[lib] plug fd leak in callout error path and and error messages

multipathd was not releasing fds when a fork failed in execute_program.
Also, the error messages from execute_program were not very
helpful. This patch fixes both

diff --git a/libmultipath/callout.c b/libmultipath/callout.c
index 4dd33c5..a0f74e9 100644 (file)
--- a/libmultipath/callout.c
+++ b/libmultipath/callout.c
@@ -64,9 +64,10 @@ int execute_program(char *path, char *value, int len)
 
        retval = pipe(fds);
 
-       if (retval != 0)
+       if (retval != 0) {
+               condlog(0, "error creating pipe for callout: %s", strerror(errno));
                return -1;
-
+       }
 
        pid = fork();
 
@@ -88,9 +89,12 @@ int execute_program(char *path, char *value, int len)
                }
 
                retval = execv(argv[0], argv);
-
+               condlog(0, "error execing %s : %s", argv[0], strerror(errno));
                exit(-1);
        case -1:
+               condlog(0, "fork failed: %s", strerror(errno));
+               close(fds[0]);
+               close(fds[1]);
                return -1;
        default:
                /* parent reads from fds[0] */
@@ -104,13 +108,16 @@ int execute_program(char *path, char *value, int len)
 
                        i += count;
                        if (i >= len-1) {
+                               condlog(0, "not enough space for response from %s", argv[0]);
                                retval = -1;
                                break;
                        }
                }
 
-               if (count < 0)
+               if (count < 0) {
+                       condlog(0, "no response from %s", argv[0]);
                        retval = -1;
+               }
 
                if (i > 0 && value[i-1] == '\n')
                        i--;
@@ -119,8 +126,18 @@ int execute_program(char *path, char *value, int len)
                wait(&status);
                close(fds[0]);
 
-               if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
-                       retval = -1;
+               retval = -1;
+               if (WIFEXITED(status)) {
+                       status = WEXITSTATUS(status);
+                       if (status == 0)
+                               retval = 0;
+                       else
+                               condlog(0, "%s exitted with %d", argv[0], status);
+               }
+               else if (WIFSIGNALED(status))
+                       condlog(0, "%s was terminated by signal %d", argv[0], WTERMSIG(status));
+               else
+                       condlog(0, "%s terminated abnormally", argv[0]);
        }
        return retval;
 }