From 9283471ba0d8b605a5ddf8cbd2814d81d4dd8550 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Wed, 20 Sep 2017 21:09:37 +0000 Subject: [PATCH] re PR sanitizer/77631 (no symbols in backtrace shown by ASan when debug info is split) PR sanitizer/77631 Support for external debug info. * elf.c: Include , , . (S_ISLNK): Define if not defined. (xstrnlen): Define if strnlen is not available. (b_elf_note): Define type. (NT_GNU_BUILD_ID): Define macro. (elf_crc32, elf_crc32_file): New static functions. (elf_is_symlink, elf_readlink): New static functions. (elf_open_debugfile_by_buildid): New static function. (elf_try_debugfile): New static function. (elf_find_debugfile_by_debuglink): New static function. (elf_open_debugfile_by_debuglink): New static function. (elf_add): Add filename and debuginfo parameters. Adjust all callers. Look for external debug info notes, and try to fetch debug info from external file. (struct phdr_data): Add exe_filename field. (phdr_callback): Pass filename to elf_add. (backtrace_initialize): Add filename parameter. * internal.h (backtrace_initialize): Add filename parameter. * fileline.c (fileline_initialize): Pass filename to backtrace_initialize. * pecoff.c (fileline_initialize): Add unused filename parameter. * unknown.c (fileline_initialize): Likewise. * xcoff.c (fileline_initialize): Likewise. * configure.ac: Check for objcopy --add-gnu-debuglink. * Makefile.am (dtest): New test target. * configure, Makefile.in: Rebuild. Co-Authored-By: Denis Khalikov From-SVN: r253032 --- libbacktrace/ChangeLog | 32 +++ libbacktrace/Makefile.am | 10 + libbacktrace/Makefile.in | 8 +- libbacktrace/configure | 78 ++++++- libbacktrace/configure.ac | 14 ++ libbacktrace/elf.c | 568 +++++++++++++++++++++++++++++++++++++++++++++- libbacktrace/fileline.c | 6 +- libbacktrace/internal.h | 1 + libbacktrace/pecoff.c | 3 +- libbacktrace/unknown.c | 1 + libbacktrace/xcoff.c | 3 +- 11 files changed, 705 insertions(+), 19 deletions(-) diff --git a/libbacktrace/ChangeLog b/libbacktrace/ChangeLog index f3b7486..731716f 100644 --- a/libbacktrace/ChangeLog +++ b/libbacktrace/ChangeLog @@ -1,3 +1,35 @@ +2017-09-20 Ian Lance Taylor + Denis Khalikov + + PR sanitizer/77631 + Support for external debug info. + * elf.c: Include , , . + (S_ISLNK): Define if not defined. + (xstrnlen): Define if strnlen is not available. + (b_elf_note): Define type. + (NT_GNU_BUILD_ID): Define macro. + (elf_crc32, elf_crc32_file): New static functions. + (elf_is_symlink, elf_readlink): New static functions. + (elf_open_debugfile_by_buildid): New static function. + (elf_try_debugfile): New static function. + (elf_find_debugfile_by_debuglink): New static function. + (elf_open_debugfile_by_debuglink): New static function. + (elf_add): Add filename and debuginfo parameters. Adjust all + callers. Look for external debug info notes, and try to fetch + debug info from external file. + (struct phdr_data): Add exe_filename field. + (phdr_callback): Pass filename to elf_add. + (backtrace_initialize): Add filename parameter. + * internal.h (backtrace_initialize): Add filename parameter. + * fileline.c (fileline_initialize): Pass filename to + backtrace_initialize. + * pecoff.c (fileline_initialize): Add unused filename parameter. + * unknown.c (fileline_initialize): Likewise. + * xcoff.c (fileline_initialize): Likewise. + * configure.ac: Check for objcopy --add-gnu-debuglink. + * Makefile.am (dtest): New test target. + * configure, Makefile.in: Rebuild. + 2017-09-12 Steve Ellcey PR other/81096 diff --git a/libbacktrace/Makefile.am b/libbacktrace/Makefile.am index 120beb1..64b888b 100644 --- a/libbacktrace/Makefile.am +++ b/libbacktrace/Makefile.am @@ -122,6 +122,16 @@ ttest_LDADD = libbacktrace.la endif HAVE_PTHREAD +if HAVE_OBJCOPY_DEBUGLINK + +TESTS += dtest + +dtest: btest + $(OBJCOPY) --only-keep-debug btest btest.debug + $(OBJCOPY) --strip-debug --add-gnu-debuglink=btest.debug btest dtest + +endif HAVE_OBJCOPY_DEBUGLINK + endif NATIVE # We can't use automake's automatic dependency tracking, because it diff --git a/libbacktrace/Makefile.in b/libbacktrace/Makefile.in index 2d8c212..66ab5bf 100644 --- a/libbacktrace/Makefile.in +++ b/libbacktrace/Makefile.in @@ -86,6 +86,7 @@ target_triplet = @target@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) @NATIVE_TRUE@am__append_1 = btest stest edtest @HAVE_PTHREAD_TRUE@@NATIVE_TRUE@am__append_2 = ttest +@HAVE_OBJCOPY_DEBUGLINK_TRUE@@NATIVE_TRUE@am__append_3 = dtest subdir = . DIST_COMMON = README ChangeLog $(srcdir)/Makefile.in \ $(srcdir)/Makefile.am $(top_srcdir)/configure \ @@ -217,6 +218,7 @@ MAKEINFO = @MAKEINFO@ MKDIR_P = @MKDIR_P@ NM = @NM@ NMEDIT = @NMEDIT@ +OBJCOPY = @OBJCOPY@ OBJDUMP = @OBJDUMP@ OBJEXT = @OBJEXT@ OTOOL = @OTOOL@ @@ -343,7 +345,7 @@ libbacktrace_la_LIBADD = \ $(ALLOC_FILE) libbacktrace_la_DEPENDENCIES = $(libbacktrace_la_LIBADD) -TESTS = $(check_PROGRAMS) +TESTS = $(check_PROGRAMS) $(am__append_3) @NATIVE_TRUE@btest_SOURCES = btest.c testlib.c @NATIVE_TRUE@btest_CFLAGS = $(AM_CFLAGS) -g -O @NATIVE_TRUE@btest_LDADD = libbacktrace.la @@ -799,6 +801,10 @@ uninstall-am: @NATIVE_TRUE@ cat $(srcdir)/edtest2.c > tmp-edtest2_build.c @NATIVE_TRUE@ $(SHELL) $(srcdir)/../move-if-change tmp-edtest2_build.c edtest2_build.c @NATIVE_TRUE@ echo timestamp > $@ + +@HAVE_OBJCOPY_DEBUGLINK_TRUE@@NATIVE_TRUE@dtest: btest +@HAVE_OBJCOPY_DEBUGLINK_TRUE@@NATIVE_TRUE@ $(OBJCOPY) --only-keep-debug btest btest.debug +@HAVE_OBJCOPY_DEBUGLINK_TRUE@@NATIVE_TRUE@ $(OBJCOPY) --strip-debug --add-gnu-debuglink=btest.debug btest dtest alloc.lo: config.h backtrace.h internal.h backtrace.lo: config.h backtrace.h internal.h btest.lo: (INCDIR)/filenames.h backtrace.h backtrace-supported.h diff --git a/libbacktrace/configure b/libbacktrace/configure index 3576734..3ef9331 100755 --- a/libbacktrace/configure +++ b/libbacktrace/configure @@ -604,6 +604,9 @@ LTLIBOBJS LIBOBJS NATIVE_FALSE NATIVE_TRUE +HAVE_OBJCOPY_DEBUGLINK_FALSE +HAVE_OBJCOPY_DEBUGLINK_TRUE +OBJCOPY HAVE_PTHREAD_FALSE HAVE_PTHREAD_TRUE PTHREAD_CFLAGS @@ -746,7 +749,8 @@ CFLAGS LDFLAGS LIBS CPPFLAGS -CPP' +CPP +OBJCOPY' # Initialize some variables set by options. @@ -1396,6 +1400,7 @@ Some influential environment variables: CPPFLAGS C/C++/Objective C preprocessor flags, e.g. -I if you have headers in a nonstandard directory CPP C preprocessor + OBJCOPY location of objcopy Use these variables to override the choices made by `configure' or to help it to find libraries and programs with nonstandard names/locations. @@ -11136,7 +11141,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11139 "configure" +#line 11144 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -11242,7 +11247,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11245 "configure" +#line 11250 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -12761,6 +12766,69 @@ else fi + +# Extract the first word of "objcopy", so it can be a program name with args. +set dummy objcopy; ac_word=$2 +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5 +$as_echo_n "checking for $ac_word... " >&6; } +if test "${ac_cv_prog_OBJCOPY+set}" = set; then : + $as_echo_n "(cached) " >&6 +else + if test -n "$OBJCOPY"; then + ac_cv_prog_OBJCOPY="$OBJCOPY" # Let the user override the test. +else +as_save_IFS=$IFS; IFS=$PATH_SEPARATOR +for as_dir in $PATH +do + IFS=$as_save_IFS + test -z "$as_dir" && as_dir=. + for ac_exec_ext in '' $ac_executable_extensions; do + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then + ac_cv_prog_OBJCOPY="objcopy" + $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 + break 2 + fi +done + done +IFS=$as_save_IFS + +fi +fi +OBJCOPY=$ac_cv_prog_OBJCOPY +if test -n "$OBJCOPY"; then + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OBJCOPY" >&5 +$as_echo "$OBJCOPY" >&6; } +else + { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5 +$as_echo "no" >&6; } +fi + + +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether objcopy supports debuglink" >&5 +$as_echo_n "checking whether objcopy supports debuglink... " >&6; } +if test "${libbacktrace_cv_objcopy_debuglink+set}" = set; then : + $as_echo_n "(cached) " >&6 +else + if test -n "${with_target_subdir}"; then + libbacktrace_cv_objcopy_debuglink=no +elif ${OBJCOPY} --add-gnu-debuglink=x /bin/ls /tmp/ls$$; then + rm -f /tmp/ls$$ + libbacktrace_cv_objcopy_debuglink=yes +else + libbacktrace_cv_objcopy_debuglink=no +fi +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libbacktrace_cv_objcopy_debuglink" >&5 +$as_echo "$libbacktrace_cv_objcopy_debuglink" >&6; } + if test "$libbacktrace_cv_objcopy_debuglink" = yes; then + HAVE_OBJCOPY_DEBUGLINK_TRUE= + HAVE_OBJCOPY_DEBUGLINK_FALSE='#' +else + HAVE_OBJCOPY_DEBUGLINK_TRUE='#' + HAVE_OBJCOPY_DEBUGLINK_FALSE= +fi + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether tests can run" >&5 $as_echo_n "checking whether tests can run... " >&6; } if test "${libbacktrace_cv_sys_native+set}" = set; then : @@ -12927,6 +12995,10 @@ if test -z "${HAVE_PTHREAD_TRUE}" && test -z "${HAVE_PTHREAD_FALSE}"; then as_fn_error "conditional \"HAVE_PTHREAD\" was never defined. Usually this means the macro was only invoked conditionally." "$LINENO" 5 fi +if test -z "${HAVE_OBJCOPY_DEBUGLINK_TRUE}" && test -z "${HAVE_OBJCOPY_DEBUGLINK_FALSE}"; then + as_fn_error "conditional \"HAVE_OBJCOPY_DEBUGLINK\" was never defined. +Usually this means the macro was only invoked conditionally." "$LINENO" 5 +fi if test -z "${NATIVE_TRUE}" && test -z "${NATIVE_FALSE}"; then as_fn_error "conditional \"NATIVE\" was never defined. Usually this means the macro was only invoked conditionally." "$LINENO" 5 diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac index e644c7d..97e6e96 100644 --- a/libbacktrace/configure.ac +++ b/libbacktrace/configure.ac @@ -404,6 +404,20 @@ AC_SUBST(PTHREAD_CFLAGS) AM_CONDITIONAL(HAVE_PTHREAD, test "$libgo_cv_lib_pthread" = yes) +AC_ARG_VAR(OBJCOPY, [location of objcopy]) +AC_CHECK_PROG(OBJCOPY, objcopy, objcopy,) +AC_CACHE_CHECK([whether objcopy supports debuglink], +[libbacktrace_cv_objcopy_debuglink], +[if test -n "${with_target_subdir}"; then + libbacktrace_cv_objcopy_debuglink=no +elif ${OBJCOPY} --add-gnu-debuglink=x /bin/ls /tmp/ls$$; then + rm -f /tmp/ls$$ + libbacktrace_cv_objcopy_debuglink=yes +else + libbacktrace_cv_objcopy_debuglink=no +fi]) +AM_CONDITIONAL(HAVE_OBJCOPY_DEBUGLINK, test "$libbacktrace_cv_objcopy_debuglink" = yes) + AC_CACHE_CHECK([whether tests can run], [libbacktrace_cv_sys_native], [AC_RUN_IFELSE([AC_LANG_PROGRAM([], [return 0;])], diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c index 1471007..530d4a2 100644 --- a/libbacktrace/elf.c +++ b/libbacktrace/elf.c @@ -32,9 +32,12 @@ POSSIBILITY OF SUCH DAMAGE. */ #include "config.h" +#include #include #include #include +#include +#include #ifdef HAVE_DL_ITERATE_PHDR #include @@ -43,6 +46,35 @@ POSSIBILITY OF SUCH DAMAGE. */ #include "backtrace.h" #include "internal.h" +#ifndef S_ISLNK + #ifndef S_IFLNK + #define S_IFLNK 0120000 + #endif + #ifndef S_IFMT + #define S_IFMT 0170000 + #endif + #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK) +#endif + +#if !defined(HAVE_DECL_STRNLEN) || !HAVE_DECL_STRNLEN + +/* If strnlen is not declared, provide our own version. */ + +static size_t +xstrnlen (const char *s, size_t maxlen) +{ + size_t i; + + for (i = 0; i < maxlen; ++i) + if (s[i] == '\0') + break; + return i; +} + +#define strnlen xstrnlen + +#endif + #ifndef HAVE_DL_ITERATE_PHDR /* Dummy version of dl_iterate_phdr for systems that don't have it. */ @@ -105,6 +137,7 @@ dl_iterate_phdr (int (*callback) (struct dl_phdr_info *, #undef SHT_DYNSYM #undef STT_OBJECT #undef STT_FUNC +#undef NT_GNU_BUILD_ID /* Basic types. */ @@ -224,6 +257,16 @@ typedef struct #define STT_OBJECT 1 #define STT_FUNC 2 +typedef struct +{ + uint32_t namesz; + uint32_t descsz; + uint32_t type; + char name[1]; +} b_elf_note; + +#define NT_GNU_BUILD_ID 3 + /* An index of ELF sections we care about. */ enum debug_section @@ -283,6 +326,102 @@ struct elf_syminfo_data size_t count; }; +/* Compute the CRC-32 of BUF/LEN. This uses the CRC used for + .gnu_debuglink files. */ + +static uint32_t +elf_crc32 (uint32_t crc, const unsigned char *buf, size_t len) +{ + static const uint32_t crc32_table[256] = + { + 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, + 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, + 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, + 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, + 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, + 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, + 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, + 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, + 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, + 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, + 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, + 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, + 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, + 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, + 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, + 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, + 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, + 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, + 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, + 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, + 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, + 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, + 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, + 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, + 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, + 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, + 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, + 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, + 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, + 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, + 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, + 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, + 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, + 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, + 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, + 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, + 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, + 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, + 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, + 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, + 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, + 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, + 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, + 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, + 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, + 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, + 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, + 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, + 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, + 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, + 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, + 0x2d02ef8d + }; + const unsigned char *end; + + crc = ~crc; + for (end = buf + len; buf < end; ++ buf) + crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8); + return ~crc; +} + +/* Return the CRC-32 of the entire file open at DESCRIPTOR. */ + +static uint32_t +elf_crc32_file (struct backtrace_state *state, int descriptor, + backtrace_error_callback error_callback, void *data) +{ + struct stat st; + struct backtrace_view file_view; + uint32_t ret; + + if (fstat (descriptor, &st) < 0) + { + error_callback (data, "fstat", errno); + return 0; + } + + if (!backtrace_get_view (state, descriptor, 0, st.st_size, error_callback, + data, &file_view)) + return 0; + + ret = elf_crc32 (0, (const unsigned char *) file_view.data, st.st_size); + + backtrace_release_view (state, &file_view, error_callback, data); + + return ret; +} + /* A dummy callback function used when we can't find any debug info. */ static int @@ -510,6 +649,293 @@ elf_syminfo (struct backtrace_state *state, uintptr_t addr, callback (data, addr, sym->name, sym->address, sym->size); } +/* Return whether FILENAME is a symlink. */ + +static int +elf_is_symlink (const char *filename) +{ + struct stat st; + + if (lstat (filename, &st) < 0) + return 0; + return S_ISLNK (st.st_mode); +} + +/* Return the results of reading the symlink FILENAME in a buffer + allocated by backtrace_alloc. Return the length of the buffer in + *LEN. */ + +static char * +elf_readlink (struct backtrace_state *state, const char *filename, + backtrace_error_callback error_callback, void *data, + size_t *plen) +{ + size_t len; + char *buf; + + len = 128; + while (1) + { + ssize_t rl; + + buf = backtrace_alloc (state, len, error_callback, data); + if (buf == NULL) + return NULL; + rl = readlink (filename, buf, len); + if (rl < 0) + { + backtrace_free (state, buf, len, error_callback, data); + return NULL; + } + if ((size_t) rl < len - 1) + { + buf[rl] = '\0'; + *plen = len; + return buf; + } + backtrace_free (state, buf, len, error_callback, data); + len *= 2; + } +} + +/* Open a separate debug info file, using the build ID to find it. + Returns an open file descriptor, or -1. + + The GDB manual says that the only place gdb looks for a debug file + when the build ID is known is in /usr/lib/debug/.build-id. */ + +static int +elf_open_debugfile_by_buildid (struct backtrace_state *state, + const char *buildid_data, size_t buildid_size, + backtrace_error_callback error_callback, + void *data) +{ + const char * const prefix = "/usr/lib/debug/.build-id/"; + const size_t prefix_len = strlen (prefix); + const char * const suffix = ".debug"; + const size_t suffix_len = strlen (suffix); + size_t len; + char *bd_filename; + char *t; + size_t i; + int ret; + int does_not_exist; + + len = prefix_len + buildid_size * 2 + suffix_len + 2; + bd_filename = backtrace_alloc (state, len, error_callback, data); + if (bd_filename == NULL) + return -1; + + t = bd_filename; + memcpy (t, prefix, prefix_len); + t += prefix_len; + for (i = 0; i < buildid_size; i++) + { + unsigned char b; + unsigned char nib; + + b = (unsigned char) buildid_data[i]; + nib = (b & 0xf0) >> 4; + *t++ = nib < 10 ? '0' + nib : 'a' + nib - 10; + nib = b & 0x0f; + *t++ = nib < 10 ? '0' + nib : 'a' + nib - 10; + if (i == 0) + *t++ = '/'; + } + memcpy (t, suffix, suffix_len); + t[suffix_len] = '\0'; + + ret = backtrace_open (bd_filename, error_callback, data, &does_not_exist); + + backtrace_free (state, bd_filename, len, error_callback, data); + + /* gdb checks that the debuginfo file has the same build ID note. + That seems kind of pointless to me--why would it have the right + name but not the right build ID?--so skipping the check. */ + + return ret; +} + +/* Try to open a file whose name is PREFIX (length PREFIX_LEN) + concatenated with PREFIX2 (length PREFIX2_LEN) concatenated with + DEBUGLINK_NAME. Returns an open file descriptor, or -1. */ + +static int +elf_try_debugfile (struct backtrace_state *state, const char *prefix, + size_t prefix_len, const char *prefix2, size_t prefix2_len, + const char *debuglink_name, + backtrace_error_callback error_callback, void *data) +{ + size_t debuglink_len; + size_t try_len; + char *try; + int does_not_exist; + int ret; + + debuglink_len = strlen (debuglink_name); + try_len = prefix_len + prefix2_len + debuglink_len + 1; + try = backtrace_alloc (state, try_len, error_callback, data); + if (try == NULL) + return -1; + + memcpy (try, prefix, prefix_len); + memcpy (try + prefix_len, prefix2, prefix2_len); + memcpy (try + prefix_len + prefix2_len, debuglink_name, debuglink_len); + try[prefix_len + prefix2_len + debuglink_len] = '\0'; + + ret = backtrace_open (try, error_callback, data, &does_not_exist); + + backtrace_free (state, try, try_len, error_callback, data); + + return ret; +} + +/* Find a separate debug info file, using the debuglink section data + to find it. Returns an open file descriptor, or -1. */ + +static int +elf_find_debugfile_by_debuglink (struct backtrace_state *state, + const char *filename, + const char *debuglink_name, + backtrace_error_callback error_callback, + void *data) +{ + int ret; + char *alc; + size_t alc_len; + const char *slash; + int ddescriptor; + const char *prefix; + size_t prefix_len; + + /* Resolve symlinks in FILENAME. Since FILENAME is fairly likely to + be /proc/self/exe, symlinks are common. We don't try to resolve + the whole path name, just the base name. */ + ret = -1; + alc = NULL; + alc_len = 0; + while (elf_is_symlink (filename)) + { + char *new_buf; + size_t new_len; + + new_buf = elf_readlink (state, filename, error_callback, data, &new_len); + if (new_buf == NULL) + break; + + if (new_buf[0] == '/') + filename = new_buf; + else + { + slash = strrchr (filename, '/'); + if (slash == NULL) + filename = new_buf; + else + { + size_t clen; + char *c; + + slash++; + clen = slash - filename + strlen (new_buf) + 1; + c = backtrace_alloc (state, clen, error_callback, data); + if (c == NULL) + goto done; + + memcpy (c, filename, slash - filename); + memcpy (c + (slash - filename), new_buf, strlen (new_buf)); + c[slash - filename + strlen (new_buf)] = '\0'; + backtrace_free (state, new_buf, new_len, error_callback, data); + filename = c; + new_buf = c; + new_len = clen; + } + } + + if (alc != NULL) + backtrace_free (state, alc, alc_len, error_callback, data); + alc = new_buf; + alc_len = new_len; + } + + /* Look for DEBUGLINK_NAME in the same directory as FILENAME. */ + + slash = strrchr (filename, '/'); + if (slash == NULL) + { + prefix = ""; + prefix_len = 0; + } + else + { + slash++; + prefix = filename; + prefix_len = slash - filename; + } + + ddescriptor = elf_try_debugfile (state, prefix, prefix_len, "", 0, + debuglink_name, error_callback, data); + if (ddescriptor >= 0) + { + ret = ddescriptor; + goto done; + } + + /* Look for DEBUGLINK_NAME in a .debug subdirectory of FILENAME. */ + + ddescriptor = elf_try_debugfile (state, prefix, prefix_len, ".debug/", + strlen (".debug/"), debuglink_name, + error_callback, data); + if (ddescriptor >= 0) + { + ret = ddescriptor; + goto done; + } + + /* Look for DEBUGLINK_NAME in /usr/lib/debug. */ + + ddescriptor = elf_try_debugfile (state, "/usr/lib/debug/", + strlen ("/usr/lib/debug/"), prefix, + prefix_len, debuglink_name, + error_callback, data); + if (ddescriptor >= 0) + ret = ddescriptor; + + done: + if (alc != NULL && alc_len > 0) + backtrace_free (state, alc, alc_len, error_callback, data); + return ret; +} + +/* Open a separate debug info file, using the debuglink section data + to find it. Returns an open file descriptor, or -1. */ + +static int +elf_open_debugfile_by_debuglink (struct backtrace_state *state, + const char *filename, + const char *debuglink_name, + uint32_t debuglink_crc, + backtrace_error_callback error_callback, + void *data) +{ + int ddescriptor; + uint32_t got_crc; + + ddescriptor = elf_find_debugfile_by_debuglink (state, filename, + debuglink_name, + error_callback, data); + if (ddescriptor < 0) + return -1; + + got_crc = elf_crc32_file (state, ddescriptor, error_callback, data); + if (got_crc != debuglink_crc) + { + backtrace_close (ddescriptor, error_callback, data); + return -1; + } + + return ddescriptor; +} + /* Add the backtrace data for one ELF file. Returns 1 on success, 0 on failure (in both cases descriptor is closed) or -1 if exe is non-zero and the ELF file is ET_DYN, which tells the caller that @@ -517,9 +943,10 @@ elf_syminfo (struct backtrace_state *state, uintptr_t addr, base_address is determined. */ static int -elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, - backtrace_error_callback error_callback, void *data, - fileline *fileline_fn, int *found_sym, int *found_dwarf, int exe) +elf_add (struct backtrace_state *state, const char *filename, int descriptor, + uintptr_t base_address, backtrace_error_callback error_callback, + void *data, fileline *fileline_fn, int *found_sym, int *found_dwarf, + int exe, int debuginfo) { struct backtrace_view ehdr_view; b_elf_ehdr ehdr; @@ -543,6 +970,14 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, int symtab_view_valid; struct backtrace_view strtab_view; int strtab_view_valid; + struct backtrace_view buildid_view; + int buildid_view_valid; + const char *buildid_data; + uint32_t buildid_size; + struct backtrace_view debuglink_view; + int debuglink_view_valid; + const char *debuglink_name; + uint32_t debuglink_crc; off_t min_offset; off_t max_offset; struct backtrace_view debug_view; @@ -555,6 +990,12 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, names_view_valid = 0; symtab_view_valid = 0; strtab_view_valid = 0; + buildid_view_valid = 0; + buildid_data = NULL; + buildid_size = 0; + debuglink_view_valid = 0; + debuglink_name = NULL; + debuglink_crc = 0; debug_view_valid = 0; if (!backtrace_get_view (state, descriptor, 0, sizeof ehdr, error_callback, @@ -707,11 +1148,61 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, break; } } + + /* Read the build ID if present. This could check for any + SHT_NOTE section with the right note name and type, but gdb + looks for a specific section name. */ + if (!debuginfo + && !buildid_view_valid + && strcmp (name, ".note.gnu.build-id") == 0) + { + const b_elf_note *note; + + if (!backtrace_get_view (state, descriptor, shdr->sh_offset, + shdr->sh_size, error_callback, data, + &buildid_view)) + goto fail; + + buildid_view_valid = 1; + note = (const b_elf_note *) buildid_view.data; + if (note->type == NT_GNU_BUILD_ID + && note->namesz == 4 + && strncmp (note->name, "GNU", 4) == 0 + && shdr->sh_size < 12 + ((note->namesz + 3) & ~ 3) + note->descsz) + { + buildid_data = ¬e->name[0] + ((note->namesz + 3) & ~ 3); + buildid_size = note->descsz; + } + } + + /* Read the debuglink file if present. */ + if (!debuginfo + && !debuglink_view_valid + && strcmp (name, ".gnu_debuglink") == 0) + { + const char *debuglink_data; + size_t crc_offset; + + if (!backtrace_get_view (state, descriptor, shdr->sh_offset, + shdr->sh_size, error_callback, data, + &debuglink_view)) + goto fail; + + debuglink_view_valid = 1; + debuglink_data = (const char *) debuglink_view.data; + crc_offset = strnlen (debuglink_data, shdr->sh_size); + crc_offset = (crc_offset + 3) & ~3; + if (crc_offset + 4 <= shdr->sh_size) + { + debuglink_name = debuglink_data; + debuglink_crc = *(const uint32_t*)(debuglink_data + crc_offset); + } + } } if (symtab_shndx == 0) symtab_shndx = dynsym_shndx; - if (symtab_shndx != 0) + if (symtab_shndx != 0 && !debuginfo) { const b_elf_shdr *symtab_shdr; unsigned int strtab_shndx; @@ -757,6 +1248,7 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, /* We no longer need the symbol table, but we hold on to the string table permanently. */ backtrace_release_view (state, &symtab_view, error_callback, data); + symtab_view_valid = 0; *found_sym = 1; @@ -770,6 +1262,53 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, backtrace_release_view (state, &names_view, error_callback, data); names_view_valid = 0; + /* If the debug info is in a separate file, read that one instead. */ + + if (buildid_data != NULL) + { + int d; + + d = elf_open_debugfile_by_buildid (state, buildid_data, buildid_size, + error_callback, data); + if (d >= 0) + { + backtrace_release_view (state, &buildid_view, error_callback, data); + if (debuglink_view_valid) + backtrace_release_view (state, &debuglink_view, error_callback, + data); + return elf_add (state, NULL, d, base_address, error_callback, data, + fileline_fn, found_sym, found_dwarf, 0, 1); + } + } + + if (buildid_view_valid) + { + backtrace_release_view (state, &buildid_view, error_callback, data); + buildid_view_valid = 0; + } + + if (debuglink_name != NULL) + { + int d; + + d = elf_open_debugfile_by_debuglink (state, filename, debuglink_name, + debuglink_crc, error_callback, + data); + if (d >= 0) + { + backtrace_release_view (state, &debuglink_view, error_callback, + data); + return elf_add (state, NULL, d, base_address, error_callback, data, + fileline_fn, found_sym, found_dwarf, 0, 1); + } + } + + if (debuglink_view_valid) + { + backtrace_release_view (state, &debuglink_view, error_callback, data); + debuglink_view_valid = 0; + } + /* Read all the debug sections in a single view, since they are probably adjacent in the file. We never release this view. */ @@ -842,6 +1381,10 @@ elf_add (struct backtrace_state *state, int descriptor, uintptr_t base_address, backtrace_release_view (state, &symtab_view, error_callback, data); if (strtab_view_valid) backtrace_release_view (state, &strtab_view, error_callback, data); + if (debuglink_view_valid) + backtrace_release_view (state, &debuglink_view, error_callback, data); + if (buildid_view_valid) + backtrace_release_view (state, &buildid_view, error_callback, data); if (debug_view_valid) backtrace_release_view (state, &debug_view, error_callback, data); if (descriptor != -1) @@ -859,6 +1402,7 @@ struct phdr_data fileline *fileline_fn; int *found_sym; int *found_dwarf; + const char *exe_filename; int exe_descriptor; }; @@ -873,6 +1417,7 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED, void *pdata) { struct phdr_data *pd = (struct phdr_data *) pdata; + const char *filename; int descriptor; int does_not_exist; fileline elf_fileline_fn; @@ -885,6 +1430,7 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED, { if (pd->exe_descriptor == -1) return 0; + filename = pd->exe_filename; descriptor = pd->exe_descriptor; pd->exe_descriptor = -1; } @@ -896,14 +1442,16 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED, pd->exe_descriptor = -1; } + filename = info->dlpi_name; descriptor = backtrace_open (info->dlpi_name, pd->error_callback, pd->data, &does_not_exist); if (descriptor < 0) return 0; } - if (elf_add (pd->state, descriptor, info->dlpi_addr, pd->error_callback, - pd->data, &elf_fileline_fn, pd->found_sym, &found_dwarf, 0)) + if (elf_add (pd->state, filename, descriptor, info->dlpi_addr, + pd->error_callback, pd->data, &elf_fileline_fn, pd->found_sym, + &found_dwarf, 0, 0)) { if (found_dwarf) { @@ -920,8 +1468,8 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED, sections. */ int -backtrace_initialize (struct backtrace_state *state, int descriptor, - backtrace_error_callback error_callback, +backtrace_initialize (struct backtrace_state *state, const char *filename, + int descriptor, backtrace_error_callback error_callback, void *data, fileline *fileline_fn) { int ret; @@ -930,8 +1478,8 @@ backtrace_initialize (struct backtrace_state *state, int descriptor, fileline elf_fileline_fn = elf_nodebug; struct phdr_data pd; - ret = elf_add (state, descriptor, 0, error_callback, data, &elf_fileline_fn, - &found_sym, &found_dwarf, 1); + ret = elf_add (state, filename, descriptor, 0, error_callback, data, + &elf_fileline_fn, &found_sym, &found_dwarf, 1, 0); if (!ret) return 0; diff --git a/libbacktrace/fileline.c b/libbacktrace/fileline.c index 6812058..babbe53 100644 --- a/libbacktrace/fileline.c +++ b/libbacktrace/fileline.c @@ -58,6 +58,7 @@ fileline_initialize (struct backtrace_state *state, int pass; int called_error_callback; int descriptor; + const char *filename; char buf[64]; if (!state->threaded) @@ -84,7 +85,6 @@ fileline_initialize (struct backtrace_state *state, called_error_callback = 0; for (pass = 0; pass < 5; ++pass) { - const char *filename; int does_not_exist; switch (pass) @@ -140,8 +140,8 @@ fileline_initialize (struct backtrace_state *state, if (!failed) { - if (!backtrace_initialize (state, descriptor, error_callback, data, - &fileline_fn)) + if (!backtrace_initialize (state, filename, descriptor, error_callback, + data, &fileline_fn)) failed = 1; } diff --git a/libbacktrace/internal.h b/libbacktrace/internal.h index 89b7bf7..f52d1f9 100644 --- a/libbacktrace/internal.h +++ b/libbacktrace/internal.h @@ -268,6 +268,7 @@ extern int backtrace_vector_release (struct backtrace_state *state, appropriate one. */ extern int backtrace_initialize (struct backtrace_state *state, + const char *filename, int descriptor, backtrace_error_callback error_callback, void *data, diff --git a/libbacktrace/pecoff.c b/libbacktrace/pecoff.c index 78152c3..2204dd0 100644 --- a/libbacktrace/pecoff.c +++ b/libbacktrace/pecoff.c @@ -890,7 +890,8 @@ coff_add (struct backtrace_state *state, int descriptor, sections. */ int -backtrace_initialize (struct backtrace_state *state, int descriptor, +backtrace_initialize (struct backtrace_state *state, + const char *filename ATTRIBUTE_UNUSED, int descriptor, backtrace_error_callback error_callback, void *data, fileline *fileline_fn) { diff --git a/libbacktrace/unknown.c b/libbacktrace/unknown.c index 867755b..5df6d15 100644 --- a/libbacktrace/unknown.c +++ b/libbacktrace/unknown.c @@ -54,6 +54,7 @@ unknown_fileline (struct backtrace_state *state ATTRIBUTE_UNUSED, int backtrace_initialize (struct backtrace_state *state ATTRIBUTE_UNUSED, + const char *filename ATTRIBUTE_UNUSED, int descriptor ATTRIBUTE_UNUSED, backtrace_error_callback error_callback ATTRIBUTE_UNUSED, void *data ATTRIBUTE_UNUSED, fileline *fileline_fn) diff --git a/libbacktrace/xcoff.c b/libbacktrace/xcoff.c index b3d7e24..f752391 100644 --- a/libbacktrace/xcoff.c +++ b/libbacktrace/xcoff.c @@ -1434,7 +1434,8 @@ xcoff_add_shared_libs (struct backtrace_state *state, Returns 1 on success, 0 on failure. */ int -backtrace_initialize (struct backtrace_state *state, int descriptor, +backtrace_initialize (struct backtrace_state *state, + const char *filename ATTRIBUTE_UNUSED, int descriptor, backtrace_error_callback error_callback, void *data, fileline *fileline_fn) { -- 2.7.4