shm.c

Apache 2.0.63 is the current stable version of the 2.0 series, and is recommended over any previous

                                 APR_READ | APR_WRITE | APR_CREATE | APR_EXCL,
                                 pool); 
        if (status != APR_SUCCESS) {
            return status;
        }

        status = apr_file_trunc(file, new_m->realsize);
        if (status != APR_SUCCESS) {
            shm_unlink(filename); /* we're failing, remove the object */
            return status;
        }
        new_m->base = mmap(NULL, reqsize, PROT_READ | PROT_WRITE,
                           MAP_SHARED, tmpfd, 0);

        /* FIXME: check for errors */

        /* FIXME: Is it ok to close this file when using shm_open?? */
        status = apr_file_close(file);
        if (status != APR_SUCCESS) {
            return status;
        }
#endif /* APR_USE_SHMEM_MMAP_SHM */

        /* store the real size in the metadata */
        *(apr_size_t*)(new_m->base) = new_m->realsize;
        /* metadata isn't usable */
        new_m->usable = (char *)new_m->base + APR_ALIGN_DEFAULT(sizeof(apr_size_t));

        apr_pool_cleanup_register(new_m->pool, new_m, shm_cleanup_owner,
                                  apr_pool_cleanup_null);
        *m = new_m;
        return APR_SUCCESS;

#endif /* APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM */

#if APR_USE_SHMEM_SHMGET
        new_m->realsize = reqsize;

        /* FIXME: APR_OS_DEFAULT is too permissive, switch to 600 I think. */
        status = apr_file_open(&file, filename, 
                               APR_WRITE | APR_CREATE | APR_EXCL,
                               APR_OS_DEFAULT, pool);
        if (status != APR_SUCCESS) {
            return status;
        }

        /* ftok() (on solaris at least) requires that the file actually
         * exist before calling ftok(). */
        shmkey = ftok(filename, 1);
        if (shmkey == (key_t)-1) {
            return errno;
        }

        if ((new_m->shmid = shmget(shmkey, new_m->realsize,
                                   SHM_R | SHM_W | IPC_CREAT | IPC_EXCL)) < 0) {
            return errno;
        }

        if ((new_m->base = shmat(new_m->shmid, NULL, 0)) == (void *)-1) {
            return errno;
        }
        new_m->usable = new_m->base;

        if (shmctl(new_m->shmid, IPC_STAT, &shmbuf) == -1) {
            return errno;
        }
        apr_uid_current(&uid, &gid, pool);
        shmbuf.shm_perm.uid = uid;
        shmbuf.shm_perm.gid = gid;
        if (shmctl(new_m->shmid, IPC_SET, &shmbuf) == -1) {
            return errno;
        }

        nbytes = sizeof(reqsize);
        status = apr_file_write(file, (const void *)&reqsize,
                                &nbytes);
        if (status != APR_SUCCESS) {
            return status;
        }
        status = apr_file_close(file);
        if (status != APR_SUCCESS) {
            return status;
        }

        apr_pool_cleanup_register(new_m->pool, new_m, shm_cleanup_owner,
                                  apr_pool_cleanup_null);
        *m = new_m; 
        return APR_SUCCESS;

#endif /* APR_USE_SHMEM_SHMGET */
    }

    return APR_ENOTIMPL;
}

APR_DECLARE(apr_status_t) apr_shm_destroy(apr_shm_t *m)
{
    return apr_pool_cleanup_run(m->pool, m, shm_cleanup_owner);
}

static apr_status_t shm_cleanup_attach(void *m_)
{
    apr_shm_t *m = (apr_shm_t *)m_;

    if (m->filename == NULL) {
        /* It doesn't make sense to detach from an anonymous memory segment. */
        return APR_EINVAL;
    }
    else {
#if APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM
        if (munmap(m->base, m->realsize) == -1) {
            return errno;
        }
        return APR_SUCCESS;
#endif /* APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM */
#if APR_USE_SHMEM_SHMGET
        if (shmdt(m->base) == -1) {
            return errno;
        }
        return APR_SUCCESS;
#endif
    }

    return APR_ENOTIMPL;
}

APR_DECLARE(apr_status_t) apr_shm_attach(apr_shm_t **m,
                                         const char *filename,
                                         apr_pool_t *pool)
{
    if (filename == NULL) {
        /* It doesn't make sense to attach to a segment if you don't know
         * the filename. */
        return APR_EINVAL;
    }
    else {
#if APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM
        apr_shm_t *new_m;
        apr_status_t status;
        int tmpfd;
        apr_file_t *file;   /* file where metadata is stored */
        apr_size_t nbytes;

        new_m = apr_palloc(pool, sizeof(apr_shm_t));
        if (!new_m) {
            return APR_ENOMEM;
        }
        new_m->pool = pool;
        new_m->filename = apr_pstrdup(pool, filename);

        status = apr_file_open(&file, filename, 
                               APR_READ | APR_WRITE,
                               APR_OS_DEFAULT, pool);
        if (status != APR_SUCCESS) {
            return status;
        }
        status = apr_os_file_get(&tmpfd, file);
        if (status != APR_SUCCESS) {
            return status;
        }

        nbytes = sizeof(new_m->realsize);
        status = apr_file_read(file, (void *)&(new_m->realsize),
                               &nbytes);
        if (status != APR_SUCCESS) {
            return status;
        }

        status = apr_os_file_get(&tmpfd, file);
        if (status != APR_SUCCESS) {
            apr_file_close(file); /* ignore errors, we're failing */
            apr_file_remove(new_m->filename, new_m->pool);
            return status;
        }

        new_m->reqsize = new_m->realsize - sizeof(apr_size_t);

        new_m->base = mmap(NULL, new_m->realsize, PROT_READ | PROT_WRITE,
                           MAP_SHARED, tmpfd, 0);
        /* FIXME: check for errors */
        
        status = apr_file_close(file);
        if (status != APR_SUCCESS) {
            return status;
        }

        /* metadata isn't part of the usable segment */
        new_m->usable = (char *)new_m->base + APR_ALIGN_DEFAULT(sizeof(apr_size_t));

        apr_pool_cleanup_register(new_m->pool, new_m, shm_cleanup_attach,
                                  apr_pool_cleanup_null);
        *m = new_m;
        return APR_SUCCESS;

#endif /* APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM */
#if APR_USE_SHMEM_SHMGET
        apr_shm_t *new_m;
        apr_status_t status;
        apr_file_t *file;   /* file where metadata is stored */
        apr_size_t nbytes;
        key_t shmkey;

        new_m = apr_palloc(pool, sizeof(apr_shm_t));
        if (!new_m) {
            return APR_ENOMEM;
        }

        /* FIXME: does APR_OS_DEFAULT matter for reading? */
        status = apr_file_open(&file, filename, 
                               APR_READ, APR_OS_DEFAULT, pool);
        if (status != APR_SUCCESS) {
            return status;
        }

        nbytes = sizeof(new_m->reqsize);
        status = apr_file_read(file, (void *)&(new_m->reqsize),
                               &nbytes);
        if (status != APR_SUCCESS) {
            return status;
        }
        status = apr_file_close(file);
        if (status != APR_SUCCESS) {
            return status;
        }

        new_m->filename = apr_pstrdup(pool, filename);
        new_m->pool = pool;
        shmkey = ftok(filename, 1);
        if (shmkey == (key_t)-1) {
            return errno;
        }
        if ((new_m->shmid = shmget(shmkey, 0, SHM_R | SHM_W)) == -1) {
            return errno;
        }
        if ((new_m->base = shmat(new_m->shmid, NULL, 0)) == (void *)-1) {
            return errno;
        }
        new_m->usable = new_m->base;
        new_m->realsize = new_m->reqsize;

        apr_pool_cleanup_register(new_m->pool, new_m, shm_cleanup_attach,
                                  apr_pool_cleanup_null);
        *m = new_m;
        return APR_SUCCESS;

#endif /* APR_USE_SHMEM_SHMGET */
    }

    return APR_ENOTIMPL;
}

APR_DECLARE(apr_status_t) apr_shm_detach(apr_shm_t *m)
{
    apr_status_t rv = shm_cleanup_attach(m);
    apr_pool_cleanup_kill(m->pool, m, shm_cleanup_attach);
    return rv;
}

APR_DECLARE(void *) apr_shm_baseaddr_get(const apr_shm_t *m)
{
    return m->usable;
}

APR_DECLARE(apr_size_t) apr_shm_size_get(const apr_shm_t *m)
{
    return m->reqsize;
}

APR_POOL_IMPLEMENT_ACCESSOR(shm)

APR_DECLARE(apr_status_t) apr_os_shm_get(apr_os_shm_t *osshm,
                                         apr_shm_t *shm)
{
    return APR_ENOTIMPL;
}

APR_DECLARE(apr_status_t) apr_os_shm_put(apr_shm_t **m,
                                         apr_os_shm_t *osshm,
                                         apr_pool_t *pool)
{
    return APR_ENOTIMPL;
}