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libbacktrace: Add support for NIX_DEBUG_INFO_DIRS
Also fix tests.
1 parent 14c5fae commit 1e03848

4 files changed

Lines changed: 259 additions & 0 deletions

‎pkgs/development/libraries/libbacktrace/0002-libbacktrace-Allow-configuring-debug-dir.patch‎

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From f409ee343fe6cdc059bb411746f27a515aec66a8 Mon Sep 17 00:00:00 2001
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From: Jan Tojnar <jtojnar@gmail.com>
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Date: Sat, 24 Dec 2022 16:46:18 +0100
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Subject: [PATCH 2/4] libbacktrace: Allow configuring debug dir
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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On platforms that do not use FHS like NixOS or GNU Guix,
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the build-id directories are not under `/usr/lib/debug`.
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Let’s add `--with-separate-debug-dir` configure flag so that
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the path can be changed. The same flag is supported by gdb:
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https://github.com/bminor/binutils-gdb/blob/095f84c7e3cf85cd68c657c46b80be078f336bc9/gdb/configure.ac#L113-L115
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---
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Makefile.am | 11 ++++++-----
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configure.ac | 8 ++++++++
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elf.c | 4 ++--
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3 files changed, 16 insertions(+), 7 deletions(-)
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diff --git a/Makefile.am b/Makefile.am
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index 6eab991..da443c1 100644
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--- a/Makefile.am
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+++ b/Makefile.am
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@@ -33,7 +33,8 @@ ACLOCAL_AMFLAGS = -I config
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AM_CPPFLAGS =
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-AM_CFLAGS = $(EXTRA_FLAGS) $(WARN_FLAGS) $(PIC_FLAG)
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+AM_CFLAGS = $(EXTRA_FLAGS) $(WARN_FLAGS) $(PIC_FLAG) \
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+ -DSYSTEM_DEBUG_DIR=\"$(SEPARATE_DEBUG_DIR)\"
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include_HEADERS = backtrace.h backtrace-supported.h
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@@ -134,7 +135,7 @@ libbacktrace_noformat_la_DEPENDENCIES = $(libbacktrace_noformat_la_LIBADD)
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if HAVE_ELF
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if HAVE_OBJCOPY_DEBUGLINK
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-TEST_BUILD_ID_DIR=$(abs_builddir)/usr/lib/debug/.build-id/
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+TEST_DEBUG_DIR=$(abs_builddir)/usr/lib/debug
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check_LTLIBRARIES += libbacktrace_elf_for_test.la
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@@ -143,8 +144,8 @@ libbacktrace_elf_for_test_la_LIBADD = $(BACKTRACE_FILE) elf_for_test.lo \
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$(VIEW_FILE) $(ALLOC_FILE)
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elf_for_test.c: elf.c
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- SEARCH='^#define SYSTEM_BUILD_ID_DIR.*$$'; \
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- REPLACE="#define SYSTEM_BUILD_ID_DIR \"$(TEST_BUILD_ID_DIR)\""; \
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+ SEARCH='^#define BUILD_ID_DIR.*$$'; \
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+ REPLACE='\0\n#undef SYSTEM_DEBUG_DIR\n#define SYSTEM_DEBUG_DIR "$(TEST_DEBUG_DIR)"'; \
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$(SED) "s%$$SEARCH%$$REPLACE%" \
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$< \
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> $@.tmp
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@@ -468,7 +469,7 @@ endif HAVE_OBJCOPY_DEBUGLINK
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%_buildid: %
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./install-debuginfo-for-buildid.sh \
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- "$(TEST_BUILD_ID_DIR)" \
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+ "$(TEST_DEBUG_DIR)/.build-id" \
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$<
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$(OBJCOPY) --strip-debug $< $@
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diff --git a/configure.ac b/configure.ac
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index 7f122cb..bb590ab 100644
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--- a/configure.ac
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+++ b/configure.ac
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@@ -67,6 +67,14 @@ AM_MAINTAINER_MODE
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AC_ARG_WITH(target-subdir,
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[ --with-target-subdir=SUBDIR Configuring in a subdirectory for target])
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+AC_ARG_WITH(separate-debug-dir,
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+[ --with-separate-debug-dir=DEBUGDIR Look for global separate debug info in this path @<:@LIBDIR/debug@:>@],
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+[separate_debug_dir=$withval],
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+[separate_debug_dir=$libdir/debug])
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+
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+SEPARATE_DEBUG_DIR=$separate_debug_dir
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+AC_SUBST(SEPARATE_DEBUG_DIR)
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+
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# We must force CC to /not/ be precious variables; otherwise
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# the wrong, non-multilib-adjusted value will be used in multilibs.
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# As a side effect, we have to subst CFLAGS ourselves.
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diff --git a/elf.c b/elf.c
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index e82ecc5..8b1189c 100644
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--- a/elf.c
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+++ b/elf.c
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@@ -856,7 +856,7 @@ elf_readlink (struct backtrace_state *state, const char *filename,
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}
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}
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-#define SYSTEM_BUILD_ID_DIR "/usr/lib/debug/.build-id/"
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+#define BUILD_ID_DIR "/.build-id/"
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/* Open a separate debug info file, using the build ID to find it.
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Returns an open file descriptor, or -1.
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@@ -870,7 +870,7 @@ elf_open_debugfile_by_buildid (struct backtrace_state *state,
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backtrace_error_callback error_callback,
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void *data)
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{
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- const char * const prefix = SYSTEM_BUILD_ID_DIR;
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+ const char * const prefix = SYSTEM_DEBUG_DIR BUILD_ID_DIR;
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const size_t prefix_len = strlen (prefix);
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const char * const suffix = ".debug";
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const size_t suffix_len = strlen (suffix);
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--
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2.38.1
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‎pkgs/development/libraries/libbacktrace/0003-libbacktrace-Support-multiple-build-id-directories.patch‎

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From de122af5382d8017cae63bdee946206c6c6c23ab Mon Sep 17 00:00:00 2001
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From: Jan Tojnar <jtojnar@gmail.com>
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Date: Sat, 24 Dec 2022 20:19:27 +0100
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Subject: [PATCH 3/4] libbacktrace: Support multiple build id directories
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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gdb supports multiple debug directories separated by colons:
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https://github.com/bminor/binutils-gdb/blob/fcbfb25dcca625a7f999ec51d48b6fc3a32123c3/gdb/build-id.c#L136-L142
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This is useful for example when using dwarffs in addition
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to debug data installed using distribution’s package manager.
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---
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elf.c | 57 ++++++++++++++++++++++++++++++++++++---------------------
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1 file changed, 36 insertions(+), 21 deletions(-)
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diff --git a/elf.c b/elf.c
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index 8b1189c..65c647a 100644
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--- a/elf.c
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+++ b/elf.c
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@@ -865,12 +865,12 @@ elf_readlink (struct backtrace_state *state, const char *filename,
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when the build ID is known is in /usr/lib/debug/.build-id. */
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static int
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-elf_open_debugfile_by_buildid (struct backtrace_state *state,
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+elf_open_debugfile_by_buildid (const char * const prefix,
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+ struct backtrace_state *state,
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const char *buildid_data, size_t buildid_size,
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backtrace_error_callback error_callback,
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void *data)
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{
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- const char * const prefix = SYSTEM_DEBUG_DIR BUILD_ID_DIR;
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const size_t prefix_len = strlen (prefix);
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const char * const suffix = ".debug";
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const size_t suffix_len = strlen (suffix);
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@@ -6936,27 +6936,42 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor,
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if (buildid_data != NULL)
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{
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int d;
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+ char debug_directories[strlen(SYSTEM_DEBUG_DIR) + 1];
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+ char *debug_dir;
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- d = elf_open_debugfile_by_buildid (state, buildid_data, buildid_size,
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- error_callback, data);
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- if (d >= 0)
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- {
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- int ret;
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+ strcpy(debug_directories, SYSTEM_DEBUG_DIR);
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- elf_release_view (state, &buildid_view, error_callback, data);
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- if (debuglink_view_valid)
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- elf_release_view (state, &debuglink_view, error_callback, data);
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- if (debugaltlink_view_valid)
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- elf_release_view (state, &debugaltlink_view, error_callback, data);
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- ret = elf_add (state, "", d, NULL, 0, base_address, error_callback,
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- data, fileline_fn, found_sym, found_dwarf, NULL, 0,
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- 1, NULL, 0);
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- if (ret < 0)
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- backtrace_close (d, error_callback, data);
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- else if (descriptor >= 0)
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- backtrace_close (descriptor, error_callback, data);
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- return ret;
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- }
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+ debug_dir = strtok (debug_directories, ":");
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+ while (debug_dir != NULL)
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+ {
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+ char prefix[strlen(debug_dir) + strlen(BUILD_ID_DIR) + 1];
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+ strcpy(prefix, debug_dir);
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+ strcat(prefix, BUILD_ID_DIR);
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+
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+ d = elf_open_debugfile_by_buildid (prefix, state, buildid_data, buildid_size,
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+ error_callback, data);
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+
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+ if (d >= 0)
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+ {
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+ int ret;
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+
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+ elf_release_view (state, &buildid_view, error_callback, data);
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+ if (debuglink_view_valid)
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+ elf_release_view (state, &debuglink_view, error_callback, data);
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+ if (debugaltlink_view_valid)
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+ elf_release_view (state, &debugaltlink_view, error_callback, data);
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+ ret = elf_add (state, "", d, NULL, 0, base_address, error_callback,
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+ data, fileline_fn, found_sym, found_dwarf, NULL, 0,
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+ 1, NULL, 0);
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+ if (ret < 0)
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+ backtrace_close (d, error_callback, data);
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+ else if (descriptor >= 0)
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+ backtrace_close (descriptor, error_callback, data);
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+ return ret;
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+ }
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+
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+ debug_dir = strtok (NULL, ":");
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+ }
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}
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if (buildid_view_valid)
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--
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2.38.1
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‎pkgs/development/libraries/libbacktrace/0004-libbacktrace-Support-NIX_DEBUG_INFO_DIRS-environment.patch‎

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From a3b7510e4c9e7201a4301f2a45d8569b06354607 Mon Sep 17 00:00:00 2001
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From: Jan Tojnar <jtojnar@gmail.com>
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Date: Sat, 24 Dec 2022 20:30:22 +0100
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Subject: [PATCH 4/4] libbacktrace: Support NIX_DEBUG_INFO_DIRS environment
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variable
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Let’s make debug data lookup work on NixOS just like in gdb.
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---
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elf.c | 11 +++++++++--
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1 file changed, 9 insertions(+), 2 deletions(-)
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diff --git a/elf.c b/elf.c
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index 65c647a..5c8abc0 100644
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--- a/elf.c
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+++ b/elf.c
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@@ -6935,11 +6935,18 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor,
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if (buildid_data != NULL)
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{
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+ const char *debug_directories_immutable;
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+ const char *nix_debug = getenv ("NIX_DEBUG_INFO_DIRS");
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+ if (nix_debug != NULL)
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+ debug_directories_immutable = nix_debug;
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+ else
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+ debug_directories_immutable = SYSTEM_DEBUG_DIR;
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+
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int d;
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- char debug_directories[strlen(SYSTEM_DEBUG_DIR) + 1];
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+ char debug_directories[strlen(debug_directories_immutable) + 1];
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char *debug_dir;
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- strcpy(debug_directories, SYSTEM_DEBUG_DIR);
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+ strcpy(debug_directories, debug_directories_immutable);
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debug_dir = strtok (debug_directories, ":");
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while (debug_dir != NULL)
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--
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2.38.1
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‎pkgs/development/libraries/libbacktrace/default.nix‎

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@@ -22,6 +22,14 @@ stdenv.mkDerivation {
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# Fix tests with shared library.
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# https://github.com/ianlancetaylor/libbacktrace/pull/99
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./0001-libbacktrace-avoid-libtool-wrapping-tests.patch
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# Support multiple debug dirs.
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# https://github.com/ianlancetaylor/libbacktrace/pull/100
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./0002-libbacktrace-Allow-configuring-debug-dir.patch
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./0003-libbacktrace-Support-multiple-build-id-directories.patch
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# Support NIX_DEBUG_INFO_DIRS environment variable.
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./0004-libbacktrace-Support-NIX_DEBUG_INFO_DIRS-environment.patch
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];
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nativeBuildInputs = [

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