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