	if (fstat(ef->entries[i].fd, &st) < 0) {
 		fr_strerror_printf("Failed to stat file %s: %s", filename, strerror(errno));
@@ -387,16 +398,19 @@ int exfile_open(exfile_t *ef, char const *filename, mode_t permissions)
 	}
 
 	/*
-	 *	It's unlinked from the file system, close the FD and
-	 *	try to re-open it.
+	 *	Maybe the file was unlinked from the file system, OR
+	 *	the file we opened is NOT the one we had cached.  If
+	 *	so, close the file and re-open it from scratch.
 	 */
-	if (st.st_nlink == 0) {
+	if ((st.st_nlink == 0) ||
+	    (st.st_dev != ef->entries[i].st_dev) ||
+	    (st.st_ino != ef->entries[i].st_ino)) {
 		close(ef->entries[i].fd);
 		goto reopen;
 	}
 
 	/*
-	 *	If we're appending, eek to the end of the file before
+	 *	If we're appending, seek to the end of the file before
 	 *	returning the FD to the caller.
 	 */
 	(void) lseek(ef->entries[i].fd, 0, SEEK_END);