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* sysdeps/generic/dl-cache.c: Optimize SEARCH_CACHE and
	HWCAP_CHECK macro code.

	* elf/dl-misc.c (_dl_sysdep_read_whole_file): Optimize code a bit.
	Now returns MAP_FAILED on error.
	* elf/rtld.c: Adjust caller.
	* sysdeps/generic/dl-cache.c: Likewise.
	* sysdeps/generic/ldsodefs.h: Adjust description.
This commit is contained in:
Ulrich Drepper 2001-11-08 01:48:57 +00:00
parent 6ed623f848
commit 40b07f5b94
5 changed files with 135 additions and 128 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
ChangeLog
View File

@ -1,5 +1,14 @@
2001-11-07 Ulrich Drepper <drepper@redhat.com>
* sysdeps/generic/dl-cache.c: Optimize SEARCH_CACHE and
HWCAP_CHECK macro code.
* elf/dl-misc.c (_dl_sysdep_read_whole_file): Optimize code a bit.
Now returns MAP_FAILED on error.
* elf/rtld.c: Adjust caller.
* sysdeps/generic/dl-cache.c: Likewise.
* sysdeps/generic/ldsodefs.h: Adjust description.
* elf/dl-version.c (match_symbol): Optimize error handling for size.
(_dl_check_map_versions): Likewise.

38
elf/dl-misc.c
View File

@ -44,40 +44,38 @@ _dl_sysdep_open_zero_fill (void)
#endif
/* Read the whole contents of FILE into new mmap'd space with given
protections. *SIZEP gets the size of the file. */
protections. *SIZEP gets the size of the file. On error MAP_FAILED
is returned. */
void *
internal_function
_dl_sysdep_read_whole_file (const char *file, size_t *sizep, int prot)
{
void *result;
void *result = MAP_FAILED;
struct stat64 st;
int fd = __open (file, O_RDONLY);
if (fd < 0)
return NULL;
if (__fxstat64 (_STAT_VER, fd, &st) < 0
/* No need to map the file if it is empty. */
|| st.st_size == 0)
result = NULL;
else
if (fd >= 0)
{
/* Map a copy of the file contents. */
result = __mmap (0, st.st_size, prot,
if (__fxstat64 (_STAT_VER, fd, &st) >= 0)
{
*sizep = st.st_size;
/* No need to map the file if it is empty. */
if (*sizep != 0)
/* Map a copy of the file contents. */
result = __mmap (NULL, *sizep, prot,
#ifdef MAP_COPY
MAP_COPY
MAP_COPY
#else
MAP_PRIVATE
MAP_PRIVATE
#endif
#ifdef MAP_FILE
| MAP_FILE
| MAP_FILE
#endif
, fd, 0);
if (result == MAP_FAILED)
result = NULL;
else
*sizep = st.st_size;
, fd, 0);
}
__close (fd);
}
__close (fd);
return result;
}

2
elf/rtld.c
View File

@ -710,7 +710,7 @@ of this helper program; chances are you did not intend to run this program.\n\
/* Read the contents of the file. */
file = _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size,
PROT_READ | PROT_WRITE);
if (__builtin_expect (file != NULL, 0))
if (__builtin_expect (file != MAP_FAILED, 0))
{
/* Parse the file. It contains names of libraries to be loaded,
separated by white spaces or `:'. It may also contain

209
sysdeps/generic/dl-cache.c
View File

@ -44,98 +44,98 @@ static size_t cachesize;
binaries. */
int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID;
#define SEARCH_CACHE(cache) \
/* We use binary search since the table is sorted in the cache file. \
The first matching entry in the table is returned. \
It is important to use the same algorithm as used while generating \
the cache file. */ \
do \
{ \
left = 0; \
right = cache->nlibs - 1; \
middle = (left + right) / 2; \
cmpres = 1; \
\
while (left <= right) \
{ \
/* Make sure string table indices are not bogus before using \
them. */ \
if (! _dl_cache_verify_ptr (cache->libs[middle].key)) \
{ \
cmpres = 1; \
break; \
} \
\
/* Actually compare the entry with the key. */ \
cmpres = _dl_cache_libcmp (name, \
cache_data + cache->libs[middle].key); \
if (cmpres == 0) \
/* Found it. */ \
break; \
\
if (cmpres < 0) \
left = middle + 1; \
else \
right = middle - 1; \
\
middle = (left + right) / 2; \
} \
\
if (cmpres == 0) \
{ \
/* LEFT now marks the last entry for which we know the name is \
correct. */ \
left = middle; \
\
/* There might be entries with this name before the one we \
found. So we have to find the beginning. */ \
while (middle > 0 \
/* Make sure string table indices are not bogus before \
using them. */ \
&& _dl_cache_verify_ptr (cache->libs[middle - 1].key) \
/* Actually compare the entry. */ \
&& (_dl_cache_libcmp (name, \
cache_data \
+ cache->libs[middle - 1].key) \
== 0)) \
--middle; \
\
do \
{ \
int flags; \
\
/* Only perform the name test if necessary. */ \
if (middle > left \
/* We haven't seen this string so far. Test whether the \
index is ok and whether the name matches. Otherwise \
we are done. */ \
&& (! _dl_cache_verify_ptr (cache->libs[middle].key) \
|| (_dl_cache_libcmp (name, \
cache_data \
+ cache->libs[middle].key) \
!= 0))) \
break; \
\
flags = cache->libs[middle].flags; \
if (_dl_cache_check_flags (flags) \
&& _dl_cache_verify_ptr (cache->libs[middle].value)) \
{ \
if (best == NULL || flags == _dl_correct_cache_id) \
{ \
HWCAP_CHECK; \
best = cache_data + cache->libs[middle].value; \
\
if (flags == _dl_correct_cache_id) \
/* We've found an exact match for the shared \
object and no general `ELF' release. Stop \
searching. */ \
break; \
} \
} \
} \
while (++middle <= right); \
} \
} \
#define SEARCH_CACHE(cache) \
/* We use binary search since the table is sorted in the cache file. \
The first matching entry in the table is returned. \
It is important to use the same algorithm as used while generating \
the cache file. */ \
do \
{ \
left = 0; \
right = cache->nlibs - 1; \
\
while (left <= right) \
{ \
__typeof__ (cache->libs[0].key) key; \
\
middle = (left + right) / 2; \
\
key = cache->libs[middle].key; \
\
/* Make sure string table indices are not bogus before using \
them. */ \
if (! _dl_cache_verify_ptr (key)) \
{ \
cmpres = 1; \
break; \
} \
\
/* Actually compare the entry with the key. */ \
cmpres = _dl_cache_libcmp (name, cache_data + key); \
if (__builtin_expect (cmpres == 0, 0)) \
{ \
/* Found it. LEFT now marks the last entry for which we \
know the name is correct. */ \
left = middle; \
\
/* There might be entries with this name before the one we \
found. So we have to find the beginning. */ \
while (middle > 0) \
{ \
__typeof__ (cache->libs[0].key) key; \
\
key = cache->libs[middle - 1].key; \
/* Make sure string table indices are not bogus before \
using them. */ \
if (! _dl_cache_verify_ptr (key) \
/* Actually compare the entry. */ \
|| _dl_cache_libcmp (name, cache_data + key) != 0) \
break; \
--middle; \
} \
\
do \
{ \
int flags; \
__typeof__ (cache->libs[0]) *lib = &cache->libs[middle]; \
\
/* Only perform the name test if necessary. */ \
if (middle > left \
/* We haven't seen this string so far. Test whether the \
index is ok and whether the name matches. Otherwise \
we are done. */ \
&& (! _dl_cache_verify_ptr (lib->key) \
|| (_dl_cache_libcmp (name, cache_data + lib->key) \
!= 0))) \
break; \
\
flags = lib->flags; \
if (_dl_cache_check_flags (flags) \
&& _dl_cache_verify_ptr (lib->value)) \
{ \
if (best == NULL || flags == _dl_correct_cache_id) \
{ \
HWCAP_CHECK; \
best = cache_data + lib->value; \
\
if (flags == _dl_correct_cache_id) \
/* We've found an exact match for the shared \
object and no general `ELF' release. Stop \
searching. */ \
break; \
} \
} \
} \
while (++middle <= right); \
break; \
} \
\
if (cmpres < 0) \
left = middle + 1; \
else \
right = middle - 1; \
} \
} \
while (0)
@ -168,7 +168,7 @@ _dl_load_cache_lookup (const char *name)
- the old format with the new format in it
- only the new format
The following checks if the cache contains any of these formats. */
if (file != NULL && cachesize > sizeof *cache
if (file != MAP_FAILED && cachesize > sizeof *cache
&& memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1) == 0)
{
size_t offset;
@ -185,7 +185,7 @@ _dl_load_cache_lookup (const char *name)
sizeof CACHEMAGIC_VERSION_NEW - 1) != 0)
cache_new = (void *) -1;
}
else if (file != NULL && cachesize > sizeof *cache_new
else if (file != MAP_FAILED && cachesize > sizeof *cache_new
&& memcmp (file, CACHEMAGIC_VERSION_NEW,
sizeof CACHEMAGIC_VERSION_NEW - 1) == 0)
{
@ -194,7 +194,7 @@ _dl_load_cache_lookup (const char *name)
}
else
{
if (file != NULL)
if (file != MAP_FAILED)
__munmap (file, cachesize);
cache = (void *) -1;
}
@ -227,16 +227,15 @@ _dl_load_cache_lookup (const char *name)
platform = 1ULL << platform;
/* Only accept hwcap if it's for the right platform. */
#define HWCAP_CHECK \
if (_dl_osversion && cache_new->libs[middle].osversion > _dl_osversion) \
continue; \
if (_DL_PLATFORMS_COUNT && platform != -1 \
&& (cache_new->libs[middle].hwcap & _DL_HWCAP_PLATFORM) != 0 \
&& (cache_new->libs[middle].hwcap & _DL_HWCAP_PLATFORM) != platform) \
continue; \
if (hwcap \
&& ((cache_new->libs[middle].hwcap & *hwcap & ~_DL_HWCAP_PLATFORM) \
> *hwcap)) \
#define HWCAP_CHECK \
if (_dl_osversion && cache_new->libs[middle].osversion > _dl_osversion) \
continue; \
if (_DL_PLATFORMS_COUNT && platform != -1 \
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != 0 \
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != platform) \
continue; \
if (hwcap \
&& ((lib->hwcap & *hwcap & ~_DL_HWCAP_PLATFORM) > *hwcap)) \
continue
SEARCH_CACHE (cache_new);
}

5
sysdeps/generic/ldsodefs.h
View File

@ -495,8 +495,9 @@ extern const char *_dl_load_cache_lookup (const char *name)
once needed. */
extern void _dl_unload_cache (void);
/* System-dependent function to read a file's whole contents
in the most convenient manner available. */
/* System-dependent function to read a file's whole contents in the
most convenient manner available. *SIZEP gets the size of the
file. On error MAP_FAILED is returned. */
extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
int prot)
internal_function;