From 4d1e00a8af426500edfb8643fa6c375b89f1f804 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 5 Aug 2009 19:02:49 -0300 Subject: [PATCH] perf symbol: Fix symbol parsing in certain cases: use the build-id as a symlink In some cases distros have binaries and debuginfo in weird places: [root@doppio tuna]# ls -la /usr/lib64/{xulrunner-1.9.1/xulrunner-stub,firefox-3.5.2/firefox} -rwxr-xr-x 1 root root 90024 2009-08-03 19:45 /usr/lib64/firefox-3.5.2/firefox -rwxr-xr-x 1 root root 90024 2009-08-03 18:23 /usr/lib64/xulrunner-1.9.1/xulrunner-stub [root@doppio tuna]# sha1sum /usr/lib64/{xulrunner-1.9.1/xulrunner-stub,firefox-3.5.2/firefox} 19a858077d263d5de22c9c5da250d3e4396ae739 /usr/lib64/xulrunner-1.9.1/xulrunner-stub 19a858077d263d5de22c9c5da250d3e4396ae739 /usr/lib64/firefox-3.5.2/firefox [root@doppio tuna]# rpm -qf /usr/lib64/{xulrunner-1.9.1/xulrunner-stub,firefox-3.5.2/firefox} xulrunner-1.9.1.2-1.fc11.x86_64 firefox-3.5.2-2.fc11.x86_64 [root@doppio tuna]# ls -la /usr/lib/debug/{usr/lib64/xulrunner-1.9.1/xulrunner-stub,usr/lib64/firefox-3.5.2/firefox}.debug ls: cannot access /usr/lib/debug/usr/lib64/firefox-3.5.2/firefox.debug: No such file or directory -rwxr-xr-x 1 root root 403608 2009-08-03 18:22 /usr/lib/debug/usr/lib64/xulrunner-1.9.1/xulrunner-stub.debug Seemingly we don't have a .symtab when we actually can find it if we use the .note.gnu.build-id ELF section put in place by some distros. Use it and find the symbols we need. Signed-off-by: Arnaldo Carvalho de Melo Acked-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- tools/perf/util/symbol.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 73 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 0580b94..16ddca2 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -661,10 +661,69 @@ out_close: return err; } +#define BUILD_ID_SIZE 128 + +static char *dso__read_build_id(struct dso *self, int verbose) +{ + int i; + GElf_Ehdr ehdr; + GElf_Shdr shdr; + Elf_Data *build_id_data; + Elf_Scn *sec; + char *build_id = NULL, *bid; + unsigned char *raw; + Elf *elf; + int fd = open(self->name, O_RDONLY); + + if (fd < 0) + goto out; + + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (elf == NULL) { + if (verbose) + fprintf(stderr, "%s: cannot read %s ELF file.\n", + __func__, self->name); + goto out_close; + } + + if (gelf_getehdr(elf, &ehdr) == NULL) { + if (verbose) + fprintf(stderr, "%s: cannot get elf header.\n", __func__); + goto out_elf_end; + } + + sec = elf_section_by_name(elf, &ehdr, &shdr, ".note.gnu.build-id", NULL); + if (sec == NULL) + goto out_elf_end; + + build_id_data = elf_getdata(sec, NULL); + if (build_id_data == NULL) + goto out_elf_end; + build_id = malloc(BUILD_ID_SIZE); + if (build_id == NULL) + goto out_elf_end; + raw = build_id_data->d_buf + 16; + bid = build_id; + + for (i = 0; i < 20; ++i) { + sprintf(bid, "%02x", *raw); + ++raw; + bid += 2; + } + if (verbose) + printf("%s(%s): %s\n", __func__, self->name, build_id); +out_elf_end: + elf_end(elf); +out_close: + close(fd); +out: + return build_id; +} + int dso__load(struct dso *self, symbol_filter_t filter, int verbose) { - int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug"); - char *name = malloc(size); + int size = PATH_MAX; + char *name = malloc(size), *build_id = NULL; int variant = 0; int ret = -1; int fd; @@ -686,7 +745,18 @@ more: case 1: /* Ubuntu */ snprintf(name, size, "/usr/lib/debug%s", self->name); break; - case 2: /* Sane people */ + case 2: + build_id = dso__read_build_id(self, verbose); + if (build_id != NULL) { + snprintf(name, size, + "/usr/lib/debug/.build-id/%.2s/%s.debug", + build_id, build_id + 2); + free(build_id); + break; + } + variant++; + /* Fall thru */ + case 3: /* Sane people */ snprintf(name, size, "%s", self->name); break; -- 2.7.4