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     char *rp = canonicalize_file_name(rel_path);
  61     return rp ? rp : nasm_strdup(rel_path);
  62 }
  63
  64 #elif defined(HAVE_REALPATH)
  65
  66 /*
  67  * POSIX.1-2008 defines realpath(..., NULL); POSIX.1-2001 doesn't guarantee
  68  * that a NULL second argument is supported.
  69  */
  70
  71 char *nasm_realpath(const char *rel_path)
  72 {
  73     char *rp;
  74
  75     rp = realpath(rel_path, NULL);
  76
  77     /* Not all implemetations of realpath() support a NULL second argument */
  78     if (!rp && errno == EINVAL) {
  79         long path_max = -1;
  80         char *rp;
  81
  82 #if defined(HAVE_PATHCONF) && defined(_PC_PATH_MAX)
  83         path_max = pathconf(rel_path, _PC_PATH_MAX); /* POSIX */
  84 #endif
  85
  86         if (path_max < 0) {
  87 #ifdef PATH_MAX
  88             path_max = PATH_MAX;    /* SUSv2 */
  89 #elif defined(MAXPATHLEN)
  90             path_max = MAXPATHLEN;  /* Solaris */
  91 #else
  92             path_max = 65536;    /* Crazily high, we hope */
  93 #endif
  94         }
  95
  96         rp = nasm_malloc(path_max);
  97
  98         if (!realpath(rel_path, rp)) {
  99             nasm_free(rp);
 100             rp = NULL;
 101         } else {
 102             /* On some systems, pathconf() can return a very large value */
 103
 104             rp[path_max - 1] = '\0'; /* Just in case overrun is possible */
 105             rp = nasm_realloc(rp, strlen(rp) + 1);
 106         }
 107     }
 108
 109     return rp ? rp : nasm_strdup(rel_path);
 110 }
 111
 112 #elif defined(HAVE__FULLPATH)
 113
 114 /*
 115  * win32/win64 API
 116  */
 117
 118 char *nasm_realpath(const char *rel_path)
 119 {
 120     char *rp = _fullpath(NULL, rel_path, 0);
 121     return rp ? rp : nasm_strdup(rel_path);
 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