Add instruction to suppress SIGUSR1 in Posix with LLDB debugger

[bhoomrs]

Add instruction to suppress SIGUSR1 in Posix with LLDB debugger (macOS)

Description

While using the macOS default LLDB debugger, a call to vTaskEndScheduler results in an unhandled SIGUSR1 (aka SIGRESUME) when restoring the scheduler thread's signals with pthread_sigmask. This crashes the program.

Added instructions in portable/ThirdParty/GCC/Posix/port.c to suppress SIGUSR1 to prevent LLDB debugger interference when exiting xPortStartScheduler

Thanks to: @johnboiles for pointing it out in 1224

Test Steps

Tested with this example:

#include <FreeRTOS.h>
#include <task.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

void task_function(void *param) {
    ( void ) param;
    printf("FreeRTOS scheduler started\n");
    vTaskDelay(pdMS_TO_TICKS(1000));
    printf("Task Done, ending scheduler\n");
    vTaskEndScheduler();
    assert(0 && "After scheduler ended (SHOULD NOT GET HERE)");
}

int main_test() {
    TaskHandle_t task;
    xTaskCreate( task_function, "start", 10000, NULL, 1, &task );
    printf("Starting FreeRTOS scheduler\n");
    vTaskStartScheduler();
    printf("FreeRTOS scheduler exited\n");
    vTaskDelete(task);
    return 0;
}

Before the fix:

(lldb) pro la
Process 28916 launched: '/Users/johnboiles/Developer/repos/FreeRTOS/freertos-pr1224/build/freertos_posix_example' (arm64)
Starting FreeRTOS scheduler
FreeRTOS scheduler started
Task Done, ending scheduler
Process 28916 stopped and restarted: thread 1 received signal: SIGUSR1
Process 28916 exited with status = 30 (0x0000001e) Terminated due to signal 30

After the fix:

(lldb) run
Process 59557 launched: '/Users/bhoomrs/P3/FreeRTOS/FreeRTOS/Demo/Posix_GCC/build/posix_demo' (arm64)

Trace started.
The trace will be dumped to disk if a call to configASSERT() fails.
Starting full demo
Starting FreeRTOS scheduler
FreeRTOS scheduler started
Task Done, ending scheduler
FreeRTOS scheduler exited
Process 59557 exited with status = 0 (0x00000000) 

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

#1224

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[johnboiles]

This still does not work for me. I had to set both PASS and STOP to false. NOTIFY had no effect for me

process handle SIGUSR1 -p false -s false

> echo 'process handle SIGUSR1 -n true -p true -s false' > ~/.lldbinit
> lldb build/freertos_posix_example
NAME         PASS     STOP     NOTIFY
===========  =======  =======  =======
SIGUSR1      true     false    true
(lldb) target create "build/freertos_posix_example"
Current executable set to '/Users/johnboiles/Developer/repos/FreeRTOS/freertos-pr1224/build/freertos_posix_example' (arm64).
(lldb) pro la
Process 92245 launched: '/Users/johnboiles/Developer/repos/FreeRTOS/freertos-pr1224/build/freertos_posix_example' (arm64)
Starting FreeRTOS scheduler
FreeRTOS scheduler started
Task Done, ending scheduler
Process 92245 stopped and restarted: thread 1 received signal: SIGUSR1
Process 92245 exited with status = 30 (0x0000001e) Terminated due to signal 30
(lldb) ^D
> echo 'process handle SIGUSR1 -p false -s false' > ~/.lldbinit
> lldb build/freertos_posix_example
NAME         PASS     STOP     NOTIFY
===========  =======  =======  =======
SIGUSR1      false    false    not set
(lldb) target create "build/freertos_posix_example"
Current executable set to '/Users/johnboiles/Developer/repos/FreeRTOS/freertos-pr1224/build/freertos_posix_example' (arm64).
(lldb) pro la
Process 24334 launched: '/Users/johnboiles/Developer/repos/FreeRTOS/freertos-pr1224/build/freertos_posix_example' (arm64)
Starting FreeRTOS scheduler
FreeRTOS scheduler started
Task Done, ending scheduler
Process 24334 stopped and restarted: thread 1 received signal: SIGUSR1
FreeRTOS scheduler exited
Process 24334 exited with status = 0 (0x00000000)

[bhoomrs]

Well, yes. That seems right! Will update that, thank you.