mcelog: Check whether we successfully changed directory for trigger.

Currenlty there is only one compiler warning when building mcelog:

trigger.c: In function ‘run_trigger’:
trigger.c:85:4: warning: ignoring return value of ‘chdir’, declared with attribute warn_unused_result [-Wunused-result]
    chdir(trigger_dir);
    ^~~~~~~~~~~~~~~~~~

If we fail to change directory to "trigger_dir" we should print an
error and not run the trigger action.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/trigger.c b/trigger.c
index 8da3b2a..4041950 100644
--- a/trigger.c
+++ b/trigger.c
@@ -81,9 +81,10 @@ void run_trigger(char *trigger, char *argv[], char **env)
 		return;
 	}
 	if (child == 0) { 
-		if (trigger_dir)
-			chdir(trigger_dir);
-		execve(trigger, argv, env);	
+		if (trigger_dir && chdir(trigger_dir) == -1)
+			SYSERRprintf("Cannot chdir(%s) for trigger", trigger_dir);
+		else
+			execve(trigger, argv, env);
 		_exit(127);	
 	}
 }