elf: Remove LD_USE_LOAD_BIAS

It is solely for prelink with PIE executables [1].

[1] https://sourceware.org/legacy-ml/libc-hacker/2003-11/msg00127.html

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
Adhemerval Zanella 2022-01-13 18:04:49 -03:00
parent d7703d3176
commit 144761540a
6 changed files with 4 additions and 22 deletions

3
NEWS
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@ -197,6 +197,9 @@ Deprecated and removed features, and other changes affecting compatibility:
functionality to obtain the program mapping address can be achieved by
using LD_TRACE_LOADED_OBJECTS to value of 2.
* The LD_USE_LOAD_BIAS has been removed. The variable was mainly used to
support prelink PIE binaries.
Changes to build and runtime requirements:
* The audit module interface version LAV_CURRENT is increased to enable

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@ -94,8 +94,7 @@ _dl_map_segments (struct link_map *l, int fd,
prefer to map such objects at; but this is only a preference,
the OS can do whatever it likes. */
ElfW(Addr) mappref
= (ELF_PREFERRED_ADDRESS (loader, maplength,
c->mapstart & GLRO(dl_use_load_bias))
= (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
- MAP_BASE_ADDR (l));
/* Remember which part of the address space this object uses. */

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@ -54,7 +54,6 @@ size_t _dl_platformlen;
int _dl_debug_mask;
int _dl_lazy;
ElfW(Addr) _dl_use_load_bias = -2;
int _dl_dynamic_weak;
/* If nonzero print warnings about problematic situations. */

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@ -365,7 +365,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
._dl_sysinfo = DL_SYSINFO_DEFAULT,
#endif
._dl_debug_fd = STDERR_FILENO,
._dl_use_load_bias = -2,
._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
#if !HAVE_TUNABLES
._dl_hwcap_mask = HWCAP_IMPORTANT,
@ -1742,12 +1741,6 @@ dl_main (const ElfW(Phdr) *phdr,
++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
++GL(dl_load_adds);
/* If LD_USE_LOAD_BIAS env variable has not been seen, default
to not using bias for non-prelinked PIEs and libraries
and using it for executables or prelinked PIEs or libraries. */
if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2)
GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0;
/* Starting from binutils-2.23, the linker will define the magic symbol
__ehdr_start to point to our own ELF header if it is visible in a
segment that also includes the phdrs. If that's not available, we use
@ -2657,12 +2650,6 @@ process_envvars (struct dl_main_state *state)
#ifdef EXTRA_LD_ENVVARS_13
EXTRA_LD_ENVVARS_13
#endif
if (!__libc_enable_secure
&& memcmp (envline, "USE_LOAD_BIAS", 13) == 0)
{
GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0;
break;
}
break;
case 14:

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@ -628,11 +628,6 @@ struct rtld_global_ro
/* Location of the binary. */
EXTERN const char *_dl_origin_path;
/* -1 if the dynamic linker should honor library load bias,
0 if not, -2 use the default (honor biases for normal
binaries, don't honor for PIEs). */
EXTERN ElfW(Addr) _dl_use_load_bias;
/* Size of the static TLS block. */
EXTERN size_t _dl_tls_static_size;

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@ -22,7 +22,6 @@
"LD_PRELOAD\0" \
"LD_PROFILE\0" \
"LD_SHOW_AUXV\0" \
"LD_USE_LOAD_BIAS\0" \
"LOCALDOMAIN\0" \
"LOCPATH\0" \
"MALLOC_TRACE\0" \