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| author | Florian Weimer <fweimer@redhat.com> | 2021-12-28 22:52:56 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2021-12-28 22:52:56 +0100 |
| commit | 5d28a8962dcb6ec056b81d730e3c6fb57185a210 (patch) | |
| tree | 3d714aaef575deba322fa5a1e29c76c6f96dc850 /dlfcn | |
| parent | 83b8d5027d2f80c4603cd706da95d6c9a09a4e16 (diff) | |
| download | glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.zip glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.tar.gz glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.tar.bz2 | |
elf: Add _dl_find_object function
It can be used to speed up the libgcc unwinder, and the internal
_dl_find_dso_for_object function (which is used for caller
identification in dlopen and related functions, and in dladdr).
_dl_find_object is in the internal namespace due to bug 28503.
If libgcc switches to _dl_find_object, this namespace issue will
be fixed. It is located in libc for two reasons: it is necessary
to forward the call to the static libc after static dlopen, and
there is a link ordering issue with -static-libgcc and libgcc_eh.a
because libc.so is not a linker script that includes ld.so in the
glibc build tree (so that GCC's internal -lc after libgcc_eh.a does
not pick up ld.so).
It is necessary to do the i386 customization in the
sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because
otherwise, multilib installations are broken.
The implementation uses software transactional memory, as suggested
by Torvald Riegel. Two copies of the supporting data structures are
used, also achieving full async-signal-safety.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'dlfcn')
| -rw-r--r-- | dlfcn/Makefile | 2 | ||||
| -rw-r--r-- | dlfcn/dlfcn.h | 27 |
2 files changed, 28 insertions, 1 deletions
diff --git a/dlfcn/Makefile b/dlfcn/Makefile index 6bbfbb8..3f5c1ba 100644 --- a/dlfcn/Makefile +++ b/dlfcn/Makefile @@ -19,7 +19,7 @@ subdir := dlfcn include ../Makeconfig -headers := bits/dlfcn.h dlfcn.h +headers := bits/dlfcn.h bits/dl_find_object.h dlfcn.h extra-libs := libdl libdl-routines := libdl-compat routines = \ diff --git a/dlfcn/dlfcn.h b/dlfcn/dlfcn.h index 4a3b870..a7e03c0 100644 --- a/dlfcn/dlfcn.h +++ b/dlfcn/dlfcn.h @@ -28,6 +28,8 @@ #ifdef __USE_GNU +#include <bits/dl_find_object.h> + /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT the run-time address of the symbol called NAME in the next shared object is returned. The "next" relation is defined by the order @@ -194,6 +196,31 @@ typedef struct Dl_serpath dls_serpath[1]; /* Actually longer, dls_cnt elements. */ # endif } Dl_serinfo; + +struct dl_find_object +{ + __extension__ unsigned long long int dlfo_flags; + void *dlfo_map_start; /* Beginning of mapping containing address. */ + void *dlfo_map_end; /* End of mapping. */ + struct link_map *dlfo_link_map; + void *dlfo_eh_frame; /* Exception handling data of the object. */ +# if DLFO_STRUCT_HAS_EH_DBASE + void *dlfo_eh_dbase; /* Base address for DW_EH_PE_datarel. */ +# if __WORDSIZE == 32 + unsigned int __dlfo_eh_dbase_pad; +# endif +# endif +# if DLFO_STRUCT_HAS_EH_COUNT + int dlfo_eh_count; /* Number of exception handling entries. */ + unsigned int __dlfo_eh_count_pad; +# endif + __extension__ unsigned long long int __dflo_reserved[7]; +}; + +/* If ADDRESS is found in an object, fill in *RESULT and return 0. + Otherwise, return -1. */ +int _dl_find_object (void *__address, struct dl_find_object *__result) __THROW; + #endif /* __USE_GNU */ |