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tile: improve simulator notification for relative paths in dlopen

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Normally, the simulator is notified of absolute pathnames by the
_dl_load_hook hook.  However, when a relative pathname is used, the
simulator may not know that the relative path matches a path that
it could figure out in the file system that it has access to.
Instead we provide a simplified version of the realpath function
so we can pass a plausible absolute pathname to the simulator.

Since we're now doing more work at object load time, we also add
a guard so we do no work at all if we're not running on the simulator.
This commit is contained in:
Chris Metcalf 2012-11-02 13:49:42 -04:00
parent cd84016efe
commit e7776fefa7
2 changed files with 92 additions and 14 deletions
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3
ports/ChangeLog.tile
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@ -1,5 +1,8 @@
2012-11-02 Chris Metcalf <cmetcalf@tilera.com>
* sysdeps/tile/dl-runtime.c (_dl_after_load): Handle simulator
notification better for dlopen() of relative paths.
* sysdeps/tile/tilegx/memcpy.c (__memcpy): Optimize.
* sysdeps/tile/memcopy.h: New file.
* sysdeps/tile/wordcopy.c: New file.

103
ports/sysdeps/tile/dl-runtime.c
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@ -1,4 +1,4 @@
/* Copyright (C) 2011 Free Software Foundation, Inc.
/* Copyright (C) 2011-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
@ -28,44 +28,119 @@
#include <sys/mman.h>
#include <arch/sim.h>
/* Support notifying the simulator about new objects. */
/* Like realpath(), but simplified: no dynamic memory use, no lstat(),
no set_errno(), no valid "rpath" on error, etc. This handles some
simple cases where the simulator might not have a valid entry for
a loaded Elf object, in particular dlopen() with a relative path.
For this relatively rare case, one could also imagine using
link_map.l_origin to avoid the getcwd() here, but the simpler code
here seems like a better solution. */
static char *
dl_realpath (const char *name, char *rpath)
{
char *dest;
const char *start, *end;
if (name[0] != '/')
{
if (!__getcwd (rpath, PATH_MAX))
return NULL;
dest = __rawmemchr (rpath, '\0');
}
else
{
rpath[0] = '/';
dest = rpath + 1;
}
for (start = end = name; *start; start = end)
{
/* Skip sequence of multiple path-separators. */
while (*start == '/')
++start;
/* Find end of path component. */
for (end = start; *end && *end != '/'; ++end)
/* Nothing. */;
if (end - start == 0)
break;
else if (end - start == 1 && start[0] == '.')
/* nothing */;
else if (end - start == 2 && start[0] == '.' && start[1] == '.')
{
/* Back up to previous component, ignore if at root already. */
if (dest > rpath + 1)
while ((--dest)[-1] != '/');
}
else
{
if (dest[-1] != '/')
*dest++ = '/';
if (dest + (end - start) >= rpath + PATH_MAX)
return NULL;
dest = __mempcpy (dest, start, end - start);
*dest = '\0';
}
}
if (dest > rpath + 1 && dest[-1] == '/')
--dest;
*dest = '\0';
return rpath;
}
/* Support notifying the simulator about new objects. */
void internal_function
_dl_after_load (struct link_map *l)
{
int shift;
char pathbuf[PATH_MAX];
char *path;
#define DLPUTC(c) __insn_mtspr(SPR_SIM_CONTROL, \
(SIM_CONTROL_DLOPEN \
| ((c) << _SIM_CONTROL_OPERATOR_BITS)))
/* Don't bother if not in the simulator. */
if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
return;
/* Write the library address in hex. */
#define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL, \
(SIM_CONTROL_DLOPEN \
| ((c) << _SIM_CONTROL_OPERATOR_BITS)))
/* Write the library address in hex. */
DLPUTC ('0');
DLPUTC ('x');
for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)
DLPUTC ("0123456789abcdef"[(l->l_map_start >> shift) & 0xF]);
DLPUTC (':');
/* Write the library path, including the terminating '\0'. */
/* Write the library path, including the terminating '\0'. */
path = dl_realpath (l->l_name, pathbuf) ?: l->l_name;
for (size_t i = 0;; i++)
{
DLPUTC (l->l_name[i]);
if (l->l_name[i] == '\0')
DLPUTC (path[i]);
if (path[i] == '\0')
break;
}
#undef DLPUTC
}
/* Support notifying the simulator about removed objects prior to munmap(). */
/* Support notifying the simulator about removed objects prior to munmap(). */
void internal_function
_dl_unmap (struct link_map *l)
{
int shift;
#define DLPUTC(c) __insn_mtspr(SPR_SIM_CONTROL, \
(SIM_CONTROL_DLCLOSE \
| ((c) << _SIM_CONTROL_OPERATOR_BITS)))
/* Don't bother if not in the simulator. */
if (__insn_mfspr (SPR_SIM_CONTROL) == 0)
return;
/* Write the library address in hex. */
#define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL, \
(SIM_CONTROL_DLCLOSE \
| ((c) << _SIM_CONTROL_OPERATOR_BITS)))
/* Write the library address in hex. */
DLPUTC ('0');
DLPUTC ('x');
for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4)