[lxc-devel] [lxc/master] 2016 02 15/lognull

[hallyn on Github]

A non-text attachment was scrubbed...
Name: not available
Type: text/x-mailbox
Size: 365 bytes
Desc: not available
URL: <http://lists.linuxcontainers.org/pipermail/lxc-devel/attachments/20160215/fb27a71f/attachment.bin>
-------------- next part --------------
From 3f53c691d248434fdb817e615495d9c419af07d1 Mon Sep 17 00:00:00 2001
From: Serge Hallyn <serge.hallyn at ubuntu.com>
Date: Mon, 15 Feb 2016 12:15:10 -0800
Subject: [PATCH 1/2] log.c:__lxc_log_set_file: fname cannot be null

fname cannot be passed in as NULL by any of its current callers.  If it
could, then build_dir() would crash as it doesn't check for it.  So make
sure we are warned if in the future we pass in NULL.

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/log.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/lxc/log.c b/src/lxc/log.c
index 20be5ac..babaebc 100644
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -20,6 +20,7 @@
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <errno.h>
 #include <limits.h>
@@ -268,7 +269,9 @@ static int __lxc_log_set_file(const char *fname, int create_dirs)
 		free(log_fname);
 	}
 
-	if (!fname || strlen(fname) == 0) {
+	assert(fname != NULL);
+
+	if (strlen(fname) == 0) {
 		log_fname = NULL;
 		return 0;
 	}

From d9c9b1808af250ec37379c7f0242941a450aa3af Mon Sep 17 00:00:00 2001
From: Serge Hallyn <serge.hallyn at ubuntu.com>
Date: Mon, 15 Feb 2016 12:18:18 -0800
Subject: [PATCH 2/2] log.c:__lxc_log_set_file: completely close log file when
 overriding

Otherwise after a shortcut on error we could end up trying to write
to the closed log fd.

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/log.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/lxc/log.c b/src/lxc/log.c
index babaebc..55fa7f5 100644
--- a/src/lxc/log.c
+++ b/src/lxc/log.c
@@ -253,6 +253,16 @@ static char *build_log_path(const char *name, const char *lxcpath)
 	return p;
 }
 
+extern void lxc_log_close(void)
+{
+	if (lxc_log_fd == -1)
+		return;
+	close(lxc_log_fd);
+	lxc_log_fd = -1;
+	free(log_fname);
+	log_fname = NULL;
+}
+
 /*
  * This can be called:
  *   1. when a program calls lxc_log_init with no logfile parameter (in which
@@ -265,8 +275,7 @@ static int __lxc_log_set_file(const char *fname, int create_dirs)
 {
 	if (lxc_log_fd != -1) {
 		// we are overriding the default.
-		close(lxc_log_fd);
-		free(log_fname);
+		lxc_log_close();
 	}
 
 	assert(fname != NULL);
@@ -383,16 +392,6 @@ extern int lxc_log_init(const char *name, const char *file,
 	return ret;
 }
 
-extern void lxc_log_close(void)
-{
-	if (lxc_log_fd == -1)
-		return;
-	close(lxc_log_fd);
-	lxc_log_fd = -1;
-	free(log_fname);
-	log_fname = NULL;
-}
-
 /*
  * This is called when we read a lxc.loglevel entry in a lxc.conf file.  This
  * happens after processing command line arguments, which override the .conf