aboutsummaryrefslogtreecommitdiff
path: root/bits
diff options
context:
space:
mode:
authorFlorian Weimer <fweimer@redhat.com>2021-12-28 22:52:56 +0100
committerFlorian Weimer <fweimer@redhat.com>2021-12-28 22:52:56 +0100
commit5d28a8962dcb6ec056b81d730e3c6fb57185a210 (patch)
tree3d714aaef575deba322fa5a1e29c76c6f96dc850 /bits
parent83b8d5027d2f80c4603cd706da95d6c9a09a4e16 (diff)
downloadglibc-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 'bits')
-rw-r--r--bits/dl_find_object.h32
1 files changed, 32 insertions, 0 deletions
diff --git a/bits/dl_find_object.h b/bits/dl_find_object.h
new file mode 100644
index 0000000..5d652c9
--- /dev/null
+++ b/bits/dl_find_object.h
@@ -0,0 +1,32 @@
+/* System dependent definitions for finding objects by address.
+ Copyright (C) 2021 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 _DLFCN_H
+# error "Never use <bits/dl_find_object.h> directly; include <dlfcn.h> instead."
+#endif
+
+/* This implementation does not have a dlfo_eh_dbase member in struct
+ dl_find_object. */
+#define DLFO_STRUCT_HAS_EH_DBASE 0
+
+/* This implementation does not have a dlfo_eh_count member in struct
+ dl_find_object. */
+#define DLFO_STRUCT_HAS_EH_COUNT 0
+
+/* The ELF segment which contains the exception handling data. */
+#define DLFO_EH_SEGMENT_TYPE PT_GNU_EH_FRAME