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      1 /*	$NetBSD: cgi-bozo.c,v 1.56 2023/09/20 08:41:35 shm Exp $	*/
      2 
      3 /*	$eterna: cgi-bozo.c,v 1.40 2011/11/18 09:21:15 mrg Exp $	*/
      4 
      5 /*
      6  * Copyright (c) 1997-2021 Matthew R. Green
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer and
     16  *    dedication in the documentation and/or other materials provided
     17  *    with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  */
     32 
     33 /* this code implements CGI/1.2 for bozohttpd */
     34 
     35 #ifndef NO_CGIBIN_SUPPORT
     36 
     37 #include <sys/param.h>
     38 #include <sys/socket.h>
     39 
     40 #include <ctype.h>
     41 #include <errno.h>
     42 #include <paths.h>
     43 #include <signal.h>
     44 #include <stdlib.h>
     45 #include <string.h>
     46 #include <syslog.h>
     47 #include <unistd.h>
     48 #include <assert.h>
     49 
     50 #include <netinet/in.h>
     51 
     52 #include "bozohttpd.h"
     53 
     54 #define CGIBIN_PREFIX		"cgi-bin/"
     55 #define CGIBIN_PREFIX_LEN	(sizeof(CGIBIN_PREFIX)-1)
     56 
     57 #ifndef USE_ARG
     58 #define USE_ARG(x)	/*LINTED*/(void)&(x)
     59 #endif
     60 
     61 /*
     62  * given the file name, return a CGI interpreter
     63  */
     64 static const char *
     65 content_cgihandler(bozohttpd_t *httpd, bozo_httpreq_t *request,
     66 		   const char *file)
     67 {
     68 	bozo_content_map_t	*map;
     69 
     70 	USE_ARG(request);
     71 	debug((httpd, DEBUG_FAT, "content_cgihandler: trying file %s", file));
     72 	map = bozo_match_content_map(httpd, file, 0);
     73 	if (map)
     74 		return map->cgihandler;
     75 	return NULL;
     76 }
     77 
     78 static int
     79 parse_header(bozo_httpreq_t *request, const char *str, ssize_t len,
     80 	     char **hdr_str, char **hdr_val)
     81 {
     82 	struct	bozohttpd_t *httpd = request->hr_httpd;
     83 	char	*name, *value;
     84 
     85 	/* if the string passed is zero-length bail out */
     86 	if (*str == '\0')
     87 		return -1;
     88 
     89 	value = bozostrdup(httpd, request, str);
     90 
     91 	/* locate the ':' separator in the header/value */
     92 	name = bozostrnsep(&value, ":", &len);
     93 
     94 	if (NULL == name || -1 == len) {
     95 		free(value);
     96 		return -1;
     97 	}
     98 
     99 	/* skip leading space/tab */
    100 	while (*value == ' ' || *value == '\t')
    101 		len--, value++;
    102 
    103 	*hdr_str = name;
    104 	*hdr_val = value;
    105 
    106 	return 0;
    107 }
    108 
    109 /*
    110  * handle parsing a CGI header output, transposing a Status: header
    111  * into the HTTP reply (ie, instead of "200 OK").
    112  */
    113 static void
    114 finish_cgi_output(bozohttpd_t *httpd, bozo_httpreq_t *request, int in, int nph)
    115 {
    116 	char	buf[BOZO_WRSZ];
    117 	char	*str;
    118 	ssize_t	len;
    119 	ssize_t rbytes;
    120 	SIMPLEQ_HEAD(, bozoheaders)	headers;
    121 	bozoheaders_t *hdr, *nhdr;
    122 	int	write_header, nheaders = 0;
    123 
    124 	/* much of this code is like bozo_read_request()'s header loop. */
    125 	SIMPLEQ_INIT(&headers);
    126 	write_header = nph == 0;
    127 	while (nph == 0 &&
    128 		(str = bozodgetln(httpd, in, &len, bozo_read)) != NULL) {
    129 		char	*hdr_name, *hdr_value;
    130 
    131 		if (parse_header(request, str, len, &hdr_name, &hdr_value))
    132 			break;
    133 
    134 		/*
    135 		 * The CGI 1.{1,2} spec both say that if the cgi program
    136 		 * returns a `Status:' header field then the server MUST
    137 		 * return it in the response.  If the cgi program does
    138 		 * not return any `Status:' header then the server should
    139 		 * respond with 200 OK.
    140 		 * The CGI 1.1 and 1.2 specification differ slightly on
    141 		 * this in that v1.2 says that the script MUST NOT return a
    142 		 * `Status:' header if it is returning a `Location:' header.
    143 		 * For compatibility we are going with the CGI 1.1 behavior.
    144 		 */
    145 		if (strcasecmp(hdr_name, "status") == 0) {
    146 			debug((httpd, DEBUG_OBESE,
    147 				"%s: writing HTTP header "
    148 				"from status %s ..", __func__, hdr_value));
    149 			bozo_printf(httpd, "%s %s\r\n", request->hr_proto,
    150 				    hdr_value);
    151 			bozo_flush(httpd, stdout);
    152 			write_header = 0;
    153 			free(hdr_name);
    154 			break;
    155 		}
    156 
    157 		hdr = bozomalloc(httpd, sizeof *hdr);
    158 		hdr->h_header = hdr_name;
    159 		hdr->h_value = hdr_value;
    160 		SIMPLEQ_INSERT_TAIL(&headers, hdr, h_next);
    161 		nheaders++;
    162 	}
    163 
    164 	if (write_header) {
    165 		debug((httpd, DEBUG_OBESE,
    166 			"%s: writing HTTP header ..", __func__));
    167 		bozo_printf(httpd,
    168 			"%s 200 OK\r\n", request->hr_proto);
    169 		bozo_flush(httpd, stdout);
    170 	}
    171 
    172 	if (nheaders) {
    173 		debug((httpd, DEBUG_OBESE,
    174 			"%s:  writing delayed HTTP headers ..", __func__));
    175 		SIMPLEQ_FOREACH_SAFE(hdr, &headers, h_next, nhdr) {
    176 			bozo_printf(httpd, "%s: %s\r\n", hdr->h_header,
    177 				    hdr->h_value);
    178 			free(hdr->h_header);
    179 			free(hdr);
    180 		}
    181 		bozo_printf(httpd, "\r\n");
    182 		bozo_flush(httpd, stdout);
    183 	}
    184 
    185 	/* CGI programs should perform their own timeouts */
    186 	while ((rbytes = read(in, buf, sizeof buf)) > 0) {
    187 		ssize_t wbytes;
    188 
    189 		while (rbytes) {
    190 			wbytes = bozo_write(httpd, STDOUT_FILENO, buf,
    191 					    (size_t)rbytes);
    192 			if (wbytes > 0)
    193 				rbytes -= wbytes;
    194 			else
    195 				bozoerr(httpd, 1,
    196 					"cgi output write failed: %s",
    197 					strerror(errno));
    198 		}
    199 	}
    200 }
    201 
    202 static void
    203 append_index_html(bozohttpd_t *httpd, char **url)
    204 {
    205 	*url = bozorealloc(httpd, *url,
    206 			strlen(*url) + strlen(httpd->index_html) + 1);
    207 	strcat(*url, httpd->index_html);
    208 	debug((httpd, DEBUG_NORMAL,
    209 		"append_index_html: url adjusted to `%s'", *url));
    210 }
    211 
    212 /* This function parse search-string according to section 4.4 of RFC3875 */
    213 static char **
    214 parse_search_string(bozo_httpreq_t *request, const char *query, size_t *args_len)
    215 {
    216 	struct	bozohttpd_t *httpd = request->hr_httpd;
    217 	size_t i;
    218 	char *s, *str, **args;
    219 
    220 	*args_len = 0;
    221 
    222 	/* URI MUST not contain any unencoded '=' - RFC3875, section 4.4 */
    223 	if (strchr(query, '='))
    224 		return NULL;
    225 
    226 	str = bozostrdup(httpd, request, query);
    227 
    228 	/*
    229 	 * there's no more arguments than '+' chars in the query string as it's
    230 	 * the separator
    231 	 */
    232 	*args_len = 1;
    233 	/* count '+' in str */
    234 	for (s = str; (s = strchr(s, '+')) != NULL; (*args_len)++)
    235 		s++;
    236 
    237 	args = bozomalloc(httpd, sizeof(*args) * (*args_len + 1));
    238 
    239 	args[0] = str;
    240 	args[*args_len] = NULL;
    241 	for (s = str, i = 1; (s = strchr(s, '+')) != NULL; i++) {
    242 		*s = '\0';
    243 		s++;
    244 		args[i] = s;
    245 	}
    246 
    247 	/*
    248 	 * check if search-strings are valid:
    249 	 *
    250 	 * RFC3875, section 4.4:
    251 	 *
    252 	 * search-string = search-word *( "+" search-word )
    253 	 * search-word   = 1*schar
    254 	 * schar		 = unreserved | escaped | xreserved
    255 	 * xreserved	 = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "," |
    256 	 *		   "$"
    257 	 *
    258 	 * section 2.3:
    259 	 *
    260 	 * hex	      = digit | "A" | "B" | "C" | "D" | "E" | "F" | "a" |
    261 	 *		"b" | "c" | "d" | "e" | "f"
    262 	 * escaped    = "%" hex hex
    263 	 * unreserved = alpha | digit | mark
    264 	 * mark	      = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
    265 	 *
    266 	 * section 2.2:
    267 	 *
    268 	 * alpha	= lowalpha | hialpha
    269 	 * lowalpha	= "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" |
    270 	 *		  "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" |
    271 	 *		  "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" |
    272 	 *		  "y" | "z"
    273 	 * hialpha	= "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" |
    274 	 *		  "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" |
    275 	 *		  "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" |
    276 	 *	          "Y" | "Z"
    277 	 * digit        = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
    278 	 *		  "8" | "9"
    279 	 */
    280 #define	UNRESERVED_CHAR	"-_.!~*'()"
    281 #define	XRESERVED_CHAR	";/?:@&=,$"
    282 
    283 	for (i = 0; i < *args_len; i++) {
    284 		s = args[i];
    285 		/* search-word MUST have at least one schar */
    286 		if (*s == '\0')
    287 			goto parse_err;
    288 		while (*s) {
    289 			/* check if it's unreserved */
    290 			if (isalpha((unsigned char)*s) ||
    291 			    isdigit((unsigned char)*s) ||
    292 			    strchr(UNRESERVED_CHAR, *s)) {
    293 				s++;
    294 				continue;
    295 			}
    296 
    297 			/* check if it's escaped */
    298 			if (*s == '%') {
    299 				if (s[1] == '\0' || s[2] == '\0')
    300 					goto parse_err;
    301 				if (!isxdigit((unsigned char)s[1]) ||
    302 				    !isxdigit((unsigned char)s[2]))
    303 					goto parse_err;
    304 				s += 3;
    305 				continue;
    306 			}
    307 
    308 			/* check if it's xreserved */
    309 
    310 			if (strchr(XRESERVED_CHAR, *s)) {
    311 				s++;
    312 				continue;
    313 			}
    314 
    315 			goto parse_err;
    316 		}
    317 	}
    318 
    319 	/* decode percent encoding */
    320 	for (i = 0; i < *args_len; i++) {
    321 		if (bozo_decode_url_percent(request, args[i]))
    322 			goto parse_err;
    323 	}
    324 
    325 	/* allocate each arg separately */
    326 	for (i = 0; i < *args_len; i++)
    327 		args[i] = bozostrdup(httpd, request, args[i]);
    328 	free(str);
    329 
    330 	return args;
    331 
    332 parse_err:
    333 
    334 	free(str);
    335 	free(args);
    336 	*args_len = 0;
    337 
    338 	return NULL;
    339 
    340 }
    341 
    342 void
    343 bozo_cgi_setbin(bozohttpd_t *httpd, const char *path)
    344 {
    345 	httpd->cgibin = bozostrdup(httpd, NULL, path);
    346 	debug((httpd, DEBUG_OBESE, "cgibin (cgi-bin directory) is %s",
    347 	       httpd->cgibin));
    348 }
    349 
    350 /* help build up the environ pointer */
    351 void
    352 bozo_setenv(bozohttpd_t *httpd, const char *env, const char *val,
    353 		char **envp)
    354 {
    355 	char *s1 = bozomalloc(httpd, strlen(env) + strlen(val) + 2);
    356 
    357 	strcpy(s1, env);
    358 	strcat(s1, "=");
    359 	strcat(s1, val);
    360 	debug((httpd, DEBUG_OBESE, "bozo_setenv: %s", s1));
    361 	*envp = s1;
    362 }
    363 
    364 /*
    365  * Checks if the request has asked for a cgi-bin.  Should only be called if
    366  * cgibin is set.  If it starts CGIBIN_PREFIX or has a ncontent handler,
    367  * process the cgi, otherwise just return.  Returns 0 if it did not handle
    368  * the request.
    369  */
    370 int
    371 bozo_process_cgi(bozo_httpreq_t *request)
    372 {
    373 	bozohttpd_t *httpd = request->hr_httpd;
    374 	char	buf[BOZO_WRSZ];
    375 	char	date[40];
    376 	bozoheaders_t *headp;
    377 	const char *type, *clen, *info, *cgihandler;
    378 	char	*query, *s, *t, *path, *env, *command, *file, *url;
    379 	char	**envp, **curenvp, **argv, **search_string_argv = NULL;
    380 	char	**lastenvp;
    381 	char	*uri;
    382 	size_t	i, len, search_string_argc = 0;
    383 	ssize_t rbytes;
    384 	pid_t	pid;
    385 	int	envpsize, ix, nph;
    386 	int	sv[2];
    387 
    388 	if (!httpd->cgibin && !httpd->process_cgi)
    389 		return 0;
    390 
    391 #ifndef NO_USER_SUPPORT
    392 	if (request->hr_user && !httpd->enable_cgi_users)
    393 		return 0;
    394 #endif /* !NO_USER_SUPPORT */
    395 
    396 	if (request->hr_oldfile && strcmp(request->hr_oldfile, "/") != 0)
    397 		uri = request->hr_oldfile;
    398 	else
    399 		uri = request->hr_file;
    400 
    401 	if (uri[0] == '/')
    402 		file = bozostrdup(httpd, request, uri);
    403 	else
    404 		bozoasprintf(httpd, &file, "/%s", uri);
    405 
    406 	if (request->hr_query && strlen(request->hr_query))
    407 		query = bozostrdup(httpd, request, request->hr_query);
    408 	else
    409 		query = NULL;
    410 
    411 	bozoasprintf(httpd, &url, "%s%s%s",
    412 		     file,
    413 		     query ? "?" : "",
    414 		     query ? query : "");
    415 	debug((httpd, DEBUG_NORMAL, "%s: url `%s'", __func__, url));
    416 
    417 	path = NULL;
    418 	envp = NULL;
    419 	cgihandler = NULL;
    420 	command = NULL;
    421 	info = NULL;
    422 
    423 	len = strlen(url);
    424 
    425 	if (bozo_auth_check(request, url + 1))
    426 		goto out;
    427 
    428 	if (!httpd->cgibin ||
    429 	    strncmp(url + 1, CGIBIN_PREFIX, CGIBIN_PREFIX_LEN) != 0) {
    430 		cgihandler = content_cgihandler(httpd, request, file + 1);
    431 		if (cgihandler == NULL) {
    432 			debug((httpd, DEBUG_FAT,
    433 				"%s: no handler, returning", __func__));
    434 			goto out;
    435 		}
    436 		if (len == 0 || file[len - 1] == '/')
    437 			append_index_html(httpd, &file);
    438 		debug((httpd, DEBUG_NORMAL, "%s: cgihandler `%s'",
    439 		    __func__, cgihandler));
    440 	} else if (len - 1 == CGIBIN_PREFIX_LEN)	/* url is "/cgi-bin/" */
    441 		append_index_html(httpd, &file);
    442 
    443 	/* RFC3875 sect. 4.4. - search-string support */
    444 	if (query != NULL) {
    445 		search_string_argv = parse_search_string(request, query,
    446 		    &search_string_argc);
    447 	}
    448 
    449 	debug((httpd, DEBUG_NORMAL, "parse_search_string args no: %zu",
    450 	    search_string_argc));
    451 	for (i = 0; i < search_string_argc; i++) {
    452 		debug((httpd, DEBUG_FAT,
    453 		    "search_string[%zu]: `%s'", i, search_string_argv[i]));
    454 	}
    455 
    456 	argv = bozomalloc(httpd, sizeof(*argv) * (3 + search_string_argc));
    457 
    458 	ix = 0;
    459 	if (cgihandler) {
    460 		command = file + 1;
    461 		path = bozostrdup(httpd, request, cgihandler);
    462 	} else {
    463 		command = file + CGIBIN_PREFIX_LEN + 1;
    464 		if ((s = strchr(command, '/')) != NULL) {
    465 			info = bozostrdup(httpd, request, s);
    466 			*s = '\0';
    467 		}
    468 		path = bozomalloc(httpd,
    469 				strlen(httpd->cgibin) + 1 + strlen(command) + 1);
    470 		strcpy(path, httpd->cgibin);
    471 		strcat(path, "/");
    472 		strcat(path, command);
    473 	}
    474 
    475 	argv[ix++] = path;
    476 
    477 	/* copy search-string args */
    478 	for (i = 0; i < search_string_argc; i++)
    479 		argv[ix++] = search_string_argv[i];
    480 
    481 	argv[ix++] = NULL;
    482 	nph = strncmp(command, "nph-", 4) == 0;
    483 
    484 	type = request->hr_content_type;
    485 	clen = request->hr_content_length;
    486 
    487 	envpsize = 13 + request->hr_nheaders +
    488 	    (info && *info ? 1 : 0) +
    489 	    (query && *query ? 1 : 0) +
    490 	    (type && *type ? 1 : 0) +
    491 	    (clen && *clen ? 1 : 0) +
    492 	    (request->hr_remotehost && *request->hr_remotehost ? 1 : 0) +
    493 	    (request->hr_remoteaddr && *request->hr_remoteaddr ? 1 : 0) +
    494 	    (cgihandler ? 1 : 0) +
    495 	    bozo_auth_cgi_count(request) +
    496 	    (request->hr_serverport && *request->hr_serverport ? 1 : 0);
    497 
    498 	debug((httpd, DEBUG_FAT,
    499 		"%s: path `%s', cmd `%s', info `%s', "
    500 		"query `%s', nph `%d', envpsize `%d'", __func__,
    501 		path, command, strornull(info),
    502 		strornull(query), nph, envpsize));
    503 
    504 	envp = bozomalloc(httpd, sizeof(*envp) * envpsize);
    505 	for (ix = 0; ix < envpsize; ix++)
    506 		envp[ix] = NULL;
    507 	curenvp = envp;
    508 	lastenvp = envp + envpsize;
    509 
    510 	SIMPLEQ_FOREACH(headp, &request->hr_headers, h_next) {
    511 		const char *s2;
    512 		env = bozomalloc(httpd, 6 + strlen(headp->h_header) + 1 +
    513 		    strlen(headp->h_value));
    514 
    515 		t = env;
    516 		strcpy(t, "HTTP_");
    517 		t += strlen(t);
    518 		for (s2 = headp->h_header; *s2; t++, s2++)
    519 			if (islower((unsigned char)*s2))
    520 				*t = toupper((unsigned char)*s2);
    521 			else if (*s2 == '-')
    522 				*t = '_';
    523 			else
    524 				*t = *s2;
    525 		*t = '\0';
    526 		debug((httpd, DEBUG_OBESE, "setting header %s as %s = %s",
    527 		    headp->h_header, env, headp->h_value));
    528 		bozo_setenv(httpd, env, headp->h_value, curenvp++);
    529 		free(env);
    530 	}
    531 
    532 #ifndef _PATH_DEFPATH
    533 #define _PATH_DEFPATH "/usr/bin:/bin"
    534 #endif
    535 
    536 	bozo_setenv(httpd, "PATH", _PATH_DEFPATH, curenvp++);
    537 	bozo_setenv(httpd, "IFS", " \t\n", curenvp++);
    538 	bozo_setenv(httpd, "SERVER_NAME", BOZOHOST(httpd,request), curenvp++);
    539 	bozo_setenv(httpd, "GATEWAY_INTERFACE", "CGI/1.1", curenvp++);
    540 	bozo_setenv(httpd, "SERVER_PROTOCOL", request->hr_proto, curenvp++);
    541 	bozo_setenv(httpd, "REQUEST_METHOD", request->hr_methodstr, curenvp++);
    542 	bozo_setenv(httpd, "SCRIPT_NAME", file, curenvp++);
    543 	bozo_setenv(httpd, "SCRIPT_FILENAME", file + 1, curenvp++);
    544 	bozo_setenv(httpd, "SERVER_SOFTWARE", httpd->server_software,
    545 			curenvp++);
    546 	bozo_setenv(httpd, "REQUEST_URI", uri, curenvp++);
    547 	bozo_setenv(httpd, "DATE_GMT", bozo_http_date(date, sizeof(date)),
    548 			curenvp++);
    549 	/* RFC3875 section 4.1.7 says that QUERY_STRING MUST be defined. */
    550 	if (query && *query)
    551 		bozo_setenv(httpd, "QUERY_STRING", query, curenvp++);
    552 	else
    553 		bozo_setenv(httpd, "QUERY_STRING", "", curenvp++);
    554 	if (info && *info)
    555 		bozo_setenv(httpd, "PATH_INFO", info, curenvp++);
    556 	if (type && *type)
    557 		bozo_setenv(httpd, "CONTENT_TYPE", type, curenvp++);
    558 	if (clen && *clen)
    559 		bozo_setenv(httpd, "CONTENT_LENGTH", clen, curenvp++);
    560 	if (request->hr_serverport && *request->hr_serverport)
    561 		bozo_setenv(httpd, "SERVER_PORT", request->hr_serverport,
    562 				curenvp++);
    563 	if (request->hr_remotehost && *request->hr_remotehost)
    564 		bozo_setenv(httpd, "REMOTE_HOST", request->hr_remotehost,
    565 				curenvp++);
    566 	if (request->hr_remoteaddr && *request->hr_remoteaddr)
    567 		bozo_setenv(httpd, "REMOTE_ADDR", request->hr_remoteaddr,
    568 				curenvp++);
    569 	/*
    570 	 * Apache does this when invoking content handlers, and PHP
    571 	 * 5.3 requires it as a "security" measure.
    572 	 */
    573 	if (cgihandler)
    574 		bozo_setenv(httpd, "REDIRECT_STATUS", "200", curenvp++);
    575 	bozo_auth_cgi_setenv(request, &curenvp);
    576 
    577 	debug((httpd, DEBUG_FAT, "%s: going exec %s with args:", __func__,
    578 	    path));
    579 
    580 	for (i = 0; argv[i] != NULL; i++) {
    581 		debug((httpd, DEBUG_FAT, "%s: argv[%zu] = `%s'", __func__,
    582 		    i, argv[i]));
    583 	}
    584 
    585 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sv) == -1)
    586 		bozoerr(httpd, 1, "child socketpair failed: %s",
    587 				strerror(errno));
    588 
    589 	*curenvp = 0;
    590 	assert(lastenvp > curenvp);
    591 
    592 	/*
    593 	 * We create 2 procs: one to become the CGI, one read from
    594 	 * the CGI and output to the network, and this parent will
    595 	 * continue reading from the network and writing to the
    596 	 * CGI procsss.
    597 	 */
    598 	switch (fork()) {
    599 	case -1: /* eep, failure */
    600 		bozoerr(httpd, 1, "child fork failed: %s", strerror(errno));
    601 		/*NOTREACHED*/
    602 	case 0:
    603 		close(sv[0]);
    604 		dup2(sv[1], STDIN_FILENO);
    605 		dup2(sv[1], STDOUT_FILENO);
    606 		close(2);
    607 		close(sv[1]);
    608 		closelog();
    609 		bozo_daemon_closefds(httpd);
    610 
    611 		if (-1 == execve(path, argv, envp)) {
    612 			int saveerrno = errno;
    613 			bozo_http_error(httpd, 404, request,
    614 				"Cannot execute CGI");
    615 			/* don't log easy to trigger events */
    616 			if (saveerrno != ENOENT &&
    617 			    saveerrno != EISDIR &&
    618 			    saveerrno != EACCES)
    619 				bozoerr(httpd, 1, "child exec failed: %s: %s",
    620 				      path, strerror(saveerrno));
    621 			_exit(1);
    622 		}
    623 		/* NOT REACHED */
    624 		bozoerr(httpd, 1, "child execve returned?!");
    625 	}
    626 
    627 	free(query);
    628 	free(file);
    629 	free(url);
    630 	for (i = 0; i < search_string_argc; i++)
    631 		free(search_string_argv[i]);
    632 	free(search_string_argv);
    633 
    634 	close(sv[1]);
    635 
    636 	/* parent: read from stdin (bozo_read()) write to sv[0] */
    637 	/* child: read from sv[0] (bozo_write()) write to stdout */
    638 	pid = fork();
    639 	if (pid == -1)
    640 		bozoerr(httpd, 1, "io child fork failed: %s", strerror(errno));
    641 	else if (pid == 0) {
    642 		/* child reader/writer */
    643 		close(STDIN_FILENO);
    644 		finish_cgi_output(httpd, request, sv[0], nph);
    645 		/* if we do SSL, send a SSL_shutdown now */
    646 		bozo_ssl_shutdown(request->hr_httpd);
    647 		/* if we're done output, our parent is useless... */
    648 		kill(getppid(), SIGKILL);
    649 		debug((httpd, DEBUG_FAT, "done processing cgi output"));
    650 		_exit(0);
    651 	}
    652 	close(STDOUT_FILENO);
    653 
    654 	/* CGI programs should perform their own timeouts */
    655 	while ((rbytes = bozo_read(httpd, STDIN_FILENO, buf, sizeof buf)) > 0) {
    656 		ssize_t wbytes;
    657 
    658 		while (rbytes) {
    659 			wbytes = write(sv[0], buf, (size_t)rbytes);
    660 			if (wbytes > 0)
    661 				rbytes -= wbytes;
    662 			else
    663 				bozoerr(httpd, 1, "write failed: %s",
    664 					strerror(errno));
    665 		}
    666 	}
    667 	debug((httpd, DEBUG_FAT, "done processing cgi input"));
    668 	exit(0);
    669 
    670  out:
    671 
    672 	for (i = 0; i < search_string_argc; i++)
    673 		free(search_string_argv[i]);
    674 	free(search_string_argv);
    675 	free(query);
    676 	free(file);
    677 	free(url);
    678 	return 0;
    679 }
    680 
    681 #ifndef NO_DYNAMIC_CONTENT
    682 /* cgi maps are simple ".postfix /path/to/prog" */
    683 void
    684 bozo_add_content_map_cgi(bozohttpd_t *httpd, const char *arg,
    685                          const char *cgihandler)
    686 {
    687 	bozo_content_map_t *map;
    688 
    689 	debug((httpd, DEBUG_NORMAL, "bozo_add_content_map_cgi: name %s cgi %s",
    690 		arg, cgihandler));
    691 
    692 	httpd->process_cgi = 1;
    693 
    694 	map = bozo_get_content_map(httpd, arg);
    695 	map->name = arg;
    696 	map->type = map->encoding = map->encoding11 = NULL;
    697 	map->cgihandler = cgihandler;
    698 }
    699 #endif /* NO_DYNAMIC_CONTENT */
    700 
    701 #endif /* NO_CGIBIN_SUPPORT */
    702