mod_cgid.c

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * http_script: keeps all script-related ramblings together.
 *
 * Compliant to cgi/1.1 spec
 *
 * Adapted by rst from original NCSA code by Rob McCool
 *
 * This modules uses a httpd core function (ap_add_common_vars) to add some new env vars, 
 * like REDIRECT_URL and REDIRECT_QUERY_STRING for custom error responses and DOCUMENT_ROOT.
 * It also adds SERVER_ADMIN - useful for scripts to know who to mail when they fail.
 * 
 */

#include "apr_lib.h"
#include "apr_strings.h"
#include "apr_general.h"
#include "apr_file_io.h"
#include "apr_portable.h"
#include "apr_buckets.h"
#include "apr_optional.h"
#include "apr_signal.h"

#define APR_WANT_STRFUNC
#include "apr_want.h"

#if APR_HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#if APR_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "util_filter.h"
#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_main.h"
#include "http_log.h"
#include "util_script.h"
#include "ap_mpm.h"
#include "mpm_common.h"
#include "mod_suexec.h"
#include "../filters/mod_include.h"

#include "mod_core.h"


/* ### should be tossed in favor of APR */
#include <sys/stat.h>
#include <sys/un.h> /* for sockaddr_un */

#if APR_HAVE_STRUCT_RLIMIT
#if defined (RLIMIT_CPU) || defined (RLIMIT_NPROC) || defined (RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_AS)
#define AP_CGID_USE_RLIMIT
#endif
#endif

module AP_MODULE_DECLARE_DATA cgid_module;

static int cgid_start(apr_pool_t *p, server_rec *main_server, apr_proc_t *procnew);
static int cgid_init(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *main_server);
static int handle_exec(include_ctx_t *ctx, ap_filter_t *f, apr_bucket_brigade *bb);

static APR_OPTIONAL_FN_TYPE(ap_register_include_handler) *cgid_pfn_reg_with_ssi;
static APR_OPTIONAL_FN_TYPE(ap_ssi_get_tag_and_value) *cgid_pfn_gtv;
static APR_OPTIONAL_FN_TYPE(ap_ssi_parse_string) *cgid_pfn_ps;

static apr_pool_t *pcgi = NULL;
static pid_t daemon_pid;
static int daemon_should_exit = 0;
static server_rec *root_server = NULL;
static apr_pool_t *root_pool = NULL;
static const char *sockname;
static struct sockaddr_un *server_addr;
static apr_socklen_t server_addr_len;
static pid_t parent_pid;
static ap_unix_identity_t empty_ugid = { (uid_t)-1, (gid_t)-1, -1 };

typedef struct { 
    apr_interval_time_t timeout;
} cgid_dirconf;

/* The APR other-child API doesn't tell us how the daemon exited
 * (SIGSEGV vs. exit(1)).  The other-child maintenance function
 * needs to decide whether to restart the daemon after a failure
 * based on whether or not it exited due to a fatal startup error
 * or something that happened at steady-state.  This exit status
 * is unlikely to collide with exit signals.
 */
#define DAEMON_STARTUP_ERROR 254

/* Read and discard the data in the brigade produced by a CGI script */
static void discard_script_output(apr_bucket_brigade *bb);

/* This doer will only ever be called when we are sure that we have
 * a valid ugid.
 */
static ap_unix_identity_t *cgid_suexec_id_doer(const request_rec *r)
{
    return (ap_unix_identity_t *)
                        ap_get_module_config(r->request_config, &cgid_module);
}

/* KLUDGE --- for back-combatibility, we don't have to check ExecCGI
 * in ScriptAliased directories, which means we need to know if this
 * request came through ScriptAlias or not... so the Alias module
 * leaves a note for us.
 */

static int is_scriptaliased(request_rec *r)
{
    const char *t = apr_table_get(r->notes, "alias-forced-type");
    return t && (!strcasecmp(t, "cgi-script"));
}

/* Configuration stuff */

#define DEFAULT_LOGBYTES 10385760
#define DEFAULT_BUFBYTES 1024
#define DEFAULT_SOCKET "cgisock"

#define CGI_REQ    1
#define SSI_REQ    2
#define GETPID_REQ 3 /* get the pid of script created for prior request */

#define ERRFN_USERDATA_KEY         "CGIDCHILDERRFN"

/* DEFAULT_CGID_LISTENBACKLOG controls the max depth on the unix socket's
 * pending connection queue.  If a bunch of cgi requests arrive at about
 * the same time, connections from httpd threads/processes will back up
 * in the queue while the cgid process slowly forks off a child to process
 * each connection on the unix socket.  If the queue is too short, the
 * httpd process will get ECONNREFUSED when trying to connect.
 */
#ifndef DEFAULT_CGID_LISTENBACKLOG
#define DEFAULT_CGID_LISTENBACKLOG 100
#endif

/* DEFAULT_CONNECT_ATTEMPTS controls how many times we'll try to connect
 * to the cgi daemon from the thread/process handling the cgi request.
 * Generally we want to retry when we get ECONNREFUSED since it is
 * probably because the listen queue is full.  We need to try harder so
 * the client doesn't see it as a 503 error.
 *
 * Set this to 0 to continually retry until the connect works or Apache
 * terminates.
 */
#ifndef DEFAULT_CONNECT_ATTEMPTS
#define DEFAULT_CONNECT_ATTEMPTS  15
#endif

#ifndef DEFAULT_CONNECT_STARTUP_DELAY
#define DEFAULT_CONNECT_STARTUP_DELAY 60
#endif

typedef struct {
    const char *logname;
    long logbytes;
    int bufbytes;
} cgid_server_conf;

#ifdef AP_CGID_USE_RLIMIT
typedef struct {
#ifdef RLIMIT_CPU
    int    limit_cpu_set;
    struct rlimit limit_cpu;
#endif
#if defined (RLIMIT_DATA) || defined (RLIMIT_VMEM) || defined(RLIMIT_AS)
    int    limit_mem_set;
    struct rlimit limit_mem;
#endif
#ifdef RLIMIT_NPROC
    int    limit_nproc_set;
    struct rlimit limit_nproc;
#endif

} cgid_rlimit_t;
#endif

typedef struct {
    int req_type; /* request type (CGI_REQ, SSI_REQ, etc.) */
    unsigned long conn_id; /* connection id; daemon uses this as a hash value
                            * to find the script pid when it is time for that
                            * process to be cleaned up
                            */
    pid_t ppid;            /* sanity check for config problems leading to
                            * wrong cgid socket use
                            */
    int env_count;
    ap_unix_identity_t ugid;
    apr_size_t filename_len;
    apr_size_t argv0_len;
    apr_size_t uri_len;
    apr_size_t args_len;
    int loglevel; /* to stuff in server_rec */

#ifdef AP_CGID_USE_RLIMIT
    cgid_rlimit_t limits;
#endif
} cgid_req_t;

/* This routine is called to create the argument list to be passed
 * to the CGI script.  When suexec is enabled, the suexec path, user, and
 * group are the first three arguments to be passed; if not, all three
 * must be NULL.  The query info is split into separate arguments, where
 * "+" is the separator between keyword arguments.
 *
 * Do not process the args if they containing an '=' assignment.
 */
static char **create_argv(apr_pool_t *p, char *path, char *user, char *group,
                          char *av0, const char *args)
{
    int x, numwords;
    char **av;
    char *w;
    int idx = 0;

    if (!(*args) || ap_strchr_c(args, '=')) {
        numwords = 0;
    }
    else {
        /* count the number of keywords */

        for (x = 0, numwords = 1; args[x]; x++) {
            if (args[x] == '+') {
                ++numwords;
            }
        }
    }

    if (numwords > APACHE_ARG_MAX - 5) {
        numwords = APACHE_ARG_MAX - 5;  /* Truncate args to prevent overrun */
    }
    av = (char **) apr_pcalloc(p, (numwords + 5) * sizeof(char *));

    if (path) {
        av[idx++] = path;
    }
    if (user) {
        av[idx++] = user;
    }
    if (group) {
        av[idx++] = group;
    }

    av[idx++] = apr_pstrdup(p, av0);

    for (x = 1; x <= numwords; x++) {
        w = ap_getword_nulls(p, &args, '+');
        ap_unescape_url(w);
        av[idx++] = ap_escape_shell_cmd(p, w);
    }
    av[idx] = NULL;
    return av;
}

#if APR_HAS_OTHER_CHILD
static void cgid_maint(int reason, void *data, apr_wait_t status)
{
    apr_proc_t *proc = data;
    int mpm_state;
    int stopping;

    switch (reason) {
        case APR_OC_REASON_DEATH:
            apr_proc_other_child_unregister(data);
            /* If apache is not terminating or restarting,
             * restart the cgid daemon
             */
            stopping = 1; /* if MPM doesn't support query,
                           * assume we shouldn't restart daemon
                           */
            if (ap_mpm_query(AP_MPMQ_MPM_STATE, &mpm_state) == APR_SUCCESS &&
                mpm_state != AP_MPMQ_STOPPING) {
                stopping = 0;
            }
            if (!stopping) {
                if (status == DAEMON_STARTUP_ERROR) {
                    ap_log_error(APLOG_MARK, APLOG_CRIT, 0, ap_server_conf, APLOGNO(01238)
                                 "cgid daemon failed to initialize");
                }
                else {
                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(01239)
                                 "cgid daemon process died, restarting");
                    cgid_start(root_pool, root_server, proc);
                }
            }
            break;
        case APR_OC_REASON_RESTART:
            /* don't do anything; server is stopping or restarting */
            apr_proc_other_child_unregister(data);
            break;
        case APR_OC_REASON_LOST:
            /* Restart the child cgid daemon process */
            apr_proc_other_child_unregister(data);
            cgid_start(root_pool, root_server, proc);
            break;
        case APR_OC_REASON_UNREGISTER:
            /* we get here when pcgi is cleaned up; pcgi gets cleaned
             * up when pconf gets cleaned up
             */
            kill(proc->pid, SIGHUP); /* send signal to daemon telling it to die */

            /* Remove the cgi socket, we must do it here in order to try and
             * guarantee the same permissions as when the socket was created.
             */
            if (unlink(sockname) < 0 && errno != ENOENT) {
                ap_log_error(APLOG_MARK, APLOG_ERR, errno, ap_server_conf, APLOGNO(01240)
                             "Couldn't unlink unix domain socket %s",
                             sockname);
            }
            break;
    }
}
#endif

static apr_status_t close_unix_socket(void *thefd)
{
    int fd = (int)((long)thefd);

    return close(fd);
}

/* deal with incomplete reads and signals
 * assume you really have to read buf_size bytes
 */
static apr_status_t sock_read(int fd, void *vbuf, size_t buf_size)
{
    char *buf = vbuf;
    int rc;
    size_t bytes_read = 0;

    do {
        do {
            rc = read(fd, buf + bytes_read, buf_size - bytes_read);
        } while (rc < 0 && errno == EINTR);
        switch(rc) {
        case -1:
            return errno;
        case 0: /* unexpected */
            return ECONNRESET;
        default:
            bytes_read += rc;
        }
    } while (bytes_read < buf_size);

    return APR_SUCCESS;
}

/* deal with signals
 */
static apr_status_t sock_write(int fd, const void *buf, size_t buf_size)
{
    int rc;

    do {
        rc = write(fd, buf, buf_size);
    } while (rc < 0 && errno == EINTR);
    if (rc < 0) {
        return errno;
    }

    return APR_SUCCESS;
}

static apr_status_t sock_writev(int fd, request_rec *r, int count, ...)
{
    va_list ap;
    int rc;
    struct iovec *vec;
    int i;

    vec = (struct iovec *)apr_palloc(r->pool, count * sizeof(struct iovec));
    va_start(ap, count);
    for (i = 0; i < count; i++) {
        vec[i].iov_base = va_arg(ap, caddr_t);
        vec[i].iov_len  = va_arg(ap, apr_size_t);
    }
    va_end(ap);

    do {
        rc = writev(fd, vec, count);
    } while (rc < 0 && errno == EINTR);
    if (rc < 0) {
        return errno;
    }

    return APR_SUCCESS;
}

static apr_status_t get_req(int fd, request_rec *r, char **argv0, char ***env,
                            cgid_req_t *req)
{
    int i;
    char **environ;
    core_request_config *temp_core;
    void **rconf;
    apr_status_t stat;

    r->server = apr_pcalloc(r->pool, sizeof(server_rec));

    /* read the request header */
    stat = sock_read(fd, req, sizeof(*req));
    if (stat != APR_SUCCESS) {
        return stat;
    }
    r->server->log.level = req->loglevel;
    if (req->req_type == GETPID_REQ) {
        /* no more data sent for this request */
        return APR_SUCCESS;
    }

    /* handle module indexes and such */
    rconf = (void **)ap_create_request_config(r->pool);

    temp_core = (core_request_config *)apr_palloc(r->pool, sizeof(core_module));
    rconf[AP_CORE_MODULE_INDEX] = (void *)temp_core;
    r->request_config = (ap_conf_vector_t *)rconf;
    ap_set_module_config(r->request_config, &cgid_module, (void *)&req->ugid);

    /* Read the filename, argv0, uri, and args */
    r->filename = apr_pcalloc(r->pool, req->filename_len + 1);
    *argv0 = apr_pcalloc(r->pool, req->argv0_len + 1);
    r->uri = apr_pcalloc(r->pool, req->uri_len + 1);
    if ((stat = sock_read(fd, r->filename, req->filename_len)) != APR_SUCCESS ||
        (stat = sock_read(fd, *argv0, req->argv0_len)) != APR_SUCCESS ||
        (stat = sock_read(fd, r->uri, req->uri_len)) != APR_SUCCESS) {
        return stat;
    }

    r->args = apr_pcalloc(r->pool, req->args_len + 1); /* empty string if no args */
    if (req->args_len) {
        if ((stat = sock_read(fd, r->args, req->args_len)) != APR_SUCCESS) {
            return stat;
        }
    }

    /* read the environment variables */
    environ = apr_pcalloc(r->pool, (req->env_count + 2) *sizeof(char *));
    for (i = 0; i < req->env_count; i++) {
        apr_size_t curlen;

        if ((stat = sock_read(fd, &curlen, sizeof(curlen))) != APR_SUCCESS) {
            return stat;
        }
        environ[i] = apr_pcalloc(r->pool, curlen + 1);
        if ((stat = sock_read(fd, environ[i], curlen)) != APR_SUCCESS) {
            return stat;
        }
    }
    *env = environ;

#ifdef AP_CGID_USE_RLIMIT
    if ((stat = sock_read(fd, &(req->limits), sizeof(cgid_rlimit_t))) != APR_SUCCESS)
         return stat;
#endif

    return APR_SUCCESS;
}

static apr_status_t send_req(int fd, request_rec *r, char *argv0, char **env,
                             int req_type)
{
    int i;
    cgid_req_t req = {0};
    apr_status_t stat;
    ap_unix_identity_t * ugid = ap_run_get_suexec_identity(r);
    core_dir_config *core_conf = ap_get_core_module_config(r->per_dir_config);


    if (ugid == NULL) {
        req.ugid = empty_ugid;
    } else {
        memcpy(&req.ugid, ugid, sizeof(ap_unix_identity_t));
    }

    req.req_type = req_type;
    req.ppid = parent_pid;
    req.conn_id = r->connection->id;
    for (req.env_count = 0; env[req.env_count]; req.env_count++) {
        continue;
    }
    req.filename_len = strlen(r->filename);
    req.argv0_len = strlen(argv0);
    req.uri_len = strlen(r->uri);
    req.args_len = r->args ? strlen(r->args) : 0;
    req.loglevel = r->server->log.level;

    /* Write the request header */
    if (req.args_len) {
        stat = sock_writev(fd, r, 5,
                           &req, sizeof(req),
                           r->filename, req.filename_len,
                           argv0, req.argv0_len,
                           r->uri, req.uri_len,
                           r->args, req.args_len);
    } else {
        stat = sock_writev(fd, r, 4,
                           &req, sizeof(req),
                           r->filename, req.filename_len,
                           argv0, req.argv0_len,
                           r->uri, req.uri_len);
    }

    if (stat != APR_SUCCESS) {
        return stat;
    }

    /* write the environment variables */
    for (i = 0; i < req.env_count; i++) {
        apr_size_t curlen = strlen(env[i]);

        if ((stat = sock_writev(fd, r, 2, &curlen, sizeof(curlen),
                                env[i], curlen)) != APR_SUCCESS) {
            return stat;
        }
    }
#if defined(RLIMIT_CPU) && defined(AP_CGID_USE_RLIMIT)
    if (core_conf->limit_cpu) {
        req.limits.limit_cpu = *(core_conf->limit_cpu);
        req.limits.limit_cpu_set = 1;
    }
    else {
        req.limits.limit_cpu_set = 0;
    }
#endif

#if defined(AP_CGID_USE_RLIMIT) && (defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_AS))
    if (core_conf->limit_mem) {
        req.limits.limit_mem = *(core_conf->limit_mem);
        req.limits.limit_mem_set = 1;
    }
    else {
        req.limits.limit_mem_set = 0;
    }

#endif

#if defined(RLIMIT_NPROC) && defined(AP_CGID_USE_RLIMIT)
    if (core_conf->limit_nproc) {
        req.limits.limit_nproc = *(core_conf->limit_nproc);
        req.limits.limit_nproc_set = 1;
    }
    else {
        req.limits.limit_nproc_set = 0;
    }
#endif

#ifdef AP_CGID_USE_RLIMIT
    if ( (stat = sock_write(fd, &(req.limits), sizeof(cgid_rlimit_t))) != APR_SUCCESS)
        return stat;
#endif

    return APR_SUCCESS;
}

static void daemon_signal_handler(int sig)
{
    if (sig == SIGHUP) {
        ++daemon_should_exit;
    }
}

static void cgid_child_errfn(apr_pool_t *pool, apr_status_t err,
                             const char *description)
{
    request_rec *r;
    void *vr;

    apr_pool_userdata_get(&vr, ERRFN_USERDATA_KEY, pool);
    r = vr;

    /* sure we got r, but don't call ap_log_rerror() because we don't
     * have r->headers_in and possibly other storage referenced by
     * ap_log_rerror()
     */
    ap_log_error(APLOG_MARK, APLOG_ERR, err, r->server, APLOGNO(01241) "%s", description);
}

static int cgid_server(void *data)
{
    int sd, sd2, rc;
    mode_t omask;
    apr_pool_t *ptrans;
    server_rec *main_server = data;
    apr_hash_t *script_hash = apr_hash_make(pcgi);
    apr_status_t rv;

    apr_pool_create(&ptrans, pcgi);

    apr_signal(SIGCHLD, SIG_IGN);
    apr_signal(SIGHUP, daemon_signal_handler);

    /* Close our copy of the listening sockets */
    ap_close_listeners();

    /* cgid should use its own suexec doer */
    ap_hook_get_suexec_identity(cgid_suexec_id_doer, NULL, NULL,
                                APR_HOOK_REALLY_FIRST);
    apr_hook_sort_all();

    if ((sd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
        ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server, APLOGNO(01242)
                     "Couldn't create unix domain socket");
        return errno;
    }

    omask = umask(0077); /* so that only Apache can use socket */
    rc = bind(sd, (struct sockaddr *)server_addr, server_addr_len);
    umask(omask); /* can't fail, so can't clobber errno */
    if (rc < 0) {
        ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server, APLOGNO(01243)
                     "Couldn't bind unix domain socket %s",
                     sockname);
        return errno;
    }

    /* Not all flavors of unix use the current umask for AF_UNIX perms */
    rv = apr_file_perms_set(sockname, APR_FPROT_UREAD|APR_FPROT_UWRITE|APR_FPROT_UEXECUTE);
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, main_server, APLOGNO(01244)
                     "Couldn't set permissions on unix domain socket %s",
                     sockname);
        return rv;
    }

    if (listen(sd, DEFAULT_CGID_LISTENBACKLOG) < 0) {
        ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server, APLOGNO(01245)
                     "Couldn't listen on unix domain socket");
        return errno;
    }

    if (!geteuid()) {
        if (chown(sockname, ap_unixd_config.user_id, -1) < 0) {
            ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server, APLOGNO(01246)
                         "Couldn't change owner of unix domain socket %s",
                         sockname);
            return errno;
        }
    }

    apr_pool_cleanup_register(pcgi, (void *)((long)sd),
                              close_unix_socket, close_unix_socket);

    /* if running as root, switch to configured user/group */
    if ((rc = ap_run_drop_privileges(pcgi, ap_server_conf)) != 0) {
        return rc;
    }

    while (!daemon_should_exit) {
        int errfileno = STDERR_FILENO;
        char *argv0 = NULL;
        char **env = NULL;
        const char * const *argv;
        apr_int32_t in_pipe;
        apr_int32_t out_pipe;
        apr_int32_t err_pipe;
        apr_cmdtype_e cmd_type;
        request_rec *r;
        apr_procattr_t *procattr = NULL;
        apr_proc_t *procnew = NULL;
        apr_file_t *inout;
        cgid_req_t cgid_req;
        apr_status_t stat;
        void *key;
        apr_socklen_t len;
        struct sockaddr_un unix_addr;

        apr_pool_clear(ptrans);

        len = sizeof(unix_addr);
        sd2 = accept(sd, (struct sockaddr *)&unix_addr, &len);
        if (sd2 < 0) {
#if defined(ENETDOWN)
            if (errno == ENETDOWN) {
                /* The network has been shut down, no need to continue. Die gracefully */
                ++daemon_should_exit;
            }
#endif
            if (errno != EINTR) {
                ap_log_error(APLOG_MARK, APLOG_ERR, errno,
                             (server_rec *)data, APLOGNO(01247)
                             "Error accepting on cgid socket");
            }
            continue;
        }

        r = apr_pcalloc(ptrans, sizeof(request_rec));
        procnew = apr_pcalloc(ptrans, sizeof(*procnew));
        r->pool = ptrans;
        stat = get_req(sd2, r, &argv0, &env, &cgid_req);
        if (stat != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, stat,
                         main_server, APLOGNO(01248)
                         "Error reading request on cgid socket");
            close(sd2);
            continue;
        }

        if (cgid_req.ppid != parent_pid) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, 0, main_server, APLOGNO(01249)
                         "CGI request received from wrong server instance; "
                         "see ScriptSock directive");
            close(sd2);
            continue;
        }

        if (cgid_req.req_type == GETPID_REQ) {
            pid_t pid;
            apr_status_t rv;

            pid = (pid_t)((long)apr_hash_get(script_hash, &cgid_req.conn_id, sizeof(cgid_req.conn_id)));
            rv = sock_write(sd2, &pid, sizeof(pid));
            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_ERR, rv,
                             main_server, APLOGNO(01250)
                             "Error writing pid %" APR_PID_T_FMT " to handler", pid);
            }
            close(sd2);
            continue;
        }

        apr_os_file_put(&r->server->error_log, &errfileno, 0, r->pool);
        apr_os_file_put(&inout, &sd2, 0, r->pool);

        if (cgid_req.req_type == SSI_REQ) {
            in_pipe  = APR_NO_PIPE;
            out_pipe = APR_FULL_BLOCK;
            err_pipe = APR_NO_PIPE;
            cmd_type = APR_SHELLCMD;
        }
        else {
            in_pipe  = APR_CHILD_BLOCK;
            out_pipe = APR_CHILD_BLOCK;
            err_pipe = APR_CHILD_BLOCK;
            cmd_type = APR_PROGRAM;
        }

        if (((rc = apr_procattr_create(&procattr, ptrans)) != APR_SUCCESS) ||
            ((cgid_req.req_type == CGI_REQ) &&
             (((rc = apr_procattr_io_set(procattr,
                                        in_pipe,
                                        out_pipe,
                                        err_pipe)) != APR_SUCCESS) ||
              /* XXX apr_procattr_child_*_set() is creating an unnecessary
               * pipe between this process and the child being created...
               * It is cleaned up with the temporary pool for this request.
               */
              ((rc = apr_procattr_child_err_set(procattr, r->server->error_log, NULL)) != APR_SUCCESS) ||
              ((rc = apr_procattr_child_in_set(procattr, inout, NULL)) != APR_SUCCESS))) ||
            ((rc = apr_procattr_child_out_set(procattr, inout, NULL)) != APR_SUCCESS) ||
            ((rc = apr_procattr_dir_set(procattr,
                                  ap_make_dirstr_parent(r->pool, r->filename))) != APR_SUCCESS) ||
            ((rc = apr_procattr_cmdtype_set(procattr, cmd_type)) != APR_SUCCESS) ||
#ifdef AP_CGID_USE_RLIMIT
#ifdef RLIMIT_CPU
        (  (cgid_req.limits.limit_cpu_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_CPU,
                                      &cgid_req.limits.limit_cpu)) != APR_SUCCESS)) ||
#endif
#if defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_AS)
        ( (cgid_req.limits.limit_mem_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_MEM,
                                      &cgid_req.limits.limit_mem)) != APR_SUCCESS)) ||
#endif
#ifdef RLIMIT_NPROC
        ( (cgid_req.limits.limit_nproc_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC,
                                      &cgid_req.limits.limit_nproc)) != APR_SUCCESS)) ||
#endif
#endif

            ((rc = apr_procattr_child_errfn_set(procattr, cgid_child_errfn)) != APR_SUCCESS)) {
            /* Something bad happened, tell the world.
             * ap_log_rerror() won't work because the header table used by
             * ap_log_rerror() hasn't been replicated in the phony r
             */
            ap_log_error(APLOG_MARK, APLOG_ERR, rc, r->server, APLOGNO(01251)
                         "couldn't set child process attributes: %s", r->filename);

            procnew->pid = 0; /* no process to clean up */
            close(sd2);
        }
        else {
            apr_pool_userdata_set(r, ERRFN_USERDATA_KEY, apr_pool_cleanup_null, ptrans);

            argv = (const char * const *)create_argv(r->pool, NULL, NULL, NULL, argv0, r->args);

           /* We want to close sd2 for the new CGI process too.
            * If it is left open it'll make ap_pass_brigade() block
            * waiting for EOF if CGI forked something running long.
            * close(sd2) here should be okay, as CGI channel
            * is already dup()ed by apr_procattr_child_{in,out}_set()
            * above.
            */
            close(sd2);

            if (memcmp(&empty_ugid, &cgid_req.ugid, sizeof(empty_ugid))) {
                /* We have a valid identity, and can be sure that
                 * cgid_suexec_id_doer will return a valid ugid
                 */
                rc = ap_os_create_privileged_process(r, procnew, argv0, argv,
                                                     (const char * const *)env,
                                                     procattr, ptrans);
            } else {
                rc = apr_proc_create(procnew, argv0, argv,
                                     (const char * const *)env,
                                     procattr, ptrans);
            }

            if (rc != APR_SUCCESS) {
                /* Bad things happened. Everyone should have cleaned up.
                 * ap_log_rerror() won't work because the header table used by
                 * ap_log_rerror() hasn't been replicated in the phony r
                 */
                ap_log_error(APLOG_MARK, APLOG_ERR, rc, r->server, APLOGNO(01252)
                             "couldn't create child process: %d: %s", rc,
                             apr_filepath_name_get(r->filename));

                procnew->pid = 0; /* no process to clean up */
            }
        }

        /* If the script process was created, remember the pid for
         * later cleanup.  If the script process wasn't created, clear
         * out any prior pid with the same key.
         *
         * We don't want to leak storage for the key, so only allocate
         * a key if the key doesn't exist yet in the hash; there are
         * only a limited number of possible keys (one for each
         * possible thread in the server), so we can allocate a copy
         * of the key the first time a thread has a cgid request.
         * Note that apr_hash_set() only uses the storage passed in
         * for the key if it is adding the key to the hash for the
         * first time; new key storage isn't needed for replacing the
         * existing value of a key.
         */

        if (apr_hash_get(script_hash, &cgid_req.conn_id, sizeof(cgid_req.conn_id))) {
            key = &cgid_req.conn_id;
        }
        else {
            key = apr_pmemdup(pcgi, &cgid_req.conn_id, sizeof(cgid_req.conn_id));
        }
        apr_hash_set(script_hash, key, sizeof(cgid_req.conn_id),
                     (void *)((long)procnew->pid));
    }
    return -1; /* should be <= 0 to distinguish from startup errors */
}

static int cgid_start(apr_pool_t *p, server_rec *main_server,
                      apr_proc_t *procnew)
{

    daemon_should_exit = 0; /* clear setting from previous generation */
    if ((daemon_pid = fork()) < 0) {
        ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server, APLOGNO(01253)
                     "mod_cgid: Couldn't spawn cgid daemon process");
        return DECLINED;
    }
    else if (daemon_pid == 0) {
        if (pcgi == NULL) {
            apr_pool_create(&pcgi, p);
        }
        exit(cgid_server(main_server) > 0 ? DAEMON_STARTUP_ERROR : -1);
    }
    procnew->pid = daemon_pid;
    procnew->err = procnew->in = procnew->out = NULL;
    apr_pool_note_subprocess(p, procnew, APR_KILL_AFTER_TIMEOUT);
#if APR_HAS_OTHER_CHILD
    apr_proc_other_child_register(procnew, cgid_maint, procnew, NULL, p);
#endif
    return OK;
}

static int cgid_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp)
{
    sockname = ap_append_pid(pconf, DEFAULT_SOCKET, ".");
    return OK;
}

static int cgid_init(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp,
                     server_rec *main_server)
{
    apr_proc_t *procnew = NULL;
    const char *userdata_key = "cgid_init";
    int ret = OK;
    void *data;

    root_server = main_server;
    root_pool = p;

    apr_pool_userdata_get(&data, userdata_key, main_server->process->pool);
    if (!data) {
        procnew = apr_pcalloc(main_server->process->pool, sizeof(*procnew));
        procnew->pid = -1;
        procnew->err = procnew->in = procnew->out = NULL;
        apr_pool_userdata_set((const void *)procnew, userdata_key,
                     apr_pool_cleanup_null, main_server->process->pool);
        return ret;
    }
    else {
        procnew = data;
    }

    if (ap_state_query(AP_SQ_MAIN_STATE) != AP_SQ_MS_CREATE_PRE_CONFIG) {
        char *tmp_sockname;

        parent_pid = getpid();
        tmp_sockname = ap_runtime_dir_relative(p, sockname);
        if (strlen(tmp_sockname) > sizeof(server_addr->sun_path) - 1) {
            tmp_sockname[sizeof(server_addr->sun_path)] = '\0';
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, main_server, APLOGNO(01254)
                        "The length of the ScriptSock path exceeds maximum, "
                        "truncating to %s", tmp_sockname);
        }
        sockname = tmp_sockname;

        server_addr_len = APR_OFFSETOF(struct sockaddr_un, sun_path) + strlen(sockname);
        server_addr = (struct sockaddr_un *)apr_palloc(p, server_addr_len + 1);
        server_addr->sun_family = AF_UNIX;
        strcpy(server_addr->sun_path, sockname);

        ret = cgid_start(p, main_server, procnew);
        if (ret != OK ) {
            return ret;
        }
        cgid_pfn_reg_with_ssi = APR_RETRIEVE_OPTIONAL_FN(ap_register_include_handler);
        cgid_pfn_gtv          = APR_RETRIEVE_OPTIONAL_FN(ap_ssi_get_tag_and_value);
        cgid_pfn_ps           = APR_RETRIEVE_OPTIONAL_FN(ap_ssi_parse_string);

        if ((cgid_pfn_reg_with_ssi) && (cgid_pfn_gtv) && (cgid_pfn_ps)) {
            /* Required by mod_include filter. This is how mod_cgid registers
             *   with mod_include to provide processing of the exec directive.
             */
            cgid_pfn_reg_with_ssi("exec", handle_exec);
        }
    }
    return ret;
}

static void *create_cgid_config(apr_pool_t *p, server_rec *s)
{
    cgid_server_conf *c =
    (cgid_server_conf *) apr_pcalloc(p, sizeof(cgid_server_conf));

    c->logname = NULL;
    c->logbytes = DEFAULT_LOGBYTES;
    c->bufbytes = DEFAULT_BUFBYTES;
    return c;
}

static void *merge_cgid_config(apr_pool_t *p, void *basev, void *overridesv)
{
    cgid_server_conf *base = (cgid_server_conf *) basev, *overrides = (cgid_server_conf *) overridesv;

    return overrides->logname ? overrides : base;
}

static void *create_cgid_dirconf(apr_pool_t *p, char *dummy)
{
    cgid_dirconf *c = (cgid_dirconf *) apr_pcalloc(p, sizeof(cgid_dirconf));
    return c;
}

static const char *set_scriptlog(cmd_parms *cmd, void *dummy, const char *arg)

{
    server_rec *s = cmd->server;
    cgid_server_conf *conf = ap_get_module_config(s->module_config,
                                                  &cgid_module);

    conf->logname = ap_server_root_relative(cmd->pool, arg);

    if (!conf->logname) {
        return apr_pstrcat(cmd->pool, "Invalid ScriptLog path ",
                           arg, NULL);
    }
    return NULL;
}