freebsd-dev/contrib/apr/shmem/unix/shm.c
2014-05-27 07:15:14 +00:00

701 lines
21 KiB
C

/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "apr_arch_shm.h"
#include "apr_general.h"
#include "apr_errno.h"
#include "apr_user.h"
#include "apr_strings.h"
#include "apr_hash.h"
#if APR_USE_SHMEM_MMAP_SHM
/*
* For portable use, a shared memory object should be identified by a name of
* the form /somename; that is, a null-terminated string of up to NAME_MAX
* (i.e., 255) characters consisting of an initial slash, followed by one or
* more characters, none of which are slashes.
*/
#ifndef NAME_MAX
#define NAME_MAX 255
#endif
/* See proc_mutex.c and sem_open for the reason for all this! */
static unsigned int rshash (const char *p) {
/* hash function from Robert Sedgwicks 'Algorithms in C' book */
unsigned int b = 378551;
unsigned int a = 63689;
unsigned int retval = 0;
for( ; *p; p++) {
retval = retval * a + (*p);
a *= b;
}
return retval;
}
static const char *make_shm_open_safe_name(const char *filename,
apr_pool_t *pool)
{
apr_ssize_t flen;
unsigned int h1, h2;
if (filename == NULL) {
return NULL;
}
flen = strlen(filename);
h1 = (apr_hashfunc_default(filename, &flen) & 0xffffffff);
h2 = (rshash(filename) & 0xffffffff);
return apr_psprintf(pool, "/ShM.%xH%x", h1, h2);
}
#endif
#if APR_USE_SHMEM_SHMGET
static key_t our_ftok(const char *filename)
{
/* to help avoid collisions while still using
* an easily recreated proj_id */
apr_ssize_t slen = strlen(filename);
return ftok(filename,
(int)apr_hashfunc_default(filename, &slen));
}
#endif
static apr_status_t shm_cleanup_owner(void *m_)
{
apr_shm_t *m = (apr_shm_t *)m_;
/* anonymous shared memory */
if (m->filename == NULL) {
#if APR_USE_SHMEM_MMAP_ZERO || APR_USE_SHMEM_MMAP_ANON
if (munmap(m->base, m->realsize) == -1) {
return errno;
}
return APR_SUCCESS;
#elif APR_USE_SHMEM_SHMGET_ANON
if (shmdt(m->base) == -1) {
return errno;
}
/* This segment will automatically remove itself after all
* references have detached. */
return APR_SUCCESS;
#endif
}
/* name-based shared memory */
else {
#if APR_USE_SHMEM_MMAP_TMP
if (munmap(m->base, m->realsize) == -1) {
return errno;
}
if (access(m->filename, F_OK)) {
return APR_SUCCESS;
}
else {
return apr_file_remove(m->filename, m->pool);
}
#elif APR_USE_SHMEM_MMAP_SHM
if (munmap(m->base, m->realsize) == -1) {
return errno;
}
if (shm_unlink(make_shm_open_safe_name(m->filename, m->pool)) == -1 && errno != ENOENT) {
return errno;
}
return APR_SUCCESS;
#elif APR_USE_SHMEM_SHMGET
/* Indicate that the segment is to be destroyed as soon
* as all processes have detached. This also disallows any
* new attachments to the segment. */
if (shmctl(m->shmid, IPC_RMID, NULL) == -1 && errno != EINVAL) {
return errno;
}
if (shmdt(m->base) == -1) {
return errno;
}
if (access(m->filename, F_OK)) {
return APR_SUCCESS;
}
else {
return apr_file_remove(m->filename, m->pool);
}
#else
return APR_ENOTIMPL;
#endif
}
}
APR_DECLARE(apr_status_t) apr_shm_create(apr_shm_t **m,
apr_size_t reqsize,
const char *filename,
apr_pool_t *pool)
{
apr_shm_t *new_m;
apr_status_t status;
#if APR_USE_SHMEM_SHMGET || APR_USE_SHMEM_SHMGET_ANON
struct shmid_ds shmbuf;
apr_uid_t uid;
apr_gid_t gid;
#endif
#if APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM || \
APR_USE_SHMEM_MMAP_ZERO
int tmpfd;
#endif
#if APR_USE_SHMEM_SHMGET
apr_size_t nbytes;
key_t shmkey;
#endif
#if APR_USE_SHMEM_MMAP_ZERO || APR_USE_SHMEM_SHMGET || \
APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM
apr_file_t *file; /* file where metadata is stored */
#endif
/* Check if they want anonymous or name-based shared memory */
if (filename == NULL) {
#if APR_USE_SHMEM_MMAP_ZERO || APR_USE_SHMEM_MMAP_ANON
new_m = apr_palloc(pool, sizeof(apr_shm_t));
new_m->pool = pool;
new_m->reqsize = reqsize;
new_m->realsize = reqsize +
APR_ALIGN_DEFAULT(sizeof(apr_size_t)); /* room for metadata */
new_m->filename = NULL;
#if APR_USE_SHMEM_MMAP_ZERO
status = apr_file_open(&file, "/dev/zero", 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;
}
new_m->base = mmap(NULL, new_m->realsize, PROT_READ|PROT_WRITE,
MAP_SHARED, tmpfd, 0);
if (new_m->base == (void *)MAP_FAILED) {
return errno;
}
status = apr_file_close(file);
if (status != APR_SUCCESS) {
return status;
}
/* 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;
#elif APR_USE_SHMEM_MMAP_ANON
new_m->base = mmap(NULL, new_m->realsize, PROT_READ|PROT_WRITE,
MAP_ANON|MAP_SHARED, -1, 0);
if (new_m->base == (void *)MAP_FAILED) {
return errno;
}
/* 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_ZERO */
#elif APR_USE_SHMEM_SHMGET_ANON
new_m = apr_palloc(pool, sizeof(apr_shm_t));
new_m->pool = pool;
new_m->reqsize = reqsize;
new_m->realsize = reqsize;
new_m->filename = NULL;
if ((new_m->shmid = shmget(IPC_PRIVATE, new_m->realsize,
SHM_R | SHM_W | IPC_CREAT)) < 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;
}
/* Remove the segment once use count hits zero.
* We will not attach to this segment again, since it is
* anonymous memory, so it is ok to mark it for deletion.
*/
if (shmctl(new_m->shmid, IPC_RMID, NULL) == -1) {
return errno;
}
apr_pool_cleanup_register(new_m->pool, new_m, shm_cleanup_owner,
apr_pool_cleanup_null);
*m = new_m;
return APR_SUCCESS;
#else
/* It is an error if they want anonymous memory but we don't have it. */
return APR_ENOTIMPL; /* requested anonymous but we don't have it */
#endif
}
/* Name-based shared memory */
else {
new_m = apr_palloc(pool, sizeof(apr_shm_t));
new_m->pool = pool;
new_m->reqsize = reqsize;
new_m->filename = apr_pstrdup(pool, filename);
#if APR_USE_SHMEM_MMAP_SHM
const char *shm_name = make_shm_open_safe_name(filename, pool);
#endif
#if APR_USE_SHMEM_MMAP_TMP || APR_USE_SHMEM_MMAP_SHM
new_m->realsize = reqsize +
APR_ALIGN_DEFAULT(sizeof(apr_size_t)); /* room for metadata */
/* FIXME: Ignore error for now. *
* status = apr_file_remove(file, pool);*/
status = APR_SUCCESS;
#if APR_USE_SHMEM_MMAP_TMP
/* FIXME: Is APR_OS_DEFAULT sufficient? */
status = apr_file_open(&file, filename,
APR_READ | APR_WRITE | APR_CREATE | APR_EXCL,
APR_OS_DEFAULT, pool);
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;
}
status = apr_file_trunc(file, new_m->realsize);
if (status != APR_SUCCESS && status != APR_ESPIPE) {
apr_file_close(file); /* ignore errors, we're failing */
apr_file_remove(new_m->filename, new_m->pool);
return status;
}
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;
}
#endif /* APR_USE_SHMEM_MMAP_TMP */
#if APR_USE_SHMEM_MMAP_SHM
/* FIXME: SysV uses 0600... should we? */
tmpfd = shm_open(shm_name, O_RDWR | O_CREAT | O_EXCL, 0644);
if (tmpfd == -1) {
return errno;
}
status = apr_os_file_put(&file, &tmpfd,
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 && status != APR_ESPIPE) {
shm_unlink(shm_name); /* we're failing, remove the object */
return status;
}
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;
}
#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;
#elif 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_FOPEN_WRITE | APR_FOPEN_CREATE | APR_FOPEN_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 = our_ftok(filename);
if (shmkey == (key_t)-1) {
apr_file_close(file);
return errno;
}
if ((new_m->shmid = shmget(shmkey, new_m->realsize,
SHM_R | SHM_W | IPC_CREAT | IPC_EXCL)) < 0) {
apr_file_close(file);
return errno;
}
if ((new_m->base = shmat(new_m->shmid, NULL, 0)) == (void *)-1) {
apr_file_close(file);
return errno;
}
new_m->usable = new_m->base;
if (shmctl(new_m->shmid, IPC_STAT, &shmbuf) == -1) {
apr_file_close(file);
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) {
apr_file_close(file);
return errno;
}
nbytes = sizeof(reqsize);
status = apr_file_write(file, (const void *)&reqsize,
&nbytes);
if (status != APR_SUCCESS) {
apr_file_close(file);
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;
#else
return APR_ENOTIMPL;
#endif
}
}
APR_DECLARE(apr_status_t) apr_shm_create_ex(apr_shm_t **m,
apr_size_t reqsize,
const char *filename,
apr_pool_t *p,
apr_int32_t flags)
{
return apr_shm_create(m, reqsize, filename, p);
}
APR_DECLARE(apr_status_t) apr_shm_remove(const char *filename,
apr_pool_t *pool)
{
#if APR_USE_SHMEM_SHMGET
apr_status_t status;
apr_file_t *file;
key_t shmkey;
int shmid;
#endif
#if APR_USE_SHMEM_MMAP_TMP
return apr_file_remove(filename, pool);
#elif APR_USE_SHMEM_MMAP_SHM
const char *shm_name = make_shm_open_safe_name(filename, pool);
if (shm_unlink(shm_name) == -1) {
return errno;
}
return APR_SUCCESS;
#elif APR_USE_SHMEM_SHMGET
/* Presume that the file already exists; just open for writing */
status = apr_file_open(&file, filename, APR_FOPEN_WRITE,
APR_OS_DEFAULT, pool);
if (status) {
return status;
}
/* ftok() (on solaris at least) requires that the file actually
* exist before calling ftok(). */
shmkey = our_ftok(filename);
if (shmkey == (key_t)-1) {
goto shm_remove_failed;
}
apr_file_close(file);
if ((shmid = shmget(shmkey, 0, SHM_R | SHM_W)) < 0) {
goto shm_remove_failed;
}
/* Indicate that the segment is to be destroyed as soon
* as all processes have detached. This also disallows any
* new attachments to the segment. */
if (shmctl(shmid, IPC_RMID, NULL) == -1) {
goto shm_remove_failed;
}
return apr_file_remove(filename, pool);
shm_remove_failed:
status = errno;
/* ensure the file has been removed anyway. */
apr_file_remove(filename, pool);
return status;
#else
/* No support for anonymous shm */
return APR_ENOTIMPL;
#endif
}
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;
#elif APR_USE_SHMEM_SHMGET
if (shmdt(m->base) == -1) {
return errno;
}
return APR_SUCCESS;
#else
return APR_ENOTIMPL;
#endif
}
}
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));
new_m->pool = pool;
new_m->filename = apr_pstrdup(pool, filename);
#if APR_USE_SHMEM_MMAP_SHM
const char *shm_name = make_shm_open_safe_name(filename, pool);
/* FIXME: SysV uses 0600... should we? */
tmpfd = shm_open(shm_name, O_RDWR, 0644);
if (tmpfd == -1) {
return errno;
}
status = apr_os_file_put(&file, &tmpfd,
APR_READ | APR_WRITE,
pool);
if (status != APR_SUCCESS) {
return status;
}
#elif APR_USE_SHMEM_MMAP_TMP
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;
}
#else
return APR_ENOTIMPL;
#endif
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;
#elif 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));
status = apr_file_open(&file, filename,
APR_FOPEN_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 = our_ftok(filename);
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;
#else
return APR_ENOTIMPL;
#endif
}
}
APR_DECLARE(apr_status_t) apr_shm_attach_ex(apr_shm_t **m,
const char *filename,
apr_pool_t *pool,
apr_int32_t flags)
{
return apr_shm_attach(m, filename, pool);
}
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;
}