commit 50a2d83c08a94a10f88a1fedeb7a6e3667a6b732
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Apr 24 22:13:03 2020 +0200
elf: Introduce <elf_machine_sym_no_match.h>
MIPS needs to ignore certain existing symbols during symbol lookup.
The old scheme uses the ELF_MACHINE_SYM_NO_MATCH macro, with an
inline function, within its own header, with a sysdeps override for
MIPS. This allows re-use of the function from another file (without
having to include <dl-machine.h> or providing the default definition
for ELF_MACHINE_SYM_NO_MATCH).
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index e4c479de9a1fd6ec..47acd134600b44b5 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -28,18 +28,12 @@
#include <libc-lock.h>
#include <tls.h>
#include <atomic.h>
+#include <elf_machine_sym_no_match.h>
#include <assert.h>
-/* Return nonzero if check_match should consider SYM to fail to match a
- symbol reference for some machine-specific reason. */
-#ifndef ELF_MACHINE_SYM_NO_MATCH
-# define ELF_MACHINE_SYM_NO_MATCH(sym) 0
-#endif
-
#define VERSTAG(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag))
-
struct sym_val
{
const ElfW(Sym) *s;
@@ -78,7 +72,7 @@ check_match (const char *const undef_name,
if (__glibc_unlikely ((sym->st_value == 0 /* No value. */
&& sym->st_shndx != SHN_ABS
&& stt != STT_TLS)
- || ELF_MACHINE_SYM_NO_MATCH (sym)
+ || elf_machine_sym_no_match (sym)
|| (type_class & (sym->st_shndx == SHN_UNDEF))))
return NULL;
diff --git a/sysdeps/generic/elf_machine_sym_no_match.h b/sysdeps/generic/elf_machine_sym_no_match.h
new file mode 100644
index 0000000000000000..27155de4c0358460
--- /dev/null
+++ b/sysdeps/generic/elf_machine_sym_no_match.h
@@ -0,0 +1,34 @@
+/* Function to ignore certain symbol matches for machine-specific reasons.
+ Copyright (C) 2020 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
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _ELF_MACHINE_SYM_NO_MATCH_H
+#define _ELF_MACHINE_SYM_NO_MATCH_H
+
+#include <link.h>
+#include <stdbool.h>
+
+/* This can be customized to ignore certain symbols during lookup in
+ case there are machine-specific rules to disregard some
+ symbols. */
+static inline bool
+elf_machine_sym_no_match (const ElfW(Sym) *sym)
+{
+ return false;
+}
+
+#endif /* _ELF_MACHINE_SYM_NO_MATCH_H */
diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h
index 91fc640388a735c7..b41e10647d81843b 100644
--- a/sysdeps/mips/dl-machine.h
+++ b/sysdeps/mips/dl-machine.h
@@ -467,21 +467,6 @@ elf_machine_plt_value (struct link_map *map, const ElfW(Rel) *reloc,
return value;
}
-/* The semantics of zero/non-zero values of undefined symbols differs
- depending on whether the non-PIC ABI is in use. Under the non-PIC
- ABI, a non-zero value indicates that there is an address reference
- to the symbol and thus it must always be resolved (except when
- resolving a jump slot relocation) to the PLT entry whose address is
- provided as the symbol's value; a zero value indicates that this
- canonical-address behaviour is not required. Yet under the classic
- MIPS psABI, a zero value indicates that there is an address
- reference to the function and the dynamic linker must resolve the
- symbol immediately upon loading. To avoid conflict, symbols for
- which the dynamic linker must assume the non-PIC ABI semantics are
- marked with the STO_MIPS_PLT flag. */
-#define ELF_MACHINE_SYM_NO_MATCH(sym) \
- ((sym)->st_shndx == SHN_UNDEF && !((sym)->st_other & STO_MIPS_PLT))
-
#endif /* !dl_machine_h */
#ifdef RESOLVE_MAP
diff --git a/sysdeps/mips/elf_machine_sym_no_match.h b/sysdeps/mips/elf_machine_sym_no_match.h
new file mode 100644
index 0000000000000000..9d09e5fa2db1ff6c
--- /dev/null
+++ b/sysdeps/mips/elf_machine_sym_no_match.h
@@ -0,0 +1,43 @@
+/* MIPS-specific handling of undefined symbols.
+ Copyright (C) 2008-2020 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
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _ELF_MACHINE_SYM_NO_MATCH_H
+#define _ELF_MACHINE_SYM_NO_MATCH_H
+
+#include <link.h>
+#include <stdbool.h>
+
+/* The semantics of zero/non-zero values of undefined symbols differs
+ depending on whether the non-PIC ABI is in use. Under the non-PIC
+ ABI, a non-zero value indicates that there is an address reference
+ to the symbol and thus it must always be resolved (except when
+ resolving a jump slot relocation) to the PLT entry whose address is
+ provided as the symbol's value; a zero value indicates that this
+ canonical-address behaviour is not required. Yet under the classic
+ MIPS psABI, a zero value indicates that there is an address
+ reference to the function and the dynamic linker must resolve the
+ symbol immediately upon loading. To avoid conflict, symbols for
+ which the dynamic linker must assume the non-PIC ABI semantics are
+ marked with the STO_MIPS_PLT flag. */
+static inline bool
+elf_machine_sym_no_match (const ElfW(Sym) *sym)
+{
+ return sym->st_shndx == SHN_UNDEF && !(sym->st_other & STO_MIPS_PLT);
+}
+
+#endif /* _ELF_MACHINE_SYM_NO_MATCH_H */