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authorFlorian Weimer <fweimer@redhat.com>2021-03-01 15:56:36 +0100
committerFlorian Weimer <fweimer@redhat.com>2021-03-01 15:58:01 +0100
commit9fc813e1a37d2e2d5e85a97d5ac4fc1c15d839fb (patch)
tree62e5002b97acab6f776476c2325a37097693b0ea /sysdeps/i386
parent764e9a0334350f52ab6953bef1db97f9b2e89ca5 (diff)
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Implement <unwind-link.h> for dynamically loading the libgcc_s unwinder
This will be used to consolidate the libgcc_s access for backtrace and pthread_cancel. Unlike the existing backtrace implementations, it provides some hardening based on pointer mangling. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps/i386')
-rw-r--r--sysdeps/i386/unwind-arch.h39
1 files changed, 39 insertions, 0 deletions
diff --git a/sysdeps/i386/unwind-arch.h b/sysdeps/i386/unwind-arch.h
new file mode 100644
index 0000000..01c74fe
--- /dev/null
+++ b/sysdeps/i386/unwind-arch.h
@@ -0,0 +1,39 @@
+/* Dynamic loading of the libgcc unwinder. i386 customization.
+ 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 _ARCH_UNWIND_LINK_H
+#define _ARCH_UNWIND_LINK_H
+
+#define UNWIND_LINK_GETIP 1
+#define UNWIND_LINK_FRAME_STATE_FOR 1
+#define UNWIND_LINK_FRAME_ADJUSTMENT 0
+#define UNWIND_LINK_EXTRA_FIELDS \
+ __typeof (_Unwind_GetGR) *ptr__Unwind_GetGR;
+#define UNWIND_LINK_EXTRA_INIT_SHARED \
+ local.ptr__Unwind_GetGR \
+ = __libc_dlsym (local_libgcc_handle, "_Unwind_GetGR"); \
+ assert (local.ptr__Unwind_GetGR != NULL);
+#ifdef PTR_MANGLE
+# define UNWIND_LINK_EXTRA_INIT \
+ UNWIND_LINK_EXTRA_INIT_SHARED \
+ PTR_MANGLE (local.ptr__Unwind_GetGR);
+#else
+# define UNWIND_LINK_EXTRA_INIT UNWIND_LINK_EXTRA_INIT_SHARED
+#endif
+
+#endif /* _ARCH_UNWIND_LINK_H */