root/trunk/cgi.c

/*
FILE
        $Id$
LEGAL
        Public Domain
        
        Note most of this is public domain from ancient ncsa code
        examples. Figure out.
 
TODO    All cgi's should only use pointers to dynamically allocated
        memory items created herein.
        Should be reviewed for security issues: Buffer overflows, etc.

        Thanks Keith for poiting out a buffer overflow attack vector!
*/              


#include <stdio.h>
#include <string.h>
void *malloc(size_t size);
void *realloc(void *ptr, size_t size);

#include "cgi.h"

#define LF 10
#define CR 13

void getword(char *word, char *line, char stop) {
    int x = 0,y;

    for(x=0;((line[x]) && (line[x] != stop)) && x<127 ;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';
            word = (char *) realloc(word, ll+1);
            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 spacetoplus(char *str) {
    register int x;

    for(x=0;str[x];x++) if(str[x] == ' ') str[x] = '+';
}

void plustospace(char *str) {
    register int x;

    for(x=0;str[x];x++) if(str[x] == '+') str[x] = ' ';
}

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("&;`'\"|*?~<>^()[]{}$\\",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 */
        }
    }
}