This is xnu-12377.1.9. See this file in:
/*
* Copyright (c) 2000-2007 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1990, 1996-1998 Apple Computer, Inc.
* All Rights Reserved.
*/
/*
* posix_sem.c : Support for POSIX semaphore APIs
*
* File: posix_sem.c
* Author: Ananthakrishna Ramesh
*
* HISTORY
* 2-Sep-1999 A.Ramesh
* Created for MacOSX
*
*/
/*
* NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
* support for mandatory and extensible security protections. This notice
* is included in support of clause 2.2 (b) of the Apple Public License,
* Version 2.0.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/file_internal.h>
#include <sys/filedesc.h>
#include <sys/stat.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/malloc.h>
#include <sys/semaphore.h>
#include <sys/sysproto.h>
#include <sys/proc_info.h>
#include <sys/random.h>
#include <net/siphash.h>
#if CONFIG_MACF
#include <sys/vnode_internal.h>
#include <security/mac_framework.h>
#endif
#include <security/audit/audit.h>
#include <mach/mach_types.h>
#include <mach/vm_prot.h>
#include <mach/semaphore.h>
#include <mach/sync_policy.h>
#include <mach/task.h>
#include <kern/kern_types.h>
#include <kern/task.h>
#include <kern/clock.h>
#include <mach/kern_return.h>
#define f_flag fp_glob->fg_flag
#define f_ops fp_glob->fg_ops
#define PSEMNAMLEN 31 /* maximum name segment length we bother with */
#define PSEMTEAMIDLEN 31 /* maximum length of team ID we consider */
struct pseminfo {
unsigned int psem_flags;
unsigned int psem_usecount;
mode_t psem_mode;
uid_t psem_uid;
gid_t psem_gid;
char psem_name[PSEMNAMLEN + 1]; /* segment name */
semaphore_t psem_semobject;
struct label * psem_label;
pid_t psem_creator_pid;
uint64_t psem_creator_uniqueid;
};
#define PSEMINFO_NULL (struct pseminfo *)0
#define PSEM_NONE 1
#define PSEM_DEFINED 2
#define PSEM_ALLOCATED 4
#define PSEM_MAPPED 8
#define PSEM_INUSE 0x10
#define PSEM_REMOVED 0x20
#define PSEM_INCREATE 0x40
#define PSEM_INDELETE 0x80
struct psemcache {
LIST_ENTRY(psemcache) psem_hash; /* hash chain */
struct pseminfo *pseminfo; /* vnode the name refers to */
size_t psem_nlen; /* length of name */
size_t psem_teamidlen; /* length of team ID */
char psem_name[PSEMNAMLEN + 1]; /* segment name */
char psem_teamid[PSEMTEAMIDLEN + 1]; /* team ID of users, if any */
};
#define PSEMCACHE_NULL (struct psemcache *)0
#define PSEMCACHE_NOTFOUND (0)
#define PSEMCACHE_FOUND (-1)
#define PSEMCACHE_NEGATIVE (ENOENT)
struct psemstats {
long pstats_hits;
long pstats_miss;
long pstats_local_hits;
long pstats_global_hits;
long pstats_local_miss;
long pstats_global_miss;
long pstats_local_collisions;
long pstats_global_collisions;
long pstats_fallback_hits; /* hits that missed local but hit global */
long pstats_fallback_miss; /* hits that missed both local and global */
long pstats_neghits; /* hits to 'negative entries' (return ENOENT) */
long pstats_longnames; /* semaphore or team ID ENAMETOOLONG */
};
struct psemname {
char *psem_nameptr; /* pointer to looked up name */
size_t psem_namelen; /* length of looked up component */
uint64_t psem_hash_local; /* hash value of looked up name and team */
uint64_t psem_hash_global; /* hash value of looked up name, without team */
const char *psem_teamidptr;
size_t psem_teamidlen;
};
struct psemnode {
struct pseminfo *pinfo;
#if DIAGNOSTIC
unsigned int readcnt;
unsigned int writecnt;
#endif
};
#define PSEMNODE_NULL (struct psemnode *)0
LIST_HEAD(psemhashhead, psemcache);
struct psemhashtable {
struct psemhashhead *psem_table;
/* Hash table mask, i.e size - 1 */
u_long psem_table_mask;
/* SipHash key, randomly assigned at boot */
uint8_t psem_siphash_key[SIPHASH_KEY_LENGTH];
};
#define PSEMHASH(table, hash) (&(table).psem_table[(hash) & (table).psem_table_mask])
struct psemhashtable psem_global, psem_local;
long posix_sem_num; /* number of POSIX semaphores on the system */
long posix_sem_max = 10000; /* max number of POSIX semaphores on the system */
SYSCTL_NODE(_kern, KERN_POSIX, posix, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Posix");
SYSCTL_NODE(_kern_posix, OID_AUTO, sem, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Semaphores");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, max, CTLFLAG_RW | CTLFLAG_LOCKED, &posix_sem_max, "max");
struct psemstats psemstats; /* cache effectiveness statistics */
#if DEBUG || DEVELOPMENT
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, hits, CTLFLAG_RD, &psemstats.pstats_hits, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, miss, CTLFLAG_RD, &psemstats.pstats_miss, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, local_hits, CTLFLAG_RD, &psemstats.pstats_local_hits, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, local_miss, CTLFLAG_RD, &psemstats.pstats_local_miss, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, global_hits, CTLFLAG_RD, &psemstats.pstats_global_hits, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, global_miss, CTLFLAG_RD, &psemstats.pstats_global_miss, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, fallback_hits, CTLFLAG_RD, &psemstats.pstats_fallback_hits, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, fallback_miss, CTLFLAG_RD, &psemstats.pstats_fallback_miss, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, local_collisions, CTLFLAG_RD, &psemstats.pstats_local_collisions, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, global_collisions, CTLFLAG_RD, &psemstats.pstats_global_collisions, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, neghits, CTLFLAG_RD, &psemstats.pstats_neghits, "");
SYSCTL_LONG(_kern_posix_sem, OID_AUTO, longnames, CTLFLAG_RD, &psemstats.pstats_longnames, "");
#endif
static int psem_access(struct pseminfo *pinfo, mode_t mode, kauth_cred_t cred);
static int psem_cache_search(struct pseminfo **,
struct psemname *, struct psemcache **);
static int psem_delete(struct pseminfo * pinfo);
static int psem_closefile(struct fileglob *fp, vfs_context_t ctx);
static int psem_unlink_internal(struct pseminfo *pinfo, struct psemcache *pcache);
static const char *psem_get_teamid(proc_t p);
static const struct fileops psemops = {
.fo_type = DTYPE_PSXSEM,
.fo_read = fo_no_read,
.fo_write = fo_no_write,
.fo_ioctl = fo_no_ioctl,
.fo_select = fo_no_select,
.fo_close = psem_closefile,
.fo_drain = fo_no_drain,
.fo_kqfilter = fo_no_kqfilter,
};
static LCK_GRP_DECLARE(psx_sem_subsys_lck_grp, "posix semaphores");
static LCK_MTX_DECLARE(psx_sem_subsys_mutex, &psx_sem_subsys_lck_grp);
#define PSEM_SUBSYS_LOCK() lck_mtx_lock(&psx_sem_subsys_mutex)
#define PSEM_SUBSYS_UNLOCK() lck_mtx_unlock(&psx_sem_subsys_mutex)
#define PSEM_SUBSYS_ASSERT_HELD() LCK_MTX_ASSERT(&psx_sem_subsys_mutex, LCK_MTX_ASSERT_OWNED)
static int psem_cache_add(struct pseminfo *psemp, struct psemname *pnp, struct psemcache *pcp);
static void psem_cache_delete(struct psemcache *pcp);
int psem_cache_purge_all(void);
static struct psemname
psem_cache_hash(char *name, size_t len, const char *teamid, size_t teamidlen)
{
SIPHASH_CTX ctx;
struct psemname nd;
nd.psem_nameptr = name;
nd.psem_namelen = len;
nd.psem_teamidptr = teamid;
nd.psem_teamidlen = teamidlen;
nd.psem_hash_local = 0;
nd.psem_hash_global = 0;
_Static_assert(sizeof(nd.psem_hash_local) == SIPHASH_DIGEST_LENGTH, "hash field is wrong size for SipHash");
_Static_assert(sizeof(nd.psem_hash_global) == SIPHASH_DIGEST_LENGTH, "hash field is wrong size for SipHash");
/*
* This routine is called before taking the subsystem lock, so we'll prepare hashes
* for both global and local tables up front.
*/
SipHash24_Init(&ctx);
SipHash_SetKey(&ctx, psem_global.psem_siphash_key);
SipHash_Update(&ctx, name, len);
SipHash_Final((u_int8_t *)&nd.psem_hash_global, &ctx);
if (teamidlen > 0) {
SipHash24_Init(&ctx);
SipHash_SetKey(&ctx, psem_local.psem_siphash_key);
SipHash_Update(&ctx, name, len);
SipHash_Update(&ctx, teamid, teamidlen);
SipHash_Final((u_int8_t *)&nd.psem_hash_local, &ctx);
}
return nd;
}
/*
* Returns 1 if the semaphore name matches what we're looking for, otherwise 0.
* When searching the local table, the team ID must match too.
*/
static int
psem_cache_is_match(struct psemcache *sem, struct psemname *target, bool local)
{
bool name_matches = target->psem_namelen == sem->psem_nlen &&
!bcmp(target->psem_nameptr, sem->psem_name, target->psem_namelen);
if (local) {
bool teamid_matches = target->psem_teamidlen == sem->psem_teamidlen &&
!bcmp(target->psem_teamidptr, sem->psem_teamid, target->psem_teamidlen);
return name_matches && teamid_matches;
}
return name_matches;
}
/*
* Lookup an entry in the cache
*
*
* status of -1 is returned if matches
* If the lookup determines that the name does not exist
* (negative cacheing), a status of ENOENT is returned. If the lookup
* fails, a status of zero is returned.
*/
static int
psem_cache_search(struct pseminfo **psemp, struct psemname *pnp,
struct psemcache **pcache)
{
struct psemcache *pcp = NULL, *nnp;
struct psemhashhead *pcpp;
if (pnp->psem_namelen > PSEMNAMLEN || pnp->psem_teamidlen > PSEMTEAMIDLEN) {
os_atomic_inc(&psemstats.pstats_longnames, relaxed);
return PSEMCACHE_NOTFOUND;
}
/* If Team ID is present, try to look up in the local table first. */
if (pnp->psem_teamidlen > 0) {
pcpp = PSEMHASH(psem_local, pnp->psem_hash_local);
for (pcp = pcpp->lh_first; pcp != 0; pcp = nnp) {
nnp = pcp->psem_hash.le_next;
if (psem_cache_is_match(pcp, pnp, true)) {
break;
}
os_atomic_inc(&psemstats.pstats_local_collisions, relaxed);
}
if (pcp == 0) {
os_atomic_inc(&psemstats.pstats_local_miss, relaxed);
} else {
os_atomic_inc(&psemstats.pstats_local_hits, relaxed);
}
}
/* Otherwise, or if the local lookup failed, search the global table. */
if (pcp == 0) {
pcpp = PSEMHASH(psem_global, pnp->psem_hash_global);
for (pcp = pcpp->lh_first; pcp != 0; pcp = nnp) {
nnp = pcp->psem_hash.le_next;
if (psem_cache_is_match(pcp, pnp, false)) {
break;
}
os_atomic_inc(&psemstats.pstats_global_collisions, relaxed);
}
if (pcp == 0) {
os_atomic_inc(&psemstats.pstats_global_miss, relaxed);
if (pnp->psem_teamidlen > 0) {
os_atomic_inc(&psemstats.pstats_fallback_miss, relaxed);
}
} else {
os_atomic_inc(&psemstats.pstats_global_hits, relaxed);
if (pnp->psem_teamidlen > 0) {
os_atomic_inc(&psemstats.pstats_fallback_hits, relaxed);
}
}
}
if (pcp == 0) {
os_atomic_inc(&psemstats.pstats_miss, relaxed);
return PSEMCACHE_NOTFOUND;
}
/* We found a "positive" match, return the vnode */
if (pcp->pseminfo) {
os_atomic_inc(&psemstats.pstats_hits, relaxed);
/* TOUCH(ncp); */
*psemp = pcp->pseminfo;
*pcache = pcp;
return PSEMCACHE_FOUND;
}
/*
* We found a "negative" match, ENOENT notifies client of this match.
* The nc_vpid field records whether this is a whiteout.
*/
os_atomic_inc(&psemstats.pstats_neghits, relaxed);
return PSEMCACHE_NEGATIVE;
}
/*
* Add an entry to the cache.
*/
static int
psem_cache_add(struct pseminfo *psemp, struct psemname *pnp, struct psemcache *pcp)
{
struct psemhashhead *pcpp;
#if DIAGNOSTIC
if (pnp->psem_namelen > PSEMNAMLEN) {
panic("cache_enter: name too long");
}
if (pnp->psem_teamidlen > PSEMTEAMIDLEN) {
panic("cache_enter: teamid too long");
}
#endif
if (posix_sem_num >= posix_sem_max) {
return ENOSPC;
}
posix_sem_num++;
/*
* Fill in cache info, if vp is NULL this is a "negative" cache entry.
* For negative entries, we have to record whether it is a whiteout.
* the whiteout flag is stored in the nc_vpid field which is
* otherwise unused.
*/
pcp->pseminfo = psemp;
pcp->psem_nlen = pnp->psem_namelen;
bcopy(pnp->psem_nameptr, pcp->psem_name, pcp->psem_nlen);
pcp->psem_teamidlen = pnp->psem_teamidlen;
bcopy(pnp->psem_teamidptr, pcp->psem_teamid, pcp->psem_teamidlen);
/* Insert into the right table based on Team ID. */
if (pcp->psem_teamidlen > 0) {
pcpp = PSEMHASH(psem_local, pnp->psem_hash_local);
} else {
pcpp = PSEMHASH(psem_global, pnp->psem_hash_global);
}
#if DIAGNOSTIC
{
struct psemcache *p;
for (p = pcpp->lh_first; p != 0; p = p->psem_hash.le_next) {
if (p == pcp) {
panic("psem:cache_enter duplicate");
}
}
}
#endif
LIST_INSERT_HEAD(pcpp, pcp, psem_hash);
return 0;
}
/*
* Name cache initialization, from vfs_init() when we are booting
*/
void
psem_cache_init(void)
{
/*
* The global table stores semaphores created by processes without a Team
* ID (such as platform binaries). The local table stores all other semaphores.
*/
psem_global.psem_table = hashinit((int)(posix_sem_max / 2), M_SHM, &psem_global.psem_table_mask);
psem_local.psem_table = hashinit((int)(posix_sem_max / 2), M_SHM, &psem_local.psem_table_mask);
read_frandom(psem_global.psem_siphash_key, sizeof(psem_global.psem_siphash_key));
read_frandom(psem_local.psem_siphash_key, sizeof(psem_local.psem_siphash_key));
}
static void
psem_cache_delete(struct psemcache *pcp)
{
#if DIAGNOSTIC
if (pcp->psem_hash.le_prev == 0) {
panic("psem namecache purge le_prev");
}
if (pcp->psem_hash.le_next == pcp) {
panic("namecache purge le_next");
}
#endif /* DIAGNOSTIC */
LIST_REMOVE(pcp, psem_hash);
pcp->psem_hash.le_prev = NULL;
posix_sem_num--;
}
static int
psem_cache_purge_table(struct psemhashtable *table)
{
struct psemcache *pcp, *tmppcp;
struct psemhashhead *pcpp;
for (pcpp = &table->psem_table[table->psem_table_mask]; pcpp >= table->psem_table; pcpp--) {
LIST_FOREACH_SAFE(pcp, pcpp, psem_hash, tmppcp) {
assert(pcp->psem_nlen);
/*
* unconditionally unlink the cache entry
*/
int error = psem_unlink_internal(pcp->pseminfo, pcp);
if (error) {
return error;
}
}
}
return 0;
}
/*
* Remove all cached psem entries. Open semaphores (with a positive refcount)
* will continue to exist, but their cache entries tying them to a particular
* name/path will be removed making all future lookups on the name fail.
*/
int
psem_cache_purge_all(void)
{
int error = 0;
if (kauth_cred_issuser(kauth_cred_get()) == 0) {
return EPERM;
}
PSEM_SUBSYS_LOCK();
error = psem_cache_purge_table(&psem_global);
if (error) {
goto out;
}
error = psem_cache_purge_table(&psem_local);
if (error) {
goto out;
}
assert(posix_sem_num == 0);
out:
PSEM_SUBSYS_UNLOCK();
if (error) {
printf("%s: Error %d removing all semaphores: %ld remain!\n",
__func__, error, posix_sem_num);
}
return error;
}
/*
* In order to support unnamed POSIX semaphores, the named
* POSIX semaphores will have to move out of the per-process
* open filetable, and into a global table that is shared with
* unnamed POSIX semaphores, since unnamed POSIX semaphores
* are typically used by declaring instances in shared memory,
* and there's no other way to do this without changing the
* underlying type, which would introduce binary compatibility
* issues.
*/
int
sem_open(proc_t p, struct sem_open_args *uap, user_addr_t *retval)
{
int indx, error;
struct psemname nd;
struct pseminfo *pinfo;
struct fileproc *fp = NULL;
char *pnbuf = NULL;
const char *teamid = NULL;
struct pseminfo *new_pinfo = PSEMINFO_NULL;
struct psemnode *new_pnode = PSEMNODE_NULL;
struct psemcache *pcache = PSEMCACHE_NULL;
char * nameptr;
size_t pathlen, plen, teamidlen;
mode_t fmode;
mode_t cmode = (mode_t)uap->mode;
int value = uap->value;
int incache = 0;
struct psemcache *pcp = PSEMCACHE_NULL;
kern_return_t kret = KERN_INVALID_ADDRESS; /* default fail */
AUDIT_ARG(fflags, uap->oflag);
AUDIT_ARG(mode, (mode_t)uap->mode);
AUDIT_ARG(value32, uap->value);
pinfo = PSEMINFO_NULL;
/*
* Preallocate everything we might need up front to avoid taking
* and dropping the lock, opening us up to race conditions.
*/
pnbuf = zalloc_flags(ZV_NAMEI, Z_WAITOK | Z_ZERO);
pathlen = MAXPATHLEN;
error = copyinstr(uap->name, pnbuf, MAXPATHLEN, &pathlen);
if (error) {
goto bad;
}
AUDIT_ARG(text, pnbuf);
if ((pathlen > PSEMNAMLEN)) {
error = ENAMETOOLONG;
goto bad;
}
#ifdef PSXSEM_NAME_RESTRICT
nameptr = pnbuf;
if (*nameptr == '/') {
while (*(nameptr++) == '/') {
plen--;
error = EINVAL;
goto bad;
}
} else {
error = EINVAL;
goto bad;
}
#endif /* PSXSEM_NAME_RESTRICT */
plen = pathlen;
nameptr = pnbuf;
teamid = psem_get_teamid(p);
teamidlen = teamid ? strlen(teamid) : 0;
if (teamidlen > PSEMTEAMIDLEN) {
error = ENAMETOOLONG;
goto bad;
}
nd = psem_cache_hash(nameptr, plen, teamid, teamidlen);
/*
* attempt to allocate a new fp; if unsuccessful, the fp will be
* left unmodified (NULL).
*/
error = falloc(p, &fp, &indx);
if (error) {
goto bad;
}
/*
* We allocate a new entry if we are less than the maximum
* allowed and the one at the front of the LRU list is in use.
* Otherwise we use the one at the front of the LRU list.
*/
pcp = kalloc_type(struct psemcache, Z_WAITOK | Z_ZERO | Z_NOFAIL);
new_pinfo = kalloc_type(struct pseminfo, Z_WAITOK | Z_ZERO | Z_NOFAIL);
#if CONFIG_MACF
mac_posixsem_label_init(new_pinfo);
#endif
/*
* Provisionally create the semaphore in the new_pinfo; we have to do
* this here to prevent locking later. We use the value of kret to
* signal success or failure, which is why we set its default value
* to KERN_INVALID_ADDRESS, above.
*/
fmode = (mode_t)FFLAGS(uap->oflag);
if ((fmode & O_CREAT)) {
if ((value < 0) || (value > SEM_VALUE_MAX)) {
error = EINVAL;
goto bad;
}
kret = semaphore_create(kernel_task, &new_pinfo->psem_semobject, SYNC_POLICY_FIFO, value);
if (kret != KERN_SUCCESS) {
switch (kret) {
case KERN_RESOURCE_SHORTAGE:
error = ENOMEM;
break;
case KERN_PROTECTION_FAILURE:
error = EACCES;
break;
default:
error = EINVAL;
}
goto bad;
}
}
new_pnode = kalloc_type(struct psemnode, Z_WAITOK | Z_ZERO | Z_NOFAIL);
PSEM_SUBSYS_LOCK();
error = psem_cache_search(&pinfo, &nd, &pcache);
if (error == PSEMCACHE_NEGATIVE) {
error = EINVAL;
goto bad_locked;
}
if (error == PSEMCACHE_FOUND) {
incache = 1;
} else {
incache = 0;
}
cmode &= ALLPERMS;
if (((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) && incache) {
/* sem exists and opened O_EXCL */
#if notyet
if (pinfo->psem_flags & PSEM_INDELETE) {
}
#endif
AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid,
pinfo->psem_gid, pinfo->psem_mode);
error = EEXIST;
goto bad_locked;
}
if (((fmode & (O_CREAT | O_EXCL)) == O_CREAT) && incache) {
/* As per POSIX, O_CREAT has no effect */
fmode &= ~O_CREAT;
}
if ((fmode & O_CREAT)) {
/* create a new one (commit the allocation) */
pinfo = new_pinfo;
pinfo->psem_flags = PSEM_DEFINED | PSEM_INCREATE;
pinfo->psem_usecount = 1;
pinfo->psem_mode = cmode;
pinfo->psem_uid = kauth_getuid();
pinfo->psem_gid = kauth_getgid();
bcopy(pnbuf, &pinfo->psem_name[0], PSEMNAMLEN);
pinfo->psem_name[PSEMNAMLEN] = 0;
pinfo->psem_flags &= ~PSEM_DEFINED;
pinfo->psem_flags |= PSEM_ALLOCATED;
pinfo->psem_creator_pid = proc_getpid(p);
pinfo->psem_creator_uniqueid = proc_uniqueid(p);
#if CONFIG_MACF
error = mac_posixsem_check_create(kauth_cred_get(), nameptr);
if (error) {
goto bad_locked;
}
mac_posixsem_label_associate(kauth_cred_get(), pinfo, nameptr);
#endif
} else {
/* semaphore should exist as it is without O_CREAT */
if (!incache) {
error = ENOENT;
goto bad_locked;
}
if (pinfo->psem_flags & PSEM_INDELETE) {
error = ENOENT;
goto bad_locked;
}
AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid,
pinfo->psem_gid, pinfo->psem_mode);
#if CONFIG_MACF
error = mac_posixsem_check_open(kauth_cred_get(), pinfo);
if (error) {
goto bad_locked;
}
#endif
if ((error = psem_access(pinfo, fmode, kauth_cred_get()))) {
goto bad_locked;
}
}
if (!incache) {
/* if successful, this will consume the pcp */
if ((error = psem_cache_add(pinfo, &nd, pcp))) {
goto bad_locked;
}
}
pinfo->psem_flags &= ~PSEM_INCREATE;
pinfo->psem_usecount++;
new_pnode->pinfo = pinfo;
PSEM_SUBSYS_UNLOCK();
/*
* if incache, we did not use the new pcp or the new pcp or the
* new . and we must free them.
*/
if (incache) {
kfree_type(struct psemcache, pcp);
pcp = PSEMCACHE_NULL;
if (new_pinfo != PSEMINFO_NULL) {
/* return value ignored - we can't _not_ do this */
(void)semaphore_destroy(kernel_task, new_pinfo->psem_semobject);
#if CONFIG_MACF
mac_posixsem_label_destroy(new_pinfo);
#endif
kfree_type(struct pseminfo, new_pinfo);
new_pinfo = PSEMINFO_NULL;
}
}
proc_fdlock(p);
fp->f_flag = fmode & FMASK;
fp->f_ops = &psemops;
fp_set_data(fp, new_pnode);
procfdtbl_releasefd(p, indx, NULL);
fp_drop(p, indx, fp, 1);
proc_fdunlock(p);
*retval = CAST_USER_ADDR_T(indx);
zfree(ZV_NAMEI, pnbuf);
return 0;
bad_locked:
PSEM_SUBSYS_UNLOCK();
bad:
kfree_type(struct psemcache, pcp);
kfree_type(struct psemnode, new_pnode);
if (fp != NULL) {
fp_free(p, indx, fp);
}
if (new_pinfo != PSEMINFO_NULL) {
/*
* kret signals whether or not we successfully created a
* Mach semaphore for this semaphore; if so, we need to
* destroy it here.
*/
if (kret == KERN_SUCCESS) {
/* return value ignored - we can't _not_ do this */
(void)semaphore_destroy(kernel_task, new_pinfo->psem_semobject);
}
#if CONFIG_MACF
mac_posixsem_label_destroy(new_pinfo);
#endif
kfree_type(struct pseminfo, new_pinfo);
}
if (pnbuf != NULL) {
zfree(ZV_NAMEI, pnbuf);
}
return error;
}
/*
* XXX This code is repeated in several places
*/
static int
psem_access(struct pseminfo *pinfo, mode_t mode, kauth_cred_t cred)
{
mode_t mode_req = ((mode & FREAD) ? S_IRUSR : 0) |
((mode & FWRITE) ? S_IWUSR : 0);
/* Otherwise, user id 0 always gets access. */
if (!suser(cred, NULL)) {
return 0;
}
return posix_cred_access(cred, pinfo->psem_uid, pinfo->psem_gid, pinfo->psem_mode, mode_req);
}
static int
psem_unlink_internal(struct pseminfo *pinfo, struct psemcache *pcache)
{
PSEM_SUBSYS_ASSERT_HELD();
if (!pinfo || !pcache) {
return EINVAL;
}
if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED)) == 0) {
return EINVAL;
}
if (pinfo->psem_flags & PSEM_INDELETE) {
return 0;
}
AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid, pinfo->psem_gid,
pinfo->psem_mode);
pinfo->psem_flags |= PSEM_INDELETE;
pinfo->psem_usecount--;
if (!pinfo->psem_usecount) {
psem_delete(pinfo);
kfree_type(struct pseminfo, pinfo);
} else {
pinfo->psem_flags |= PSEM_REMOVED;
}
psem_cache_delete(pcache);
kfree_type(struct psemcache, pcache);
return 0;
}
static const char *
psem_get_teamid(proc_t p)
{
#if XNU_TARGET_OS_OSX
#pragma unused(p)
return NULL;
#else
return csproc_get_teamid(p);
#endif
}
int
sem_unlink(__unused proc_t p, struct sem_unlink_args *uap, __unused int32_t *retval)
{
int error = 0;
struct psemname nd;
struct pseminfo *pinfo;
char * nameptr;
char * pnbuf;
const char *teamid;
size_t pathlen, teamidlen;
struct psemcache *pcache = PSEMCACHE_NULL;
pinfo = PSEMINFO_NULL;
pnbuf = zalloc(ZV_NAMEI);
pathlen = MAXPATHLEN;
error = copyinstr(uap->name, pnbuf, MAXPATHLEN, &pathlen);
if (error) {
goto bad;
}
AUDIT_ARG(text, pnbuf);
if (pathlen > PSEMNAMLEN) {
error = ENAMETOOLONG;
goto bad;
}
nameptr = pnbuf;
#ifdef PSXSEM_NAME_RESTRICT
if (*nameptr == '/') {
while (*(nameptr++) == '/') {
pathlen--;
error = EINVAL;
goto bad;
}
} else {
error = EINVAL;
goto bad;
}
#endif /* PSXSEM_NAME_RESTRICT */
teamid = psem_get_teamid(p);
teamidlen = teamid ? strlen(teamid) : 0;
if (teamidlen > PSEMTEAMIDLEN) {
error = ENAMETOOLONG;
goto bad;
}
nd = psem_cache_hash(nameptr, pathlen, teamid, teamidlen);
PSEM_SUBSYS_LOCK();
error = psem_cache_search(&pinfo, &nd, &pcache);
if (error != PSEMCACHE_FOUND) {
PSEM_SUBSYS_UNLOCK();
error = ENOENT;
goto bad;
}
#if CONFIG_MACF
error = mac_posixsem_check_unlink(kauth_cred_get(), pinfo, nameptr);
if (error) {
PSEM_SUBSYS_UNLOCK();
goto bad;
}
#endif
if ((error = psem_access(pinfo, pinfo->psem_mode, kauth_cred_get()))) {
PSEM_SUBSYS_UNLOCK();
goto bad;
}
error = psem_unlink_internal(pinfo, pcache);
PSEM_SUBSYS_UNLOCK();
bad:
zfree(ZV_NAMEI, pnbuf);
return error;
}
int
sem_close(proc_t p, struct sem_close_args *uap, __unused int32_t *retval)
{
int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
kauth_cred_t p_cred;
struct fileproc *fp;
AUDIT_ARG(fd, fd); /* XXX This seems wrong; uap->sem is a pointer */
proc_fdlock(p);
if ((fp = fp_get_noref_locked(p, fd)) == NULL) {
proc_fdunlock(p);
return EBADF;
}
if (FILEGLOB_DTYPE(fp->fp_glob) != DTYPE_PSXSEM) {
proc_fdunlock(p);
return EBADF;
}
p_cred = current_cached_proc_cred(p);
return fp_close_and_unlock(p, p_cred, fd, fp, 0);
}
int
sem_wait(proc_t p, struct sem_wait_args *uap, int32_t *retval)
{
__pthread_testcancel(1);
return sem_wait_nocancel(p, (struct sem_wait_nocancel_args *)uap, retval);
}
int
sem_wait_nocancel(proc_t p, struct sem_wait_nocancel_args *uap, __unused int32_t *retval)
{
int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
struct fileproc *fp;
struct pseminfo * pinfo;
struct psemnode * pnode;
kern_return_t kret;
int error;
error = fp_get_ftype(p, fd, DTYPE_PSXSEM, EBADF, &fp);
if (error) {
return error;
}
pnode = (struct psemnode *)fp_get_data(fp);
PSEM_SUBSYS_LOCK();
if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
!= PSEM_ALLOCATED) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
#if CONFIG_MACF
error = mac_posixsem_check_wait(kauth_cred_get(), pinfo);
if (error) {
PSEM_SUBSYS_UNLOCK();
goto out;
}
#endif
PSEM_SUBSYS_UNLOCK();
kret = semaphore_wait(pinfo->psem_semobject);
switch (kret) {
case KERN_INVALID_ADDRESS:
case KERN_PROTECTION_FAILURE:
error = EACCES;
break;
case KERN_ABORTED:
case KERN_OPERATION_TIMED_OUT:
error = EINTR;
break;
case KERN_SUCCESS:
error = 0;
break;
default:
error = EINVAL;
break;
}
out:
fp_drop(p, fd, fp, 0);
return error;
}
int
sem_trywait(proc_t p, struct sem_trywait_args *uap, __unused int32_t *retval)
{
int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
struct fileproc *fp;
struct pseminfo * pinfo;
struct psemnode * pnode;
kern_return_t kret;
mach_timespec_t wait_time;
int error;
error = fp_get_ftype(p, fd, DTYPE_PSXSEM, EBADF, &fp);
if (error) {
return error;
}
pnode = (struct psemnode *)fp_get_data(fp);
PSEM_SUBSYS_LOCK();
if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
!= PSEM_ALLOCATED) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
#if CONFIG_MACF
error = mac_posixsem_check_wait(kauth_cred_get(), pinfo);
if (error) {
PSEM_SUBSYS_UNLOCK();
goto out;
}
#endif
PSEM_SUBSYS_UNLOCK();
wait_time.tv_sec = 0;
wait_time.tv_nsec = 0;
kret = semaphore_timedwait(pinfo->psem_semobject, MACH_TIMESPEC_ZERO);
switch (kret) {
case KERN_INVALID_ADDRESS:
case KERN_PROTECTION_FAILURE:
error = EINVAL;
break;
case KERN_ABORTED:
error = EINTR;
break;
case KERN_OPERATION_TIMED_OUT:
error = EAGAIN;
break;
case KERN_SUCCESS:
error = 0;
break;
default:
error = EINVAL;
break;
}
out:
fp_drop(p, fd, fp, 0);
return error;
}
int
sem_post(proc_t p, struct sem_post_args *uap, __unused int32_t *retval)
{
int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
struct fileproc *fp;
struct pseminfo * pinfo;
struct psemnode * pnode;
kern_return_t kret;
int error;
error = fp_get_ftype(p, fd, DTYPE_PSXSEM, EBADF, &fp);
if (error) {
return error;
}
pnode = (struct psemnode *)fp_get_data(fp);
PSEM_SUBSYS_LOCK();
if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
!= PSEM_ALLOCATED) {
PSEM_SUBSYS_UNLOCK();
error = EINVAL;
goto out;
}
#if CONFIG_MACF
error = mac_posixsem_check_post(kauth_cred_get(), pinfo);
if (error) {
PSEM_SUBSYS_UNLOCK();
goto out;
}
#endif
PSEM_SUBSYS_UNLOCK();
kret = semaphore_signal(pinfo->psem_semobject);
switch (kret) {
case KERN_INVALID_ADDRESS:
case KERN_PROTECTION_FAILURE:
error = EINVAL;
break;
case KERN_ABORTED:
case KERN_OPERATION_TIMED_OUT:
error = EINTR;
break;
case KERN_SUCCESS:
error = 0;
break;
default:
error = EINVAL;
break;
}
out:
fp_drop(p, fd, fp, 0);
return error;
}
static int
psem_close(struct psemnode *pnode)
{
int error = 0;
struct pseminfo *pinfo;
PSEM_SUBSYS_LOCK();
if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
PSEM_SUBSYS_UNLOCK();
return EINVAL;
}
if ((pinfo->psem_flags & PSEM_ALLOCATED) != PSEM_ALLOCATED) {
PSEM_SUBSYS_UNLOCK();
return EINVAL;
}
#if DIAGNOSTIC
if (!pinfo->psem_usecount) {
kprintf("negative usecount in psem_close\n");
}
#endif /* DIAGNOSTIC */
pinfo->psem_usecount--;
if ((pinfo->psem_flags & PSEM_REMOVED) && !pinfo->psem_usecount) {
PSEM_SUBSYS_UNLOCK();
/* lock dropped as only semaphore is destroyed here */
error = psem_delete(pinfo);
kfree_type(struct pseminfo, pinfo);
} else {
PSEM_SUBSYS_UNLOCK();
}
/* subsystem lock is dropped when we get here */
kfree_type(struct psemnode, pnode);
return error;
}
static int
psem_closefile(struct fileglob *fg, __unused vfs_context_t ctx)
{
/*
* Not locked as psem_close is called only from here and is locked
* properly
*/
return psem_close((struct psemnode *)fg_get_data(fg));
}
static int
psem_delete(struct pseminfo * pinfo)
{
kern_return_t kret;
kret = semaphore_destroy(kernel_task, pinfo->psem_semobject);
#if CONFIG_MACF
mac_posixsem_label_destroy(pinfo);
#endif
switch (kret) {
case KERN_INVALID_ADDRESS:
case KERN_PROTECTION_FAILURE:
return EINVAL;
case KERN_ABORTED:
case KERN_OPERATION_TIMED_OUT:
return EINTR;
case KERN_SUCCESS:
return 0;
default:
return EINVAL;
}
}
int
fill_pseminfo(struct psemnode *pnode, struct psem_info * info)
{
struct pseminfo *pinfo;
struct vinfo_stat *sb;
PSEM_SUBSYS_LOCK();
if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
PSEM_SUBSYS_UNLOCK();
return EINVAL;
}
#if 0
if ((pinfo->psem_flags & PSEM_ALLOCATED) != PSEM_ALLOCATED) {
PSEM_SUBSYS_UNLOCK();
return EINVAL;
}
#endif
sb = &info->psem_stat;
bzero(sb, sizeof(struct vinfo_stat));
sb->vst_mode = pinfo->psem_mode;
sb->vst_uid = pinfo->psem_uid;
sb->vst_gid = pinfo->psem_gid;
sb->vst_size = pinfo->psem_usecount;
bcopy(&pinfo->psem_name[0], &info->psem_name[0], PSEMNAMLEN + 1);
PSEM_SUBSYS_UNLOCK();
return 0;
}
#if CONFIG_MACF
void
psem_label_associate(struct fileproc *fp, struct vnode *vp, vfs_context_t ctx)
{
struct psemnode *pnode;
struct pseminfo *psem;
PSEM_SUBSYS_LOCK();
pnode = (struct psemnode *)fp_get_data(fp);
if (pnode != NULL) {
psem = pnode->pinfo;
if (psem != NULL) {
mac_posixsem_vnode_label_associate(
vfs_context_ucred(ctx), psem,
mac_posixsem_label(psem),
vp, mac_vnode_label(vp));
}
}
PSEM_SUBSYS_UNLOCK();
}
#endif