1static char *sccsid = "@(#)chsh.sh 4.1 (Berkeley) 10/01/80"; 2/* 3 * chsh 4 */ 5#include <stdio.h> 6#include <signal.h> 7#include <pwd.h> 8 9char passwd[] = "/etc/passwd"; 10char temp[] = "/etc/ptmp"; 11struct passwd *pwd; 12struct passwd *getpwent(); 13int endpwent(); 14char *crypt(); 15char *getpass(); 16char *pw; 17char pwbuf[10]; 18char buf[BUFSIZ]; 19 20main(argc, argv) 21char *argv[]; 22{ 23 char *p; 24 int i; 25 char saltc[2]; 26 long salt; 27 int u,fi,fo; 28 int insist; 29 int ok, flags; 30 int c; 31 int pwlen; 32 FILE *tf; 33 34 insist = 0; 35 if(argc < 2 || argc > 3) { 36 printf("Usage: chsh user [ /bin/oldcsh ] [ /bin/csh ]\n"); 37 goto bex; 38 } 39 if (argc == 2) 40 argv[2] = ""; 41 else if (strcmp(argv[2], "/bin/oldcsh") && strcmp(argv[2], "/bin/csh") && getuid()) { 42 printf("Only /bin/oldcsh or /bin/csh may be specified\n"); 43 exit(1); 44 } 45 while((pwd=getpwent()) != NULL){ 46 if(strcmp(pwd->pw_name,argv[1]) == 0){ 47 u = getuid(); 48 if(u!=0 && u != pwd->pw_uid){ 49 printf("Permission denied.\n"); 50 goto bex; 51 } 52 break; 53 } 54 } 55 endpwent(); 56 signal(SIGHUP, 1); 57 signal(SIGINT, 1); 58 signal(SIGQUIT, 1); 59 signal(SIGTSTP, 1); 60 61 if(access(temp, 0) >= 0) { 62 printf("Temporary file busy -- try again\n"); 63 goto bex; 64 } 65 if((tf=fopen(temp,"w")) == NULL) { 66 printf("Cannot create temporary file\n"); 67 goto bex; 68 } 69 70/* 71 * copy passwd to temp, replacing matching lines 72 * with new shell. 73 */ 74 75 while((pwd=getpwent()) != NULL) { 76 if(strcmp(pwd->pw_name,argv[1]) == 0) { 77 u = getuid(); 78 if(u != 0 && u != pwd->pw_uid) { 79 printf("Permission denied.\n"); 80 goto out; 81 } 82 pwd->pw_shell = argv[2]; 83 } 84 fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n", 85 pwd->pw_name, 86 pwd->pw_passwd, 87 pwd->pw_uid, 88 pwd->pw_gid, 89 pwd->pw_gecos, 90 pwd->pw_dir, 91 pwd->pw_shell); 92 } 93 endpwent(); 94 fclose(tf); 95 96/* 97 * copy temp back to passwd file 98 */ 99 100 if((fi=open(temp,0)) < 0) { 101 printf("Temp file disappeared!\n"); 102 goto out; 103 } 104 if((fo=creat(passwd, 0644)) < 0) { 105 printf("Cannot recreat passwd file.\n"); 106 goto out; 107 } 108 while((u=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,u); 109 110out: 111 unlink(temp); 112 113bex: 114 exit(1); 115} 116