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Appendix B. The echo Program
The following listing is echo.c
:
#include <stdio.h>
#include <stdlib.h>
#define MAX_ENTRIES 10000
typedef struct
{
char *name;
char *val;
} entry;
char *makeword(char *line, char stop);
char *fmakeword(FILE *f, char stop, int *len);
char x2c(char *what);
void unescape_url(char *url);
void plustospace(char *str);
int main(int argc, char *argv[])
{
entry entries[MAX_ENTRIES];
register int x,m=0;
int cl;
char mbuf[200];
printf("Content-type: text/html\n\n");
if(strcmp(getenv("REQUEST_METHOD"),"POST"))
{
printf("This script should be referenced with a METHOD of POST.\n");
exit(1);
}
if(strcmp(getenv("CONTENT_TYPE"),"application/x-www-form-urlencoded"))
{
printf("This script can only be used to decode form results. \n");
exit(1);
}
cl = atoi(getenv("CONTENT_LENGTH"));
// Returns the length of data to come.
for(x=0;cl && (!feof(stdin));x++)
{
m=x;
entries[x].val = fmakeword(stdin,'&',&cl);
plustospace(entries[x].val);
unescape_url(entries[x].val);
entries[x].name = makeword(entries[x].val,'=');
}
//Reads in the data, breaking at the "&" symbols
printf("<H1>Query Results</H1>");
//Sends the top of the return HTML document.
printf("You submitted the following name/value pairs:<p>%c",10);
printf("<ul>%c",10);
for(x=0; x <= m; x++)
printf("<li> <code>%s = %s</code>%c",entries[x].name,
entries[x].val,10);
//Lists the fields in the original form with the values filled in by
//the customer.
printf("</ul>%c",10);
}
This listing is the helper program
echo2.c:
#include <stdio.h>
#define CR 13
#define LF 10
void getword(char *word, char *line, char stop) {
int x = 0,y;
for(x=0;((line[x]) && (line[x] != stop));x++)
word[x] = line[x];
word[x] = '\0'.
if(line[x]) ++x;
y=0;
while(line[y++] = line[x++]);
}
char *makeword(char *line, char stop) {
int x = 0,y;
char *word = (char *) malloc(sizeof(char) * (strlen(line) + 1));
for(x=0;((line[x]) && (line[x] != stop));x++)
word[x] = line[x];
word[x] = '\0'.
if(line[x]) ++x;
y=0;
while(line[y++] = line[x++]);
return word;
}
char *fmakeword(FILE *f, char stop, int *cl) {
int wsize;
char *word;
int ll;
wsize = 102400;
ll=0;
word = (char *) malloc(sizeof(char) * (wsize + 1));
while(1) {
word[ll] = (char)fgetc(f);
if(ll==wsize) {
word[ll+1] = '\0'.
wsize+=102400;
word = (char *)realloc(word,sizeof(char)*(wsize+1));
}
--(*cl);
if((word[ll] == stop) || (feof(f)) || (!(*cl))) {
if(word[ll] != stop) ll++;
word[ll] = '\0'.
return word;
}
++ll;
}
}
char x2c(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);
}
void unescape_url(char *url) {
register int x,y;
for(x=0,y=0;url[y];++x,++y) {
if((url[x] = url[y]) == '%'. {
url[x] = x2c(&url[y+1]);
y+=2;
}
}
url[x] = '\0'.
}
void plustospace(char *str) {
register int x;
for(x=0;str[x];x++) if(str[x] == '+'. str[x] = ' ';
}
int rind(char *s, char c) {
register int x;
for(x=strlen(s) - 1;x != -1; x--)
if(s[x] == c) return x;
return -1;
}
int getline(char *s, int n, FILE *f) {
register int i=0;
while(1) {
s[i] = (char)fgetc(f);
if(s[i] == CR)
s[i] = fgetc(f);
if((s[i] == 0x4) || (s[i] == LF) || (i == (n-1))) {
s[i] = '\0'.
return (feof(f) ? 1 : 0);
}
++i;
}
}
void send_fd(FILE *f, FILE *fd)
{
int num_chars=0;
char c;
while (1) {
c = fgetc(f);
if(feof(f))
return;
fputc(c,fd);
}
}
int ind(char *s, char c) {
register int x;
for(x=0;s[x];x++)
if(s[x] == c) return x;
return -1;
}
void escape_shell_cmd(char *cmd) {
register int x,y,l;
l=strlen(cmd);
for(x=0;cmd[x];x++) {
if(ind("&;'.q\"|*?~<>^()[]{}$\\",cmd[x]) != -1){
for(y=l+1;y>x;y--)
cmd[y] = cmd[y-1];
l++; /* length has been increased */
cmd[x] = '\\'.
x++; /* skip the character */
}
}
}
 |  |  | | A. Support Organizations |  | C. NCSA and Apache Compatibility |
Copyright © 2001 O'Reilly & Associates. All rights reserved.
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