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elf: Remove legacy hwcaps support from the dynamic loader

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Remove support for the legacy hwcaps subdirectories from the dynamic
loader.

Signed-off-by: Javier Pello <devel@otheo.eu>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
This commit is contained in:
Javier Pello 2022-09-27 20:05:59 +02:00 committed by Adhemerval Zanella
parent d178c67535
commit 6099908fb8
3 changed files with 10 additions and 212 deletions
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6
elf/Makefile
View File

@ -2689,12 +2689,6 @@ $(objpfx)tst-rtld-help.out: $(objpfx)ld.so
$(test-wrapper) $(rtld-prefix) --help > $@; \
status=$$?; \
echo "info: ld.so exit status: $$status" >> $@; \
if ! grep -q 'Legacy HWCAP subdirectories under library search path directories' $@; then \
echo "error: missing subdirectory pattern" >> $@; \
if test $$status -eq 0; then \
status=1; \
fi; \
fi; \
(exit $$status); \
$(evaluate-test)

184
elf/dl-hwcaps.c
View File

@ -170,17 +170,7 @@ _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
const char *glibc_hwcaps_mask,
size_t *sz, size_t *max_capstrlen)
{
uint64_t hwcap_mask = GET_HWCAP_MASK();
/* Determine how many important bits are set. */
uint64_t masked = GLRO(dl_hwcap) & hwcap_mask;
size_t cnt = GLRO (dl_platform) != NULL;
size_t n, m;
struct r_strlenpair *result;
struct r_strlenpair *rp;
char *cp;
/* glibc-hwcaps subdirectories. These are exempted from the power
set construction below. */
/* glibc-hwcaps subdirectories. */
uint32_t hwcaps_subdirs_active = _dl_hwcaps_subdirs_active ();
struct hwcaps_counts hwcaps_counts = { 0, };
update_hwcaps_counts (&hwcaps_counts, glibc_hwcaps_prepend, -1, NULL);
@ -193,72 +183,14 @@ _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
/* Each hwcaps subdirectory has a GLIBC_HWCAPS_PREFIX string prefix
and a "/" suffix once stored in the result. */
hwcaps_counts.maximum_length += strlen (GLIBC_HWCAPS_PREFIX) + 1;
size_t hwcaps_sz = (hwcaps_counts.count * (strlen (GLIBC_HWCAPS_PREFIX) + 1)
size_t total = (hwcaps_counts.count * (strlen (GLIBC_HWCAPS_PREFIX) + 1)
+ hwcaps_counts.total_length);
/* Count the number of bits set in the masked value. */
for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n)
if ((masked & (1ULL << n)) != 0)
++cnt;
*sz = hwcaps_counts.count + 1;
/* For TLS enabled builds always add 'tls'. */
++cnt;
/* Create temporary data structure to generate result table. */
struct r_strlenpair temp[cnt];
m = 0;
for (n = 0; masked != 0; ++n)
if ((masked & (1ULL << n)) != 0)
{
temp[m].str = _dl_hwcap_string (n);
temp[m].len = strlen (temp[m].str);
masked ^= 1ULL << n;
++m;
}
if (GLRO (dl_platform) != NULL)
{
temp[m].str = GLRO (dl_platform);
temp[m].len = GLRO (dl_platformlen);
++m;
}
temp[m].str = "tls";
temp[m].len = 3;
++m;
assert (m == cnt);
/* Determine the total size of all strings together. */
size_t total;
if (cnt == 1)
total = temp[0].len + 1;
else
{
total = temp[0].len + temp[cnt - 1].len + 2;
if (cnt > 2)
{
total <<= 1;
for (n = 1; n + 1 < cnt; ++n)
total += temp[n].len + 1;
if (cnt > 3
&& (cnt >= sizeof (size_t) * 8
|| total + (sizeof (*result) << 3)
>= (1UL << (sizeof (size_t) * 8 - cnt + 3))))
_dl_signal_error (ENOMEM, NULL, NULL,
N_("cannot create capability list"));
total <<= cnt - 3;
}
}
*sz = hwcaps_counts.count + (1 << cnt);
/* This is the overall result, including both glibc-hwcaps
subdirectories and the legacy hwcaps subdirectories using the
power set construction. */
total += hwcaps_sz;
/* This is the overall result. */
struct r_strlenpair *overall_result
= malloc (*sz * sizeof (*result) + total);
= malloc (*sz * sizeof (*overall_result) + total);
if (overall_result == NULL)
_dl_signal_error (ENOMEM, NULL, NULL,
N_("cannot create capability list"));
@ -271,110 +203,14 @@ _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
copy_hwcaps (&target, glibc_hwcaps_prepend, -1, NULL);
copy_hwcaps (&target, _dl_hwcaps_subdirs,
hwcaps_subdirs_active, glibc_hwcaps_mask);
/* Set up the write target for the power set construction. */
result = target.next_pair;
cp = target.next_string;
/* Append an empty entry for the base directory itself. */
target.next_pair->str = target.next_string;
target.next_pair->len = 0;
}
/* Power set construction begins here. We use a very compressed way
to store the various combinations of capability names. */
if (cnt == 1)
{
result[0].str = cp;
result[0].len = temp[0].len + 1;
result[1].str = cp;
result[1].len = 0;
cp = __mempcpy (cp, temp[0].str, temp[0].len);
*cp = '/';
if (result[0].len > hwcaps_counts.maximum_length)
*max_capstrlen = result[0].len;
else
*max_capstrlen = hwcaps_counts.maximum_length;
return overall_result;
}
/* Fill in the information. This follows the following scheme
(indices from TEMP for four strings):
entry #0: 0, 1, 2, 3 binary: 1111
#1: 0, 1, 3 1101
#2: 0, 2, 3 1011
#3: 0, 3 1001
This allows the representation of all possible combinations of
capability names in the string. First generate the strings. */
result[1].str = result[0].str = cp;
#define add(idx) \
cp = __mempcpy (__mempcpy (cp, temp[idx].str, temp[idx].len), "/", 1);
if (cnt == 2)
{
add (1);
add (0);
}
else
{
n = 1 << (cnt - 1);
do
{
n -= 2;
/* We always add the last string. */
add (cnt - 1);
/* Add the strings which have the bit set in N. */
for (m = cnt - 2; m > 0; --m)
if ((n & (1 << m)) != 0)
add (m);
/* Always add the first string. */
add (0);
}
while (n != 0);
}
#undef add
/* Now we are ready to install the string pointers and length. */
for (n = 0; n < (1UL << cnt); ++n)
result[n].len = 0;
n = cnt;
do
{
size_t mask = 1 << --n;
rp = result;
for (m = 1 << cnt; m > 0; ++rp)
if ((--m & mask) != 0)
rp->len += temp[n].len + 1;
}
while (n != 0);
/* The first half of the strings all include the first string. */
n = (1 << cnt) - 2;
rp = &result[2];
while (n != (1UL << (cnt - 1)))
{
if ((--n & 1) != 0)
rp[0].str = rp[-2].str + rp[-2].len;
else
rp[0].str = rp[-1].str;
++rp;
}
/* The second half starts right after the first part of the string of
the corresponding entry in the first half. */
do
{
rp[0].str = rp[-(1 << (cnt - 1))].str + temp[cnt - 1].len + 1;
++rp;
}
while (--n != 0);
/* The maximum string length. */
if (result[0].len > hwcaps_counts.maximum_length)
*max_capstrlen = result[0].len;
else
*max_capstrlen = hwcaps_counts.maximum_length;
*max_capstrlen = hwcaps_counts.maximum_length;
return overall_result;
}

32
elf/dl-usage.c
View File

@ -193,37 +193,6 @@ print_hwcaps_subdirectories (const struct dl_main_state *state)
No subdirectories of glibc-hwcaps directories are searched.\n");
}
/* Write a list of hwcap subdirectories to standard output. See
_dl_important_hwcaps in dl-hwcaps.c. */
static void
print_legacy_hwcap_directories (void)
{
_dl_printf ("\n\
Legacy HWCAP subdirectories under library search path directories:\n");
const char *platform = GLRO (dl_platform);
if (platform != NULL)
_dl_printf (" %s (AT_PLATFORM; supported, searched)\n", platform);
_dl_printf (" tls (supported, searched)\n");
uint64_t hwcap_mask = GET_HWCAP_MASK();
uint64_t searched = GLRO (dl_hwcap) & hwcap_mask;
for (int n = 63; n >= 0; --n)
{
uint64_t bit = 1ULL << n;
if (HWCAP_IMPORTANT & bit)
{
_dl_printf (" %s", _dl_hwcap_string (n));
bool first = true;
print_hwcap_1 (&first, GLRO (dl_hwcap) & bit, "supported");
print_hwcap_1 (&first, !(hwcap_mask & bit), "masked");
print_hwcap_1 (&first, searched & bit, "searched");
print_hwcap_1_finish (&first);
}
}
}
void
_dl_help (const char *argv0, struct dl_main_state *state)
{
@ -270,6 +239,5 @@ This program interpreter self-identifies as: " RTLD "\n\
argv0);
print_search_path_for_help (state);
print_hwcaps_subdirectories (state);
print_legacy_hwcap_directories ();
_exit (EXIT_SUCCESS);
}