lib/other/getpass.c

   1 /*      getpass() - read a password             Author: Kees J. Bot
   2  *                                                      Feb 16 1993
   3  */
   4 #define open _open
   5 #define sigaction _sigaction
   6 #define sigemptyset _sigemptyset
   7 #define tcgetattr _tcgetattr
   8 #define tcsetattr _tcsetattr
   9 #define write _write
  10 #define read _read
  11 #define close _close
  12 #include <sys/types.h>
  13 #include <fcntl.h>
  14 #include <unistd.h>
  15 #include <signal.h>
  16 #include <termios.h>
  17 #include <string.h>
  18
  19 static int intr;
  20
  21 static void catch(int sig)
  22 {
  23         intr= 1;
  24 }
  25
  26 char *getpass(const char *prompt)
  27 {
  28         struct sigaction osa, sa;
  29         struct termios cooked, raw;
  30         static char password[32+1];
  31         int fd, n= 0;
  32
  33         /* Try to open the controlling terminal. */
  34         if ((fd= open("/dev/tty", O_RDONLY)) < 0) return NULL;
  35
  36         /* Trap interrupts unless ignored. */
  37         intr= 0;
  38         sigaction(SIGINT, NULL, &osa);
  39         if (osa.sa_handler != SIG_IGN) {
  40                 sigemptyset(&sa.sa_mask);
  41                 sa.sa_flags= 0;
  42                 sa.sa_handler= catch;
  43                 sigaction(SIGINT, &sa, &osa);
  44         }
  45
  46         /* Set the terminal to non-echo mode. */
  47         tcgetattr(fd, &cooked);
  48         raw= cooked;
  49         raw.c_iflag|= ICRNL;
  50         raw.c_lflag&= ~ECHO;
  51         raw.c_lflag|= ECHONL;
  52         raw.c_oflag|= OPOST | ONLCR;
  53         tcsetattr(fd, TCSANOW, &raw);
  54
  55         /* Print the prompt.  (After setting non-echo!) */
  56         write(2, prompt, strlen(prompt));
  57
  58         /* Read the password, 32 characters max. */
  59         while (read(fd, password+n, 1) > 0) {
  60                 if (password[n] == '\n') break;
  61                 if (n < 32) n++;
  62         }
  63         password[n]= 0;
  64
  65         /* Terminal back to cooked mode. */
  66         tcsetattr(fd, TCSANOW, &cooked);
  67
  68         close(fd);
  69
  70         /* Interrupt? */
  71         sigaction(SIGINT, &osa, NULL);
  72         if (intr) raise(SIGINT);
  73
  74         return password;
  75 }