cde/programs/dtksh/ksh93/src/lib/libast/preroot/getpreroot.c

   1 /*
   2  * CDE - Common Desktop Environment
   3  *
   4  * Copyright (c) 1993-2012, The Open Group. All rights reserved.
   5  *
   6  * These libraries and programs are free software; you can
   7  * redistribute them and/or modify them under the terms of the GNU
   8  * Lesser General Public License as published by the Free Software
   9  * Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * These libraries and programs are distributed in the hope that
  13  * they will be useful, but WITHOUT ANY WARRANTY; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with these librararies and programs; if not, write
  20  * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
  21  * Floor, Boston, MA 02110-1301 USA
  22  */
  23 /* $XConsortium: getpreroot.c /main/3 1995/11/01 18:21:07 rswiston $ */
  24 /***************************************************************
  25 *                                                              *
  26 *                      AT&T - PROPRIETARY                      *
  27 *                                                              *
  28 *         THIS IS PROPRIETARY SOURCE CODE LICENSED BY          *
  29 *                          AT&T CORP.                          *
  30 *                                                              *
  31 *                Copyright (c) 1995 AT&T Corp.                 *
  32 *                     All Rights Reserved                      *
  33 *                                                              *
  34 *           This software is licensed by AT&T Corp.            *
  35 *       under the terms and conditions of the license in       *
  36 *       http://www.research.att.com/orgs/ssr/book/reuse        *
  37 *                                                              *
  38 *               This software was created by the               *
  39 *           Software Engineering Research Department           *
  40 *                    AT&T Bell Laboratories                    *
  41 *                                                              *
  42 *               For further information contact                *
  43 *                     gsf@research.att.com                     *
  44 *                                                              *
  45 ***************************************************************/
  46
  47 /* : : generated by proto : : */
  48
  49 #if !defined(__PROTO__)
  50 #if defined(__STDC__) || defined(__cplusplus) || defined(_proto) || defined(c_plusplus)
  51 #if defined(__cplusplus)
  52 #define __MANGLE__      "C"
  53 #else
  54 #define __MANGLE__
  55 #endif
  56 #define __STDARG__
  57 #define __PROTO__(x)    x
  58 #define __OTORP__(x)
  59 #define __PARAM__(n,o)  n
  60 #if !defined(__STDC__) && !defined(__cplusplus)
  61 #if !defined(c_plusplus)
  62 #define const
  63 #endif
  64 #define signed
  65 #define void            int
  66 #define volatile
  67 #define __V_            char
  68 #else
  69 #define __V_            void
  70 #endif
  71 #else
  72 #define __PROTO__(x)    ()
  73 #define __OTORP__(x)    x
  74 #define __PARAM__(n,o)  o
  75 #define __MANGLE__
  76 #define __V_            char
  77 #define const
  78 #define signed
  79 #define void            int
  80 #define volatile
  81 #endif
  82 #if defined(__cplusplus) || defined(c_plusplus)
  83 #define __VARARG__      ...
  84 #else
  85 #define __VARARG__
  86 #endif
  87 #if defined(__STDARG__)
  88 #define __VA_START__(p,a)       va_start(p,a)
  89 #else
  90 #define __VA_START__(p,a)       va_start(p)
  91 #endif
  92 #endif
  93 #include <ast.h>
  94 #include <preroot.h>
  95
  96 #if FS_PREROOT
  97
  98 #include "dirlib.h"
  99 #include <ls.h>
 100 #include <error.h>
 101 #include <stdio.h>
 102
 103 #ifndef ERANGE
 104 #define ERANGE          E2BIG
 105 #endif
 106
 107 #define ERROR(e)        {errno=e;goto error;}
 108
 109 char*
 110 getpreroot __PARAM__((char* path, const char* cmd), (path, cmd)) __OTORP__(char* path; const char* cmd;){
 111         register int    c;
 112         register FILE*  fp;
 113         register char*  p;
 114         char            buf[PATH_MAX];
 115
 116         if (!path) path = buf;
 117         if (cmd)
 118         {
 119                 sfsprintf(buf, sizeof(buf), "set x `%s= %s - </dev/null 2>&1`\nwhile :\ndo\nshift\ncase $# in\n[012]) break ;;\nesac\ncase \"$1 $2\" in\n\"+ %s\")      echo $3; exit ;;\nesac\ndone\necho\n", PR_SILENT, cmd, PR_COMMAND);
 120                 if (!(fp = popen(buf, "rug"))) return(0);
 121                 for (p = path; (c = getc(fp)) != EOF && c != '\n'; *p++ = c);
 122                 *p = 0;
 123                 pclose(fp);
 124                 if (path == p) return(0);
 125                 return(path == buf ? strdup(path) : path);
 126         }
 127         else
 128         {
 129                 char*           d;
 130                 DIR*            dirp = 0;
 131                 int             namlen;
 132                 int             euid;
 133                 int             ruid;
 134                 struct dirent*  entry;
 135                 struct stat*    cur;
 136                 struct stat*    par;
 137                 struct stat*    tmp;
 138                 struct stat     curst;
 139                 struct stat     parst;
 140                 struct stat     tstst;
 141                 char            dots[PATH_MAX];
 142
 143                 cur = &curst;
 144                 par = &parst;
 145                 if ((ruid = getuid()) != (euid = geteuid())) setuid(ruid);
 146                 if (stat(PR_REAL, cur) || stat("/", par) || cur->st_dev == par->st_dev && cur->st_ino == par->st_ino) ERROR(ENOTDIR);
 147
 148                 /*
 149                  * like getcwd() but starting at the preroot
 150                  */
 151
 152                 d = dots;
 153                 *d++ = '/';
 154                 p = path + PATH_MAX - 1;
 155                 *p = 0;
 156                 for (;;)
 157                 {
 158                         tmp = cur;
 159                         cur = par;
 160                         par = tmp;
 161                         if ((d - dots) > (PATH_MAX - 4)) ERROR(ERANGE);
 162                         *d++ = '.';
 163                         *d++ = '.';
 164                         *d = 0;
 165                         if (!(dirp = opendir(dots))) ERROR(errno);
 166 #if !_dir_ok || _mem_dd_fd_DIR
 167                         if (fstat(dirp->dd_fd, par)) ERROR(errno);
 168 #else
 169                         if (stat(dots, par)) ERROR(errno);
 170 #endif
 171                         *d++ = '/';
 172                         if (par->st_dev == cur->st_dev)
 173                         {
 174                                 if (par->st_ino == cur->st_ino)
 175                                 {
 176                                         closedir(dirp);
 177                                         *--p = '/';
 178                                         if (ruid != euid) setuid(euid);
 179                                         if (path == buf) return(strdup(p));
 180                                         if (path != p)
 181                                         {
 182                                                 d = path;
 183                                                 while (*d++ = *p++);
 184                                         }
 185                                         return(path);
 186                                 }
 187 #if _mem_d_fileno_dirent || _mem_d_ino_dirent
 188 #if !_mem_d_fileno_dirent
 189 #define d_fileno        d_ino
 190 #endif
 191                                 while (entry = readdir(dirp))
 192                                         if (entry->d_fileno == cur->st_ino)
 193                                         {
 194 #if _mem_d_namlen_dirent
 195                                                 namlen = entry->d_namlen;
 196 #else
 197                                                 namlen = strlen(entry->d_name);
 198 #endif
 199                                                 goto found;
 200                                         }
 201
 202                                 /*
 203                                  * this fallthrough handles logical naming
 204                                  */
 205
 206                                 rewinddir(dirp);
 207 #endif
 208                         }
 209                         do
 210                         {
 211                                 if (!(entry = readdir(dirp))) ERROR(ENOENT);
 212 #if _mem_d_namlen_dirent
 213                                 namlen = entry->d_namlen;
 214 #else
 215                                 namlen = strlen(entry->d_name);
 216 #endif
 217                                 if ((d - dots) > (PATH_MAX - 1 - namlen)) ERROR(ERANGE);
 218                                 memcpy(d, entry->d_name, namlen + 1);
 219                                 if (stat(dots, &tstst)) ERROR(errno);
 220                         } while (tstst.st_ino != cur->st_ino || tstst.st_dev != cur->st_dev);
 221                 found:
 222                         if (*p) *--p = '/';
 223                         if ((p -= namlen) <= (path + 1)) ERROR(ERANGE);
 224                         memcpy(p, entry->d_name, namlen);
 225                         closedir(dirp);
 226                         dirp = 0;
 227                 }
 228         error:
 229                 if (dirp) closedir(dirp);
 230                 if (ruid != euid) setuid(euid);
 231         }
 232         return(0);
 233 }
 234
 235 #else
 236
 237 NoN(getpreroot)
 238
 239 #endif