mod_cgi.c

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/* 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
 *
 * Apache adds some new env vars; REDIRECT_URL and REDIRECT_QUERY_STRING for
 * custom error responses, and DOCUMENT_ROOT because we found it useful.
 * It also adds SERVER_ADMIN - useful for scripts to know who to mail when 
 * they fail.
 */

#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 "http_conf_globals.h"

module MODULE_VAR_EXPORT cgi_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 = ap_table_get(r->notes, "alias-forced-type");
    return t && (!strcasecmp(t, "cgi-script"));
}

/* Configuration stuff */

#define DEFAULT_LOGBYTES 10385760
#define DEFAULT_BUFBYTES 1024

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

static void *create_cgi_config(pool *p, server_rec *s)
{
    cgi_server_conf *c =
    (cgi_server_conf *) ap_pcalloc(p, sizeof(cgi_server_conf));

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

    return c;
}

static void *merge_cgi_config(pool *p, void *basev, void *overridesv)
{
    cgi_server_conf *base = (cgi_server_conf *) basev, *overrides = (cgi_server_conf *) overridesv;

    return overrides->logname ? overrides : base;
}

static const char *set_scriptlog(cmd_parms *cmd, void *dummy, char *arg)
{
    server_rec *s = cmd->server;
    cgi_server_conf *conf =
    (cgi_server_conf *) ap_get_module_config(s->module_config, &cgi_module);

    conf->logname = arg;
    return NULL;
}

static const char *set_scriptlog_length(cmd_parms *cmd, void *dummy, char *arg)
{
    server_rec *s = cmd->server;
    cgi_server_conf *conf =
    (cgi_server_conf *) ap_get_module_config(s->module_config, &cgi_module);

    conf->logbytes = atol(arg);
    return NULL;
}

static const char *set_scriptlog_buffer(cmd_parms *cmd, void *dummy, char *arg)
{
    server_rec *s = cmd->server;
    cgi_server_conf *conf =
    (cgi_server_conf *) ap_get_module_config(s->module_config, &cgi_module);

    conf->bufbytes = atoi(arg);
    return NULL;
}

static const command_rec cgi_cmds[] =
{
    {"ScriptLog", set_scriptlog, NULL, RSRC_CONF, TAKE1,
     "the name of a log for script debugging info"},
    {"ScriptLogLength", set_scriptlog_length, NULL, RSRC_CONF, TAKE1,
     "the maximum length (in bytes) of the script debug log"},
    {"ScriptLogBuffer", set_scriptlog_buffer, NULL, RSRC_CONF, TAKE1,
     "the maximum size (in bytes) to record of a POST request"},
    {NULL}
};

static int log_scripterror(request_rec *r, cgi_server_conf * conf, int ret,
			   int show_errno, char *error)
{
    FILE *f;
    struct stat finfo;

    ap_log_rerror(APLOG_MARK, show_errno|APLOG_ERR, r, 
		"%s: %s", error, r->filename);

    if (!conf->logname ||
	((stat(ap_server_root_relative(r->pool, conf->logname), &finfo) == 0)
	 &&   (finfo.st_size > conf->logbytes)) ||
         ((f = ap_pfopen(r->pool, ap_server_root_relative(r->pool, conf->logname),
		      "a")) == NULL)) {
	return ret;
    }

    /* "%% [Wed Jun 19 10:53:21 1996] GET /cgi-bin/printenv HTTP/1.0" */
    fprintf(f, "%%%% [%s] %s %s%s%s %s\n", ap_get_time(), r->method, r->uri,
	    r->args ? "?" : "", r->args ? r->args : "", r->protocol);
    /* "%% 500 /usr/local/apache/cgi-bin */
    fprintf(f, "%%%% %d %s\n", ret, r->filename);

    fprintf(f, "%%error\n%s\n", error);

    ap_pfclose(r->pool, f);
    return ret;
}

static int log_script(request_rec *r, cgi_server_conf * conf, int ret,
		  char *dbuf, const char *sbuf, BUFF *script_in, BUFF *script_err)
{
    array_header *hdrs_arr = ap_table_elts(r->headers_in);
    table_entry *hdrs = (table_entry *) hdrs_arr->elts;
    char argsbuffer[HUGE_STRING_LEN];
    FILE *f;
    int i;
    struct stat finfo;

    if (!conf->logname ||
	((stat(ap_server_root_relative(r->pool, conf->logname), &finfo) == 0)
	 &&   (finfo.st_size > conf->logbytes)) ||
         ((f = ap_pfopen(r->pool, ap_server_root_relative(r->pool, conf->logname),
		      "a")) == NULL)) {
	/* Soak up script output */
	while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_in) > 0)
	    continue;
#if defined(WIN32) || defined(NETWARE)
        /* Soak up stderr and redirect it to the error log.
         * Script output to stderr is already directed to the error log
         * on Unix, thanks to the magic of fork().
         */
        while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, r, 
                          "%s", argsbuffer);            
        }
#else
	while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0)
	    continue;
#endif
	return ret;
    }

    /* "%% [Wed Jun 19 10:53:21 1996] GET /cgi-bin/printenv HTTP/1.0" */
    fprintf(f, "%%%% [%s] %s %s%s%s %s\n", ap_get_time(), r->method, r->uri,
	    r->args ? "?" : "", r->args ? r->args : "", r->protocol);
    /* "%% 500 /usr/local/apache/cgi-bin" */
    fprintf(f, "%%%% %d %s\n", ret, r->filename);

    fputs("%request\n", f);
    for (i = 0; i < hdrs_arr->nelts; ++i) {
	if (!hdrs[i].key)
	    continue;
	fprintf(f, "%s: %s\n", hdrs[i].key, hdrs[i].val);
    }
    if ((r->method_number == M_POST || r->method_number == M_PUT)
	&& dbuf && *dbuf) {
	fprintf(f, "\n%s\n", dbuf);
    }

    fputs("%response\n", f);
    hdrs_arr = ap_table_elts(r->err_headers_out);
    hdrs = (table_entry *) hdrs_arr->elts;

    for (i = 0; i < hdrs_arr->nelts; ++i) {
	if (!hdrs[i].key)
	    continue;
	fprintf(f, "%s: %s\n", hdrs[i].key, hdrs[i].val);
    }

    if (sbuf && *sbuf)
	fprintf(f, "%s\n", sbuf);

    if (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_in) > 0) {
	fputs("%stdout\n", f);
	fputs(argsbuffer, f);
	while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_in) > 0)
	    fputs(argsbuffer, f);
	fputs("\n", f);
    }

    if (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0) {
	fputs("%stderr\n", f);
	fputs(argsbuffer, f);
	while (ap_bgets(argsbuffer, HUGE_STRING_LEN, script_err) > 0)
	    fputs(argsbuffer, f);
	fputs("\n", f);
    }

    ap_bclose(script_in);
    ap_bclose(script_err);

    ap_pfclose(r->pool, f);
    return ret;
}

/****************************************************************
 *
 * Actual CGI handling...
 */


struct cgi_child_stuff {
#ifdef TPF
    TPF_FORK_CHILD t;
#endif
    request_rec *r;
    int nph;
    int debug;
    char *argv0;
};

static int cgi_child(void *child_stuff, child_info *pinfo)
{
    struct cgi_child_stuff *cld = (struct cgi_child_stuff *) child_stuff;
    request_rec *r = cld->r;
    char *argv0 = cld->argv0;
    int child_pid;

#ifdef DEBUG_CGI
#ifdef OS2
    /* Under OS/2 need to use device con. */
    FILE *dbg = fopen("con", "w");
#else
    FILE *dbg = fopen("/dev/tty", "w");
#endif
    int i;
#endif

    char **env;

    RAISE_SIGSTOP(CGI_CHILD);
#ifdef DEBUG_CGI
    fprintf(dbg, "Attempting to exec %s as %sCGI child (argv0 = %s)\n",
	    r->filename, cld->nph ? "NPH " : "", argv0);
#endif

    ap_add_cgi_vars(r);
    env = ap_create_environment(r->pool, r->subprocess_env);

#ifdef DEBUG_CGI
    fprintf(dbg, "Environment: \n");
    for (i = 0; env[i]; ++i)
	fprintf(dbg, "'%s'\n", env[i]);
#endif

#ifndef WIN32