BSD 4 release

[unix-history] / usr / src / cmd / chsh.c

static char *sccsid = "@(#)chsh.c       4.1 (Berkeley) 10/1/80";
/*
* chsh
*/
#include <stdio.h>
#include <signal.h>
#include <pwd.h>

char    passwd[] = "/etc/passwd";
char    temp[]   = "/etc/ptmp";
struct  passwd *pwd;
struct  passwd *getpwent();
int     endpwent();
char    *crypt();
char    *getpass();
char    *pw;
char    pwbuf[10];
char    buf[BUFSIZ];

main(argc, argv)
char *argv[];
{
       char *p;
       int i;
       char saltc[2];
       long salt;
       int u,fi,fo;
       int insist;
       int ok, flags;
       int c;
       int pwlen;
       FILE *tf;

       insist = 0;
       if(argc < 2 || argc > 3) {
               printf("Usage: chsh user [ /bin/oldcsh ] [ /bin/csh ]\n");
               goto bex;
       }
       if (argc == 2)
               argv[2] = "";
       else if (strcmp(argv[2], "/bin/oldcsh") && strcmp(argv[2], "/bin/csh") && getuid()) {
               printf("Only /bin/oldcsh or /bin/csh may be specified\n");
               exit(1);
       }
       while((pwd=getpwent()) != NULL){
               if(strcmp(pwd->pw_name,argv[1]) == 0){
                       u = getuid();
                       if(u!=0 && u != pwd->pw_uid){
                               printf("Permission denied.\n");
                               goto bex;
                               }
                       break;
                       }
               }
       endpwent();
       signal(SIGHUP, 1);
       signal(SIGINT, 1);
       signal(SIGQUIT, 1);
       signal(SIGTSTP, 1);

       if(access(temp, 0) >= 0) {
               printf("Temporary file busy -- try again\n");
               goto bex;
       }
       if((tf=fopen(temp,"w")) == NULL) {
               printf("Cannot create temporary file\n");
               goto bex;
       }

/*
*      copy passwd to temp, replacing matching lines
*      with new shell.
*/

       while((pwd=getpwent()) != NULL) {
               if(strcmp(pwd->pw_name,argv[1]) == 0) {
                       u = getuid();
                       if(u != 0 && u != pwd->pw_uid) {
                               printf("Permission denied.\n");
                               goto out;
                       }
                       pwd->pw_shell = argv[2];
               }
               fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n",
                       pwd->pw_name,
                       pwd->pw_passwd,
                       pwd->pw_uid,
                       pwd->pw_gid,
                       pwd->pw_gecos,
                       pwd->pw_dir,
                       pwd->pw_shell);
       }
       endpwent();
       fclose(tf);

/*
*      copy temp back to passwd file
*/

       if((fi=open(temp,0)) < 0) {
               printf("Temp file disappeared!\n");
               goto out;
       }
       if((fo=creat(passwd, 0644)) < 0) {
               printf("Cannot recreat passwd file.\n");
               goto out;
       }
       while((u=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,u);

out:
       unlink(temp);

bex:
       exit(1);
}