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Message-Id: <1427213980-9015-15-git-send-email-acme@kernel.org>
Date: Tue, 24 Mar 2015 13:19:29 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Borislav Petkov <bp@...e.de>, David Ahern <dsahern@...il.com>,
Don Zickus <dzickus@...hat.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Namhyung Kim <namhyung@...nel.org>,
Stephane Eranian <eranian@...gle.com>
Subject: [PATCH 14/25] perf symbols: Save DSO loading errno to better report errors
From: Arnaldo Carvalho de Melo <acme@...hat.com>
Before, when some problem happened while trying to load the kernel
symtab, 'perf top' would show:
┌─Warning:───────────────────────────┐
│The vmlinux file can't be used. │
│Kernel samples will not be resolved.│
│ │
│ │
│Press any key... │
└────────────────────────────────────┘
Now, it reports:
# perf top --vmlinux /dev/null
┌─Warning:───────────────────────────────────────────┐
│The /tmp/passwd file can't be used: Invalid ELF file│
│Kernel samples will not be resolved. │
│ │
│ │
│Press any key... │
└────────────────────────────────────────────────────┘
This is possible because we now register the reason for not being able
to load the symtab in the dso->load_errno member, and provide a
dso__strerror_load() routine to format this error into a strerror like
string with a short reason for the error while loading.
That can be just forwarding the dso__strerror_load() call to
strerror_r(), or, for a separate errno range providing a custom message.
Reported-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: David Ahern <dsahern@...il.com>
Cc: Don Zickus <dzickus@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Stephane Eranian <eranian@...gle.com>
Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/perf/builtin-top.c | 6 ++++--
tools/perf/util/dso.c | 33 +++++++++++++++++++++++++++++++++
tools/perf/util/dso.h | 28 ++++++++++++++++++++++++++++
tools/perf/util/symbol-elf.c | 37 +++++++++++++++++++++++++++----------
tools/perf/util/symbol-minimal.c | 7 ++++---
5 files changed, 96 insertions(+), 15 deletions(-)
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 5fb8723c7128..1cb3436276d1 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -757,8 +757,10 @@ static void perf_event__process_sample(struct perf_tool *tool,
al.map == machine->vmlinux_maps[MAP__FUNCTION] &&
RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION])) {
if (symbol_conf.vmlinux_name) {
- ui__warning("The %s file can't be used.\n%s",
- symbol_conf.vmlinux_name, msg);
+ char serr[256];
+ dso__strerror_load(al.map->dso, serr, sizeof(serr));
+ ui__warning("The %s file can't be used: %s\n%s",
+ symbol_conf.vmlinux_name, serr, msg);
} else {
ui__warning("A vmlinux file was not found.\n%s",
msg);
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 0d3667f92023..fc0ddd5792a9 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1137,3 +1137,36 @@ enum dso_type dso__type(struct dso *dso, struct machine *machine)
return dso__type_fd(fd);
}
+
+int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
+{
+ int idx, errnum = dso->load_errno;
+ /*
+ * This must have a same ordering as the enum dso_load_errno.
+ */
+ static const char *dso_load__error_str[] = {
+ "Internal tools/perf/ library error",
+ "Invalid ELF file",
+ "Can not read build id",
+ "Mismatching build id",
+ "Decompression failure",
+ };
+
+ BUG_ON(buflen == 0);
+
+ if (errnum >= 0) {
+ const char *err = strerror_r(errnum, buf, buflen);
+
+ if (err != buf)
+ scnprintf(buf, buflen, "%s", err);
+
+ return 0;
+ }
+
+ if (errnum < __DSO_LOAD_ERRNO__START || errnum >= __DSO_LOAD_ERRNO__END)
+ return -1;
+
+ idx = errnum - __DSO_LOAD_ERRNO__START;
+ scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
+ return 0;
+}
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 88f345cc5be2..e0901b4ed8de 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -60,6 +60,31 @@ enum dso_type {
DSO__TYPE_X32BIT,
};
+enum dso_load_errno {
+ DSO_LOAD_ERRNO__SUCCESS = 0,
+
+ /*
+ * Choose an arbitrary negative big number not to clash with standard
+ * errno since SUS requires the errno has distinct positive values.
+ * See 'Issue 6' in the link below.
+ *
+ * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+ */
+ __DSO_LOAD_ERRNO__START = -10000,
+
+ DSO_LOAD_ERRNO__INTERNAL_ERROR = __DSO_LOAD_ERRNO__START,
+
+ /* for symsrc__init() */
+ DSO_LOAD_ERRNO__INVALID_ELF,
+ DSO_LOAD_ERRNO__CANNOT_READ_BUILDID,
+ DSO_LOAD_ERRNO__MISMATCHING_BUILDID,
+
+ /* for decompress_kmodule */
+ DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE,
+
+ __DSO_LOAD_ERRNO__END,
+};
+
#define DSO__SWAP(dso, type, val) \
({ \
type ____r = val; \
@@ -113,6 +138,7 @@ struct dso {
enum dso_swap_type needs_swap;
enum dso_binary_type symtab_type;
enum dso_binary_type binary_type;
+ enum dso_load_errno load_errno;
u8 adjust_symbols:1;
u8 has_build_id:1;
u8 has_srcline:1;
@@ -294,4 +320,6 @@ void dso__free_a2l(struct dso *dso);
enum dso_type dso__type(struct dso *dso, struct machine *machine);
+int dso__strerror_load(struct dso *dso, char *buf, size_t buflen);
+
#endif /* __PERF_DSO */
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 78ffde9df9bf..476268c99431 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -595,10 +595,13 @@ static int decompress_kmodule(struct dso *dso, const char *name,
return -1;
fd = mkstemp(tmpbuf);
- if (fd < 0)
+ if (fd < 0) {
+ dso->load_errno = errno;
goto out;
+ }
if (!decompress_to_file(m.ext, name, fd)) {
+ dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
close(fd);
fd = -1;
}
@@ -635,37 +638,49 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
Elf *elf;
int fd;
- if (dso__needs_decompress(dso))
+ if (dso__needs_decompress(dso)) {
fd = decompress_kmodule(dso, name, type);
- else
+ if (fd < 0)
+ return -1;
+ } else {
fd = open(name, O_RDONLY);
-
- if (fd < 0)
- return -1;
+ if (fd < 0) {
+ dso->load_errno = errno;
+ return -1;
+ }
+ }
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
+ dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
goto out_close;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
+ dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
pr_debug("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
- if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
+ if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
+ dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
goto out_elf_end;
+ }
/* Always reject images with a mismatched build-id: */
if (dso->has_build_id) {
u8 build_id[BUILD_ID_SIZE];
- if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
+ if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
+ dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
goto out_elf_end;
+ }
- if (!dso__build_id_equal(dso, build_id))
+ if (!dso__build_id_equal(dso, build_id)) {
+ dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
goto out_elf_end;
+ }
}
ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
@@ -701,8 +716,10 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
}
ss->name = strdup(name);
- if (!ss->name)
+ if (!ss->name) {
+ dso->load_errno = errno;
goto out_elf_end;
+ }
ss->elf = elf;
ss->fd = fd;
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
index d7efb03b3f9a..fd8477cacf88 100644
--- a/tools/perf/util/symbol-minimal.c
+++ b/tools/perf/util/symbol-minimal.c
@@ -246,13 +246,12 @@ out:
return ret;
}
-int symsrc__init(struct symsrc *ss, struct dso *dso __maybe_unused,
- const char *name,
+int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
enum dso_binary_type type)
{
int fd = open(name, O_RDONLY);
if (fd < 0)
- return -1;
+ goto out_errno;
ss->name = strdup(name);
if (!ss->name)
@@ -264,6 +263,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso __maybe_unused,
return 0;
out_close:
close(fd);
+out_errno:
+ dso->load_errno = errno;
return -1;
}
--
1.9.3
--
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