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 */ } } }
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