Mark child as volatile

git-core · git-core · commit fb7c8d1d2449 · 2012-08-01T18:32:23.000+04:00
It's shared between the SIGCHLD signal handler and normal flow. Its type is
still pid_t, however, not sig_atomic_t.
diff --git a/activity.c b/activity.c
@@ -64,10 +64,12 @@ int send_intent(struct su_context *ctx, allow_t allow, const char *action)
     __sighandler_t handler;
     pid_t pid;
 
-    if (ctx->child) {
-        kill_child(ctx->child);
-        if (ctx->child) {
-            LOGE("child %d is still running", ctx->child);
+    pid = ctx->child;
+    if (pid) {
+        kill_child(pid);
+        pid = ctx->child;
+        if (pid) {
+            LOGE("child %d is still running", pid);
             return -1;
         }
     }
diff --git a/su.c b/su.c
@@ -151,14 +151,13 @@ static void socket_cleanup(struct su_context *ctx)
 
 static void child_cleanup(struct su_context *ctx)
 {
-    pid_t pid = (ctx && ctx->child) ? ctx->child : -1;
+    pid_t pid = ctx->child;
     int rc;
 
-    if (!ctx)
-        LOGE("no context present");
-    if (!ctx->child)
+    if (!pid) {
         LOGE("unexpected child");
-
+        pid = -1;	/* pick up any child */
+    }
     pid = waitpid(pid, &rc, WNOHANG);
     if (pid < 0) {
         PLOGE("waitpid");
@@ -173,9 +172,7 @@ static void child_cleanup(struct su_context *ctx)
         exit(EXIT_FAILURE);
     }
     LOGD("child %d terminated, status %d", pid, rc);
-
-    if (ctx)
-        ctx->child = 0;
+    ctx->child = 0;
 }
 
 /*
diff --git a/su.h b/su.h
@@ -70,7 +70,7 @@ struct su_context {
     struct su_initiator from;
     struct su_request to;
     mode_t umask;
-    pid_t child;
+    volatile pid_t child;
     char sock_path[PATH_MAX];
 };
 
