140 lines
2.6 KiB
C
140 lines
2.6 KiB
C
|
// SPDX-License-Identifier: GPL-2.0+
|
||
|
|
/*
|
||
|
|
* Helper functions to sync execution between parent and child processes.
|
||
|
|
*
|
||
|
|
* Copyright 2018, Thiago Jung Bauermann, IBM Corporation.
|
||
|
|
*/
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdbool.h>
|
||
|
|
#include <semaphore.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Information in a shared memory location for synchronization between child and
|
||
|
|
* parent.
|
||
|
|
*/
|
||
|
|
struct child_sync {
|
||
|
|
/* The parent waits on this semaphore. */
|
||
|
|
sem_t sem_parent;
|
||
|
|
|
||
|
|
/* If true, the child should give up as well. */
|
||
|
|
bool parent_gave_up;
|
||
|
|
|
||
|
|
/* The child waits on this semaphore. */
|
||
|
|
sem_t sem_child;
|
||
|
|
|
||
|
|
/* If true, the parent should give up as well. */
|
||
|
|
bool child_gave_up;
|
||
|
|
};
|
||
|
|
|
||
|
|
#define CHILD_FAIL_IF(x, sync) \
|
||
|
|
do { \
|
||
|
|
if (x) { \
|
||
|
|
fprintf(stderr, \
|
||
|
|
"[FAIL] Test FAILED on line %d\n", __LINE__); \
|
||
|
|
(sync)->child_gave_up = true; \
|
||
|
|
prod_parent(sync); \
|
||
|
|
return 1; \
|
||
|
|
} \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#define PARENT_FAIL_IF(x, sync) \
|
||
|
|
do { \
|
||
|
|
if (x) { \
|
||
|
|
fprintf(stderr, \
|
||
|
|
"[FAIL] Test FAILED on line %d\n", __LINE__); \
|
||
|
|
(sync)->parent_gave_up = true; \
|
||
|
|
prod_child(sync); \
|
||
|
|
return 1; \
|
||
|
|
} \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#define PARENT_SKIP_IF_UNSUPPORTED(x, sync) \
|
||
|
|
do { \
|
||
|
|
if ((x) == -1 && (errno == ENODEV || errno == EINVAL)) { \
|
||
|
|
(sync)->parent_gave_up = true; \
|
||
|
|
prod_child(sync); \
|
||
|
|
SKIP_IF(1); \
|
||
|
|
} \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
int init_child_sync(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
ret = sem_init(&sync->sem_parent, 1, 0);
|
||
|
|
if (ret) {
|
||
|
|
perror("Semaphore initialization failed");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = sem_init(&sync->sem_child, 1, 0);
|
||
|
|
if (ret) {
|
||
|
|
perror("Semaphore initialization failed");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void destroy_child_sync(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
sem_destroy(&sync->sem_parent);
|
||
|
|
sem_destroy(&sync->sem_child);
|
||
|
|
}
|
||
|
|
|
||
|
|
int wait_child(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
/* Wait until the child prods us. */
|
||
|
|
ret = sem_wait(&sync->sem_parent);
|
||
|
|
if (ret) {
|
||
|
|
perror("Error waiting for child");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return sync->child_gave_up;
|
||
|
|
}
|
||
|
|
|
||
|
|
int prod_child(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
/* Unblock the child now. */
|
||
|
|
ret = sem_post(&sync->sem_child);
|
||
|
|
if (ret) {
|
||
|
|
perror("Error prodding child");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int wait_parent(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
/* Wait until the parent prods us. */
|
||
|
|
ret = sem_wait(&sync->sem_child);
|
||
|
|
if (ret) {
|
||
|
|
perror("Error waiting for parent");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return sync->parent_gave_up;
|
||
|
|
}
|
||
|
|
|
||
|
|
int prod_parent(struct child_sync *sync)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
/* Unblock the parent now. */
|
||
|
|
ret = sem_post(&sync->sem_parent);
|
||
|
|
if (ret) {
|
||
|
|
perror("Error prodding parent");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|