/********************************************************************** * Copyright (c) Digital Equipment Corporation 1984, 1985, 1986. * * All Rights Reserved. * * Reference "/usr/src/COPYRIGHT" for applicable restrictions. * **********************************************************************/ static char Sccsid[] = "@(#)chfn.c 3.0 4/22/86"; /* * Based on "@(#)chfn.c 4.3 (Berkeley) 5/18/83" */ /* * changefinger - change finger entries */ #include <stdio.h> #include <signal.h> #include <pwd.h> #include <ctype.h> #include <sys/types.h> struct default_values { char *name; char *office_num; char *office_phone; char *home_phone; }; char passwd[] = "/etc/passwd"; char temp[] = "/etc/ptmp"; struct passwd *pwd; struct passwd *getpwent(), *getpwnam(), *getpwuid(); int endpwent(); char *crypt(); char *getpass(); char buf[BUFSIZ]; main(argc, argv) int argc; char *argv[]; { int user_uid; unsigned num_bytes; int fi, fo; char replacement[4*BUFSIZ]; FILE *tf; if (argc > 2) { printf("Usage: chfn [user]\n"); exit(1); } /* * Error check to make sure the user (foolishly) typed their own name. */ user_uid = getuid(); if ((argc == 2) && (user_uid != 0)) { pwd = getpwnam(argv[1]); if (pwd == NULL) { printf("%s%s%s%s%s%s%s%s", "There is no account for ", argv[1], " on this machine.\n", "You probably mispelled your login name;\n", "only root is allowed to change another", " person's finger entry.\n", "Note: you do not need to type your login", " name as an argument.\n"); exit(1); } if (pwd->pw_uid != user_uid) { printf("%s%s", "You are not allowed to change another", " person's finger entry.\n"); exit(1); } } /* * If root is changing a finger entry, then find the uid that * corresponds to the user's login name. */ if ((argc == 2) && (user_uid == 0)) { pwd = getpwnam(argv[1]); if (pwd == NULL) { printf("There is no account for %s on this machine\n", argv[1]); exit(1); } user_uid = pwd->pw_uid; } if (argc == 1) { pwd = getpwuid(user_uid); if (pwd == NULL) { fprintf(stderr, "No passwd file entry!?\n"); exit(1); } } /* * Collect name, room number, school phone, and home phone. */ get_info(pwd->pw_gecos, replacement); /* * Update the entry in the password file. */ while (access(temp, 0) >= 0) { printf("Password file busy -- waiting for it to be free.\n"); sleep(10); } signal(SIGHUP, SIG_IGN); signal(SIGINT, SIG_IGN); signal(SIGQUIT, SIG_IGN); #ifdef SIGTSTP signal(SIGTSTP, SIG_IGN); #endif /* * Race condition -- the locking mechinism is not my idea (ns) */ if (access(temp, 0) >= 0) { printf("It's not your day! Password file is busy again.\n"); printf("Try again later.\n"); exit(1); } if ((tf=fopen(temp,"w")) == NULL) { printf("Cannot create temporary file\n"); exit(1); } /* * There is another race condition here: if the passwd file * has changed since the error checking at the beginning of the program, * then user_uid may not be in the file. Of course, the uid might have * been changed, but this is not supposed to happen. */ if (getpwuid(user_uid) == NULL) { printf("%s%d%s\n", "Passwd file has changed. Uid ", user_uid, " is no longer in the file!?"); goto out; } /* * copy passwd to temp, replacing matching line * with new finger entry (gecos field). */ while ((pwd=getpwent()) != NULL) { if (pwd->pw_uid == user_uid) { pwd->pw_gecos = replacement; } 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 password 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((num_bytes=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,num_bytes); out: unlink(temp); } /* * Get name, Work location, Work phone, and home phone. */ get_info(gecos_field, answer) char *gecos_field; char *answer; { char *strcpy(), *strcat(); char in_str[BUFSIZ]; struct default_values *defaults, *get_defaults(); answer[0] = '\0'; defaults = get_defaults(gecos_field); printf("Default values are printed inside of of '[]'.\n"); printf("To accept the default, type <return>.\n"); printf("To have a blank entry, type the word 'none'.\n"); /* * Get name. */ do { printf("\nName [%s]: ", defaults->name); fgets(in_str, BUFSIZ, stdin); if (special_case(in_str, defaults->name)) break; } while (ill_input(in_str)); strcpy(answer, in_str); /* * Get room number. */ do { printf("Office location [%s]: ", defaults->office_num); fgets(in_str, BUFSIZ, stdin); if (special_case(in_str, defaults->office_num)) break; } while (ill_input(in_str)); strcat(strcat(answer, ","), in_str); /* * Get office phone number. * Remove hyphens and 642, x2, or 2 prefixes if present. */ do { printf("Office Phone (Ex: 1632) [%s]: ", defaults->office_phone); fgets(in_str, BUFSIZ, stdin); if (special_case(in_str, defaults->office_phone)) break; remove_hyphens(in_str); if ((strlen(in_str) == 6) && (in_str[0] == 'x')) strcpy(in_str, in_str+1); } while (ill_input(in_str) || not_all_digits(in_str) || wrong_length(in_str)); strcat(strcat(answer, ","), in_str); /* * Get home phone number. * Remove hyphens if present. */ do { printf("Home Phone (Ex: 9875432) [%s]: ", defaults->home_phone); fgets(in_str, BUFSIZ, stdin); if (special_case(in_str, defaults->home_phone)) break; remove_hyphens(in_str); } while (ill_input(in_str) || not_all_digits(in_str)); strcat(strcat(answer, ","), in_str); } /* * Prints an error message if a ':' or a newline is found in the string. * A message is also printed if the input string is too long. * The password file uses :'s as seperators, and are not allowed in the "gcos" * field. Newlines serve as delimiters between users in the password file, * and so, those too, are checked for. (I don't think that it is possible to * type them in, but better safe than sorry) * * Returns '1' if a colon or newline is found or the input line is too long. */ ill_input(input_str) char *input_str; { char *index(); char *ptr; int error_flag = 0; int length = strlen(input_str); if (index(input_str, ':')) { printf("':' is not allowed.\n"); error_flag = 1; } if (input_str[length-1] != '\n') { /* the newline and the '\0' eat up two characters */ printf("Maximum number of characters allowed is %d\n", BUFSIZ-2); /* flush the rest of the input line */ while (getchar() != '\n') /* void */; error_flag = 1; } /* * Delete newline by shortening string by 1. */ input_str[length-1] = '\0'; /* * Don't allow control characters, etc in input string. */ for (ptr=input_str; *ptr != '\0'; ptr++) { if ((int) *ptr < 040) { printf("Control characters are not allowed.\n"); error_flag = 1; break; } } return(error_flag); } /* * Removes '-'s from the input string. */ remove_hyphens(str) char *str; { char *hyphen, *index(), *strcpy(); while ((hyphen=index(str, '-')) != NULL) { strcpy(hyphen, hyphen+1); } } /* * Checks to see if 'str' contains only digits (0-9). If not, then * an error message is printed and '1' is returned. */ not_all_digits(str) char *str; { char *ptr; for (ptr=str; *ptr != '\0'; ++ptr) { if (!isdigit(*ptr)) { printf("Phone numbers can only contain digits.\n"); return(1); } } return(0); } /* * Returns 1 when the length of the input string is not * 4, 5, 7 or 9 in length. * Prints an error message in this case. */ wrong_length(str) char *str; { register int n; n = strlen(str); if (n != 0 && n != 4 && n != 5 && n != 7 && n != 9) { printf("The phone number should be 4, 5, or 7 digits long.\n"); return(1); } return(0); } /* get_defaults picks apart "str" and returns a structure points. * "str" contains up to 4 fields separated by commas. * Any field that is missing is set to blank. */ struct default_values *get_defaults(str) char *str; { struct default_values *answer; char *malloc(), *index(); answer = (struct default_values *) malloc((unsigned)sizeof(struct default_values)); if (answer == (struct default_values *) NULL) { fprintf(stderr, "\nUnable to allocate storage in get_defaults!\n"); exit(1); } /* * Values if no corresponding string in "str". */ answer->name = str; answer->office_num = ""; answer->office_phone = ""; answer->home_phone = ""; str = index(answer->name, ','); if (str == 0) return(answer); *str = '\0'; answer->office_num = str + 1; str = index(answer->office_num, ','); if (str == 0) return(answer); *str = '\0'; answer->office_phone = str + 1; str = index(answer->office_phone, ','); if (str == 0) return(answer); *str = '\0'; answer->home_phone = str + 1; return(answer); } /* * special_case returns true when either the default is accepted * (str = '\n'), or when 'none' is typed. 'none' is accepted in * either upper or lower case (or any combination). 'str' is modified * in these two cases. */ int special_case(str,default_str) char *str; char *default_str; { static char word[] = "none\n"; char *ptr, *wordptr; /* * If the default is accepted, then change the old string do the * default string. */ if (*str == '\n') { strcpy(str, default_str); return(1); } /* * Check to see if str is 'none'. (It is questionable if case * insensitivity is worth the hair). */ wordptr = word-1; for (ptr=str; *ptr != '\0'; ++ptr) { ++wordptr; if (*wordptr == '\0') /* then words are different sizes */ return(0); if (*ptr == *wordptr) continue; if (isupper(*ptr) && (tolower(*ptr) == *wordptr)) continue; /* * At this point we have a mismatch, so we return */ return(0); } /* * Make sure that words are the same length. */ if (*(wordptr+1) != '\0') return(0); /* * Change 'str' to be the null string */ *str = '\0'; return(1); }