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authorMattias Andrée <maandree@operamail.com>2015-04-14 07:29:38 +0200
committerMattias Andrée <maandree@operamail.com>2015-04-14 07:29:38 +0200
commit0e2876b9e16f37878955de5fddbeea912eb045e5 (patch)
treeac8a8b4839bb14d45f43bedd25a01871f5e92158 /src/semaphore.c
parentfirst sync draft (diff)
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second draft
Signed-off-by: Mattias Andrée <maandree@operamail.com>
Diffstat (limited to 'src/semaphore.c')
-rw-r--r--src/semaphore.c223
1 files changed, 0 insertions, 223 deletions
diff --git a/src/semaphore.c b/src/semaphore.c
deleted file mode 100644
index 8c9f099..0000000
--- a/src/semaphore.c
+++ /dev/null
@@ -1,223 +0,0 @@
-#include <stdlib.h>
-#include <stdio.h>
-#include <time.h>
-#include <errno.h>
-#include <string.h>
-
-#include <sys/ipc.h>
-#include <sys/sem.h>
-
-
-#ifdef _SEM_SEMUN_UNDEFINED
-union semun {
- int val;
- struct semid_ds *buf;
- unsigned short *array;
-};
-#endif
-
-
-#define P 0
-#define Q 1
-#define N 2
-
-#define SEMAPHORES 3
-
-
-char *argv0;
-
-
-static int
-create_semaphores(void)
-{
- key_t key;
- int id = -1, saved_errno;
- union semun values;
-
- values.array = NULL;
-
- /* Create semaphore array. */
- srand(time(NULL));
- for (;;) {
- double r = (double)rand();
- r /= (double)RAND_MAX + 1;
- r *= (1 << (8 * sizeof(key_t) - 2)) - 1;
- key = (key_t)r + 1;
- if (key == IPC_PRIVATE)
- continue;
- id = semget(key, SEMAPHORES, IPC_CREAT | IPC_EXCL | 0600);
- if (id != -1)
- break;
- if ((errno != EEXIST) && (errno != EINTR))
- goto fail;
- }
-
- /* Initialise the array. */
- values.array = calloc(SEMAPHORES, sizeof(unsigned short));
- if (values.array == NULL)
- goto fail;
- if (semctl(id, 0, SETALL, values.array) == -1)
- goto fail;
- free(values.array);
- values.array = NULL;
-
- printf("key:%zi(x%zx), id:%i\n", (ssize_t)key, (size_t)key, id);
- return 0;
-
-fail:
- saved_errno = errno;
- if ((id != -1) && (semctl(id, 0, IPC_RMID) == -1))
- perror(argv0);
- free(values.array);
- errno = saved_errno;
- return -1;
-}
-
-
-static int
-remove_semaphores(key_t key)
-{
- int id = semget(key, SEMAPHORES, 0600);
-
- if (id == -1)
- return -1;
-
- if (semctl(id, 0, IPC_RMID) == -1)
- return -1;
-
- return 0;
-}
-
-
-static int
-acquire_semaphore(key_t key, int semaphore, int delta)
-{
- struct sembuf op;
- int id;
-
- id = semget(key, SEMAPHORES, 0600);
- if (id == -1)
- return -1;
-
- op.sem_op = -delta;
- op.sem_num = semaphore;
- op.sem_flg = 0;
-
- return semop(id, &op, 1);
-}
-
-
-static int
-release_semaphore(key_t key, int semaphore, int delta)
-{
- struct sembuf op;
- int id;
-
- id = semget(key, SEMAPHORES, 0600);
- if (id == -1)
- return -1;
-
- op.sem_op = delta;
- op.sem_num = semaphore;
- op.sem_flg = 0;
-
- return semop(id, &op, 1);
-}
-
-
-static int
-zero_semaphore(key_t key, int semaphore)
-{
- struct sembuf op;
- int id;
-
- id = semget(key, SEMAPHORES, 0600);
- if (id == -1)
- return -1;
-
- op.sem_op = 0;
- op.sem_num = semaphore;
- op.sem_flg = 0;
-
- return semop(id, &op, 1);
-}
-
-
-static int
-read_semaphore(key_t key, int semaphore, int *z, int *n, int *v)
-{
- struct sembuf op;
- int id, r;
-
- id = semget(key, SEMAPHORES, 0600);
- if (id == -1)
- return -1;
-
- if (r = semctl(id, semaphore, GETZCNT), r == -1)
- return -1;
- if (z)
- *z = r;
-
- if (r = semctl(id, semaphore, GETNCNT), r == -1)
- return -1;
- if (n)
- *n = r;
-
- if (r = semctl(id, semaphore, GETVAL), r == -1)
- return -1;
- if (v)
- *v = r;
-
- return 0;
-}
-
-
-int
-main(int argc, char *argv[])
-{
- int r = -1, saved_errno, value;
- key_t key = argc > 2 ? (key_t)atoll(argv[2]) : 0;
-
- argv0 = *argv;
-
- if (!strcmp(argv[1], "create")) {
- r = create_semaphores();
- } else if (!strcmp(argv[1], "remove")) {
- r = remove_semaphores(key);
- } else if (!strcmp(argv[1], "pick-up")) {
- r = release_semaphore(key, N, 1);
- } else if (!strcmp(argv[1], "hang-up")) {
- r = acquire_semaphore(key, N, 1);
- } else if (!strcmp(argv[1], "listen")) {
- r = acquire_semaphore(key, Q, 1);
- if (r) {
- saved_errno = errno;
- r = release_semaphore(key, P, 1);
- if (r)
- perror(argv0);
- errno = saved_errno;
- goto fail;
- }
- printf("read here\n");
- r = release_semaphore(key, P, 1);
- } else if (!strcmp(argv[1], "speak")) {
- printf("write here\n");
- r = read_semaphore(key, N, NULL, NULL, &value);
- if (r)
- goto fail;
- r = release_semaphore(key, Q, value);
- if (r)
- goto fail;
- r = acquire_semaphore(key, P, value);
- } else
- return 2;
-
- if (r)
- goto fail;
- return 0;
-
-fail:
- perror(argv0);
- return 1;
-}
-