/* Hardware capability support for run-time dynamic loader.
- Copyright (C) 2012-2020 Free Software Foundation, Inc.
+ Copyright (C) 2012-2024 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
else
to_compare = previous->name_length;
int cmp = memcmp (current->name, previous->name, to_compare);
- if (cmp >= 0
+ if (cmp > 0
|| (cmp == 0 && current->name_length >= previous->name_length))
break;
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);
/* 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 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;
-
- /* 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. */
- 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;
- *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. */
+ /* 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"));
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;
- }
-
- /* 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);
+ /* Append an empty entry for the base directory itself. */
+ target.next_pair->str = target.next_string;
+ target.next_pair->len = 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;
}
projects / thirdparty / glibc.git / blobdiff