static int open_file(struct perf_data *data)
{
int fd;
fd = perf_data__is_read(data) ?
open_file_read(data) : open_file_write(data);
data->file.fd = fd;
return fd < 0 ? -1 : 0;
}
int main(void)
{
// Shared memory. shm1 used for circular buffer, shm2 used for metadata
int shmid, shmid2;
void *shared_memory1 = (void *)0;
void *shared_memory2 = (void *)0;
struct buffer_block *shared_buffer;
struct metadata *shared_metadata;
int buffer_index;
// Semaphores. S: mutual exclusion. N: synch producer before consumer. E: buffer space
int sem_S_id, sem_N_id, sem_E_id;
// Output file
int file_out;
int nWrite_file; // Num bytes written to file
/* Creating shared memory (circular buffer) */
if (init_shm_circularBuffer(SHM_KEY, &shmid, &shared_memory1) == -1) {
exit(EXIT_FAILURE);
}
printf("[C] Shared Memory (circular buffer) attached at: %p. shmid: %d\n", (int*)shared_memory1, shmid);
shared_buffer = (struct buffer_block*) shared_memory1; // Assigns shared_memory segment to shared_buffer
buffer_index = 0;
/* Creating shared memory (metadata) */
if (init_shm_metadata(SHM2_KEY, &shmid2, &shared_memory2) == -1) {
exit(EXIT_FAILURE);
}
printf("[C] Shared Memory (metadata) attached at %p, shmid: %d\n", (int*)shared_memory2, shmid2);
shared_metadata = (struct metadata*) shared_memory2; // Assigns shared_memory2 segment to shared_metadata
printf(" - - - - - - - - - - - - - - - - - - - - - - \n");
/* Creating semaphores */
sem_S_id = semget((key_t)SEM_S_KEY, 1, 0666 | IPC_CREAT);
sem_N_id = semget((key_t)SEM_N_KEY, 1, 0666 | IPC_CREAT);
sem_E_id = semget((key_t)SEM_E_KEY, 1, 0666 | IPC_CREAT);
// Open file for writing
open_file_write(&file_out);
// Wait for producer first so that the number of bytes read from file is known
printf("[C] Waiting for producer to get input file size...\n");
semaphore_wait(sem_N_id);
printf("[C] File size information from producer: %d bytes\n", shared_metadata->file_byte_count);
/* Start time difference. For Bonus */
struct timeval start_time, end_time;
gettimeofday(&start_time, NULL);
/* Copy contents from shared memory to the output file */
printf("[C] Reading from shared memory and writing to file...\n");
nWrite_file = 0;
while (nWrite_file < shared_metadata->file_byte_count) {
semaphore_wait(sem_N_id);
semaphore_wait(sem_S_id);
nWrite_file += copy_to_file(file_out, shared_buffer, &buffer_index);
semaphore_signal(sem_S_id);
semaphore_signal(sem_E_id);
printf("[C] Bytes written to file: %d\n", nWrite_file);
}
printf(" - - - - - - - - - - - - - - - - - - - - - - \n");
printf("[C] Total Bytes written to '%s': %d\n", FILE_OUT, nWrite_file);
/* Calculate time difference. For Bonus */
gettimeofday(&end_time, NULL);
printf(">> %ld microseconds\n", ((end_time.tv_sec * MICRO_SEC_IN_SEC + end_time.tv_usec) - (start_time.tv_sec * MICRO_SEC_IN_SEC + start_time.tv_usec)));
/* Cleanup */
// Close file
if (close(file_out) == -1) {
fprintf(stderr, "[C] File close failed\n");
}
// Shared memory is detached and deleted
if (shmdt(shared_memory1) == -1) {
fprintf(stderr, "[C] shmdt failed\n");
exit(EXIT_FAILURE);
}
if (shmctl(shmid, IPC_RMID, 0) == -1) {
fprintf(stderr, "[C] shmctl(IPC_RMID) failed\n");
exit(EXIT_FAILURE);
}
if (shmdt(shared_memory2) == -1) {
fprintf(stderr, "[C] shmdt failed\n");
exit(EXIT_FAILURE);
}
if (shmctl(shmid2, IPC_RMID, 0) == -1) {
fprintf(stderr, "[C] shmctl(IPC_RMID) failed\n");
exit(EXIT_FAILURE);
}
// Delete Semaphores
del_semvalue(sem_S_id);
del_semvalue(sem_N_id);
del_semvalue(sem_E_id);
exit(EXIT_SUCCESS);
}
