/*
 * htpasswd.c: simple program for manipulating password file for NCSA httpd
 * 
 * Rob McCool
 */

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <sys/signal.h>
#include <stdlib.h>
#include <time.h>

#define LF 10
#define CR 13

#define MAX_STRING_LEN 256

char *tn;

char *strd(char *s) {
    char *d;

    d=(char *)malloc(strlen(s) + 1);
    strcpy(d,s);
    return(d);
}

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

    for(x=0;((line[x]) && (line[x] != stop));x++)
        word[x] = line[x];

    word[x] = '\0';

    while(line[x] && line[++x]!=stop);
    if (line[x]) x++;
    while(line[y++] = line[x++]);
}

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 putline(FILE *f,char *l) {
    int x;

    for(x=0;l[x];x++) fputc(l[x],f);
    fputc('\n',f);
}


/* From local_passwd.c (C) Regents of Univ. of California blah blah */
static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
        "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

to64(s, v, n)
  register char *s;
  register long v;
  register int n;
{
    while (--n >= 0) {
        *s++ = itoa64[v&0x3f];
        v >>= 6;
    }
}

char *crypt(char *pw, char *salt); /* why aren't these prototyped in include */

void add_password(char *user, char *rest, FILE *f, char *pw) {
    char *cpw, salt[3];

    (void)srand((int)time((time_t *)NULL));
    to64(&salt[0],rand(),2);
    cpw = crypt(pw,salt);
    fprintf(f,"%s:%s:%s\n",user,cpw,rest);
}

void usage() {
    fprintf(stderr,"Usage: change_pw passwordfile username password\n");
    exit(1);
}

void interrupted() {
    fprintf(stderr,"Interrupted.\n");
    if(tn) unlink(tn);
    exit(1);
}

main(int argc, char *argv[]) {
    FILE *tfp,*f;
    char user[MAX_STRING_LEN];
    char line[MAX_STRING_LEN];
    char l[MAX_STRING_LEN];
    char w[MAX_STRING_LEN];
    char command[MAX_STRING_LEN];
    int found;

    tn = NULL;
    signal(SIGINT,(void (*)())interrupted);

    if (argc!=3) usage;

    tn = tmpnam(NULL);
    if(!(tfp = fopen(tn,"w"))) {
        fprintf(stderr,"Could not open temp file.\n");
        exit(1);
    }

    if(!(f = fopen(argv[1],"r"))) {
        fprintf(stderr,
                "Could not open passwd file %s for reading.\n",argv[1]);
        exit(1);
    }
    strcpy(user,argv[2]);

    found = 0;
    while(!(getline(line,MAX_STRING_LEN,f))) {
        if(found || (line[0] == '#') || (!line[0])) {
            putline(tfp,line);
            continue;
        }
        strcpy(l,line);
        getword(w,l,':');
        if(strcmp(user,w)) {
            putline(tfp,line);
            continue;
        } else {
            printf("Pa&szlig;wort f&uuml;r Nutzer %s wurde ge&auml;ndert.\n",user);
            if (strcmp(argv[3],"*")) {
		    add_password(user,l,tfp,argv[3]);
            } else {
		    fprintf(tfp,"%s:*:%s\n",user,l);
            }
            found = 1;
        }
    }
    if(!found) {
        printf("Nutzer %s existiert nicht.\n",user);
    }
    fclose(f);
    fclose(tfp);
    sprintf(command,"cp %s %s",tn,argv[1]);
    system(command);
    unlink(tn);
}