mdw@git.distorted.org.uk Git - fwd/blob - fattr.c

   1 /* -*-c-*-
   2  *
   3  * $Id: fattr.c,v 1.3 2002/01/13 14:50:22 mdw Exp $
   4  *
   5  * Handling of file attributes
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' 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 General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: fattr.c,v $
  32  * Revision 1.3  2002/01/13 14:50:22  mdw
  33  * Delimiter-setting function names change.
  34  *
  35  * Revision 1.2  1999/08/19 18:32:48  mdw
  36  * Improve lexical analysis.  In particular, `chmod' patterns don't have to
  37  * be quoted any more.
  38  *
  39  * Revision 1.1  1999/07/26 23:33:56  mdw
  40  * Support code for new design.
  41  *
  42  */
  43
  44 /*----- Header files ------------------------------------------------------*/
  45
  46 #include "config.h"
  47
  48 #include <ctype.h>
  49 #include <errno.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53
  54 #include <sys/types.h>
  55 #include <sys/stat.h>
  56 #include <unistd.h>
  57
  58 #include <pwd.h>
  59 #include <grp.h>
  60
  61 #include "conf.h"
  62 #include "fattr.h"
  63 #include "scan.h"
  64
  65 /*----- Global variables --------------------------------------------------*/
  66
  67 fattr fattr_global;
  68
  69 /*----- Main code ---------------------------------------------------------*/
  70
  71 /* --- @fattr_init@ --- *
  72  *
  73  * Arguments:   @fattr *f@ = pointer to file attributes
  74  *
  75  * Returns:     ---
  76  *
  77  * Use:         Initializes a set of file attributes to default values.
  78  */
  79
  80 void fattr_init(fattr *f)
  81 {
  82   unsigned um = umask(0);
  83   umask(um);
  84   f->mode = 0666 & ~um;
  85   f->uid = -1;
  86   f->gid = -1;
  87 }
  88
  89 /* --- @fattr_option@ --- *
  90  *
  91  * Arguments:   @scanner *sc@ = pointer to scanner to read
  92  *              @fattr *f@ = pointer to file attributes to set
  93  *
  94  * Returns:     Whether the option was claimed.
  95  *
  96  * Use:         Reads file attributes from a scanner.
  97  */
  98
  99 int fattr_option(scanner *sc, fattr *f)
 100 {
 101   CONF_BEGIN(sc, "fattr", "file attribute")
 102
 103   /* --- Read a file mode specification --- */
 104
 105   if (strcmp(sc->d.buf, "mode") == 0) {
 106     unsigned mode = 0;
 107
 108     /* --- Gobble an optional `=' sign --- */
 109
 110     conf_undelim(sc, 0, ",=+-");
 111     token(sc);
 112     if (sc->t == '=')
 113       token(sc);
 114
 115     if (sc->t != CTOK_WORD)
 116       error(sc, "parse error, expected file mode");
 117     conf_undelim(sc, 0, 0);
 118
 119     /* --- If it looks digitlike, read as octal --- */
 120
 121     if (isdigit((unsigned char)*sc->d.buf))
 122       mode = strtoul(sc->d.buf, 0, 8) & 07777;
 123
 124     /* --- Otherise read as chmod-like characters --- */
 125
 126     else {
 127       const char *p;
 128       unsigned mask = 04700;
 129       unsigned state = 0;
 130       unsigned or = 1;
 131
 132       /* --- Set the default from the umask --- */
 133
 134       {
 135         unsigned um = umask(0);
 136         umask(um);
 137         mode = 0666 & ~um;
 138       }
 139
 140       /* --- Parse the characters --- *
 141        *
 142        * This is a particularly lenient implementation of the usual chmod-
 143        * style mode language.
 144        */
 145
 146       for (p = sc->d.buf; *p; p++) {
 147         switch (*p) {
 148           case ',': break;
 149
 150           case 'a': mask = (mask & state) | 07777; state = 07777; break;
 151           case 'u': mask = (mask & state) | 04700; state = 07777; break;
 152           case 'g': mask = (mask & state) | 02070; state = 07777; break;
 153           case 'o': mask = (mask & state) | 01007; state = 07777; break;
 154
 155           case '=': mode &= ~mask; /* Drop through */
 156           case '+': state = 0; or = 1; break;
 157           case '-': state = 0; or = 0; break;
 158
 159 #define APPLY(m) if (or) mode |= ((m) & mask); else mode &= ~((m) & mask);
 160           case 'r': state = 0; APPLY(00444); break;
 161           case 'w': state = 0; APPLY(00222); break;
 162           case 'x': state = 0; APPLY(00111); break;
 163           case 's': state = 0; APPLY(06000); break;
 164           case 't': state = 0; APPLY(01000); break;
 165 #undef APPLY
 166
 167           default: error(sc, "unknown mode character `%c'", *p);
 168         }
 169       }
 170     }
 171
 172     token(sc);
 173     f->mode = mode;
 174     CONF_ACCEPT;
 175   }
 176
 177   /* --- Read a file uid specification --- */
 178
 179   if (strcmp(sc->d.buf, "uid") == 0 ||
 180       strcmp(sc->d.buf, "user") == 0 ||
 181       strcmp(sc->d.buf, "owner") == 0) {
 182     token(sc);
 183     if (sc->t == '=')
 184       token(sc);
 185     if (sc->t != CTOK_WORD)
 186       error(sc, "parse error, expected user name or uid");
 187     if (isdigit((unsigned char)*sc->d.buf))
 188       f->uid = atoi(sc->d.buf);
 189     else {
 190       struct passwd *pw = getpwnam(sc->d.buf);
 191       if (!pw)
 192         error(sc, "unknown user name `%s'", sc->d.buf);
 193       f->uid = pw->pw_uid;
 194     }
 195     token(sc);
 196     CONF_ACCEPT;
 197   }
 198
 199   /* --- Read a file gid specification --- */
 200
 201   if (strcmp(sc->d.buf, "gid") == 0 ||
 202       strcmp(sc->d.buf, "group") == 0) {
 203     token(sc);
 204     if (sc->t == '=')
 205       token(sc);
 206     if (sc->t != CTOK_WORD)
 207       error(sc, "parse error, expected group name or gid");
 208     if (isdigit((unsigned char)*sc->d.buf))
 209       f->gid = atoi(sc->d.buf);
 210     else {
 211       struct group *gr = getgrnam(sc->d.buf);
 212       if (!gr)
 213         error(sc, "unknown user name `%s'", sc->d.buf);
 214       f->gid = gr->gr_gid;
 215     }
 216     token(sc);
 217     CONF_ACCEPT;
 218   }
 219
 220   /* --- Nothing here for me --- */
 221
 222   CONF_END;
 223 }
 224
 225 /* --- @fattr_apply@ --- *
 226  *
 227  * Arguments:   @const char *file@ = pointer to filename
 228  *              @fattr *f@ = pointer to attribute set
 229  *
 230  * Returns:     @-1@ if it failed.
 231  *
 232  * Use:         Applies file attributes to a file.  For best results, try to
 233  *              create the file with the right permissions and so on.  This
 234  *              call will fix everything up, but there are potential races
 235  *              which might catch you out if you're not careful.
 236  */
 237
 238 int fattr_apply(const char *file, fattr *f)
 239 {
 240   if (chown(file, f->uid, f->gid) == -1 ||
 241       chmod(file, f->mode) == -1)
 242     return (-1);
 243   return (0);
 244 }
 245
 246 /*----- That's all, folks -------------------------------------------------*/