On Sun, Feb 23 2020 14:48:36 +0200, Lauri Tirkkonen wrote:
> So, diff below makes struct __sem non-opaque and removes the indirect
> allocations, so that the application is required to provide storage and
> can therefore control where it's stored (which could be eg. shm).
followup diff that makes sem_init() ignore pshared arg -- it doesn't
need to care, if the application puts the semaphore in shm. I tested an
unnamed shm_init() semaphore in shm_mkstemp() -created shm with this,
passing the fd to a child process and mmap()ing in the child process;
sharing a semaphore this way does seem to work.
diff --git a/lib/librthread/rthread_sem.c b/lib/librthread/rthread_sem.c
index 984e5fb0047..441843d87ca 100644
--- a/lib/librthread/rthread_sem.c
+++ b/lib/librthread/rthread_sem.c
@@ -105,41 +105,6 @@ sem_init(sem_t *sem, int pshared, unsigned int value)
return (-1);
}
- if (pshared) {
- errno = EPERM;
- return (-1);
-#ifdef notyet
- char name[SEM_RANDOM_NAME_LEN];
- sem_t *sempshared;
- int i;
-
- for (;;) {
- for (i = 0; i < SEM_RANDOM_NAME_LEN - 1; i++)
- name[i] = arc4random_uniform(255) + 1;
- name[SEM_RANDOM_NAME_LEN - 1] = '\0';
- sempshared = sem_open(name, O_CREAT | O_EXCL, 0, value);
- if (sempshared != SEM_FAILED)
- break;
- if (errno == EEXIST)
- continue;
- if (errno != EPERM)
- errno = ENOSPC;
- return (-1);
- }
-
- /* unnamed semaphore should not be opened twice */
- if (sem_unlink(name) == -1) {
- sem_close(sempshared);
- errno = ENOSPC;
- return (-1);
- }
-
- *semp = *sempshared;
- free(sempshared);
- return (0);
-#endif
- }
-
bzero(sem, sizeof(*sem));
sem->value = value;
diff --git a/lib/librthread/rthread_sem_compat.c
b/lib/librthread/rthread_sem_compat.c
index 91c888cd49b..8dc863a04d3 100644
--- a/lib/librthread/rthread_sem_compat.c
+++ b/lib/librthread/rthread_sem_compat.c
@@ -116,41 +116,6 @@ sem_init(sem_t *sem, int pshared, unsigned int value)
return (-1);
}
- if (pshared) {
- errno = EPERM;
- return (-1);
-#ifdef notyet
- char name[SEM_RANDOM_NAME_LEN];
- sem_t *sempshared;
- int i;
-
- for (;;) {
- for (i = 0; i < SEM_RANDOM_NAME_LEN - 1; i++)
- name[i] = arc4random_uniform(255) + 1;
- name[SEM_RANDOM_NAME_LEN - 1] = '\0';
- sempshared = sem_open(name, O_CREAT | O_EXCL, 0, value);
- if (sempshared != SEM_FAILED)
- break;
- if (errno == EEXIST)
- continue;
- if (errno != EPERM)
- errno = ENOSPC;
- return (-1);
- }
-
- /* unnamed semaphore should not be opened twice */
- if (sem_unlink(name) == -1) {
- sem_close(sempshared);
- errno = ENOSPC;
- return (-1);
- }
-
- *semp = *sempshared;
- free(sempshared);
- return (0);
-#endif
- }
-
bzero(sem, sizeof(*sem));
sem->lock = _SPINLOCK_UNLOCKED;
sem->value = value;
--
Lauri Tirkkonen | lotheac @ IRCnet
