Child process doesn't terminate if execvp fails

[Voxel07]

In process_utils.cpp at L80, the child process should not return the execvp value but exit with it.

return ret; should be _exit(ret);

Otherwise, if the exec command fails, the child process will not be terminated and continue to run the main process code.

Question return or exit
Question _exit or exit

Log Snipped:

2021-07-27T09:23:54.3444Z [I] Installing image file: 'appUpdate' type: 'application' [Install]
2021-07-27T09:23:54.3444Z [I] Starting ChildProcess [ADUC_LaunchChildProcess]
2021-07-27T09:23:54.3445Z [I] Arg 0 = -af [ADUC_LaunchChildProcess]
2021-07-27T09:23:54.3445Z [I] Arg 1 = /tmp/aduc-dl-210727092348/appUpdate [ADUC_LaunchChildProcess]
2021-07-27T09:23:54.3445Z [I] Arg 2 = --debug [ADUC_LaunchChildProcess]
execvp failed, ret -1, error 2
2021-07-27T09:23:54.7003Z [E] Install failed, extendedResultCode = -1 [Install]
2021-07-27T09:23:54.7025Z [I] Action 'Install' complete. Result: 0, -1 [ADUC_Workflow_WorkCompletionCallback]
2021-07-27T09:23:54.7026Z [E] Install failed. error 0, -1 - Expecting service to send Cancel action [ADUC_Workflow_WorkCompletionCallback]
2021-07-27T09:23:54.7026Z [I] Setting UpdateState to Failed [ADUC_SetUpdateStateHelper]
2021-07-27T09:23:54.7026Z [I] Reporting state: 255, Failed (255); HTTP 500; result 0, -1 [AzureDeviceUpdateCoreInterface_ReportStateAndResultAsync]
2021-07-27T09:23:54.7072Z [I] Child process terminated normally, signal 0 [ADUC_LaunchChildProcess]
2021-07-27T09:23:54.7073Z [I] Install succeeded [Install]
2021-07-27T09:23:54.7073Z [I] Action 'Install' complete. Result: 1, 0 [ADUC_Workflow_WorkCompletionCallback]
2021-07-27T09:23:54.7074Z [I] WorkCompletionCallback: Install succeeded. Going to state InstallSucceeded [ADUC_Workflow_WorkCompletionCallback]
2021-07-27T09:23:54.7074Z [I] Setting UpdateState to InstallSucceeded [ADUC_SetUpdateStateHelper]
2021-07-27T09:23:54.7074Z [I] Reporting state: InstallSucceeded (4) [AzureDeviceUpdateCoreInterface_ReportStateAndResultAsync]
2021-07-27T09:23:54.7075Z [I] Calling ADUC_RebootSystem [ADUC_MethodCall_RebootSystem]
2021-07-27T09:23:54.7075Z [I] ADUC_RebootSystem called. Rebooting system. [ADUC_RebootSystem]
2021-07-27T09:23:54.7132Z [E] Reboot failed. [ADUC_RebootSystem]

[ValOlson]

Hi @Voxel07,

Thank you for raising this issue. We will investigate and add a fix in our code.

[wasabii]

#113

[jw-msft]

Thank you for your contributions @wasabii and @Voxel07. The fix was included with the 0.8.0 release. It is mentioned in the CHANGELOG.md and release notes under Notable fixes.

[jw-msft]

--- a/src/utils/process_utils/src/process_utils.cpp
+++ b/src/utils/process_utils/src/process_utils.cpp
@@ -80,11 +80,11 @@ int ADUC_LaunchChildProcess(const std::string& command, std::vector<std::string>

         // The exec() functions only return if an error has occurred.
         // The return value is -1, and errno is set to indicate the error.
-        int ret = execvp(command.c_str(), &argv[0]);
+        int status = execvp(command.c_str(), &argv[0]);

-        fprintf(stderr, "execvp failed, ret %d, error %d\n", ret, errno);
+        fprintf(stderr, "execvp failed, returned %d, error %d\n", status, errno);

-        return ret;
+        _exit(EXIT_FAILURE);
     }

     close(filedes[WRITE_END]);