mono/utils/mono-path.c

   1 /*
   2  * mono-path.c: Routines for handling path names.
   3  *
   4  * Authors:
   5  *      Gonzalo Paniagua Javier (gonzalo@novell.com)
   6  *      Miguel de Icaza (miguel@novell.com)
   7  *
   8  * (C) 2006 Novell, Inc.  http://www.novell.com
   9  *
  10  */
  11 #include <config.h>
  12 #include <glib.h>
  13 #include <errno.h>
  14 #include <string.h>
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 /* This is only needed for the mono_path_canonicalize code, MAXSYMLINKS, could be moved */
  18 #include <sys/param.h>
  19
  20 #include "mono-path.h"
  21
  22 /* Resolves '..' and '.' references in a path. If the path provided is relative,
  23  * it will be relative to the current directory */
  24 gchar *
  25 mono_path_canonicalize (const char *path)
  26 {
  27         gchar *abspath, *pos, *lastpos, *dest;
  28         int backc;
  29
  30         if (g_path_is_absolute (path)) {
  31                 abspath = g_strdup (path);
  32         } else {
  33                 gchar *tmpdir = g_get_current_dir ();
  34                 abspath = g_build_filename (tmpdir, path, NULL);
  35                 g_free (tmpdir);
  36         }
  37
  38         abspath = g_strreverse (abspath);
  39
  40         backc = 0;
  41         dest = lastpos = abspath;
  42         pos = strchr (lastpos, G_DIR_SEPARATOR);
  43
  44         while (pos != NULL) {
  45                 int len = pos - lastpos;
  46                 if (len == 1 && lastpos [0] == '.') {
  47                         // nop
  48                 } else if (len == 2 && lastpos [0] == '.' && lastpos [1] == '.') {
  49                         backc++;
  50                 } else if (len > 0) {
  51                         if (backc > 0) {
  52                                 backc--;
  53                         } else {
  54                                 if (dest != lastpos)
  55                                         /* The two strings can overlap */
  56                                         memmove (dest, lastpos, len + 1);
  57                                 dest += len + 1;
  58                         }
  59                 }
  60                 lastpos = pos + 1;
  61                 pos = strchr (lastpos, G_DIR_SEPARATOR);
  62         }
  63
  64         if (dest != lastpos) strcpy (dest, lastpos);
  65         return g_strreverse (abspath);
  66 }
  67
  68 /*
  69  * This ensures that the path that we store points to the final file
  70  * not a path to a symlink.
  71  */
  72 gchar *
  73 mono_path_resolve_symlinks (const char *path)
  74 {
  75 #if PLATFORM_WIN32
  76         return mono_path_canonicalize (path);
  77 #else
  78         char *p, *concat, *dir;
  79         char buffer [PATH_MAX+1];
  80         int n, iterations = 0;
  81
  82         p = g_strdup (path);
  83         do {
  84                 iterations++;
  85                 n = readlink (p, buffer, sizeof (buffer)-1);
  86                 if (n < 0){
  87                         char *copy = p;
  88                         p = mono_path_canonicalize (copy);
  89                         g_free (copy);
  90                         return p;
  91                 }
  92
  93                 buffer [n] = 0;
  94                 if (!g_path_is_absolute (buffer)) {
  95                         dir = g_path_get_dirname (p);
  96                         concat = g_build_filename (dir, buffer, NULL);
  97                         g_free (dir);
  98                 } else {
  99                         concat = g_strdup (buffer);
 100                 }
 101                 g_free (p);
 102                 p = mono_path_canonicalize (concat);
 103                 g_free (concat);
 104         } while (iterations < MAXSYMLINKS);
 105
 106         return p;
 107 #endif
 108 }
 109