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/*
* getcgivars.c - routine to read CGI input variables into an array.
*
* Copyright 2002 Jonathan McDowell <noodles@earth.li>
*
* The x2c() and unescape_url() routines were lifted directly
* from NCSA's sample program util.c, packaged with their HTTPD.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include "getcgi.h"
/**
* txt2html - Takes a string and converts it to HTML.
* @string: The string to HTMLize.
*
* Takes a string and escapes any HTML entities.
*/
char *txt2html(const char *string)
{
static char buf[1024];
char *ptr = NULL;
char *nextptr = NULL;
memset(buf, 0, 1024);
ptr = strchr(string, '<');
if (ptr != NULL) {
nextptr = ptr + 1;
*ptr = 0;
strncpy(buf, string, 1023);
strncat(buf, "<", 1023 - strlen(buf));
string = nextptr;
}
ptr = strchr(string, '>');
if (ptr != NULL) {
nextptr = ptr + 1;
*ptr = 0;
strncat(buf, string, 1023 - strlen(buf));
strncat(buf, ">", 1023 - strlen(buf));
string = nextptr;
}
/*
* TODO: We need to while() this really as each entity may appear more
* than once. We need to start with & and ; as we replace with those
* throughout. Fuck it for the moment though; it's Easter and < & > are
* the most common and tend to only appear once.
*/
strncat(buf, string, 1023 - strlen(buf));
return buf;
}
/*
* start_html - Start HTML output.
* @title: The title for the HTML.
*
* Takes a title string and starts HTML output, including the
* Content-Type header all the way up to <BODY>.
*/
void start_html(const char *title)
{
puts("Content-Type: text/html; charset=UTF-8\n");
puts("<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 3.2 Final//EN'>");
puts("<HTML>");
puts("<HEAD>");
printf("<TITLE>%s</TITLE>\n", title);
puts("</HEAD>");
puts("<BODY>");
return;
}
/*
* end_html - End HTML output.
*
* Ends HTML output - closes the BODY and HTML tags.
*/
void end_html(void)
{
puts("</BODY>");
puts("</HTML>");
return;
}
/* Convert a two-char hex string into the char it represents */
char x2c(const char *what)
{
register char digit;
digit = (what[0] >= 'A' ? ((what[0] & 0xdf) - 'A')+10 :
(what[0] - '0'));
digit *= 16;
digit += (what[1] >= 'A' ? ((what[1] & 0xdf) - 'A')+10 :
(what[1] - '0'));
return(digit);
}
/* Reduce any %xx escape sequences to the characters they represent */
void unescape_url(char *url)
{
register int i,j;
for(i=0,j=0; url[j]; ++i,++j) {
if((url[i] = url[j]) == '%') {
url[i]=x2c(&url[j+1]);
j+=2;
}
}
url[i] = '\0';
}
/* Read the CGI input and place all name/val pairs into list. */
/* Returns list containing name1, value1, name2, value2, ... , NULL */
char **getcgivars(int argc, char *argv[])
{
int i;
char *request_method;
int content_length, paircount;
char *cgiinput = NULL;
char **cgivars = NULL;
char **pairlist = NULL;
char *nvpair,*eqpos;
/* Depending on the request method, read all CGI input into cgiinput */
/* (really should produce HTML error messages, instead of exit()ing) */
request_method = getenv("REQUEST_METHOD");
if (request_method == NULL) {
if (argc > 1) {
cgiinput = strdup(argv[1]);
} else {
return NULL;
}
} else if (strlen(request_method)==0) {
return NULL;
} else if (!strcmp(request_method, "GET") ||
!strcmp(request_method, "HEAD")) {
cgiinput=strdup(getenv("QUERY_STRING"));
} else if (!strcmp(request_method, "POST")) {
if (getenv("CONTENT_TYPE") != NULL &&
strcasecmp(getenv("CONTENT_TYPE"),
"application/x-www-form-urlencoded")) {
printf("getcgivars(): Unsupported Content-Type.\n");
exit(1);
}
if (!(content_length = atoi(getenv("CONTENT_LENGTH")))) {
printf("getcgivars(): No Content-Length was sent with"
" the POST request.\n");
exit(1);
}
if (!(cgiinput= (char *) malloc(content_length+1))) {
printf("getcgivars(): Could not malloc for "
"cgiinput.\n");
exit(1);
}
if (!fread(cgiinput, content_length, 1, stdin)) {
printf("Couldn't read CGI input from STDIN.\n");
exit(1);
}
cgiinput[content_length]='\0';
} else {
printf("getcgivars(): unsupported REQUEST_METHOD\n");
exit(1);
}
/* Change all plusses back to spaces */
for(i=0; cgiinput[i]; i++) if (cgiinput[i]=='+') cgiinput[i] = ' ';
/* First, split on "&" to extract the name-value pairs into pairlist */
pairlist= malloc(256*sizeof(char *));
paircount=0;
nvpair=strtok(cgiinput, "&");
while (nvpair) {
pairlist[paircount++]= strdup(nvpair) ;
if (!(paircount%256)) {
pairlist= realloc(pairlist,
(paircount+256)*sizeof(char *));
}
nvpair=strtok(NULL, "&") ;
}
pairlist[paircount]=0; /* terminate the list with NULL */
/* Then, from the list of pairs, extract the names and values */
cgivars= malloc((paircount*2+1)*sizeof(char *));
for (i=0; i<paircount; i++) {
if ((eqpos=strchr(pairlist[i], '='))!=NULL) {
*eqpos='\0';
unescape_url(cgivars[i*2+1]=strdup(eqpos+1));
} else {
unescape_url(cgivars[i*2+1]=strdup(""));
}
unescape_url(cgivars[i*2]= strdup(pairlist[i])) ;
}
cgivars[paircount*2]=NULL; /* terminate the list with NULL */
/* Free anything that needs to be freed */
free(cgiinput);
for (i=0; pairlist[i]; i++) free(pairlist[i]);
free(pairlist);
/* Return the list of name-value strings */
return cgivars;
}
/**
* cleanupcgi - free the memory allocated for our CGI parameters.
* @cgivars: The CGI parameter list to free.
*
* Frees up the elements of the CGI parameter array and then frees the
* array.
*/
void cleanupcgi(char **cgivars)
{
int i;
if (cgivars != NULL) {
for (i = 0; cgivars[i] != NULL; i++) {
free(cgivars[i]);
cgivars[i] = NULL;
}
free(cgivars);
cgivars = NULL;
}
return;
}
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