moth/doc/2012-07-DC20/generalstatics.com/cgi.c

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2012-06-27 13:46:32 -06:00
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include "cgi.h"
#ifdef NODUMP
# define DUMPf(fmt, args...)
#else
# define DUMPf(fmt, args...) fprintf(stderr, "%s:%s:%d " fmt "\n", __FILE__, __FUNCTION__, __LINE__, ##args)
#endif
#define DUMP() DUMPf("")
#define DUMP_d(v) DUMPf("%s = %d", #v, v)
#define DUMP_x(v) DUMPf("%s = 0x%x", #v, v)
#define DUMP_s(v) DUMPf("%s = %s", #v, v)
#define DUMP_c(v) DUMPf("%s = '%c' (0x%02x)", #v, v, v)
#define DUMP_p(v) DUMPf("%s = %p", #v, v)
#define POST_MAX 1024
/*
* CGI
*/
static int is_cgi = 0;
static char **argv = NULL;
static int
read_char_argv()
{
static int arg = 0;
static char *p;
if (NULL == argv) {
return EOF;
}
if (0 == arg) {
arg = 1;
p = argv[1];
}
if (! p) {
return EOF;
} else if (! *p) {
arg += 1;
p = argv[arg];
return '&';
}
return *(p++);
}
static int
read_char_stdin()
{
static int inlen = -1;
if (-1 == inlen) {
char *p = getenv("CONTENT_LENGTH");
if (p) {
inlen = atoi(p);
if (inlen > POST_MAX) {
inlen = POST_MAX;
}
if (inlen < 0) {
inlen = 0;
}
} else {
inlen = 0;
}
}
if (inlen) {
inlen -= 1;
return getchar();
}
return EOF;
}
static int
read_char_query_string()
{
static char *p = (char *)-1;
if ((char *)-1 == p) {
p = getenv("QUERY_STRING");
}
if (! p) {
return EOF;
} else if (! *p) {
return EOF;
} else {
return *(p++);
}
}
static int (* read_char)() = read_char_argv;
int
cgi_init(char *global_argv[])
{
char *rm = getenv("REQUEST_METHOD");
if (! rm) {
read_char = read_char_argv;
argv = global_argv;
} else if (0 == strcmp(rm, "POST")) {
read_char = read_char_stdin;
is_cgi = 1;
} else if (0 == strcmp(rm, "GET")) {
read_char = read_char_query_string;
is_cgi = 1;
} else {
printf(("405 Method not allowed\r\n"
"Allow: GET, POST\r\n"
"Content-type: text/plain\r\n"
"\r\n"
"%s is not allowed.\n"),
rm);
return -1;
}
return 0;
}
static char
tonum(int c)
{
if ((c >= '0') && (c <= '9')) {
return c - '0';
}
if ((c >= 'a') && (c <= 'f')) {
return 10 + c - 'a';
}
if ((c >= 'A') && (c <= 'F')) {
return 10 + c - 'A';
}
return 0;
}
static char
read_hex()
{
int a = read_char();
int b = read_char();
return tonum(a)*16 + tonum(b);
}
/* Read a key or a value. Since & and = aren't supposed to appear
outside of boundaries, we can use the same function for both.
*/
size_t
cgi_item(char *str, size_t maxlen)
{
int c;
size_t pos = 0;
while (1) {
c = read_char();
switch (c) {
case EOF:
case '=':
case '&':
str[pos] = '\0';
return pos;
case '%':
c = read_hex();
break;
case '+':
c = ' ';
break;
}
if (pos < maxlen - 1) {
str[pos] = c;
pos += 1;
}
}
}
void
cgi_head(char *title)
{
if (is_cgi) {
printf("Content-type: text/html\r\n\r\n");
}
printf(("<!DOCTYPE html>\n"
"<html>\n"
" <head>\n"
" <title>%s</title>\n"
" </head>\n"
" <body>\n"
" <h1>%s</h1>\n"),
title, title);
}
void
cgi_foot()
{
printf("\n"
" </body>\n"
"</html>\n");
}
void
cgi_result(int code, char *desc, char *fmt, ...)
{
va_list ap;
if (is_cgi) {
printf("%d %s\r\n", code, desc);
}
cgi_head(desc);
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
cgi_foot();
exit(0);
}
void
cgi_page(char *title, char *fmt, ...)
{
va_list ap;
cgi_head(title);
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
cgi_foot();
exit(0);
}
void
cgi_error(char *text)
{
cgi_result(500, "Internal error", "<p>%s</p>", text);
}