date and time created 83/02/11 15:45:15 by rrh

[unix-history] / usr / src / usr.bin / su / su.c

#ifndef lint
static char *sccsid = "@(#)su.c 4.4 (Berkeley) 4.4";
#endif

#include <stdio.h>
#include <pwd.h>

struct  passwd *pwd,*getpwnam();
char    *crypt();
char    *getpass();

main(argc,argv)
       int argc;
       char **argv;
{
       char *nptr = "root";
       char *password;
       char *shell = "/bin/sh";

       if (argc > 1)
               nptr = argv[1];
       if ((pwd = getpwnam(nptr)) == NULL) {
               printf("Unknown id: %s\n",nptr);
               exit(1);
       }
       if (pwd->pw_passwd[0] == '\0' || getuid() == 0)
               goto ok;
       password = getpass("Password:");
       if (strcmp(pwd->pw_passwd, crypt(password, pwd->pw_passwd)) != 0) {
               printf("Sorry\n");
               if (pwd->pw_uid == 0) {
                       FILE *console = fopen("/dev/console", "w");
                       if (console != NULL) {
                               fprintf(console, "BADSU: %s %s\r\n",
                                       getlogin(), ttyname(2));
                               fclose(console);
                       }
               }
               exit(2);
       }
ok:
       endpwent();
       if (pwd->pw_uid == 0) {
               FILE *console = fopen("/dev/console", "w");
               if (console != NULL) {
                       fprintf(console, "SU: %s %s\r\n",
                               getlogin(), ttyname(2));
                       fclose(console);
               }
       }
       if (setgid(pwd->pw_gid) < 0) {
               perror("su: setgid");
               exit(3);
       }
       if (initgroups(nptr, pwd->pw_gid)) {
               fprintf(stderr, "su: initgroups failed\n");
               exit(4);
       }
       if (setuid(pwd->pw_uid) < 0) {
               perror("su: setuid");
               exit(5);
       }
       if (pwd->pw_shell && *pwd->pw_shell)
               shell = pwd->pw_shell;
       homeis(pwd->pw_dir);
       shellis(shell);
       execl(shell, "su", 0);
       printf("No shell\n");
       exit(3);
}

char    **environ;

homeis(hp)
       char *hp;
{
       register char *cp, *dp;
       register char **ep = environ;
       static char homebuf[128];

       while (dp = *ep++) {
               for (cp = "HOME"; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0)) {
                       strcpy(homebuf, "HOME=");
                       strcat(homebuf, hp);
                       *--ep = homebuf;
                       return;
               }
       }
}

shellis(sp)
       char *sp;
{
       register char *cp, *dp;
       register char **ep = environ;
       static char shellbuf[128];

       while (dp = *ep++) {
               for (cp = "SHELL"; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0)) {
                       strcpy(shellbuf, "SHELL=");
                       strcat(shellbuf, sp);
                       *--ep = shellbuf;
                       return;
               }
       }
}