trace-cmd: Close open fds on exec

trace-cmd's record mode allows child processes to inherit
tracing-related file descriptors:

$ trace-cmd record -esched: ls -l /proc/self/fd

total 0
lrwx------. 1 root root 64 May 20 12:44 0 -> /dev/pts/11
lrwx------. 1 root root 64 May 20 12:44 1 -> /dev/pts/11
lrwx------. 1 root root 64 May 20 12:44 2 -> /dev/pts/11
lrwx------. 1 root root 64 May 20 12:44 3 -> /sys/kernel/debug/tracing/tracing_on
l-wx------. 1 root root 64 May 20 12:44 4 -> /sys/kernel/debug/tracing/set_ftrace_pid
l-wx------. 1 root root 64 May 20 12:44 5 -> /sys/kernel/debug/tracing/tracing_enabled
lr-x------. 1 root root 64 May 20 12:44 6 -> /proc/31036/fd

This can be problematic for applications (such as lxc) that
interrogate their open file descriptors.

Open these with O_CLOEXEC so they are not inherited.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Link: http://lkml.kernel.org/r/1305915732.2429.4.camel@orca.stoopid.dyndns.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/trace-record.c b/trace-record.c
index 9b331ef..62758e8 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -343,7 +343,7 @@ static void update_ftrace_pid(const char *pid, int reset)
                         path = tracecmd_get_tracing_file("set_ftrace_pid");
                 if (!path)
                         return;
-                fd = open(path, O_WRONLY | (reset ? O_TRUNC : 0));
+                fd = open(path, O_WRONLY | O_CLOEXEC | (reset ? O_TRUNC : 0));
                 if (fd < 0)
                         return;
         }
@@ -795,7 +795,7 @@ static void check_tracing_enabled(void)
 
         if (fd < 0) {
                 path = tracecmd_get_tracing_file("tracing_enabled");
-                fd = open(path, O_WRONLY);
+                fd = open(path, O_WRONLY | O_CLOEXEC);
                 tracecmd_put_tracing_file(path);
 
                 if (fd < 0)
@@ -815,7 +815,7 @@ static int open_tracing_on(void)
                 return fd;
 
         path = tracecmd_get_tracing_file("tracing_on");
-        fd = open(path, O_RDWR);
+        fd = open(path, O_RDWR | O_CLOEXEC);
         if (fd < 0)
                 die("opening '%s'", path);
         tracecmd_put_tracing_file(path);