mirror of https://github.com/pygos/init.git
80 lines
1.3 KiB
C
80 lines
1.3 KiB
C
/* SPDX-License-Identifier: ISC */
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#include <stdbool.h>
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#include <stddef.h>
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#include <string.h>
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#include <errno.h>
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#include "service.h"
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static bool has_dependencies(service_t *list, service_t *svc)
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{
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const char *ptr;
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int i;
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while (list != NULL) {
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for (ptr = svc->after, i = 0; i < svc->num_after; ++i) {
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if (!strcmp(ptr, list->name))
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return true;
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ptr += strlen(ptr) + 1;
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}
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for (ptr = list->before, i = 0; i < list->num_before; ++i) {
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if (!strcmp(ptr, svc->name))
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return true;
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ptr += strlen(ptr) + 1;
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}
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list = list->next;
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}
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return false;
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}
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service_t *svc_tsort(service_t *list)
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{
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service_t *nl = NULL, *end = NULL;
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service_t *svc, *prev;
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while (list != NULL) {
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/* remove first service without dependencies */
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prev = NULL;
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svc = list;
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while (svc != NULL) {
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if (has_dependencies(list, svc)) {
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prev = svc;
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svc = svc->next;
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} else {
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if (prev != NULL) {
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prev->next = svc->next;
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} else {
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list = svc->next;
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}
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svc->next = NULL;
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break;
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}
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}
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/* cycle! */
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if (svc == NULL) {
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if (end == NULL) {
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nl = list;
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} else {
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end->next = list;
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}
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errno = ELOOP;
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break;
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}
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/* append to new list */
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if (end == NULL) {
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nl = end = svc;
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} else {
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end->next = svc;
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end = svc;
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}
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}
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return nl;
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}
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