1 files changed, 36 insertions, 2 deletions

diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 6e25c2659e0a..a2976a6de033 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 #include <signal.h>
 
 #include <linux/genetlink.h>
@@ -266,11 +267,13 @@ int main(int argc, char *argv[])
         int containerset = 0;
         char containerpath[1024];
         int cfd = 0;
+        int forking = 0;
+        sigset_t sigset;
 
         struct msgtemplate msg;
 
-        while (1) {
-                c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:");
+        while (!forking) {
+                c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:c:");
                 if (c < 0)
                         break;
 
@@ -319,6 +322,28 @@ int main(int argc, char *argv[])
                                 err(1, "Invalid pid\n");
                         cmd_type = TASKSTATS_CMD_ATTR_PID;
                         break;
+                case 'c':
+
+                        /* Block SIGCHLD for sigwait() later */
+                        if (sigemptyset(&sigset) == -1)
+                                err(1, "Failed to empty sigset");
+                        if (sigaddset(&sigset, SIGCHLD))
+                                err(1, "Failed to set sigchld in sigset");
+                        sigprocmask(SIG_BLOCK, &sigset, NULL);
+
+                        /* fork/exec a child */
+                        tid = fork();
+                        if (tid < 0)
+                                err(1, "Fork failed\n");
+                        if (tid == 0)
+                                if (execvp(argv[optind - 1],
+                                    &argv[optind - 1]) < 0)
+                                        exit(-1);
+
+                        /* Set the command type and avoid further processing */
+                        cmd_type = TASKSTATS_CMD_ATTR_PID;
+                        forking = 1;
+                        break;
                 case 'v':
                         printf("debug on\n");
                         dbg = 1;
@@ -370,6 +395,15 @@ int main(int argc, char *argv[])
                 goto err;
         }
 
+        /*
+         * If we forked a child, wait for it to exit. Cannot use waitpid()
+         * as all the delicious data would be reaped as part of the wait
+         */
+        if (tid && forking) {
+                int sig_received;
+                sigwait(&sigset, &sig_received);
+        }
+
         if (tid) {
                 rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
                               cmd_type, &tid, sizeof(__u32));