/* 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.

 */

/*

 * util_mutex.c: Useful functions for determining allowable

 *               mutexes and mutex settings

 */

#include "apr.h"

#include "apr_hash.h"

#include "apr_strings.h"

#include "apr_lib.h"

#define APR_WANT_STRFUNC

#include "apr_want.h"

#include "ap_config.h"

#include "httpd.h"

#include "http_main.h"

#include "http_config.h"

#include "http_core.h"

#include "http_log.h"

#include "util_mutex.h"

#if AP_NEED_SET_MUTEX_PERMS

#include "unixd.h"

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h> /* getpid() */

#endif

/* we know core's module_index is 0 */

#undef APLOG_MODULE_INDEX

#define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX

AP_DECLARE(apr_status_t) ap_parse_mutex(const char *arg, apr_pool_t *pool,

                                        apr_lockmech_e *mutexmech,

                                        const char **mutexfile)

{

    /* Split arg into meth and file */

    char *meth = apr_pstrdup(pool, arg);

    char *file = strchr(meth, ':');

    if (file) {

        *(file++) = '\0';

        if (!*file) {

            file = NULL;

        }

    }

    /* APR determines temporary filename unless overridden below,

     * we presume file indicates an mutexfile is a file path

     * unless the method sets mutexfile=file and NULLs file

     */

    *mutexfile = NULL;

    if (!strcasecmp(meth, "none") || !strcasecmp(meth, "no")) {

        return APR_ENOLOCK;

    }

    /* NOTE: previously, 'yes' implied 'sem' */

    if (!strcasecmp(meth, "default") || !strcasecmp(meth, "yes")) {

        *mutexmech = APR_LOCK_DEFAULT;

    }

#if APR_HAS_FCNTL_SERIALIZE

    else if (!strcasecmp(meth, "fcntl") || !strcasecmp(meth, "file")) {

        *mutexmech = APR_LOCK_FCNTL;

    }

#endif

#if APR_HAS_FLOCK_SERIALIZE

    else if (!strcasecmp(meth, "flock") || !strcasecmp(meth, "file")) {

        *mutexmech = APR_LOCK_FLOCK;

    }

#endif

#if APR_HAS_POSIXSEM_SERIALIZE

    else if (!strcasecmp(meth, "posixsem") || !strcasecmp(meth, "sem")) {

        *mutexmech = APR_LOCK_POSIXSEM;

        /* Posix/SysV semaphores aren't file based, use the literal name

         * if provided and fall back on APR's default if not.  Today, APR

         * will ignore it, but once supported it has an absurdly short limit.

         */

        if (file) {

            *mutexfile = apr_pstrdup(pool, file);

            file = NULL;

        }

    }

#endif

#if APR_HAS_SYSVSEM_SERIALIZE

    else if (!strcasecmp(meth, "sysvsem") || !strcasecmp(meth, "sem")) {

        *mutexmech = APR_LOCK_SYSVSEM;

    }

#endif

#if APR_HAS_PROC_PTHREAD_SERIALIZE

    else if (!strcasecmp(meth, "pthread")) {

        *mutexmech = APR_LOCK_PROC_PTHREAD;

    }

#endif

    else {

        return APR_ENOTIMPL;

    }

    /* Unless the method above assumed responsibility for setting up

     * mutexfile and NULLing out file, presume it is a file we

     * are looking to use

     */

    if (file) {

        *mutexfile = ap_server_root_relative(pool, file);

        if (!*mutexfile) {

            return APR_BADARG;

        }

    }

    return APR_SUCCESS;

}

typedef struct {

    apr_int32_t options;

    int set;

    int none;

    int omit_pid;

    apr_lockmech_e mech;

    const char *dir;

} mutex_cfg_t;

/* hash is created the first time a module calls ap_mutex_register(),

 * rather than attempting to be the REALLY_REALLY_FIRST pre-config

 * hook; it is cleaned up when the associated pool goes away; assume

 * pconf is the pool passed to ap_mutex_register()

 */

static apr_hash_t *mxcfg_by_type;

AP_DECLARE_NONSTD(void) ap_mutex_init(apr_pool_t *p)

{

    mutex_cfg_t *def;

    if (mxcfg_by_type) {

        return;

    }

    mxcfg_by_type = apr_hash_make(p);

    apr_pool_cleanup_register(p, &mxcfg_by_type, ap_pool_cleanup_set_null,

        apr_pool_cleanup_null);

    /* initialize default mutex configuration */

    def = apr_pcalloc(p, sizeof *def);

    def->mech = APR_LOCK_DEFAULT;

    def->dir = ap_runtime_dir_relative(p, "");

    apr_hash_set(mxcfg_by_type, "default", APR_HASH_KEY_STRING, def);

}

AP_DECLARE_NONSTD(const char *)ap_set_mutex(cmd_parms *cmd, void *dummy,

                                            const char *arg)

{

    apr_pool_t *p = cmd->pool;

    apr_pool_t *ptemp = cmd->temp_pool;

    const char **elt;

    const char *mechdir;

    int no_mutex = 0, omit_pid = 0;

    apr_array_header_t *type_list;

    apr_lockmech_e mech;

    apr_status_t rv;

    const char *mutexdir;

    mutex_cfg_t *mxcfg;

    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

    if (err != NULL) {

        return err;

    }

    mechdir = ap_getword_conf(cmd->pool, &arg;;

    if (*mechdir == '\0') {

        return "Mutex requires at least a mechanism argument ("

               AP_ALL_AVAILABLE_MUTEXES_STRING ")";

    }

    rv = ap_parse_mutex(mechdir, p, &mech, &mutexdir);

    if (rv == APR_ENOTIMPL) {

        return apr_pstrcat(p, "Invalid Mutex argument ", mechdir,

                           " (" AP_ALL_AVAILABLE_MUTEXES_STRING ")", NULL);

    }

    else if (rv == APR_BADARG

             || (mutexdir && !ap_is_directory(ptemp, mutexdir))) {

        return apr_pstrcat(p, "Invalid Mutex directory in argument ",

                           mechdir, NULL);

    }

    else if (rv == APR_ENOLOCK) { /* "none" */

        no_mutex = 1;

    }

    /* "OmitPID" can appear at the end of the list, so build a list of

     * mutex type names while looking for "OmitPID" (anywhere) or the end

     */

    type_list = apr_array_make(cmd->pool, 4, sizeof(const char *));

    while (*arg) {

        const char *s = ap_getword_conf(cmd->pool, &arg;;

        if (!strcasecmp(s, "omitpid")) {

            omit_pid = 1;

        }

        else {

            const char **new_type = (const char **)apr_array_push(type_list);

            *new_type = s;

        }

    }

    if (apr_is_empty_array(type_list)) { /* no mutex type?  assume "default" */

        const char **new_type = (const char **)apr_array_push(type_list);

        *new_type = "default";

    }

    while ((elt = (const char **)apr_array_pop(type_list)) != NULL) {

        const char *type = *elt;

        mxcfg = apr_hash_get(mxcfg_by_type, type, APR_HASH_KEY_STRING);

        if (!mxcfg) {

            return apr_psprintf(p, "Mutex type %s is not valid", type);

        }

        mxcfg->none = 0; /* in case that was the default */

        mxcfg->omit_pid = omit_pid;

        mxcfg->set = 1;

        if (no_mutex) {

            if (!(mxcfg->options & AP_MUTEX_ALLOW_NONE)) {

                return apr_psprintf(p,

                                    "None is not allowed for mutex type %s",

                                    type);

            }

            mxcfg->none = 1;

        }

        else {

            mxcfg->mech = mech;

            if (mutexdir) { /* retain mutex default if not configured */

                mxcfg->dir = mutexdir;

            }

        }

    }

    return NULL;

}

AP_DECLARE(apr_status_t) ap_mutex_register(apr_pool_t *pconf,

                                           const char *type,

                                           const char *default_dir,

                                           apr_lockmech_e default_mech,

                                           apr_int32_t options)

{

    mutex_cfg_t *mxcfg = apr_pcalloc(pconf, sizeof *mxcfg);

    if ((options & ~(AP_MUTEX_ALLOW_NONE | AP_MUTEX_DEFAULT_NONE))) {

        return APR_EINVAL;

    }

    ap_mutex_init(pconf); /* in case this mod's pre-config ran before core's */

    mxcfg->options = options;

    if (options & AP_MUTEX_DEFAULT_NONE) {

        mxcfg->none = 1;

    }

    mxcfg->dir = default_dir; /* usually NULL */

    mxcfg->mech = default_mech; /* usually APR_LOCK_DEFAULT */

    apr_hash_set(mxcfg_by_type, type, APR_HASH_KEY_STRING, mxcfg);

    return APR_SUCCESS;

}

static int mutex_needs_file(apr_lockmech_e mech)

{

    if (mech != APR_LOCK_FLOCK

        && mech != APR_LOCK_FCNTL

#if APR_USE_FLOCK_SERIALIZE || APR_USE_FCNTL_SERIALIZE

        && mech != APR_LOCK_DEFAULT

#endif

        ) {

        return 0;

    }

    return 1;

}

static const char *get_mutex_filename(apr_pool_t *p, mutex_cfg_t *mxcfg,

                                      const char *type,

                                      const char *instance_id)

{

    const char *pid_suffix = "";

    if (!mutex_needs_file(mxcfg->mech)) {

        return NULL;

    }

#if HAVE_UNISTD_H

    if (!mxcfg->omit_pid) {

        pid_suffix = apr_psprintf(p, ".%" APR_PID_T_FMT, getpid());

    }

#endif

    return ap_server_root_relative(p,

                                   apr_pstrcat(p,

                                               mxcfg->dir,

                                               "/",

                                               type,

                                               instance_id ? "-" : "",

                                               instance_id ? instance_id : "",

                                               pid_suffix,

                                               NULL));

}

static mutex_cfg_t *mxcfg_lookup(apr_pool_t *p, const char *type)

{

    mutex_cfg_t *defcfg, *mxcfg, *newcfg;

    defcfg = apr_hash_get(mxcfg_by_type, "default", APR_HASH_KEY_STRING);

    /* MUST exist in table, or wasn't registered */

    mxcfg = apr_hash_get(mxcfg_by_type, type, APR_HASH_KEY_STRING);

    if (!mxcfg) {

        return NULL;

    }

    /* order of precedence:

     * 1. Mutex directive for this mutex

     * 2. Mutex directive for "default"

     * 3. Defaults for this mutex from ap_mutex_register()

     * 4. Global defaults

     */

    if (mxcfg->set) {

        newcfg = mxcfg;

    }

    else if (defcfg->set) {

        newcfg = defcfg;

    }

    else if (mxcfg->none || mxcfg->mech != APR_LOCK_DEFAULT) {

        newcfg = mxcfg;

    }

    else {

        newcfg = defcfg;

    }

    if (!newcfg->none && mutex_needs_file(newcfg->mech) && !newcfg->dir) {

        /* a file-based mutex mechanism was configured, but

         * without a mutex file directory; go back through

         * the chain to find the directory, store in new

         * mutex cfg structure

         */

        newcfg = apr_pmemdup(p, newcfg, sizeof *newcfg);

        /* !true if dir not already set: mxcfg->set && defcfg->dir */

        if (defcfg->set && defcfg->dir) {

            newcfg->dir = defcfg->dir;

        }

        else if (mxcfg->dir) {

            newcfg->dir = mxcfg->dir;

        }

        else {

            newcfg->dir = defcfg->dir;

        }

    }

    return newcfg;

}

static void log_bad_create_options(server_rec *s, const char *type)

{

    ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(00021)

                 "Invalid options were specified when creating the %s mutex",

                 type);

}

static void log_unknown_type(server_rec *s, const char *type)

{

    ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(00022)

                 "Can't create mutex of unknown type %s", type);

}

static void log_create_failure(apr_status_t rv, server_rec *s, const char *type,

                               const char *fname)

{

    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(00023)

                 "Couldn't create the %s mutex %s%s%s", type,

                 fname ? "(file " : "",

                 fname ? fname : "",

                 fname ? ")" : "");

}

#ifdef AP_NEED_SET_MUTEX_PERMS

static void log_perms_failure(apr_status_t rv, server_rec *s, const char *type)

{

    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(00024)

                 "Couldn't set permissions on the %s mutex; "

                 "check User and Group directives",

                 type);

}

#endif

AP_DECLARE(apr_status_t) ap_global_mutex_create(apr_global_mutex_t **mutex,

                                                const char **name,

                                                const char *type,

                                                const char *instance_id,

                                                server_rec *s, apr_pool_t *p,

                                                apr_int32_t options)

{

    apr_status_t rv;

    const char *fname;

    mutex_cfg_t *mxcfg = mxcfg_lookup(p, type);

    if (options) {

        log_bad_create_options(s, type);

        return APR_EINVAL;

    }

    if (!mxcfg) {

        log_unknown_type(s, type);

        return APR_EINVAL;

    }

    if (mxcfg->none) {

        *mutex = NULL;

        return APR_SUCCESS;

    }

    fname = get_mutex_filename(p, mxcfg, type, instance_id);

    rv = apr_global_mutex_create(mutex, fname, mxcfg->mech, p);

    if (rv != APR_SUCCESS) {

        log_create_failure(rv, s, type, fname);

        return rv;

    }

    if (name)

        *name = fname;

#ifdef AP_NEED_SET_MUTEX_PERMS

    rv = ap_unixd_set_global_mutex_perms(*mutex);

    if (rv != APR_SUCCESS) {

        log_perms_failure(rv, s, type);

    }

#endif

    return rv;

}

AP_DECLARE(apr_status_t) ap_proc_mutex_create(apr_proc_mutex_t **mutex,

                                              const char **name,

                                              const char *type,

                                              const char *instance_id,

                                              server_rec *s, apr_pool_t *p,

                                              apr_int32_t options)

{

    apr_status_t rv;

    const char *fname;

    mutex_cfg_t *mxcfg = mxcfg_lookup(p, type);

    if (options) {

        log_bad_create_options(s, type);

        return APR_EINVAL;

    }

    if (!mxcfg) {

        log_unknown_type(s, type);

        return APR_EINVAL;

    }

    if (mxcfg->none) {

        *mutex = NULL;

        return APR_SUCCESS;

    }

    fname = get_mutex_filename(p, mxcfg, type, instance_id);

    rv = apr_proc_mutex_create(mutex, fname, mxcfg->mech, p);

    if (rv != APR_SUCCESS) {

        log_create_failure(rv, s, type, fname);

        return rv;

    }

    if (name)

        *name = fname;

#ifdef AP_NEED_SET_MUTEX_PERMS

    rv = ap_unixd_set_proc_mutex_perms(*mutex);

    if (rv != APR_SUCCESS) {

        log_perms_failure(rv, s, type);

    }

#endif

    return rv;

}

AP_CORE_DECLARE(void) ap_dump_mutexes(apr_pool_t *p, server_rec *s, apr_file_t *out)

{

    apr_hash_index_t *idx;

    mutex_cfg_t *defcfg = apr_hash_get(mxcfg_by_type, "default", APR_HASH_KEY_STRING);

    for (idx = apr_hash_first(p, mxcfg_by_type); idx; idx = apr_hash_next(idx))

    {

        mutex_cfg_t *mxcfg;

        const char *name, *mech = "<unknown>";

        const void *name_;

        const char *dir = "";

        apr_hash_this(idx, &name_, NULL, NULL);

        name = name_;

        mxcfg = mxcfg_lookup(p, name);

        if (mxcfg == defcfg && strcmp(name, "default") != 0) {

            apr_file_printf(out, "Mutex %s: using_defaults\n", name);

            continue;

        }

        if (mxcfg->none) {

            apr_file_printf(out, "Mutex %s: none\n", name);

            continue;

        }

        switch (mxcfg->mech) {

        case APR_LOCK_DEFAULT:

            mech = "default";

            break;

#if APR_HAS_FCNTL_SERIALIZE

        case APR_LOCK_FCNTL:

            mech = "fcntl";

            break;

#endif

#if APR_HAS_FLOCK_SERIALIZE

        case APR_LOCK_FLOCK:

            mech = "flock";

            break;

#endif

#if APR_HAS_POSIXSEM_SERIALIZE

        case APR_LOCK_POSIXSEM:

            mech = "posixsem";

            break;

#endif

#if APR_HAS_SYSVSEM_SERIALIZE

        case APR_LOCK_SYSVSEM:

            mech = "sysvsem";

            break;

#endif

#if APR_HAS_PROC_PTHREAD_SERIALIZE

        case APR_LOCK_PROC_PTHREAD:

            mech = "pthread";

            break;

#endif

        default:

            ap_assert(0);

        }

        if (mxcfg->dir)

            dir = ap_server_root_relative(p, mxcfg->dir);

        apr_file_printf(out, "Mutex %s: dir=\"%s\" mechanism=%s %s\n", name, dir, mech,

                        mxcfg->omit_pid ? "[OmitPid]" : "");

    }

}