2.9BSD - /usr/src/ucb/pwhash/src/cmd/chsh.c

   1:     char *sccsid[] = "@(#)chsh.c	2.4";
   2: /*
   3:  * chsh
   4:  */
   5: #include <whoami.h>
   6: #include <stdio.h>
   7: #include <signal.h>
   8: #include <pwd.h>
   9: 
  10: #define NSHELLS 2   /* Number of shells in valid list */
  11: #define SMLROOT     /* Not enough space in /etc for duplicate of passwd */
  12: 
  13: char    pwfile[] = "/etc/passwd";
  14: #ifndef SMLROOT
  15: char    temp[] = "/etc/ptmp";
  16: #else
  17: char    temp[] = "/tmp/pwdXXXXXX";
  18: #endif
  19: 
  20: char    *shells[NSHELLS] = {        /* First in list is default shell */
  21:         "/bin/csh",
  22:         "/bin/sh"
  23:     };
  24: char    *defsh;
  25: struct  passwd *pwd;
  26: struct  passwd *getpwent();
  27: int endpwent();
  28: char    *crypt();
  29: char    *getpass();
  30: char    buf[BUFSIZ];
  31: 
  32: main(argc, argv)
  33: char *argv[];
  34: {
  35:     int u,fi,fo;
  36:     int i;
  37:     FILE *tf;
  38: #ifdef UCB_GRPMAST
  39:     int g;
  40: #endif
  41: 
  42:     defsh = shells[0];
  43:     if(argc < 2 || argc > 3) {
  44:         printf("Usage: chsh user [ shell ]\n");
  45:         goto bex;
  46:     }
  47:     if (argc == 2)
  48:         argv[2] = defsh;
  49:     u = getuid();
  50: #ifdef UCB_GRPMAST
  51:     g = getgid();
  52: #endif
  53:     if (u) {
  54:         for (i=0; i<NSHELLS; i++)
  55:             if (!strcmp(argv[2], shells[i]))
  56:                 goto doit;
  57:         printf("Invalid shell.  Valid shells are:\n");
  58:         for(i=0; i<NSHELLS; i++)
  59:             printf("\t%s\n", shells[i]);
  60:         exit(1);
  61:     }
  62: 
  63:     doit:
  64:     if (!strcmp(argv[2], defsh))
  65:         argv[2] = "";
  66:     while((pwd=getpwent()) != NULL){
  67:         if(strcmp(pwd->pw_name,argv[1]) == 0){
  68:             if(u!=0 && u != pwd->pw_uid
  69: #ifdef UCB_GRPMAST
  70:                 && !(u==g && g==pwd->pw_gid)
  71: #endif
  72:                 ){
  73:                 printf("Permission denied.\n");
  74:                 goto bex;
  75:             }
  76:             if (u) {
  77:                 if (*pwd->pw_shell == '\0')
  78:                     pwd->pw_shell = defsh;
  79:                 for (i=0; i<NSHELLS; i++)
  80:                     if (!strcmp(pwd->pw_shell, shells[i]))
  81:                         goto ok;
  82:                 printf("Can't change shell for %s\n", pwd->pw_name);
  83:             }
  84:             ok:
  85:             break;
  86:             }
  87:         }
  88:     endpwent();
  89:     signal(SIGHUP, SIG_IGN);
  90:     signal(SIGINT, SIG_IGN);
  91:     signal(SIGQUIT, SIG_IGN);
  92: 
  93:     if (pwlock("w")) {
  94:         fprintf(stderr,"Password file busy -- try again");
  95:         goto bex;
  96:     }
  97: #ifdef SMLROOT
  98:     mktemp(temp);
  99: #endif
 100:     if((tf=fopen(temp,"w")) == NULL) {
 101:         printf("Cannot create temporary file\n");
 102:         goto bex;
 103:     }
 104: 
 105: /*
 106:  *	copy passwd to temp, replacing matching lines
 107:  *	with new shell.
 108:  */
 109: 
 110:     while((pwd=getpwent()) != NULL) {
 111:         if(strcmp(pwd->pw_name,argv[1]) == 0) {
 112:             u = getuid();
 113:             if(u!=0 && u != pwd->pw_uid
 114: #ifdef UCB_GRPMAST
 115:                 && !(u==g && g==pwd->pw_gid)
 116: #endif
 117:                 ){
 118:                 printf("Permission denied.\n");
 119:                 goto out;
 120:             }
 121:             pwd->pw_shell = argv[2];
 122:         }
 123:         fprintf(tf,"%s:%s:%u:%u:%s:%s:%s\n",
 124:             pwd->pw_name,
 125:             pwd->pw_passwd,
 126:             pwd->pw_uid,
 127:             pwd->pw_gid,
 128:             pwd->pw_gecos,
 129:             pwd->pw_dir,
 130:             pwd->pw_shell);
 131:     }
 132:     endpwent();
 133:     fclose(tf);
 134: 
 135: /*
 136:  *	copy temp back to passwd file
 137:  */
 138: 
 139:     if((fi=open(temp,0)) < 0) {
 140:         printf("Temp file disappeared!\n");
 141:         goto out;
 142:     }
 143:     if((fo=creat(pwfile, 0644)) < 0) {
 144:         printf("Cannot recreat passwd file.\n");
 145:         printf("Not removing temp file.\n");
 146:         goto bex;
 147:     }
 148:     while((u=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,u);
 149: 
 150: out:
 151:     unlink(temp);
 152:     pwunlock();
 153: 
 154: bex:
 155:     exit(1);
 156: }

Defined functions

Defined variables

Defined macros