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

#ifndef lint
static char *sccsid = "@(#)su.c 4.5 (Berkeley) %G%";
#endif

#include <stdio.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

char    userbuf[16]     = "USER=";
char    homebuf[128]    = "HOME=";
char    shellbuf[128]   = "SHELL=";
char    pathbuf[128]    = "PATH=:/usr/ucb:/bin:/usr/bin";
char    *cleanenv[] = { userbuf, homebuf, shellbuf, pathbuf, 0, 0 };
char    *user = "root";
char    *shell = "/bin/sh";
int     fulllogin;
int     fastlogin;

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

main(argc,argv)
       int argc;
       char *argv[];
{
       char *password;

again:
       if (argc > 1 && strcmp(argv[1], "-f") == 0) {
               fastlogin++;
               argc--, argv++;
               goto again;
       }
       if (argc > 1 && strcmp(argv[1], "-") == 0) {
               fulllogin++;
               argc--, argv++;
               goto again;
       }
       if (argc > 1 && argv[1][0] != '-') {
               user = argv[1];
               argc--, argv++;
       }
       if (strcmp(user, "root") == 0)
               setpriority(PRIO_PROCESS, 0, -2);
       if ((pwd = getpwnam(user)) == NULL) {
               fprintf(stderr, "Unknown login: %s\n", user);
               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) {
               fprintf(stderr, "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(user, 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;
       if (fulllogin) {
               cleanenv[4] = getenv("TERM");
               environ = cleanenv;
       }
       setenv("USER", pwd->pw_name, userbuf);
       setenv("SHELL", shell, shellbuf);
       setenv("HOME", pwd->pw_dir, homebuf);
       setpriority(PRIO_PROCESS, 0, 0);
       if (fastlogin) {
               *argv-- = "-f";
               *argv = "su";
       } else if (fulllogin) {
               if (chdir(pwd->pw_dir) < 0) {
                       fprintf(stderr, "No directory\n");
                       exit(6);
               }
               *argv = "-su";
       } else
               *argv = "su";
       execv(shell, argv);
       fprintf(stderr, "No shell\n");
       exit(7);
}

setenv(ename, eval, buf)
       char *ename, *eval, *buf;
{
       register char *cp, *dp;
       register char **ep = environ;

       /*
        * this assumes an environment variable "ename" already exists
        */
       while (dp = *ep++) {
               for (cp = ename; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0)) {
                       strcat(buf, eval);
                       *--ep = buf;
                       return;
               }
       }
}

char *
getenv(ename)
       char *ename;
{
       register char *cp, *dp;
       register char **ep = environ;

       while (dp = *ep++) {
               for (cp = ename; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0))
                       return (*--ep);
       }
       return ((char *)0);
}