nasmlib/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 <errno.h>
  41 #ifdef HAVE_UNISTD_H
  42 # include <unistd.h>
  43 #endif
  44 #ifdef HAVE_SYS_PARAM_H
  45 # include <sys/param.h>
  46 #endif
  47
  48 #include "nasmlib.h"
  49
  50 #ifdef HAVE_CANONICALIZE_FILE_NAME
  51
  52 /*
  53  * GNU-specific, but avoids the realpath(..., NULL)
  54  * portability problem if it exists.
  55  */
  56 char *nasm_realpath(const char *rel_path)
  57 {
  58     char *rp = canonicalize_file_name(rel_path);
  59     return rp ? rp : nasm_strdup(rel_path);
  60 }
  61
  62 #elif defined(HAVE_REALPATH)
  63
  64 /*
  65  * POSIX.1-2008 defines realpath(..., NULL); POSIX.1-2001 doesn't guarantee
  66  * that a NULL second argument is supported.
  67  */
  68
  69 char *nasm_realpath(const char *rel_path)
  70 {
  71     char *rp;
  72
  73     rp = realpath(rel_path, NULL);
  74
  75     /* Not all implemetations of realpath() support a NULL second argument */
  76     if (!rp && errno == EINVAL) {
  77         long path_max = -1;
  78         char *rp;
  79
  80 #if defined(HAVE_PATHCONF) && defined(_PC_PATH_MAX)
  81         path_max = pathconf(rel_path, _PC_PATH_MAX); /* POSIX */
  82 #endif
  83
  84         if (path_max < 0) {
  85 #ifdef PATH_MAX
  86             path_max = PATH_MAX;    /* SUSv2 */
  87 #elif defined(MAXPATHLEN)
  88             path_max = MAXPATHLEN;  /* Solaris */
  89 #else
  90             path_max = 65536;    /* Crazily high, we hope */
  91 #endif
  92         }
  93
  94         rp = nasm_malloc(path_max);
  95
  96         if (!realpath(rel_path, rp)) {
  97             nasm_free(rp);
  98             rp = NULL;
  99         } else {
 100             /* On some systems, pathconf() can return a very large value */
 101
 102             rp[path_max - 1] = '\0'; /* Just in case overrun is possible */
 103             rp = nasm_realloc(rp, strlen(rp) + 1);
 104         }
 105     }
 106
 107     return rp ? rp : nasm_strdup(rel_path);
 108 }
 109
 110 #elif defined(HAVE__FULLPATH)
 111
 112 /*
 113  * win32/win64 API
 114  */
 115
 116 char *nasm_realpath(const char *rel_path)
 117 {
 118     char *rp = _fullpath(NULL, rel_path, 0);
 119     return rp ? rp : nasm_strdup(rel_path);
 120 }
 121
 122 #else
 123
 124 /*
 125  * There is nothing we know how to do here, so hope it just works anyway.
 126  */
 127
 128 char *nasm_realpath(const char *rel_path)
 129 {
 130     return nasm_strdup(rel_path);
 131 }
 132
 133 #endif