From ba0509dcb7f806403b23234320711c45be9dccec Mon Sep 17 00:00:00 2001 From: Remi Bernon Date: Fri, 21 Aug 2020 18:52:36 +0200 Subject: [PATCH] perf dso: Use libbfd to read build_id and .gnu_debuglink section Wine generates PE binaries for most of its modules and perf is unable to parse these files to get build_id or .gnu_debuglink section. Using libbfd when available, instead of libelf, makes it possible to resolve debug file location regardless of the dso binary format. Committer notes: Made the filename__read_build_id() variant that uses abfd->build_id depend on the feature test that defines HAVE_LIBBFD_BUILDID_SUPPORT, to get this to continue building with older libbfd/binutils. Signed-off-by: Remi Bernon Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Jacek Caban Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20200821165238.1340315-1-rbernon@codeweavers.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol-elf.c | 80 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 77 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 8cc4b0059fb0..94a156df22d5 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -50,6 +50,10 @@ typedef Elf64_Nhdr GElf_Nhdr; #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ #endif +#ifdef HAVE_LIBBFD_SUPPORT +#define PACKAGE 'perf' +#include +#else #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT extern char *cplus_demangle(const char *, int); @@ -65,9 +69,7 @@ static inline char *bfd_demangle(void __maybe_unused *v, { return NULL; } -#else -#define PACKAGE 'perf' -#include +#endif #endif #endif @@ -530,6 +532,36 @@ out: return err; } +#ifdef HAVE_LIBBFD_BUILDID_SUPPORT + +int filename__read_build_id(const char *filename, void *bf, size_t size) +{ + int err = -1; + bfd *abfd; + + abfd = bfd_openr(filename, NULL); + if (!abfd) + return -1; + + if (!bfd_check_format(abfd, bfd_object)) { + pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); + goto out_close; + } + + if (!abfd->build_id || abfd->build_id->size > size) + goto out_close; + + memcpy(bf, abfd->build_id->data, abfd->build_id->size); + memset(bf + abfd->build_id->size, 0, size - abfd->build_id->size); + err = abfd->build_id->size; + +out_close: + bfd_close(abfd); + return err; +} + +#else // HAVE_LIBBFD_BUILDID_SUPPORT + int filename__read_build_id(const char *filename, void *bf, size_t size) { int fd, err = -1; @@ -557,6 +589,8 @@ out: return err; } +#endif // HAVE_LIBBFD_BUILDID_SUPPORT + int sysfs__read_build_id(const char *filename, void *build_id, size_t size) { int fd, err = -1; @@ -608,6 +642,44 @@ out: return err; } +#ifdef HAVE_LIBBFD_SUPPORT + +int filename__read_debuglink(const char *filename, char *debuglink, + size_t size) +{ + int err = -1; + asection *section; + bfd *abfd; + + abfd = bfd_openr(filename, NULL); + if (!abfd) + return -1; + + if (!bfd_check_format(abfd, bfd_object)) { + pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); + goto out_close; + } + + section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); + if (!section) + goto out_close; + + if (section->size > size) + goto out_close; + + if (!bfd_get_section_contents(abfd, section, debuglink, 0, + section->size)) + goto out_close; + + err = 0; + +out_close: + bfd_close(abfd); + return err; +} + +#else + int filename__read_debuglink(const char *filename, char *debuglink, size_t size) { @@ -660,6 +732,8 @@ out: return err; } +#endif + static int dso__swap_init(struct dso *dso, unsigned char eidata) { static unsigned int const endian = 1; -- 2.11.0