ports/sysdeps/tile/dl-runtime.c

   1 /* Copyright (C) 2011-2013 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /* Like x86_64, we pass the index of the relocation and not its offset.
  20    In _dl_profile_fixup and _dl_call_pltexit we also use the index.
  21    Therefore it is wasteful to compute the offset in the trampoline
  22    just to reverse the operation immediately afterwards.  */
  23 #define reloc_offset reloc_arg * sizeof (PLTREL)
  24 #define reloc_index  reloc_arg
  25
  26 #include <elf/dl-runtime.c>
  27
  28 #include <sys/mman.h>
  29 #include <arch/sim.h>
  30
  31 /* Like realpath(), but simplified: no dynamic memory use, no lstat(),
  32    no set_errno(), no valid "rpath" on error, etc.  This handles some
  33    simple cases where the simulator might not have a valid entry for
  34    a loaded Elf object, in particular dlopen() with a relative path.
  35    For this relatively rare case, one could also imagine using
  36    link_map.l_origin to avoid the getcwd() here, but the simpler code
  37    here seems like a better solution.  */
  38 static char *
  39 dl_realpath (const char *name, char *rpath)
  40 {
  41   char *dest;
  42   const char *start, *end;
  43
  44   if (name[0] != '/')
  45     {
  46       if (!__getcwd (rpath, PATH_MAX))
  47         return NULL;
  48       dest = __rawmemchr (rpath, '\0');
  49     }
  50   else
  51     {
  52       rpath[0] = '/';
  53       dest = rpath + 1;
  54     }
  55
  56   for (start = end = name; *start; start = end)
  57     {
  58       /* Skip sequence of multiple path-separators.  */
  59       while (*start == '/')
  60         ++start;
  61
  62       /* Find end of path component.  */
  63       for (end = start; *end && *end != '/'; ++end)
  64         /* Nothing.  */;
  65
  66       if (end - start == 0)
  67         break;
  68       else if (end - start == 1 && start[0] == '.')
  69         /* nothing */;
  70       else if (end - start == 2 && start[0] == '.' && start[1] == '.')
  71         {
  72           /* Back up to previous component, ignore if at root already.  */
  73           if (dest > rpath + 1)
  74             while ((--dest)[-1] != '/');
  75         }
  76       else
  77         {
  78           if (dest[-1] != '/')
  79             *dest++ = '/';
  80
  81           if (dest + (end - start) >= rpath + PATH_MAX)
  82             return NULL;
  83
  84           dest = __mempcpy (dest, start, end - start);
  85           *dest = '\0';
  86         }
  87     }
  88   if (dest > rpath + 1 && dest[-1] == '/')
  89     --dest;
  90   *dest = '\0';
  91
  92   return rpath;
  93 }
  94
  95 /* Support notifying the simulator about new objects.  */
  96 void internal_function
  97 _dl_after_load (struct link_map *l)
  98 {
  99   int shift;
 100   char pathbuf[PATH_MAX];
 101   char *path;
 102
 103   /* Don't bother if not in the simulator. */
 104   if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
 105     return;
 106
 107 #define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL,                         \
 108                                 (SIM_CONTROL_DLOPEN                      \
 109                                  | ((c) << _SIM_CONTROL_OPERATOR_BITS)))
 110
 111   /* Write the library address in hex.  */
 112   DLPUTC ('0');
 113   DLPUTC ('x');
 114   for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)
 115     DLPUTC ("0123456789abcdef"[(l->l_map_start >> shift) & 0xF]);
 116   DLPUTC (':');
 117
 118   /* Write the library path, including the terminating '\0'.  */
 119   path = dl_realpath (l->l_name, pathbuf) ?: l->l_name;
 120   for (size_t i = 0;; i++)
 121     {
 122       DLPUTC (path[i]);
 123       if (path[i] == '\0')
 124         break;
 125     }
 126 #undef DLPUTC
 127 }
 128
 129 /* Support notifying the simulator about removed objects prior to munmap().  */
 130 void internal_function
 131 _dl_unmap (struct link_map *l)
 132 {
 133   int shift;
 134
 135   /* Don't bother if not in the simulator.  */
 136   if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
 137     return;
 138
 139 #define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL,                         \
 140                                 (SIM_CONTROL_DLCLOSE                     \
 141                                  | ((c) << _SIM_CONTROL_OPERATOR_BITS)))
 142
 143   /* Write the library address in hex.  */
 144   DLPUTC ('0');
 145   DLPUTC ('x');
 146   for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)
 147     DLPUTC ("0123456789abcdef"[(l->l_map_start >> shift) & 0xF]);
 148   DLPUTC ('\0');
 149 #undef DLPUTC
 150
 151   __munmap ((void *) l->l_map_start, l->l_map_end - l->l_map_start);
 152 }