mod_cgi.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

/* 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 "apr.h"
#include "apr_strings.h"
#include "apr_thread_proc.h"    /* for RLIMIT stuff */
#include "apr_optional.h"
#include "apr_buckets.h"
#include "apr_lib.h"
#include "apr_poll.h"

#define APR_WANT_STRFUNC
#define APR_WANT_MEMFUNC
#include "apr_want.h"

#define CORE_PRIVATE

#include "util_filter.h"
#include "ap_config.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 "mod_core.h"
#include "mod_cgi.h"

module AP_MODULE_DECLARE_DATA cgi_module;

static APR_OPTIONAL_FN_TYPE(ap_register_include_handler) *cgi_pfn_reg_with_ssi;
static APR_OPTIONAL_FN_TYPE(ap_ssi_get_tag_and_value) *cgi_pfn_gtv;
static APR_OPTIONAL_FN_TYPE(ap_ssi_parse_string) *cgi_pfn_ps;
static APR_OPTIONAL_FN_TYPE(ap_cgi_build_command) *cgi_build_command;

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

/* 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

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

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

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

    return c;
}

static void *merge_cgi_config(apr_pool_t *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, const char *arg)
{
    server_rec *s = cmd->server;
    cgi_server_conf *conf = ap_get_module_config(s->module_config,
                                                 &cgi_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;
}

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

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

static const command_rec cgi_cmds[] =
{
AP_INIT_TAKE1("ScriptLog", set_scriptlog, NULL, RSRC_CONF,
     "the name of a log for script debugging info"),
AP_INIT_TAKE1("ScriptLogLength", set_scriptlog_length, NULL, RSRC_CONF,
     "the maximum length (in bytes) of the script debug log"),
AP_INIT_TAKE1("ScriptLogBuffer", set_scriptlog_buffer, NULL, RSRC_CONF,
     "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,
                           apr_status_t rv, char *error)
{
    apr_file_t *f = NULL;
    apr_finfo_t finfo;
    char time_str[APR_CTIME_LEN];
    int log_flags = rv ? APLOG_ERR : APLOG_ERR;

    ap_log_rerror(APLOG_MARK, log_flags, rv, r,
                  "%s: %s", error, r->filename);

    /* XXX Very expensive mainline case! Open, then getfileinfo! */
    if (!conf->logname ||
        ((apr_stat(&finfo, conf->logname,
                   APR_FINFO_SIZE, r->pool) == APR_SUCCESS) &&
         (finfo.size > conf->logbytes)) ||
        (apr_file_open(&f, conf->logname,
                       APR_APPEND|APR_WRITE|APR_CREATE, APR_OS_DEFAULT,
                       r->pool) != APR_SUCCESS)) {
        return ret;
    }

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

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

    apr_file_close(f);
    return ret;
}

/* Soak up stderr from a script and redirect it to the error log.
 */
static apr_status_t log_script_err(request_rec *r, apr_file_t *script_err)
{
    char argsbuffer[HUGE_STRING_LEN];
    char *newline;
    apr_status_t rv;

    while ((rv = apr_file_gets(argsbuffer, HUGE_STRING_LEN,
                               script_err)) == APR_SUCCESS) {
        newline = strchr(argsbuffer, '\n');
        if (newline) {
            *newline = '\0';
        }
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      "%s", argsbuffer);
    }

    return rv;
}

static int log_script(request_rec *r, cgi_server_conf * conf, int ret,
                      char *dbuf, const char *sbuf, apr_bucket_brigade *bb,
                      apr_file_t *script_err)
{
    const apr_array_header_t *hdrs_arr = apr_table_elts(r->headers_in);
    const apr_table_entry_t *hdrs = (const apr_table_entry_t *) hdrs_arr->elts;
    char argsbuffer[HUGE_STRING_LEN];
    apr_file_t *f = NULL;
    apr_bucket *e;
    const char *buf;
    apr_size_t len;
    apr_status_t rv;
    int first;
    int i;
    apr_finfo_t finfo;
    char time_str[APR_CTIME_LEN];

    /* XXX Very expensive mainline case! Open, then getfileinfo! */
    if (!conf->logname ||
        ((apr_stat(&finfo, conf->logname,
                   APR_FINFO_SIZE, r->pool) == APR_SUCCESS) &&
         (finfo.size > conf->logbytes)) ||
        (apr_file_open(&f, conf->logname,
                       APR_APPEND|APR_WRITE|APR_CREATE, APR_OS_DEFAULT,
                       r->pool) != APR_SUCCESS)) {
        /* Soak up script output */
        discard_script_output(bb);
        log_script_err(r, script_err);
        return ret;
    }

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

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

    apr_file_puts("%response\n", f);
    hdrs_arr = apr_table_elts(r->err_headers_out);
    hdrs = (const apr_table_entry_t *) hdrs_arr->elts;

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

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

    first = 1;
    for (e = APR_BRIGADE_FIRST(bb);
         e != APR_BRIGADE_SENTINEL(bb);
         e = APR_BUCKET_NEXT(e))
    {
        if (APR_BUCKET_IS_EOS(e)) {
            break;
        }
        rv = apr_bucket_read(e, &buf, &len, APR_BLOCK_READ);
        if (rv != APR_SUCCESS || (len == 0)) {
            break;
        }
        if (first) {
            apr_file_puts("%stdout\n", f);
            first = 0;
        }
        apr_file_write(f, buf, &len);
        apr_file_puts("\n", f);
    }

    if (apr_file_gets(argsbuffer, HUGE_STRING_LEN, script_err) == APR_SUCCESS) {
        apr_file_puts("%stderr\n", f);
        apr_file_puts(argsbuffer, f);
        while (apr_file_gets(argsbuffer, HUGE_STRING_LEN,
                             script_err) == APR_SUCCESS) {
            apr_file_puts(argsbuffer, f);
        }
        apr_file_puts("\n", f);
    }

    apr_brigade_destroy(bb);
    apr_file_close(script_err);

    apr_file_close(f);
    return ret;
}


/* This is the special environment used for running the "exec cmd="
 *   variety of SSI directives.
 */
static void add_ssi_vars(request_rec *r)
{
    apr_table_t *e = r->subprocess_env;

    if (r->path_info && r->path_info[0] != '\0') {
        request_rec *pa_req;

        apr_table_setn(e, "PATH_INFO", ap_escape_shell_cmd(r->pool,
                                                           r->path_info));

        pa_req = ap_sub_req_lookup_uri(ap_escape_uri(r->pool, r->path_info),
                                       r, NULL);
        if (pa_req->filename) {
            apr_table_setn(e, "PATH_TRANSLATED",
                           apr_pstrcat(r->pool, pa_req->filename,
                                       pa_req->path_info, NULL));
        }
        ap_destroy_sub_req(pa_req);
    }

    if (r->args) {
        char *arg_copy = apr_pstrdup(r->pool, r->args);

        apr_table_setn(e, "QUERY_STRING", r->args);
        ap_unescape_url(arg_copy);
        apr_table_setn(e, "QUERY_STRING_UNESCAPED",
                       ap_escape_shell_cmd(r->pool, arg_copy));
    }
}

static void cgi_child_errfn(apr_pool_t *pool, apr_status_t err,
                            const char *description)
{
    apr_file_t *stderr_log;
    char errbuf[200];

    apr_file_open_stderr(&stderr_log, pool);
    /* Escape the logged string because it may be something that
     * came in over the network.
     */
    apr_file_printf(stderr_log,
                    "(%d)%s: %s\n",
                    err,
                    apr_strerror(err, errbuf, sizeof(errbuf)),
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
                    ap_escape_logitem(pool,
#endif
                    description
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
                    )
#endif
                    );
}

static apr_status_t run_cgi_child(apr_file_t **script_out,
                                  apr_file_t **script_in,
                                  apr_file_t **script_err,
                                  const char *command,
                                  const char * const argv[],
                                  request_rec *r,
                                  apr_pool_t *p,
                                  cgi_exec_info_t *e_info)
{
    const char * const *env;
    apr_procattr_t *procattr;
    apr_proc_t *procnew;
    apr_status_t rc = APR_SUCCESS;

#if defined(RLIMIT_CPU)  || defined(RLIMIT_NPROC) || \
    defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined (RLIMIT_AS)

    core_dir_config *conf = ap_get_module_config(r->per_dir_config,
                                                 &core_module);
#endif

#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

    RAISE_SIGSTOP(CGI_CHILD);
#ifdef DEBUG_CGI
    fprintf(dbg, "Attempting to exec %s as CGI child (argv0 = %s)\n",
            r->filename, argv[0]);
#endif

    env = (const char * const *)ap_create_environment(p, r->subprocess_env);

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

    /* Transmute ourselves into the script.
     * NB only ISINDEX scripts get decoded arguments.
     */
    if (((rc = apr_procattr_create(&procattr, p)) != APR_SUCCESS) ||
        ((rc = apr_procattr_io_set(procattr,