/* 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.

 */

/* The purpose of this file is to store the code that MOST mpm's will need

 * this does not mean a function only goes into this file if every MPM needs

 * it.  It means that if a function is needed by more than one MPM, and

 * future maintenance would be served by making the code common, then the

 * function belongs here.

 *

 * This is going in src/main because it is not platform specific, it is

 * specific to multi-process servers, but NOT to Unix.  Which is why it

 * does not belong in src/os/unix

 */

#include "apr.h"

#include "apr_thread_proc.h"

#include "apr_signal.h"

#include "apr_strings.h"

#define APR_WANT_STRFUNC

#include "apr_want.h"

#include "apr_getopt.h"

#include "apr_optional.h"

#include "apr_allocator.h"

#include "httpd.h"

#include "http_config.h"

#include "http_core.h"

#include "http_log.h"

#include "http_main.h"

#include "mpm_common.h"

#include "mod_core.h"

#include "ap_mpm.h"

#include "ap_listen.h"

#include "util_mutex.h"

#include "scoreboard.h"

#ifdef HAVE_PWD_H

#include <pwd.h>

#endif

#ifdef HAVE_GRP_H

#include <grp.h>

#endif

#if APR_HAVE_UNISTD_H

#include <unistd.h>

#endif

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

#undef APLOG_MODULE_INDEX

#define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX

#define DEFAULT_HOOK_LINKS \

    APR_HOOK_LINK(monitor) \

    APR_HOOK_LINK(drop_privileges) \

    APR_HOOK_LINK(mpm) \

    APR_HOOK_LINK(mpm_query) \

    APR_HOOK_LINK(mpm_register_timed_callback) \

    APR_HOOK_LINK(mpm_register_poll_callback) \

    APR_HOOK_LINK(mpm_register_poll_callback_timeout) \

    APR_HOOK_LINK(mpm_get_name) \

    APR_HOOK_LINK(mpm_resume_suspended) \

    APR_HOOK_LINK(end_generation) \

    APR_HOOK_LINK(child_status) \

    APR_HOOK_LINK(output_pending) \

    APR_HOOK_LINK(input_pending) \

    APR_HOOK_LINK(suspend_connection) \

    APR_HOOK_LINK(resume_connection) \

    APR_HOOK_LINK(child_stopping) \

    APR_HOOK_LINK(child_stopped)

#if AP_ENABLE_EXCEPTION_HOOK

APR_HOOK_STRUCT(

    APR_HOOK_LINK(fatal_exception)

    DEFAULT_HOOK_LINKS

)

AP_IMPLEMENT_HOOK_RUN_ALL(int, fatal_exception,

                          (ap_exception_info_t *ei), (ei), OK, DECLINED)

#else

APR_HOOK_STRUCT(

    DEFAULT_HOOK_LINKS

)

#endif

AP_IMPLEMENT_HOOK_RUN_ALL(int, monitor,

                          (apr_pool_t *p, server_rec *s), (p, s), OK, DECLINED)

AP_IMPLEMENT_HOOK_RUN_ALL(int, drop_privileges,

                          (apr_pool_t * pchild, server_rec * s),

                          (pchild, s), OK, DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(int, mpm,

                            (apr_pool_t *pconf, apr_pool_t *plog, server_rec *s),

                            (pconf, plog, s), DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(int, mpm_query,

                            (int query_code, int *result, apr_status_t *_rv),

                            (query_code, result, _rv), DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t, mpm_register_timed_callback,

                            (apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton),

                            (t, cbfn, baton), APR_ENOTIMPL)

AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t, mpm_resume_suspended,

                            (conn_rec *c),

                            (c), APR_ENOTIMPL)

AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t, mpm_register_poll_callback,

                            (apr_pool_t *p, const apr_array_header_t *pds,

                             ap_mpm_callback_fn_t *cbfn, void *baton),

                            (p, pds, cbfn, baton), APR_ENOTIMPL)

AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t, mpm_register_poll_callback_timeout,

                            (apr_pool_t *p, const apr_array_header_t *pds,

                             ap_mpm_callback_fn_t *cbfn,

                             ap_mpm_callback_fn_t *tofn,

                             void *baton, apr_time_t timeout),

                            (p, pds, cbfn, tofn, baton, timeout), APR_ENOTIMPL)

AP_IMPLEMENT_HOOK_RUN_FIRST(int, output_pending,

                            (conn_rec *c), (c), DECLINED)

AP_IMPLEMENT_HOOK_RUN_FIRST(int, input_pending,

                            (conn_rec *c), (c), DECLINED)

AP_IMPLEMENT_HOOK_VOID(end_generation,

                       (server_rec *s, ap_generation_t gen),

                       (s, gen))

AP_IMPLEMENT_HOOK_VOID(child_status,

                       (server_rec *s, pid_t pid, ap_generation_t gen, int slot, mpm_child_status status),

                       (s,pid,gen,slot,status))

AP_IMPLEMENT_HOOK_VOID(suspend_connection,

                       (conn_rec *c, request_rec *r),

                       (c, r))

AP_IMPLEMENT_HOOK_VOID(resume_connection,

                       (conn_rec *c, request_rec *r),

                       (c, r))

AP_IMPLEMENT_HOOK_VOID(child_stopping,

                       (apr_pool_t *pchild, int graceful),

                       (pchild, graceful))

AP_IMPLEMENT_HOOK_VOID(child_stopped,

                       (apr_pool_t *pchild, int graceful),

                       (pchild, graceful))

/* hooks with no args are implemented last, after disabling APR hook probes */

#if defined(APR_HOOK_PROBES_ENABLED)

#undef APR_HOOK_PROBES_ENABLED

#undef APR_HOOK_PROBE_ENTRY

#define APR_HOOK_PROBE_ENTRY(ud,ns,name,args)

#undef APR_HOOK_PROBE_RETURN

#define APR_HOOK_PROBE_RETURN(ud,ns,name,rv,args)

#undef APR_HOOK_PROBE_INVOKE

#define APR_HOOK_PROBE_INVOKE(ud,ns,name,src,args)

#undef APR_HOOK_PROBE_COMPLETE

#define APR_HOOK_PROBE_COMPLETE(ud,ns,name,src,rv,args)

#undef APR_HOOK_INT_DCL_UD

#define APR_HOOK_INT_DCL_UD

#endif

AP_IMPLEMENT_HOOK_RUN_FIRST(const char *, mpm_get_name,

                            (void),

                            (), NULL)

typedef struct mpm_gen_info_t {

    APR_RING_ENTRY(mpm_gen_info_t) link;

    int gen;          /* which gen? */

    int active;       /* number of active processes */

    int done;         /* gen finished? (whether or not active processes) */

} mpm_gen_info_t;

APR_RING_HEAD(mpm_gen_info_head_t, mpm_gen_info_t);

static struct mpm_gen_info_head_t *geninfo, *unused_geninfo;

static int gen_head_init; /* yuck */

/* variables representing config directives implemented here */

AP_DECLARE_DATA const char *ap_pid_fname;

AP_DECLARE_DATA int ap_max_requests_per_child;

AP_DECLARE_DATA char ap_coredump_dir[MAX_STRING_LEN];

AP_DECLARE_DATA int ap_coredumpdir_configured;

AP_DECLARE_DATA int ap_graceful_shutdown_timeout;

AP_DECLARE_DATA apr_size_t ap_thread_stacksize;

#define ALLOCATOR_MAX_FREE_DEFAULT (2048*1024)

AP_DECLARE_DATA apr_uint32_t ap_max_mem_free = ALLOCATOR_MAX_FREE_DEFAULT;

/* Set defaults for config directives implemented here.  This is

 * called from core's pre-config hook, so MPMs which need to override

 * one of these should run their pre-config hook after that of core.

 */

void mpm_common_pre_config(apr_pool_t *pconf)

{

    ap_pid_fname = DEFAULT_PIDLOG;

    ap_max_requests_per_child = 0; /* unlimited */

    apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));

    ap_coredumpdir_configured = 0;

    ap_graceful_shutdown_timeout = 0; /* unlimited */

    ap_max_mem_free = ALLOCATOR_MAX_FREE_DEFAULT;

    ap_thread_stacksize = 0; /* use system default */

}

/* number of calls to wait_or_timeout between writable probes */

#ifndef INTERVAL_OF_WRITABLE_PROBES

#define INTERVAL_OF_WRITABLE_PROBES 10

#endif

static int wait_or_timeout_counter;

AP_DECLARE(void) ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode,

                                    apr_proc_t *ret, apr_pool_t *p,

                                    server_rec *s)

{

    apr_status_t rv;

    ++wait_or_timeout_counter;

    if (wait_or_timeout_counter == INTERVAL_OF_WRITABLE_PROBES) {

        wait_or_timeout_counter = 0;

        ap_run_monitor(p, s);

    }

    rv = apr_proc_wait_all_procs(ret, exitcode, status, APR_NOWAIT, p);

    ap_update_global_status();

    if (APR_STATUS_IS_EINTR(rv)) {

        ret->pid = -1;

        return;

    }

    if (APR_STATUS_IS_CHILD_DONE(rv)) {

        return;

    }

    apr_sleep(apr_time_from_sec(1));

    ret->pid = -1;

}

#if defined(TCP_NODELAY)

void ap_sock_disable_nagle(apr_socket_t *s)

{

    /* The Nagle algorithm says that we should delay sending partial

     * packets in hopes of getting more data.  We don't want to do

     * this; we are not telnet.  There are bad interactions between

     * persistent connections and Nagle's algorithm that have very severe

     * performance penalties.  (Failing to disable Nagle is not much of a

     * problem with simple HTTP.)

     *

     * In spite of these problems, failure here is not a shooting offense.

     */

    apr_status_t status = apr_socket_opt_set(s, APR_TCP_NODELAY, 1);

    if (status != APR_SUCCESS) {

        ap_log_error(APLOG_MARK, APLOG_WARNING, status, ap_server_conf, APLOGNO(00542)

                     "apr_socket_opt_set: (TCP_NODELAY)");

    }

}

#endif

#ifdef HAVE_GETPWNAM

AP_DECLARE(uid_t) ap_uname2id(const char *name)

{

    struct passwd *ent;

    if (name[0] == '#')

        return (atoi(&name[1]));

    if (!(ent = getpwnam(name))) {

        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, APLOGNO(00543)

                     "%s: bad user name %s", ap_server_argv0, name);

        exit(1);

    }

    return (ent->pw_uid);

}

#endif

#ifdef HAVE_GETGRNAM

AP_DECLARE(gid_t) ap_gname2id(const char *name)

{

    struct group *ent;

    if (name[0] == '#')

        return (atoi(&name[1]));

    if (!(ent = getgrnam(name))) {

        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, APLOGNO(00544)

                     "%s: bad group name %s", ap_server_argv0, name);

        exit(1);

    }

    return (ent->gr_gid);

}

#endif

#ifndef HAVE_INITGROUPS

int initgroups(const char *name, gid_t basegid)

{

#if defined(_OSD_POSIX) || defined(OS2) || defined(WIN32) || defined(NETWARE)

    return 0;

#else

    gid_t groups[NGROUPS_MAX];

    struct group *g;

    int index = 0;

    setgrent();

    groups[index++] = basegid;

    while (index < NGROUPS_MAX && ((g = getgrent()) != NULL)) {

        if (g->gr_gid != basegid) {

            char **names;

            for (names = g->gr_mem; *names != NULL; ++names) {

                if (!strcmp(*names, name))

                    groups[index++] = g->gr_gid;

            }

        }

    }

    endgrent();

    return setgroups(index, groups);

#endif

}

#endif /* def HAVE_INITGROUPS */

/* standard mpm configuration handling */

const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy,

                               const char *arg)

{

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

    if (err != NULL) {

        return err;

    }

    if (cmd->server->is_virtual) {

        return "PidFile directive not allowed in <VirtualHost>";

    }

    ap_pid_fname = arg;

    return NULL;

}

void ap_mpm_dump_pidfile(apr_pool_t *p, apr_file_t *out)

{

    apr_file_printf(out, "PidFile: \"%s\"\n",

                    ap_runtime_dir_relative(p, ap_pid_fname));

}

const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy,

                                    const char *arg)

{

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

    if (err != NULL) {

        return err;

    }

    if (!strcasecmp(cmd->cmd->name, "MaxRequestsPerChild")) {

        ap_log_error(APLOG_MARK, APLOG_INFO, 0, NULL, APLOGNO(00545)

                     "MaxRequestsPerChild is deprecated, use "

                     "MaxConnectionsPerChild instead.");

    }

    ap_max_requests_per_child = atoi(arg);

    return NULL;

}

const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy,

                                   const char *arg)

{

    apr_finfo_t finfo;

    const char *fname;

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

    if (err != NULL) {

        return err;

    }

    fname = ap_server_root_relative(cmd->temp_pool, arg);

    if (!fname) {

        return apr_pstrcat(cmd->pool, "Invalid CoreDumpDirectory path ",

                           arg, NULL);

    }

    if (apr_stat(&finfo, fname, APR_FINFO_TYPE, cmd->pool) != APR_SUCCESS) {

        return apr_pstrcat(cmd->pool, "CoreDumpDirectory ", fname,

                           " does not exist", NULL);

    }

    if (finfo.filetype != APR_DIR) {

        return apr_pstrcat(cmd->pool, "CoreDumpDirectory ", fname,

                           " is not a directory", NULL);

    }

    apr_cpystrn(ap_coredump_dir, fname, sizeof(ap_coredump_dir));

    ap_coredumpdir_configured = 1;

    return NULL;

}

AP_DECLARE(const char *)ap_mpm_set_graceful_shutdown(cmd_parms *cmd,

                                                     void *dummy,

                                                     const char *arg)

{

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

    if (err != NULL) {

        return err;

    }

    ap_graceful_shutdown_timeout = atoi(arg);

    return NULL;

}

const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy,

                                    const char *arg)

{

    long value;

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

    if (err != NULL) {

        return err;

    }

    errno = 0;

    value = strtol(arg, NULL, 10);

    if (value < 0 || errno == ERANGE)

        return apr_pstrcat(cmd->pool, "Invalid MaxMemFree value: ",

                           arg, NULL);

    ap_max_mem_free = (apr_uint32_t)value * 1024;

    return NULL;

}

const char *ap_mpm_set_thread_stacksize(cmd_parms *cmd, void *dummy,

                                        const char *arg)

{

    long value;

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

    if (err != NULL) {

        return err;

    }

    errno = 0;

    value = strtol(arg, NULL, 10);

    if (value < 0 || errno == ERANGE)

        return apr_pstrcat(cmd->pool, "Invalid ThreadStackSize value: ",

                           arg, NULL);

    ap_thread_stacksize = (apr_size_t)value;

    return NULL;

}

AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)

{

    apr_status_t rv;

    if (ap_run_mpm_query(query_code, result, &rv) == DECLINED) {

        rv = APR_EGENERAL;

    }

    return rv;

}

static void end_gen(mpm_gen_info_t *gi)

{

    ap_log_error(APLOG_MARK, APLOG_TRACE4, 0, ap_server_conf,

                 "end of generation %d", gi->gen);

    ap_run_end_generation(ap_server_conf, gi->gen);

    APR_RING_REMOVE(gi, link);

    APR_RING_INSERT_HEAD(unused_geninfo, gi, mpm_gen_info_t, link);

}

apr_status_t ap_mpm_end_gen_helper(void *unused) /* cleanup on pconf */

{

    int gen = ap_config_generation - 1; /* differs from MPM generation */

    mpm_gen_info_t *cur;

    if (geninfo == NULL) {

        /* initial pconf teardown, MPM hasn't run */

        return APR_SUCCESS;

    }

    cur = APR_RING_FIRST(geninfo);

    while (cur != APR_RING_SENTINEL(geninfo, mpm_gen_info_t, link) &&

           cur->gen != gen) {

        cur = APR_RING_NEXT(cur, link);

    }

    if (cur == APR_RING_SENTINEL(geninfo, mpm_gen_info_t, link)) {

        /* last child of generation already exited */

        ap_log_error(APLOG_MARK, APLOG_TRACE4, 0, ap_server_conf,

                     "no record of generation %d", gen);

    }

    else {

        cur->done = 1;

        if (cur->active == 0) {

            end_gen(cur);

        }

    }

    return APR_SUCCESS;

}

/* core's child-status hook

 * tracks number of remaining children per generation and

 * runs the end-generation hook when the last child of

 * a generation exits

 */

void ap_core_child_status(server_rec *s, pid_t pid,

                          ap_generation_t gen, int slot,

                          mpm_child_status status)

{

    mpm_gen_info_t *cur;

    const char *status_msg = "unknown status";

    if (!gen_head_init) { /* where to run this? */

        gen_head_init = 1;

        geninfo = apr_pcalloc(s->process->pool, sizeof *geninfo);

        unused_geninfo = apr_pcalloc(s->process->pool, sizeof *unused_geninfo);

        APR_RING_INIT(geninfo, mpm_gen_info_t, link);

        APR_RING_INIT(unused_geninfo, mpm_gen_info_t, link);

    }

    cur = APR_RING_FIRST(geninfo);

    while (cur != APR_RING_SENTINEL(geninfo, mpm_gen_info_t, link) &&

           cur->gen != gen) {

        cur = APR_RING_NEXT(cur, link);

    }

    switch(status) {

    case MPM_CHILD_STARTED:

        status_msg = "started";

        if (cur == APR_RING_SENTINEL(geninfo, mpm_gen_info_t, link)) {

            /* first child for this generation */

            if (!APR_RING_EMPTY(unused_geninfo, mpm_gen_info_t, link)) {

                cur = APR_RING_FIRST(unused_geninfo);

                APR_RING_REMOVE(cur, link);

                cur->active = cur->done = 0;

            }

            else {

                cur = apr_pcalloc(s->process->pool, sizeof *cur);

            }

            cur->gen = gen;

            APR_RING_ELEM_INIT(cur, link);

            APR_RING_INSERT_HEAD(geninfo, cur, mpm_gen_info_t, link);

        }

        ap_random_parent_after_fork();

        ++cur->active;

        break;

    case MPM_CHILD_EXITED:

        ap_update_global_status();

        status_msg = "exited";

        if (cur == APR_RING_SENTINEL(geninfo, mpm_gen_info_t, link)) {

            ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00546)

                         "no record of generation %d of exiting child %" APR_PID_T_FMT,

                         gen, pid);

        }

        else {

            --cur->active;

            if (!cur->active && cur->done) { /* no children, server has stopped/restarted */

                end_gen(cur);

            }

        }

        break;

    case MPM_CHILD_LOST_SLOT:

        status_msg = "lost slot";

        /* we don't track by slot, so it doesn't matter */

        break;

    }

    ap_log_error(APLOG_MARK, APLOG_TRACE4, 0, s,

                 "mpm child %" APR_PID_T_FMT " (gen %d/slot %d) %s",

                 pid, gen, slot, status_msg);

}

AP_DECLARE(apr_status_t) ap_mpm_resume_suspended(conn_rec *c)

{

    return ap_run_mpm_resume_suspended(c);

}

AP_DECLARE(apr_status_t) ap_mpm_register_timed_callback(apr_time_t t,

        ap_mpm_callback_fn_t *cbfn, void *baton)

{

    return ap_run_mpm_register_timed_callback(t, cbfn, baton);

}

AP_DECLARE(apr_status_t) ap_mpm_register_poll_callback(

        apr_pool_t *p, const apr_array_header_t *pfds,

        ap_mpm_callback_fn_t *cbfn, void *baton)

{

    return ap_run_mpm_register_poll_callback(p, pfds, cbfn, baton);

}

AP_DECLARE(apr_status_t) ap_mpm_register_poll_callback_timeout(

        apr_pool_t *p, const apr_array_header_t *pfds,

        ap_mpm_callback_fn_t *cbfn, ap_mpm_callback_fn_t *tofn,

        void *baton, apr_time_t timeout)

{

    return ap_run_mpm_register_poll_callback_timeout(p, pfds, cbfn, tofn,

                                                     baton, timeout);

}

AP_DECLARE(const char *)ap_show_mpm(void)

{

    const char *name = ap_run_mpm_get_name();

    if (!name) {

        name = "";

    }

    return name;

}

AP_DECLARE(const char *)ap_check_mpm(void)

{

    static const char *last_mpm_name = NULL;

    if (!_hooks.link_mpm || _hooks.link_mpm->nelts == 0)

        return "No MPM loaded.";

    else if (_hooks.link_mpm->nelts > 1)

        return "More than one MPM loaded.";

    if (last_mpm_name) {

        if (strcmp(last_mpm_name, ap_show_mpm())) {

            return "The MPM cannot be changed during restart.";

        }

    }

    else {

        last_mpm_name = apr_pstrdup(ap_pglobal, ap_show_mpm());

    }

    return NULL;

}