git.distorted.org.uk Git - u/mdw/catacomb/blob - pixie-common.c

   1 /* -*-c-*-
   2  *
   3  * $Id: pixie-common.c,v 1.2 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Common code for Pixie client and server (Unix-specific)
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <errno.h>
  33 #include <stddef.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37
  38 #include <sys/types.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <termios.h>
  42 #include <pwd.h>
  43
  44 #include <sys/socket.h>
  45 #include <sys/un.h>
  46
  47 #include <mLib/alloc.h>
  48 #include <mLib/dstr.h>
  49
  50 #include "pixie.h"
  51
  52 /*----- Main code ---------------------------------------------------------*/
  53
  54 /* --- @pixie_address@ --- *
  55  *
  56  * Arguments:   @const char *sock@ = pointer to socket name
  57  *              @size_t *psz@ = where to write the address size
  58  *
  59  * Returns:     Pointer to filled-in Unix-domain socket address.
  60  *
  61  * Use:         Returns a Unix-domain socket address to use to find the
  62  *              passphrase pixie.
  63  */
  64
  65 struct sockaddr_un *pixie_address(const char *sock, size_t *psz)
  66 {
  67   dstr d = DSTR_INIT;
  68
  69   /* --- Get the default socket path if none specified --- */
  70
  71   if (!sock)
  72     sock = getenv("CATACOMB_PIXIE_SOCKET");
  73   if (!sock)
  74     sock = "%h/.catacomb/pixie";
  75
  76   /* --- Substitute interesting sequences in the path --- */
  77
  78   {
  79     const char *q, *qq;
  80
  81     q = sock;
  82     for (;;) {
  83       qq = strchr(q, '%');
  84       if (!qq || !qq[1]) {
  85         DPUTS(&d, q);
  86         break;
  87       }
  88       DPUTM(&d, q, qq - q);
  89       q = qq + 1;
  90       switch (*q) {
  91         case 'u':
  92           qq = getenv("USER");
  93           if (!qq)
  94             qq = getenv("LOGNAME");
  95           if (!qq) {
  96             struct passwd *pw = getpwuid(getuid());
  97             if (pw)
  98               qq = pw->pw_name;
  99             else
 100               qq = "<unknown>";
 101           }
 102           DPUTS(&d, qq);
 103           break;
 104         case 'h':
 105           qq = getenv("HOME");
 106           if (!qq) {
 107             struct passwd *pw = getpwuid(getuid());
 108             if (pw)
 109               qq = pw->pw_dir;
 110             else
 111               qq = "<unknown>";
 112           }
 113           DPUTS(&d, qq);
 114           break;
 115         default:
 116           DPUTC(&d, '%');
 117           DPUTC(&d, *q);
 118           break;
 119       }
 120       q++;
 121     }
 122     DPUTZ(&d);
 123   }
 124
 125   /* --- Allocate and initialize the socket address --- */
 126
 127   {
 128     struct sockaddr_un *sun;
 129     size_t bsz = offsetof(struct sockaddr_un, sun_path);
 130     *psz = bsz + d.len + 1;
 131     sun = xmalloc(bsz + d.len + 1);
 132     memset(sun, 0, bsz);
 133     sun->sun_family = AF_UNIX;
 134     memcpy(sun->sun_path, d.buf, d.len + 1);
 135     dstr_destroy(&d);
 136     return (sun);
 137   }
 138 }
 139
 140 /* --- @pixie_fdline@ --- *
 141  *
 142  * Arguments:   @int fd@ = file descriptor to read from
 143  *              @char *buf@ = pointer to buffer
 144  *              @size_t sz@ = size of buffer
 145  *
 146  * Returns:     ---
 147  *
 148  * Use:         Reads a line from a file descriptor.  The read is done one
 149  *              character at a time.  If the entire line won't fit, the end
 150  *              is truncated.  The line is null terminated.
 151  */
 152
 153 void pixie_fdline(int fd, char *buf, size_t sz)
 154 {
 155   char *p = buf;
 156   char *q = p + sz - 1;
 157
 158   for (;;) {
 159     char c;
 160     if (read(fd, &c, 1) < 1)
 161       break;
 162     if (c == '\n')
 163       break;
 164     if (p < q)
 165       *p++ = c;
 166   }
 167   *p = 0;
 168 }
 169
 170 /* --- @pixie_getpass@ --- *
 171  *
 172  * Arguments:   @const char *prompt@ = pointer to prompt string
 173  *              @char *buf@ = pointer to buffer
 174  *              @size_t sz@ = size of buffer
 175  *
 176  * Returns:     Zero if it worked OK, nonzero otherwise.
 177  *
 178  * Use:         Reads a passphrase from the terminal or some other requested
 179  *              source.
 180  */
 181
 182 int pixie_getpass(const char *prompt, char *buf, size_t sz)
 183 {
 184   const char *pfd = getenv("CATACOMB_PASSPHRASE_FD");
 185   int fd = 0;
 186
 187   /* --- See whether a terminal is what's wanted --- */
 188
 189   if (pfd) {
 190     fd = atoi(pfd);
 191     pixie_fdline(fd, buf, sz);
 192   } else {
 193     struct termios ta;
 194     struct termios ota;
 195     char nl = '\n';
 196
 197     if ((fd = open("/dev/tty", O_RDWR)) < 0)
 198       goto fail_0;
 199     if (tcgetattr(fd, &ta) < 0)
 200       goto fail_1;
 201     ota = ta;
 202     ta.c_lflag &= ~(ECHO | ISIG);
 203     if (tcsetattr(fd, TCSAFLUSH, &ta))
 204       goto fail_1;
 205     write(fd, prompt, strlen(prompt));
 206     pixie_fdline(fd, buf, sz);
 207     tcsetattr(fd, TCSAFLUSH, &ota);
 208     write(fd, &nl, 1);
 209     close(fd);
 210   }
 211   return (0);
 212
 213   /* --- Tidy up if things went wrong --- */
 214
 215 fail_1:
 216   close(fd);
 217 fail_0:
 218   return (-1);
 219 }
 220
 221
 222 /*----- That's all, folks -------------------------------------------------*/
 223