sysdeps/tile/dl-runtime.c

   1 /* Copyright (C) 2011-2017 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 #include <dl-unmap-segments.h>
  31
  32 /* Like realpath(), but simplified: no dynamic memory use, no lstat(),
  33    no set_errno(), no valid "rpath" on error, etc.  This handles some
  34    simple cases where the simulator might not have a valid entry for
  35    a loaded Elf object, in particular dlopen() with a relative path.
  36    For this relatively rare case, one could also imagine using
  37    link_map.l_origin to avoid the getcwd() here, but the simpler code
  38    here seems like a better solution.  */
  39 static char *
  40 dl_realpath (const char *name, char *rpath)
  41 {
  42   char *dest;
  43   const char *start, *end;
  44
  45   if (name[0] != '/')
  46     {
  47       if (!__getcwd (rpath, PATH_MAX))
  48         return NULL;
  49       dest = __rawmemchr (rpath, '\0');
  50     }
  51   else
  52     {
  53       rpath[0] = '/';
  54       dest = rpath + 1;
  55     }
  56
  57   for (start = end = name; *start; start = end)
  58     {
  59       /* Skip sequence of multiple path-separators.  */
  60       while (*start == '/')
  61         ++start;
  62
  63       /* Find end of path component.  */
  64       for (end = start; *end && *end != '/'; ++end)
  65         /* Nothing.  */;
  66
  67       if (end - start == 0)
  68         break;
  69       else if (end - start == 1 && start[0] == '.')
  70         /* nothing */;
  71       else if (end - start == 2 && start[0] == '.' && start[1] == '.')
  72         {
  73           /* Back up to previous component, ignore if at root already.  */
  74           if (dest > rpath + 1)
  75             while ((--dest)[-1] != '/');
  76         }
  77       else
  78         {
  79           if (dest[-1] != '/')
  80             *dest++ = '/';
  81
  82           if (dest + (end - start) >= rpath + PATH_MAX)
  83             return NULL;
  84
  85           dest = __mempcpy (dest, start, end - start);
  86           *dest = '\0';
  87         }
  88     }
  89   if (dest > rpath + 1 && dest[-1] == '/')
  90     --dest;
  91   *dest = '\0';
  92
  93   return rpath;
  94 }
  95
  96 /* Support notifying the simulator about new objects.  */
  97 void internal_function
  98 _dl_after_load (struct link_map *l)
  99 {
 100   int shift;
 101   char pathbuf[PATH_MAX];
 102   char *path;
 103
 104   /* Don't bother if not in the simulator. */
 105   if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
 106     return;
 107
 108 #define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL,                         \
 109                                 (SIM_CONTROL_DLOPEN                      \
 110                                  | ((c) << _SIM_CONTROL_OPERATOR_BITS)))
 111
 112   /* Write the library address in hex.  */
 113   DLPUTC ('0');
 114   DLPUTC ('x');
 115   for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)
 116     DLPUTC ("0123456789abcdef"[(l->l_map_start >> shift) & 0xF]);
 117   DLPUTC (':');
 118
 119   /* Write the library path, including the terminating '\0'.  */
 120   path = dl_realpath (l->l_name, pathbuf) ?: l->l_name;
 121   for (size_t i = 0;; i++)
 122     {
 123       DLPUTC (path[i]);
 124       if (path[i] == '\0')
 125         break;
 126     }
 127 #undef DLPUTC
 128 }
 129
 130 /* Support notifying the simulator about removed objects prior to munmap().  */
 131 static void
 132 sim_dlclose (ElfW(Addr) map_start)
 133 {
 134   int shift;
 135
 136   /* Don't bother if not in the simulator.  */
 137   if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
 138     return;
 139
 140 #define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL,                         \
 141                                 (SIM_CONTROL_DLCLOSE                     \
 142                                  | ((c) << _SIM_CONTROL_OPERATOR_BITS)))
 143
 144   /* Write the library address in hex.  */
 145   DLPUTC ('0');
 146   DLPUTC ('x');
 147   for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)
 148     DLPUTC ("0123456789abcdef"[(map_start >> shift) & 0xF]);
 149   DLPUTC ('\0');
 150
 151 #undef DLPUTC
 152 }
 153
 154 void internal_function
 155 _dl_unmap (struct link_map *map)
 156 {
 157   sim_dlclose (map->l_map_start);
 158   _dl_unmap_segments (map);
 159 }