realpath.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2016 The NASM Authors - All Rights Reserved
   4  *   See the file AUTHORS included with the NASM distribution for
   5  *   the specific copyright holders.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following
   9  *   conditions are met:
  10  *
  11  *   * Redistributions of source code must retain the above copyright
  12  *     notice, this list of conditions and the following disclaimer.
  13  *   * Redistributions in binary form must reproduce the above
  14  *     copyright notice, this list of conditions and the following
  15  *     disclaimer in the documentation and/or other materials provided
  16  *     with the distribution.
  17  *
  18  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  19  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  20  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  21  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  22  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  23  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  26  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  29  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  30  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  * ----------------------------------------------------------------------- */
  33
  34 /*
  35  * realpath.c   As system-independent as possible implementation of realpath()
  36  */
  37
  38 #include "compiler.h"
  39
  40 #include <stdlib.h>
  41 #include <errno.h>
  42 #include <limits.h>
  43 #ifdef HAVE_UNISTD_H
  44 # include <unistd.h>
  45 #endif
  46 #ifdef HAVE_SYS_PARAM_H
  47 # include <sys/param.h>
  48 #endif
  49
  50 #include "nasmlib.h"
  51
  52 #ifdef HAVE_CANONICALIZE_FILE_NAME
  53
  54 /*
  55  * GNU-specific, but avoids the realpath(..., NULL)
  56  * portability problem if it exists.
  57  */
  58 char *nasm_realpath(const char *rel_path)
  59 {
  60     return canonicalize_file_name(rel_path);
  61 }
  62
  63 #elif defined(HAVE_REALPATH)
  64
  65 /*
  66  * POSIX.1-2008 defines realpath(..., NULL); POSIX.1-2001 doesn't guarantee
  67  * that a NULL second argument is supported.
  68  */
  69
  70 char *nasm_realpath(const char *rel_path)
  71 {
  72     char *buf;
  73
  74     buf = realpath(rel_path, NULL);
  75     if (buf)
  76         return buf;
  77
  78     /* Not all implemetations of realpath() support a NULL second argument */
  79     if (errno == EINVAL) {
  80         int path_max = -1;
  81         char *buf;
  82
  83 #if defined(HAVE_PATHCONF) && defined(_PC_PATH_MAX)
  84         path_max = pathconf(rel_path, _PC_PATH_MAX); /* POSIX */
  85 #endif
  86
  87         if (path_max < 0) {
  88 #ifdef PATH_MAX
  89             path_max = PATH_MAX;    /* SUSv2 */
  90 #elif defined(MAXPATHLEN)
  91             path_max = MAXPATHLEN;  /* Solaris */
  92 #else
  93             path_max = 65536;    /* Crazily high, we hope */
  94 #endif
  95         }
  96
  97         buf = nasm_malloc(path_max);
  98
  99         if (!realpath(rel_path, buf)) {
 100             nasm_free(buf);
 101             buf = NULL;
 102         } else {
 103             /* On some systems, pathconf() can return a very large value */
 104
 105             buf[path_max - 1] = '\0'; /* Just in case overrun is possible */
 106             buf = nasm_realloc(buf, strlen(buf) + 1);
 107         }
 108     }
 109
 110     return buf;
 111 }
 112
 113 #elif defined(HAVE__FULLPATH)
 114
 115 /*
 116  * win32/win64 API
 117  */
 118
 119 char *nasm_realpath(const char *rel_path)
 120 {
 121     return _fullpath(NULL, rel_path, 0);
 122 }
 123
 124 #else
 125
 126 /*
 127  * There is nothing we know how to do here, so hope it just works anyway.
 128  */
 129
 130 char *nasm_realpath(const char *rel_path)
 131 {
 132     return nasm_strdup(rel_path);
 133 }
 134
 135 #endif