minix/commands/simple/passwd.c
2009-11-09 10:26:00 +00:00

260 lines
5 KiB
C

/* passwd - change a passwd Author: Adri Koppes */
/* chfn, chsh - change full name, shell Added by: Kees J. Bot */
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <signal.h>
#include <pwd.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <sys/stat.h>
#include <minix/minlib.h>
#include <stdio.h>
_PROTOTYPE(void report, (char *label));
_PROTOTYPE(void quit, (int ex_stat));
_PROTOTYPE(void fatal, (char *label));
_PROTOTYPE(void usage, (void));
_PROTOTYPE(int goodchars, (char *s));
_PROTOTYPE(int main, (int argc, char **argv));
char pw_file[] = "/etc/passwd";
char sh_file[] = "/etc/shadow";
char pw_tmp[] = "/etc/ptmp";
char bad[] = "Permission denied\n";
char buf[1024];
enum action {
PASSWD, CHFN, CHSH
} action = PASSWD;
char *arg0;
void report(label)
char *label;
{
int e = errno;
fprintf(stderr, "%s: ", arg0);
fflush(stderr);
errno = e;
perror(label);
}
void quit(ex_stat)
int ex_stat;
{
if (unlink(pw_tmp) < 0 && errno != ENOENT) {
report(pw_tmp);
ex_stat = 1;
}
exit(ex_stat);
}
void fatal(label)
char *label;
{
report(label);
quit(1);
}
void usage()
{
static char *usages[] = {
"passwd [user]\n",
"chfn [user] fullname\n",
"chsh [user] shell\n"
};
std_err(usages[(int) action]);
exit(1);
}
int goodchars(s)
char *s;
{
int c;
while ((c = *s++) != 0) {
if (c == ':' || c < ' ' || c >= 127) return(0);
}
return(1);
}
int main(argc, argv)
int argc;
char *argv[];
{
int uid, cn, n;
int fd_pwd, fd_tmp;
FILE *fp_tmp;
time_t salt;
struct passwd *pwd;
char *name, pwname[9], oldpwd[9], newpwd[9], newcrypted[14], sl[2];
char *argn;
int shadow = 0;
if ((arg0 = strrchr(argv[0], '/')) != 0)
arg0++;
else
arg0 = argv[0];
if (strcmp(arg0, "chfn") == 0)
action = CHFN;
else if (strcmp(arg0, "chsh") == 0)
action = CHSH;
uid = getuid();
n = action == PASSWD ? 1 : 2;
if (argc != n && argc != n + 1) usage();
if (argc == n) {
pwd = getpwuid(uid);
strcpy(pwname, pwd->pw_name);
name = pwname;
} else {
name = argv[1];
pwd = getpwnam(name);
}
if (pwd == NULL || ((uid != pwd->pw_uid) && uid != 0)) {
std_err(bad);
exit(1);
}
switch (action) {
case PASSWD:
if (pwd->pw_passwd[0] == '#' && pwd->pw_passwd[1] == '#') {
/* The password is found in the shadow password file. */
shadow = 1;
strncpy(pwname, pwd->pw_passwd + 2, 8);
pwname[8] = 0;
name = pwname;
setpwfile(sh_file);
if ((pwd= getpwnam(name)) == NULL) {
std_err(bad);
exit(1);
}
printf("Changing the shadow password of %s\n", name);
} else {
printf("Changing the password of %s\n", name);
}
oldpwd[0] = 0;
if (pwd->pw_passwd[0] != '\0' && uid != 0) {
strcpy(oldpwd, getpass("Old password:"));
if (strcmp(pwd->pw_passwd, crypt(oldpwd, pwd->pw_passwd)) != 0)
{
std_err(bad);
exit(1);
}
}
for (;;) {
strcpy(newpwd, getpass("New password:"));
if (newpwd[0] == '\0')
std_err("Password cannot be null");
else if (strcmp(newpwd, getpass("Retype password:")) != 0)
std_err("Passwords don't match");
else
break;
std_err(", try again\n");
}
time(&salt);
sl[0] = (salt & 077) + '.';
sl[1] = ((salt >> 6) & 077) + '.';
for (cn = 0; cn < 2; cn++) {
if (sl[cn] > '9') sl[cn] += 7;
if (sl[cn] > 'Z') sl[cn] += 6;
}
strcpy(newcrypted, crypt(newpwd, sl));
break;
case CHFN:
case CHSH:
argn = argv[argc - 1];
if (strlen(argn) > (action == CHFN ? 80 : 60) || !goodchars(argn)) {
std_err(bad);
exit(1);
}
}
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
umask(0);
n = 10;
while ((fd_tmp = open(pw_tmp, O_RDWR | O_CREAT | O_EXCL, 0400)) < 0) {
if (errno != EEXIST) fatal("Can't create temporary file");
if (n-- > 0) {
sleep(2);
} else {
fprintf(stderr, "Password file busy, try again later.\n");
exit(1);
}
}
if ((fp_tmp = fdopen(fd_tmp, "w+")) == NULL) fatal(pw_tmp);
setpwent();
while ((pwd = getpwent()) != 0) {
if (strcmp(name, pwd->pw_name) == 0) {
switch (action) {
case PASSWD:
pwd->pw_passwd = newcrypted;
break;
case CHFN:
pwd->pw_gecos = argn;
break;
case CHSH:
pwd->pw_shell = argn;
break;
}
}
if (strcmp(pwd->pw_shell, "/bin/sh") == 0
|| strcmp(pwd->pw_shell, "/usr/bin/sh") == 0
)
pwd->pw_shell = "";
fprintf(fp_tmp, "%s:%s:%s:",
pwd->pw_name,
pwd->pw_passwd,
itoa(pwd->pw_uid)
);
if (ferror(fp_tmp)) fatal(pw_tmp);
fprintf(fp_tmp, "%s:%s:%s:%s\n",
itoa(pwd->pw_gid),
pwd->pw_gecos,
pwd->pw_dir,
pwd->pw_shell
);
if (ferror(fp_tmp)) fatal(pw_tmp);
}
endpwent();
if (fflush(fp_tmp) == EOF) fatal(pw_tmp);
if (lseek(fd_tmp, (off_t) 0, SEEK_SET) != 0)
fatal("Can't reread temp file");
if ((fd_pwd = open(shadow ? sh_file : pw_file, O_WRONLY | O_TRUNC)) < 0)
fatal("Can't recreate password file");
while ((n = read(fd_tmp, buf, sizeof(buf))) != 0) {
if (n < 0 || write(fd_pwd, buf, n) != n) {
report("Error rewriting password file, tell root!");
exit(1);
}
}
close(fd_tmp);
close(fd_pwd);
quit(0);
}