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/* Using NaCl interface tables.
Copyright (C) 2015-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <nacl-interfaces.h>
#include <ldsodefs.h>
/* These magic symbols are provided implicitly by the linker to
give us the bounds of the specially-named sections. */
extern const struct nacl_interface __start_nacl_mandatory_interface_names[]
attribute_hidden;
extern const struct nacl_interface __stop_nacl_mandatory_interface_names[]
attribute_hidden;
extern uintptr_t __start_nacl_mandatory_interface_tables[]
attribute_hidden;
extern uintptr_t __stop_nacl_mandatory_interface_tables[]
attribute_hidden;
/* We use weak references for the optional ones, since they
might not be included at all in any given statically-linked program. */
extern const struct nacl_interface __start_nacl_optional_interface_names[]
attribute_hidden __attribute__ ((weak));
extern const struct nacl_interface __stop_nacl_optional_interface_names[]
attribute_hidden __attribute__ ((weak));
extern uintptr_t __start_nacl_optional_interface_tables[]
attribute_hidden __attribute__ ((weak));
extern uintptr_t __stop_nacl_optional_interface_tables[]
attribute_hidden __attribute__ ((weak));
static uintptr_t *
next_nacl_table (uintptr_t *t, const struct nacl_interface *i)
{
return (void *) t + i->table_size;
}
static void __attribute__ ((noreturn))
missing_mandatory_interface (const struct nacl_interface *i)
{
static const char before[] =
"FATAL: NaCl IRT interface query failed for essential interface \"";
static const char after[] =
"\"\n";
if (__nacl_irt_fdio.write != NULL)
{
size_t wrote;
(*__nacl_irt_fdio.write) (2, before, sizeof before - 1, &wrote);
(*__nacl_irt_fdio.write) (2, i->name, i->namelen - 1, &wrote);
(*__nacl_irt_fdio.write) (2, after, sizeof after - 1, &wrote);
}
if (__nacl_irt_basic.exit != NULL)
(*__nacl_irt_basic.exit) (-1);
__builtin_trap ();
}
static void
initialize_mandatory_interfaces (void)
{
const struct nacl_interface *i = __start_nacl_mandatory_interface_names;
uintptr_t *t = __start_nacl_mandatory_interface_tables;
while (i < __stop_nacl_mandatory_interface_names)
{
if (__nacl_irt_query (i->name, t, i->table_size) != i->table_size)
missing_mandatory_interface (i);
t = next_nacl_table (t, i);
i = next_nacl_interface (i);
}
}
static int
nacl_missing_optional_interface (void)
{
return ENOSYS;
}
static void
initialize_optional_interfaces (void)
{
const struct nacl_interface *i = __start_nacl_optional_interface_names;
uintptr_t *t = __start_nacl_optional_interface_tables;
while (i < __stop_nacl_optional_interface_names)
{
size_t filled = __nacl_irt_query (i->name, t, i->table_size);
if (filled != i->table_size)
for (size_t slot = 0; slot < i->table_size / sizeof *t; ++slot)
t[slot] = (uintptr_t) &nacl_missing_optional_interface;
t = next_nacl_table (t, i);
i = next_nacl_interface (i);
}
}
void attribute_hidden
__nacl_initialize_interfaces (void)
{
initialize_mandatory_interfaces ();
initialize_optional_interfaces ();
}
static bool
try_supply (const struct nacl_interface *const start,
const struct nacl_interface *const stop,
uintptr_t *all_tables,
const char *ident, size_t ident_len,
const void *table, size_t tablesize)
{
const struct nacl_interface *i = start;
uintptr_t *t = all_tables;
while (i < stop)
{
if (i->table_size == tablesize
&& i->namelen == ident_len
&& !memcmp (i->name, ident, ident_len))
{
memcpy (t, table, tablesize);
return true;
}
t = next_nacl_table (t, i);
i = next_nacl_interface (i);
}
return false;
}
internal_function
bool
PASTE_NAME (__nacl_supply_interface_, MODULE_NAME)
(const char *ident, size_t ident_len, const void *table, size_t tablesize)
{
return (try_supply (__start_nacl_mandatory_interface_names,
__stop_nacl_mandatory_interface_names,
__start_nacl_mandatory_interface_tables,
ident, ident_len, table, tablesize)
|| try_supply (__start_nacl_optional_interface_names,
__stop_nacl_optional_interface_names,
__start_nacl_optional_interface_tables,
ident, ident_len, table, tablesize));
}
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