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demo: fix stack corruption in ping_pong demo #96

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demo: fix stack corruption in ping_pong demo #96

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30 changes: 18 additions & 12 deletions rclc/ping_pong/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,9 @@

#include <std_msgs/msg/header.h>

#include <rcutils/allocator.h>
#include <rosidl_runtime_c/string_functions.h>

#include <stdio.h>
#include <unistd.h>
#include <time.h>
Expand Down Expand Up @@ -110,24 +113,27 @@ int main()
RCCHECK(rclc_executor_add_subscription(&executor, &ping_subscriber, &incoming_ping, &ping_subscription_callback, ON_NEW_DATA));
RCCHECK(rclc_executor_add_subscription(&executor, &pong_subscriber, &incoming_pong, &pong_subscription_callback, ON_NEW_DATA));

// Create and allocate the pingpong messages

char outcoming_ping_buffer[STRING_BUFFER_LEN];
outcoming_ping.frame_id.data = outcoming_ping_buffer;
// Allocate frame_id buffers via the rcutils allocator before spinning.
// The deserializer calls realloc() on frame_id.data when a message arrives;
// Remember to pair these with a call to rosidl_runtime_c__String__fini.
// outcoming_ping must be preallocated for sprintf to work. The others
// are used on paths that automatically realloc().
rcutils_allocator_t alloc = rcutils_get_default_allocator();
outcoming_ping.frame_id.data = alloc.allocate(STRING_BUFFER_LEN, alloc.state);
outcoming_ping.frame_id.capacity = STRING_BUFFER_LEN;
outcoming_ping.frame_id.size = 0;

char incoming_ping_buffer[STRING_BUFFER_LEN];
incoming_ping.frame_id.data = incoming_ping_buffer;
incoming_ping.frame_id.capacity = STRING_BUFFER_LEN;

char incoming_pong_buffer[STRING_BUFFER_LEN];
incoming_pong.frame_id.data = incoming_pong_buffer;
incoming_pong.frame_id.capacity = STRING_BUFFER_LEN;
(void) rosidl_runtime_c__String__init(&incoming_ping.frame_id);
(void) rosidl_runtime_c__String__init(&incoming_pong.frame_id);

device_id = rand();

rclc_executor_spin(&executor);


rosidl_runtime_c__String__fini(&outcoming_ping.frame_id);
rosidl_runtime_c__String__fini(&incoming_ping.frame_id);
rosidl_runtime_c__String__fini(&incoming_pong.frame_id);

RCCHECK(rcl_publisher_fini(&ping_publisher, &node));
RCCHECK(rcl_publisher_fini(&pong_publisher, &node));
RCCHECK(rcl_subscription_fini(&ping_subscriber, &node));
Expand Down