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double_queue.c
228 lines (214 loc) · 6.33 KB
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double_queue.c
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#include "double_queue.h"
#include "debug.h"
#include "util.h"
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
const int DOUBLE_QUEUE_INTERRUPTED = 7;
int double_queue_init_err(double_queue_t *q, int owner, key_t key1, key_t key2, int flags1, int flags2, int(*error_f)(void*), void *error_a) {
q->owner = owner;
q->id1 = q->id2 = -1;
q->id1 = msgget(key1, flags1);
if(q->id1 == -1) {
error("Creation of message queue failed.");
return error_f(error_a);
}
q->id2 = msgget(key2, flags2);
if(q->id2 == -1) {
error("Creation of message queue failed.");
return error_f(error_a);
}
return 0;
}
int double_queue_init(double_queue_t *q, int owner, key_t key1, key_t key2, int flags1, int flags2) {
return double_queue_init_err(q, owner, key1, key2, flags1, flags2, simple_error, NULL);
}
void double_queue_close(double_queue_t *q) {
if(q->owner) {
if(q->id1 >= 0) {
if(msgctl(q->id1, IPC_RMID, NULL) == -1) warning("Closing of message queue (direction C->S) failed.");
}
if(q->id2 >= 0) {
if(msgctl(q->id2, IPC_RMID, NULL) == -1) warning("Closing of message queue (direction S->C) failed.");
}
}
}
// Query - sends query and waits for result (client side)
int double_queue_query_err(
double_queue_t *q,
void * query, size_t query_length,
void ** result, size_t *result_length,
int *exit_after_signal,
long source, long destination,
int (*error_f)(void*), void *error_a) {
// Parameter checks
if(query_length > 1024 /* maksymalna długość komunikatu */) {
error("Too long message.");
return error_f(error_a);
}
// Prepare query
void * real_query = NULL;
size_t real_query_length;
char * res = NULL;
char * answer_buffer = malloc(1024+sizeof(long));
if(answer_buffer == NULL)
goto allocation_failed;
if(combine(&real_query, &real_query_length, "%l %b %l", destination, query, query_length, source) != 0)
goto allocation_failed;
// Send query
resend:
if(msgsnd(q->id1, real_query, real_query_length - sizeof(long), 0) == -1) {
if(errno == EINTR) {
log("Interrupted during waiting...");
if(*exit_after_signal) {
free(real_query);
free(answer_buffer);
return DOUBLE_QUEUE_INTERRUPTED;
} else {
goto resend;
}
}
errorp();
free(real_query);
free(answer_buffer);
return error_f(error_a);
}
free(real_query);
// Wait for result
int ret;
rerecv:
ret = msgrcv(q->id2, answer_buffer, 1024+sizeof(long) /* nie potrzebujemy adresu zwrotnego */, source, 0);
if(ret == -1 && errno == EINTR) {
log("Message receiving interrupted.");
if(*exit_after_signal) {
free(answer_buffer);
return DOUBLE_QUEUE_INTERRUPTED;
} else {
goto rerecv;
}
}
if(ret == -1 || ret == 0) {
errorp();
free(answer_buffer);
return error_f(error_a);
}
res = malloc(ret);
if(res == NULL)
goto allocation_failed;
memcpy(res, answer_buffer+sizeof(long), ret);
(*result) = res;
(*result_length) = ret;
free(answer_buffer);
return 0;
allocation_failed:
if(real_query) free(real_query);
if(answer_buffer) free(answer_buffer);
if(res) free(res);
error("Allocation failed.");
return error_f(error_a);
}
int double_queue_query(
double_queue_t *q,
void * query, size_t query_length,
void ** result, size_t *result_length,
int *exit_after_signal,
long source, long destination) {
return double_queue_query_err(q, query, query_length, result, result_length, exit_after_signal, source, destination, simple_error, NULL);
}
// Listen - receives query and sends result (server side)
int double_queue_listen_err(
double_queue_t *q,
int (*server)(void *, size_t, void **, size_t *, int, void*),
void *arg, int *exit_after_signal,
int destination,
int (*error_f)(void*), void *error_a) {
// Prepare buffers
void *response = NULL;
size_t response_length;
unsigned char * response_buffer = NULL;
void * query = NULL;
query = malloc(1024+2*sizeof(long) /* message + source */);
if(query == NULL) goto allocation_failed;
// Receive
int ret;
rerecv:
ret = msgrcv(q->id1, query, 1024+2*sizeof(long), destination, 0);
if(ret == -1 && errno == EINTR) {
log("Message receiving interrupted.");
if(*exit_after_signal) {
free(query);
return DOUBLE_QUEUE_INTERRUPTED;
} else {
goto rerecv;
}
}
if(ret == -1 || ret < sizeof(long)) {
error("Message received failed.");
free(query);
return error_f(error_a);
}
long source = 0;
ret -= sizeof(long);
memcpy(&source, query + ret + sizeof(long), sizeof(long));
if(server(query+sizeof(long), ret, &response, &response_length, source, arg) == -1) {
error("Server procedure failed.");
free(query);
if(response != NULL) free(response);
return error_f(error_a);
}
if(response_length > 1024) {
error("Response is too long.");
free(query);
free(response);
return error_f(error_a);
}
if(response == NULL) {
error("No response");
free(query);
free(response);
return error_f(error_a);
}
response_buffer = malloc(1024 + sizeof(long) /* address + body */);
if(response_buffer == NULL)
goto allocation_failed;
memcpy(response_buffer, &source, sizeof(long));
memcpy(response_buffer + sizeof(long), response, response_length);
resend:
if(msgsnd(q->id2, response_buffer, response_length, 0) == -1) {
if(errno == EINTR) {
log("Message sending interrupted.");
if(*exit_after_signal) {
free(query);
free(response);
free(response_buffer);
return DOUBLE_QUEUE_INTERRUPTED;
} else {
goto resend;
}
} else {
error("Sending of data failed.");
free(query);
free(response);
free(response_buffer);
return error_f(error_a);
}
}
free(response);
free(response_buffer);
free(query);
return 0;
allocation_failed:
error("Allocation failed.");
if(query) free(query);
if(response) free(response);
if(response_buffer) free(response_buffer);
return error_f(error_a);
}
int double_queue_listen(
double_queue_t *q,
int (*server)(void*, size_t, void **, size_t*, int, void*),
void *arg, int *exit_after_signal,
int destination) {
return double_queue_listen_err(q, server, arg, exit_after_signal, destination, simple_error, NULL);
}