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server.c
124 lines (103 loc) · 2.67 KB
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server.c
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#include <sys/mman.h>
#include <unistd.h>
#include "mq_common.h"
#include "crypto.h"
#define MQ_GATEWAY "/gateway"
typedef int (*pdecryptf_t) (void*, int, void*);
pdecryptf_t v[4] = {decrypt_base64, decrypt_des, decrypt_bf, decrypt_rc2};
pdecryptf_t choose_decryption(int server_id)
{
return v[server_id-1];
}
static void* open_shared_memory(char* shm_name, int shm_size, int* shm_fd)
{
*shm_fd = shm_open(shm_name, O_RDWR, 0666);
if (*shm_fd == -1) {
perror("shm_open");
return NULL;
}
void* mem = mmap(0, shm_size, PROT_WRITE | PROT_READ,
MAP_SHARED, *shm_fd, 0);
if (mem == MAP_FAILED) {
int rc = close(*shm_fd);
if (rc == -1) {
perror("close");
return NULL;
}
perror("mmap");
return NULL;
}
return mem;
}
static int close_shared_memory(void* mem, int shm_size, int shm_fd, char* shm_name)
{
/* unmap shm */
int rc = munmap(mem, shm_size);
if (rc == -1) {
perror("munmap");
return -1;
}
/* close descriptor */
rc = close(shm_fd);
if (rc == -1) {
perror("close");
return -1;
}
return 0;
}
int main(int argc, char** argv)
{
if (argc < 2) {
fprintf(stderr, "Too few arguments given to server.\n./server N\n");
exit(EXIT_FAILURE);
}
int server_id = atoi(argv[1]);
pdecryptf_t decrypt = choose_decryption(server_id);
char mq_name[13];
sprintf(mq_name, "/mq_server_%d", server_id);
mqd_t mq = open_msg_queue(mq_name);
Command cmd;
int ret = receive_command(mq, &cmd);
if (ret == -1)
exit(EXIT_FAILURE);
Command *command = &cmd;
mqd_t ret_mq;
while(strcmp(command->name, "exit") != 0) {
//open shared memory
char* shm_name = command->name;
int shm_size = command->dim;
int shm_fd;
void* mem = open_shared_memory(shm_name, shm_size, &shm_fd);
if (mem == NULL) {
exit(EXIT_FAILURE);
}
// get size of the message from the first
// integer in the shared memory
int dim_message;
memcpy(&dim_message, mem, sizeof(int));
// decrypt message
void* out = malloc(1000);
int decrypt_size = decrypt(mem+sizeof(int), dim_message, out);
// copy result back in shared memory
memcpy(mem, &decrypt_size, sizeof(int));
memcpy(mem + sizeof(int), out, decrypt_size);
// Close shared memory
close_shared_memory(mem, shm_size, shm_fd, shm_name);
// Send message back to gateway with self removed
int i;
for (i = 1; i < 17; i++)
command->crypt[i-1] = command->crypt[i];
ret_mq = open_msg_queue(MQ_GATEWAY);
ret = send_command(ret_mq, command);
if (ret == -1)
exit(EXIT_FAILURE);
mq_close(ret_mq);
// Get another message from the mq
ret = receive_command(mq, command);
if (ret == -1)
exit(EXIT_FAILURE);
}
mq_close(mq);
mq_close(ret_mq);
return 0;
}