refactor mpm_common.c into itself and mpm_unix.c for unix-specific quirks

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@758367 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 925 insertions, 0 deletions

diff --git a/server/mpm_unix.c b/server/mpm_unix.c
new file mode 100644
index 0000000000..eadfa33aa3
--- /dev/null
+++ b/server/mpm_unix.c
@@ -0,0 +1,925 @@
+/* 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_log.h"
+#include "http_main.h"
+#include "mpm_common.h"
+#include "ap_mpm.h"
+#include "ap_listen.h"
+#include "util_mutex.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
+
+
+typedef enum {DO_NOTHING, SEND_SIGTERM, SEND_SIGKILL, GIVEUP} action_t;
+
+typedef struct extra_process_t {
+    struct extra_process_t *next;
+    pid_t pid;
+} extra_process_t;
+
+static extra_process_t *extras;
+
+void ap_register_extra_mpm_process(pid_t pid)
+{
+    extra_process_t *p = (extra_process_t *)malloc(sizeof(extra_process_t));
+
+    p->next = extras;
+    p->pid = pid;
+    extras = p;
+}
+
+int ap_unregister_extra_mpm_process(pid_t pid)
+{
+    extra_process_t *cur = extras;
+    extra_process_t *prev = NULL;
+
+    while (cur && cur->pid != pid) {
+        prev = cur;
+        cur = cur->next;
+    }
+
+    if (cur) {
+        if (prev) {
+            prev->next = cur->next;
+        }
+        else {
+            extras = cur->next;
+        }
+        free(cur);
+        return 1; /* found */
+    }
+    else {
+        /* we don't know about any such process */
+        return 0;
+    }
+}
+
+static int reclaim_one_pid(pid_t pid, action_t action)
+{
+    apr_proc_t proc;
+    apr_status_t waitret;
+    apr_exit_why_e why;
+    int status;
+
+    /* Ensure pid sanity. */
+    if (pid < 1) {
+        return 1;
+    }        
+
+    proc.pid = pid;
+    waitret = apr_proc_wait(&proc, &status, &why, APR_NOWAIT);
+    if (waitret != APR_CHILD_NOTDONE) {
+        if (waitret == APR_CHILD_DONE)
+            ap_process_child_status(&proc, why, status);
+        return 1;
+    }
+
+    switch(action) {
+    case DO_NOTHING:
+        break;
+
+    case SEND_SIGTERM:
+        /* ok, now it's being annoying */
+        ap_log_error(APLOG_MARK, APLOG_WARNING,
+                     0, ap_server_conf,
+                     "child process %" APR_PID_T_FMT
+                     " still did not exit, "
+                     "sending a SIGTERM",
+                     pid);
+        kill(pid, SIGTERM);
+        break;
+
+    case SEND_SIGKILL:
+        ap_log_error(APLOG_MARK, APLOG_ERR,
+                     0, ap_server_conf,
+                     "child process %" APR_PID_T_FMT
+                     " still did not exit, "
+                     "sending a SIGKILL",
+                     pid);
+#ifndef BEOS
+        kill(pid, SIGKILL);
+#else
+        /* sending a SIGKILL kills the entire team on BeOS, and as
+         * httpd thread is part of that team it removes any chance
+         * of ever doing a restart.  To counter this I'm changing to
+         * use a kinder, gentler way of killing a specific thread
+         * that is just as effective.
+         */
+        kill_thread(pid);
+#endif
+        break;
+
+    case GIVEUP:
+        /* gave it our best shot, but alas...  If this really
+         * is a child we are trying to kill and it really hasn't
+         * exited, we will likely fail to bind to the port
+         * after the restart.
+         */
+        ap_log_error(APLOG_MARK, APLOG_ERR,
+                     0, ap_server_conf,
+                     "could not make child process %" APR_PID_T_FMT
+                     " exit, "
+                     "attempting to continue anyway",
+                     pid);
+        break;
+    }
+
+    return 0;
+}
+
+void ap_reclaim_child_processes(int terminate)
+{
+    apr_time_t waittime = 1024 * 16;
+    int i;
+    extra_process_t *cur_extra;
+    int not_dead_yet;
+    int max_daemons;
+    apr_time_t starttime = apr_time_now();
+    /* this table of actions and elapsed times tells what action is taken
+     * at which elapsed time from starting the reclaim
+     */
+    struct {
+        action_t action;
+        apr_time_t action_time;
+    } action_table[] = {
+        {DO_NOTHING, 0}, /* dummy entry for iterations where we reap
+                          * children but take no action against
+                          * stragglers
+                          */
+        {SEND_SIGTERM, apr_time_from_sec(3)},
+        {SEND_SIGTERM, apr_time_from_sec(5)},
+        {SEND_SIGTERM, apr_time_from_sec(7)},
+        {SEND_SIGKILL, apr_time_from_sec(9)},
+        {GIVEUP,       apr_time_from_sec(10)}
+    };
+    int cur_action;      /* index of action we decided to take this
+                          * iteration
+                          */
+    int next_action = 1; /* index of first real action */
+
+    ap_mpm_query(AP_MPMQ_MAX_DAEMON_USED, &max_daemons);
+
+    do {
+        apr_sleep(waittime);
+        /* don't let waittime get longer than 1 second; otherwise, we don't
+         * react quickly to the last child exiting, and taking action can
+         * be delayed
+         */
+        waittime = waittime * 4;
+        if (waittime > apr_time_from_sec(1)) {
+            waittime = apr_time_from_sec(1);
+        }
+
+        /* see what action to take, if any */
+        if (action_table[next_action].action_time <= apr_time_now() - starttime) {
+            cur_action = next_action;
+            ++next_action;
+        }
+        else {
+            cur_action = 0; /* nothing to do */
+        }
+
+        /* now see who is done */
+        not_dead_yet = 0;
+        for (i = 0; i < max_daemons; ++i) {
+            pid_t pid = ap_mpm_get_child_pid(i);
+
+            if (pid == 0) {
+                continue; /* not every scoreboard entry is in use */
+            }
+
+            if (reclaim_one_pid(pid, action_table[cur_action].action)) {
+                ap_mpm_note_child_killed(i);
+            }
+            else {
+                ++not_dead_yet;
+            }
+        }
+
+        cur_extra = extras;
+        while (cur_extra) {
+            extra_process_t *next = cur_extra->next;
+
+            if (reclaim_one_pid(cur_extra->pid, action_table[cur_action].action)) {
+                AP_DEBUG_ASSERT(1 == ap_unregister_extra_mpm_process(cur_extra->pid));
+            }
+            else {
+                ++not_dead_yet;
+            }
+            cur_extra = next;
+        }
+#if APR_HAS_OTHER_CHILD
+        apr_proc_other_child_refresh_all(APR_OC_REASON_RESTART);
+#endif
+
+    } while (not_dead_yet > 0 &&
+             action_table[cur_action].action != GIVEUP);
+}
+
+void ap_relieve_child_processes(void)
+{
+    int i;
+    extra_process_t *cur_extra;
+    int max_daemons;
+
+    ap_mpm_query(AP_MPMQ_MAX_DAEMON_USED, &max_daemons);
+
+    /* now see who is done */
+    for (i = 0; i < max_daemons; ++i) {
+        pid_t pid = ap_mpm_get_child_pid(i);
+
+        if (pid == 0) {
+            continue; /* not every scoreboard entry is in use */
+        }
+
+        if (reclaim_one_pid(pid, DO_NOTHING)) {
+            ap_mpm_note_child_killed(i);
+        }
+    }
+
+    cur_extra = extras;
+    while (cur_extra) {
+        extra_process_t *next = cur_extra->next;
+
+        if (reclaim_one_pid(cur_extra->pid, DO_NOTHING)) {
+            AP_DEBUG_ASSERT(1 == ap_unregister_extra_mpm_process(cur_extra->pid));
+        }
+        cur_extra = next;
+    }
+}
+
+/* Before sending the signal to the pid this function verifies that
+ * the pid is a member of the current process group; either using
+ * apr_proc_wait(), where waitpid() guarantees to fail for non-child
+ * processes; or by using getpgid() directly, if available. */
+apr_status_t ap_mpm_safe_kill(pid_t pid, int sig)
+{
+#ifndef HAVE_GETPGID
+    apr_proc_t proc;
+    apr_status_t rv;
+    apr_exit_why_e why;
+    int status;
+
+    /* Ensure pid sanity */
+    if (pid < 1) {
+        return APR_EINVAL;
+    }
+
+    proc.pid = pid;
+    rv = apr_proc_wait(&proc, &status, &why, APR_NOWAIT);
+    if (rv == APR_CHILD_DONE) {
+        /* The child already died - log the termination status if
+         * necessary: */
+        ap_process_child_status(&proc, why, status);
+        return APR_EINVAL;
+    }
+    else if (rv != APR_CHILD_NOTDONE) {
+        /* The child is already dead and reaped, or was a bogus pid -
+         * log this either way. */
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, rv, ap_server_conf,
+                     "cannot send signal %d to pid %ld (non-child or "
+                     "already dead)", sig, (long)pid);
+        return APR_EINVAL;
+    }
+#else
+    pid_t pg;
+
+    /* Ensure pid sanity. */
+    if (pid < 1) {
+        return APR_EINVAL;
+    }
+
+    pg = getpgid(pid);    
+    if (pg == -1) {
+        /* Process already dead... */
+        return errno;
+    }
+
+    if (pg != getpgrp()) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, 0, ap_server_conf,
+                     "refusing to send signal %d to pid %ld outside "
+                     "process group", sig, (long)pid);
+        return APR_EINVAL;
+    }
+#endif        
+
+    return kill(pid, sig) ? errno : APR_SUCCESS;
+}
+
+
+int ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status)
+{
+    int signum = status;
+    const char *sigdesc;
+
+    /* Child died... if it died due to a fatal error,
+     * we should simply bail out.  The caller needs to
+     * check for bad rc from us and exit, running any
+     * appropriate cleanups.
+     *
+     * If the child died due to a resource shortage,
+     * the parent should limit the rate of forking
+     */
+    if (APR_PROC_CHECK_EXIT(why)) {
+        if (status == APEXIT_CHILDSICK) {
+            return status;
+        }
+
+        if (status == APEXIT_CHILDFATAL) {
+            ap_log_error(APLOG_MARK, APLOG_ALERT,
+                         0, ap_server_conf,
+                         "Child %" APR_PID_T_FMT
+                         " returned a Fatal error... Apache is exiting!",
+                         pid->pid);
+            return APEXIT_CHILDFATAL;
+        }
+
+        return 0;
+    }
+
+    if (APR_PROC_CHECK_SIGNALED(why)) {
+        sigdesc = apr_signal_description_get(signum);
+
+        switch (signum) {
+        case SIGTERM:
+        case SIGHUP:
+        case AP_SIG_GRACEFUL:
+        case SIGKILL:
+            break;
+
+        default:
+            if (APR_PROC_CHECK_CORE_DUMP(why)) {
+                ap_log_error(APLOG_MARK, APLOG_NOTICE,
+                             0, ap_server_conf,
+                             "child pid %ld exit signal %s (%d), "
+                             "possible coredump in %s",
+                             (long)pid->pid, sigdesc, signum,
+                             ap_coredump_dir);
+            }
+            else {
+                ap_log_error(APLOG_MARK, APLOG_NOTICE,
+                             0, ap_server_conf,
+                             "child pid %ld exit signal %s (%d)",
+                             (long)pid->pid, sigdesc, signum);
+            }
+        }
+    }
+    return 0;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod)
+{
+    apr_status_t rv;
+
+    *pod = apr_palloc(p, sizeof(**pod));
+    rv = apr_file_pipe_create_ex(&((*pod)->pod_in), &((*pod)->pod_out),
+                                 APR_WRITE_BLOCK, p);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    apr_file_pipe_timeout_set((*pod)->pod_in, 0);
+    (*pod)->p = p;
+
+    /* close these before exec. */
+    apr_file_inherit_unset((*pod)->pod_in);
+    apr_file_inherit_unset((*pod)->pod_out);
+
+    return APR_SUCCESS;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod)
+{
+    char c;
+    apr_size_t len = 1;
+    apr_status_t rv;
+
+    rv = apr_file_read(pod->pod_in, &c, &len);
+
+    if ((rv == APR_SUCCESS) && (len == 1)) {
+        return APR_SUCCESS;
+    }
+
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    return AP_NORESTART;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod)
+{
+    apr_status_t rv;
+
+    rv = apr_file_close(pod->pod_out);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    rv = apr_file_close(pod->pod_in);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t pod_signal_internal(ap_pod_t *pod)
+{
+    apr_status_t rv;
+    char char_of_death = '!';
+    apr_size_t one = 1;
+
+    rv = apr_file_write(pod->pod_out, &char_of_death, &one);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
+                     "write pipe_of_death");
+    }
+
+    return rv;
+}
+
+/* This function connects to the server, then immediately closes the connection.
+ * This permits the MPM to skip the poll when there is only one listening
+ * socket, because it provides a alternate way to unblock an accept() when
+ * the pod is used.
+ */
+static apr_status_t dummy_connection(ap_pod_t *pod)
+{
+    char *srequest;
+    apr_status_t rv;
+    apr_socket_t *sock;
+    apr_pool_t *p;
+    apr_size_t len;
+    ap_listen_rec *lp;
+
+    /* create a temporary pool for the socket.  pconf stays around too long */
+    rv = apr_pool_create(&p, pod->p);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    /* If possible, find a listener which is configured for
+     * plain-HTTP, not SSL; using an SSL port would either be
+     * expensive to do correctly (performing a complete SSL handshake)
+     * or cause log spam by doing incorrectly (simply sending EOF). */
+    lp = ap_listeners;
+    while (lp && lp->protocol && strcasecmp(lp->protocol, "http") != 0) {
+        lp = lp->next;
+    }
+    if (!lp) {
+        lp = ap_listeners;
+    }
+
+    rv = apr_socket_create(&sock, lp->bind_addr->family, SOCK_STREAM, 0, p);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
+                     "get socket to connect to listener");
+        apr_pool_destroy(p);
+        return rv;
+    }
+
+    /* on some platforms (e.g., FreeBSD), the kernel won't accept many
+     * queued connections before it starts blocking local connects...
+     * we need to keep from blocking too long and instead return an error,
+     * because the MPM won't want to hold up a graceful restart for a
+     * long time
+     */
+    rv = apr_socket_timeout_set(sock, apr_time_from_sec(3));
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
+                     "set timeout on socket to connect to listener");
+        apr_socket_close(sock);
+        apr_pool_destroy(p);
+        return rv;
+    }
+
+    rv = apr_socket_connect(sock, lp->bind_addr);
+    if (rv != APR_SUCCESS) {
+        int log_level = APLOG_WARNING;
+
+        if (APR_STATUS_IS_TIMEUP(rv)) {
+            /* probably some server processes bailed out already and there
+             * is nobody around to call accept and clear out the kernel
+             * connection queue; usually this is not worth logging
+             */
+            log_level = APLOG_DEBUG;
+        }
+
+        ap_log_error(APLOG_MARK, log_level, rv, ap_server_conf,
+                     "connect to listener on %pI", lp->bind_addr);
+    }
+
+    /* Create the request string. We include a User-Agent so that
+     * adminstrators can track down the cause of the odd-looking
+     * requests in their logs.
+     */
+    srequest = apr_pstrcat(p, "OPTIONS * HTTP/1.0\r\nUser-Agent: ",
+                           ap_get_server_banner(),
+                           " (internal dummy connection)\r\n\r\n", NULL);
+
+    /* Since some operating systems support buffering of data or entire
+     * requests in the kernel, we send a simple request, to make sure
+     * the server pops out of a blocking accept().
+     */
+    /* XXX: This is HTTP specific. We should look at the Protocol for each
+     * listener, and send the correct type of request to trigger any Accept
+     * Filters.
+     */
+    len = strlen(srequest);
+    apr_socket_send(sock, srequest, &len);
+    apr_socket_close(sock);
+    apr_pool_destroy(p);
+
+    return rv;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod)
+{
+    apr_status_t rv;
+
+    rv = pod_signal_internal(pod);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    return dummy_connection(pod);
+}
+
+void ap_mpm_pod_killpg(ap_pod_t *pod, int num)
+{
+    int i;
+    apr_status_t rv = APR_SUCCESS;
+
+    /* we don't write anything to the pod here...  we assume
+     * that the would-be reader of the pod has another way to
+     * see that it is time to die once we wake it up
+     *
+     * writing lots of things to the pod at once is very
+     * problematic... we can fill the kernel pipe buffer and
+     * be blocked until somebody consumes some bytes or
+     * we hit a timeout...  if we hit a timeout we can't just
+     * keep trying because maybe we'll never successfully
+     * write again...  but then maybe we'll leave would-be
+     * readers stranded (a number of them could be tied up for
+     * a while serving time-consuming requests)
+     */
+    for (i = 0; i < num && rv == APR_SUCCESS; i++) {
+        rv = dummy_connection(pod);
+    }
+}
+
+static const char *dash_k_arg;
+
+static int send_signal(pid_t pid, int sig)
+{
+    if (kill(pid, sig) < 0) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, errno, NULL,
+                     "sending signal to server");
+        return 1;
+    }
+    return 0;
+}
+
+int ap_signal_server(int *exit_status, apr_pool_t *pconf)
+{
+    apr_status_t rv;
+    pid_t otherpid;
+    int running = 0;
+    int have_pid_file = 0;
+    const char *status;
+
+    *exit_status = 0;
+
+    rv = ap_read_pid(pconf, ap_pid_fname, &otherpid);
+    if (rv != APR_SUCCESS) {
+        if (rv != APR_ENOENT) {
+            ap_log_error(APLOG_MARK, APLOG_STARTUP, rv, NULL,
+                         "Error retrieving pid file %s", ap_pid_fname);
+            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                         "Remove it before continuing if it is corrupted.");
+            *exit_status = 1;
+            return 1;
+        }
+        status = "httpd (no pid file) not running";
+    }
+    else {
+        have_pid_file = 1;
+        if (kill(otherpid, 0) == 0) {
+            running = 1;
+            status = apr_psprintf(pconf,
+                                  "httpd (pid %" APR_PID_T_FMT ") already "
+                                  "running", otherpid);
+        }
+        else {
+            status = apr_psprintf(pconf,
+                                  "httpd (pid %" APR_PID_T_FMT "?) not running",
+                                  otherpid);
+        }
+    }
+
+    if (!strcmp(dash_k_arg, "start")) {
+        if (running) {
+            printf("%s\n", status);
+            return 1;
+        }
+    }
+
+    if (!strcmp(dash_k_arg, "stop")) {
+        if (!running) {
+            printf("%s\n", status);
+        }
+        else {
+            send_signal(otherpid, SIGTERM);
+        }
+        return 1;
+    }
+
+    if (!strcmp(dash_k_arg, "restart")) {
+        if (!running) {
+            printf("httpd not running, trying to start\n");
+        }
+        else {
+            *exit_status = send_signal(otherpid, SIGHUP);
+            return 1;
+        }
+    }
+
+    if (!strcmp(dash_k_arg, "graceful")) {
+        if (!running) {
+            printf("httpd not running, trying to start\n");
+        }
+        else {
+            *exit_status = send_signal(otherpid, AP_SIG_GRACEFUL);
+            return 1;
+        }
+    }
+
+    if (!strcmp(dash_k_arg, "graceful-stop")) {
+        if (!running) {
+            printf("%s\n", status);
+        }
+        else {
+            *exit_status = send_signal(otherpid, AP_SIG_GRACEFUL_STOP);
+        }
+        return 1;
+    }
+
+    return 0;
+}
+
+void ap_mpm_rewrite_args(process_rec *process)
+{
+    apr_array_header_t *mpm_new_argv;
+    apr_status_t rv;
+    apr_getopt_t *opt;
+    char optbuf[3];
+    const char *optarg;
+    int fixed_args;
+
+    mpm_new_argv = apr_array_make(process->pool, process->argc,
+                                  sizeof(const char **));
+    *(const char **)apr_array_push(mpm_new_argv) = process->argv[0];
+    fixed_args = mpm_new_argv->nelts;
+    apr_getopt_init(&opt, process->pool, process->argc, process->argv);
+    opt->errfn = NULL;
+    optbuf[0] = '-';
+    /* option char returned by apr_getopt() will be stored in optbuf[1] */
+    optbuf[2] = '\0';
+    while ((rv = apr_getopt(opt, "k:" AP_SERVER_BASEARGS,
+                            optbuf + 1, &optarg)) == APR_SUCCESS) {
+        switch(optbuf[1]) {
+        case 'k':
+            if (!dash_k_arg) {
+                if (!strcmp(optarg, "start") || !strcmp(optarg, "stop") ||
+                    !strcmp(optarg, "restart") || !strcmp(optarg, "graceful") ||
+                    !strcmp(optarg, "graceful-stop")) {
+                    dash_k_arg = optarg;
+                    break;
+                }
+            }
+        default:
+            *(const char **)apr_array_push(mpm_new_argv) =
+                apr_pstrdup(process->pool, optbuf);
+            if (optarg) {
+                *(const char **)apr_array_push(mpm_new_argv) = optarg;
+            }
+        }
+    }
+
+    /* back up to capture the bad argument */
+    if (rv == APR_BADCH || rv == APR_BADARG) {
+        opt->ind--;
+    }
+
+    while (opt->ind < opt->argc) {
+        *(const char **)apr_array_push(mpm_new_argv) =
+            apr_pstrdup(process->pool, opt->argv[opt->ind++]);
+    }
+
+    process->argc = mpm_new_argv->nelts;
+    process->argv = (const char * const *)mpm_new_argv->elts;
+
+    if (dash_k_arg) {
+        APR_REGISTER_OPTIONAL_FN(ap_signal_server);
+    }
+}
+
+static pid_t parent_pid, my_pid;
+static apr_pool_t *pconf;
+
+#if AP_ENABLE_EXCEPTION_HOOK
+
+static int exception_hook_enabled;
+
+const char *ap_mpm_set_exception_hook(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 "EnableExceptionHook directive not allowed in <VirtualHost>";
+    }
+
+    if (strcasecmp(arg, "on") == 0) {
+        exception_hook_enabled = 1;
+    }
+    else if (strcasecmp(arg, "off") == 0) {
+        exception_hook_enabled = 0;
+    }
+    else {
+        return "parameter must be 'on' or 'off'";
+    }
+
+    return NULL;
+}
+
+static void run_fatal_exception_hook(int sig)
+{
+    ap_exception_info_t ei = {0};
+
+    if (exception_hook_enabled &&
+        geteuid() != 0 &&
+        my_pid != parent_pid) {
+        ei.sig = sig;
+        ei.pid = my_pid;
+        ap_run_fatal_exception(&ei);
+    }
+}
+#endif /* AP_ENABLE_EXCEPTION_HOOK */
+
+/* handle all varieties of core dumping signals */
+static void sig_coredump(int sig)
+{
+    apr_filepath_set(ap_coredump_dir, pconf);
+    apr_signal(sig, SIG_DFL);
+#if AP_ENABLE_EXCEPTION_HOOK
+    run_fatal_exception_hook(sig);
+#endif
+    /* linuxthreads issue calling getpid() here:
+     *   This comparison won't match if the crashing thread is
+     *   some module's thread that runs in the parent process.
+     *   The fallout, which is limited to linuxthreads:
+     *   The special log message won't be written when such a
+     *   thread in the parent causes the parent to crash.
+     */
+    if (getpid() == parent_pid) {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE,
+                     0, ap_server_conf,
+                     "seg fault or similar nasty error detected "
+                     "in the parent process");
+        /* XXX we can probably add some rudimentary cleanup code here,
+         * like getting rid of the pid file.  If any additional bad stuff
+         * happens, we are protected from recursive errors taking down the
+         * system since this function is no longer the signal handler   GLA
+         */
+    }
+    kill(getpid(), sig);
+    /* At this point we've got sig blocked, because we're still inside
+     * the signal handler.  When we leave the signal handler it will
+     * be unblocked, and we'll take the signal... and coredump or whatever
+     * is appropriate for this particular Unix.  In addition the parent
+     * will see the real signal we received -- whereas if we called
+     * abort() here, the parent would only see SIGABRT.
+     */
+}
+
+apr_status_t ap_fatal_signal_child_setup(server_rec *s)
+{
+    my_pid = getpid();
+    return APR_SUCCESS;
+}
+
+apr_status_t ap_fatal_signal_setup(server_rec *s, apr_pool_t *in_pconf)
+{
+#ifndef NO_USE_SIGACTION
+    struct sigaction sa;
+
+    sigemptyset(&sa.sa_mask);
+
+#if defined(SA_ONESHOT)
+    sa.sa_flags = SA_ONESHOT;
+#elif defined(SA_RESETHAND)
+    sa.sa_flags = SA_RESETHAND;
+#else
+    sa.sa_flags = 0;
+#endif
+
+    sa.sa_handler = sig_coredump;
+    if (sigaction(SIGSEGV, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGSEGV)");
+#ifdef SIGBUS
+    if (sigaction(SIGBUS, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGBUS)");
+#endif
+#ifdef SIGABORT
+    if (sigaction(SIGABORT, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGABORT)");
+#endif
+#ifdef SIGABRT
+    if (sigaction(SIGABRT, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGABRT)");
+#endif
+#ifdef SIGILL
+    if (sigaction(SIGILL, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGILL)");
+#endif
+#ifdef SIGFPE
+    if (sigaction(SIGFPE, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, s, "sigaction(SIGFPE)");
+#endif
+
+#else /* NO_USE_SIGACTION */
+
+    apr_signal(SIGSEGV, sig_coredump);
+#ifdef SIGBUS
+    apr_signal(SIGBUS, sig_coredump);
+#endif /* SIGBUS */
+#ifdef SIGABORT
+    apr_signal(SIGABORT, sig_coredump);
+#endif /* SIGABORT */
+#ifdef SIGABRT
+    apr_signal(SIGABRT, sig_coredump);
+#endif /* SIGABRT */
+#ifdef SIGILL
+    apr_signal(SIGILL, sig_coredump);
+#endif /* SIGILL */
+#ifdef SIGFPE
+    apr_signal(SIGFPE, sig_coredump);
+#endif /* SIGFPE */
+
+#endif /* NO_USE_SIGACTION */
+
+    pconf = in_pconf;
+    parent_pid = my_pid = getpid();
+
+    return APR_SUCCESS;
+}