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| author | Alan Modra <amodra@gmail.com> | 2022-04-27 14:39:10 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2022-04-28 08:50:11 +0930 |
| commit | 6f043e0ee7e477f50a44024ed0cb579d5e3f511d (patch) | |
| tree | 4529aa08035a4e795b1f18daf7f42f67c9db143e | |
| parent | 911c63a51c690dd1a97dfc587097277029baf00f (diff) | |
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Use __ehdr_start rather than _begin in _dl_start_final
__ehdr_start is already used in rltld.c:dl_main, and can serve the
same purpose as _begin. Besides tidying the code, using linker
defined section relative symbols rather than "-defsym _begin=0" better
reflects the intent of _dl_start_final use of _begin, which is to
refer to the load address of ld.so rather than absolute address zero.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
| -rw-r--r-- | elf/Makefile | 3 | ||||
| -rw-r--r-- | elf/rtld.c | 7 |
2 files changed, 4 insertions, 6 deletions
diff --git a/elf/Makefile b/elf/Makefile index 80e8552c59..fc9860edee 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1336,8 +1336,7 @@ $(objpfx)ld.so: $(objpfx)librtld.os $(ld-map) $(LINK.o) -nostdlib -nostartfiles -shared -o $@.new \ $(LDFLAGS-rtld) -Wl,-z,defs $(z-now-$(bind-now)) \ $(filter-out $(map-file),$^) $(load-map-file) \ - -Wl,-soname=$(rtld-installed-name) \ - -Wl,-defsym=_begin=0 + -Wl,-soname=$(rtld-installed-name) $(call after-link,$@.new) $(READELF) -s $@.new \ | $(AWK) '($$7 ~ /^UND(|EF)$$/ && $$1 != "0:" && $$4 != "REGISTER") { print; p=1 } END { exit p != 0 }' diff --git a/elf/rtld.c b/elf/rtld.c index be6daa1c44..3b2e05bf4c 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -440,8 +440,8 @@ static ElfW(Addr) _dl_start_final (void *arg, struct dl_start_final_info *info); #endif -/* These defined magically in the linker script. */ -extern char _begin[] attribute_hidden; +/* These are defined magically by the linker. */ +extern const ElfW(Ehdr) __ehdr_start attribute_hidden; extern char _etext[] attribute_hidden; extern char _end[] attribute_hidden; @@ -490,7 +490,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info) #endif _dl_setup_hash (&GL(dl_rtld_map)); GL(dl_rtld_map).l_real = &GL(dl_rtld_map); - GL(dl_rtld_map).l_map_start = (ElfW(Addr)) _begin; + GL(dl_rtld_map).l_map_start = (ElfW(Addr)) &__ehdr_start; GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end; GL(dl_rtld_map).l_text_end = (ElfW(Addr)) _etext; /* Copy the TLS related data if necessary. */ @@ -1741,7 +1741,6 @@ dl_main (const ElfW(Phdr) *phdr, segment that also includes the phdrs. If that's not available, we use the old method that assumes the beginning of the file is part of the lowest-addressed PT_LOAD segment. */ - extern const ElfW(Ehdr) __ehdr_start __attribute__ ((visibility ("hidden"))); /* Set up the program header information for the dynamic linker itself. It is needed in the dl_iterate_phdr callbacks. */ |