diff options
Diffstat (limited to 'examples/shm/shm.c')
| -rw-r--r-- | examples/shm/shm.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/examples/shm/shm.c b/examples/shm/shm.c new file mode 100644 index 0000000..2469115 --- /dev/null +++ b/examples/shm/shm.c @@ -0,0 +1,178 @@ +#include <unistd.h> +#include <sys/types.h> +#include <sys/ipc.h> +#include <sys/shm.h> +#include <sys/wait.h> +#include <sys/time.h> +#include <semaphore.h> +#include <stdio.h> +#include <aes.h> + +sem_t *enc_sem, *get_sem; + +#define SHM_SIZE 64*1024 + +void child(pid_t parent, void* mem) +{ + char key[16]; + char iv[16]; + struct crypto_aes_ctx ctx; + uint32_t mem_size; + + for (;;) { + memset(key, 0xa3, sizeof(key)); + memset(iv, 0x3, sizeof(iv)); + + sem_wait(enc_sem); + + crypto_aes_expand_key(&ctx, (void*)key, sizeof(key)); + + memcpy(&mem_size, mem, sizeof(mem_size)); + + crypto_cbc_encrypt(&ctx, mem, mem_size, mem, iv); + + sem_post(get_sem); + } +} + +static int must_finish = 0; + +static void alarm_handler(int signo) +{ + must_finish = 1; +} + +static double udifftimeval(struct timeval start, struct timeval end) +{ + return (double)(end.tv_usec - start.tv_usec) + + (double)(end.tv_sec - start.tv_sec) * 1000 * 1000; +} + +static void value2human(double bytes, double time, double* data, double* speed,char* metric) +{ + if (bytes > 1000 && bytes < 1000*1000) { + *data = ((double)bytes)/1000; + *speed = *data/time; + strcpy(metric, "Kb"); + return; + } else if (bytes >= 1000*1000 && bytes < 1000*1000*1000) { + *data = ((double)bytes)/(1000*1000); + *speed = *data/time; + strcpy(metric, "Mb"); + return; + } else if (bytes >= 1000*1000*1000) { + *data = ((double)bytes)/(1000*1000*1000); + *speed = *data/time; + strcpy(metric, "Gb"); + return; + } else { + *data = (double)bytes; + *speed = *data/time; + strcpy(metric, "bytes"); + return; + } +} + +void parent(pid_t child, void* mem) +{ +struct timeval start, end; +uint32_t chunksize; +double total = 0; +double secs, ddata, dspeed; +char metric[16]; + + signal(SIGALRM, alarm_handler); + + /* set a default value in shared memory */ + + for (chunksize = 256; chunksize <= (64 * 1024); chunksize *= 2) { + memset(mem, 0x33, chunksize); + + printf("\tEncrypting in chunks of %d bytes: ", chunksize); + fflush(stdout); + + total = 0; + must_finish = 0; + alarm(5); + gettimeofday(&start, NULL); + + do { + memcpy(mem, &chunksize, sizeof(chunksize)); + + sem_post(enc_sem); + + sem_wait(get_sem); + total+=chunksize; + } while(must_finish == 0); + + gettimeofday(&end, NULL); + + secs = udifftimeval(start, end)/ 1000000.0; + value2human(total, secs, &ddata, &dspeed, metric); + printf ("done. %.2f %s in %.2f secs: ", ddata, metric, secs); + printf ("%.2f %s/sec\n", dspeed, metric); + } + +} + +int main() +{ + int shmid, shmid2; + char c, *shm, *s, *semmem; + pid_t pid; + + signal(SIGUSR1, SIG_IGN); + signal(SIGUSR2, SIG_IGN); + + if ((shmid = shmget(IPC_PRIVATE, SHM_SIZE, IPC_CREAT | 0660)) < 0) { + perror("shmget fail"); + return 1; + } + + if ((shm = (char *) shmat(shmid, 0, 0)) == (char *) -1) { + perror("shmat : parent"); + return 2; + } + + if ((shmid2 = shmget(IPC_PRIVATE, 2*sizeof(sem_t), IPC_CREAT | 0660)) < 0) { + perror("shmget fail"); + return 1; + } + + if ((semmem = (char *) shmat(shmid2, 0, 0)) == (char *) -1) { + perror("shmat : parent"); + return 2; + } + + enc_sem = (void*)semmem; + get_sem = (void*)semmem + sizeof(sem_t); + + sem_init(enc_sem, 1, 0); + sem_init(get_sem, 1, 0); + + printf("Addresses in parent\n"); + printf("shared mem: %p\n", shm); + + s = shm; // s now references shared mem + for (c = 'A'; c <= 'Z'; ++c) // put some info there + *s++ = c; + *s = '\0'; // terminate the sequence + + switch (pid=fork()) { + case -1: + perror("fork"); + return 3; + default: + parent(pid, shm); + kill(pid, SIGTERM); + wait(0); // let the child finish + shmdt(shm); + shmctl(shmid, IPC_RMID, (struct shmid_ds *) 0); + break; + case 0: + child(getppid(), shm); + shmdt(shm); + break; + } + return 0; +} |