[tip:perf/urgent] perf annotate: Introduce strerror for handling symbol__disassemble() errors

From: tip-bot for Arnaldo Carvalho de Melo
Date: Thu Aug 04 2016 - 05:30:40 EST

Commit-ID: ee51d851392e1fe3e8be30b3c5847f34da343424
Gitweb: http://git.kernel.org/tip/ee51d851392e1fe3e8be30b3c5847f34da343424
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 29 Jul 2016 16:27:18 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 1 Aug 2016 18:18:16 -0300

perf annotate: Introduce strerror for handling symbol__disassemble() errors

We were just using pr_error() which makes it difficult for non stdio UIs
to provide errors using its widgets, as they need to somehow catch what
was passed to pr_error().

Fix it by introducing a __strerror() interface like the ones used
elsewhere, for instance target__strerror().

This is just the initial step, more work will be done, but first some
error handling bugs noticed while working on this need to be dealt with.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-dgd22zl2xg7x4vcnoa83jxfb@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-top.c | 4 +++
tools/perf/ui/browsers/annotate.c | 9 ++++--
tools/perf/ui/gtk/annotate.c | 8 +++--
tools/perf/util/annotate.c | 68 ++++++++++++++++++++++++---------------
tools/perf/util/annotate.h | 20 ++++++++++++
5 files changed, 78 insertions(+), 31 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 823dbbb..418ed94 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -132,6 +132,10 @@ static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
if (err == 0) {
out_assign:
top->sym_filter_entry = he;
+ } else {
+ char msg[BUFSIZ];
+ symbol__strerror_disassemble(sym, map, err, msg, sizeof(msg));
+ pr_err("Couldn't annotate %s: %s\n", sym->name, msg);
}

pthread_mutex_unlock(&notes->lock);
diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
index f4d6a8a..2e2d100 100644
--- a/tools/perf/ui/browsers/annotate.c
+++ b/tools/perf/ui/browsers/annotate.c
@@ -1026,7 +1026,7 @@ int symbol__tui_annotate(struct symbol *sym, struct map *map,
.use_navkeypressed = true,
},
};
- int ret = -1;
+ int ret = -1, err;
int nr_pcnt = 1;
size_t sizeof_bdl = sizeof(struct browser_disasm_line);

@@ -1050,8 +1050,11 @@ int symbol__tui_annotate(struct symbol *sym, struct map *map,
(nr_pcnt - 1);
}

- if (symbol__disassemble(sym, map, sizeof_bdl) < 0) {
- ui__error("%s", ui_helpline__last_msg);
+ err = symbol__disassemble(sym, map, sizeof_bdl);
+ if (err) {
+ char msg[BUFSIZ];
+ symbol__strerror_disassemble(sym, map, err, msg, sizeof(msg));
+ ui__error("Couldn't annotate %s:\n%s", sym->name, msg);
goto out_free_offsets;
}

diff --git a/tools/perf/ui/gtk/annotate.c b/tools/perf/ui/gtk/annotate.c
index 35e4b9e..42d3199 100644
--- a/tools/perf/ui/gtk/annotate.c
+++ b/tools/perf/ui/gtk/annotate.c
@@ -162,12 +162,16 @@ static int symbol__gtk_annotate(struct symbol *sym, struct map *map,
GtkWidget *notebook;
GtkWidget *scrolled_window;
GtkWidget *tab_label;
+ int err;

if (map->dso->annotate_warned)
return -1;

- if (symbol__disassemble(sym, map, 0) < 0) {
- ui__error("%s", ui_helpline__current);
+ err = symbol__disassemble(sym, map, 0);
+ if (err) {
+ char msg[BUFSIZ];
+ symbol__strerror_disassemble(sym, map, err, msg, sizeof(msg));
+ ui__error("Couldn't annotate %s: %s\n", sym->name, msg);
return -1;
}

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 4f47b606..4982ed4 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1123,6 +1123,45 @@ static void delete_last_nop(struct symbol *sym)
}
}

+int symbol__strerror_disassemble(struct symbol *sym __maybe_unused, struct map *map,
+ int errnum, char *buf, size_t buflen)
+{
+ struct dso *dso = map->dso;
+
+ BUG_ON(buflen == 0);
+
+ if (errnum >= 0) {
+ str_error_r(errnum, buf, buflen);
+ return 0;
+ }
+
+ switch (errnum) {
+ case SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX: {
+ char bf[SBUILD_ID_SIZE + 15] = " with build id ";
+ char *build_id_msg = NULL;
+
+ if (dso->has_build_id) {
+ build_id__sprintf(dso->build_id,
+ sizeof(dso->build_id), bf + 15);
+ build_id_msg = bf;
+ }
+ scnprintf(buf, buflen,
+ "No vmlinux file%s\nwas found in the path.\n\n"
+ "Note that annotation using /proc/kcore requires CAP_SYS_RAWIO capability.\n\n"
+ "Please use:\n\n"
+ " perf buildid-cache -vu vmlinux\n\n"
+ "or:\n\n"
+ " --vmlinux vmlinux\n", build_id_msg ?: "");
+ }
+ break;
+ default:
+ scnprintf(buf, buflen, "Internal error: Invalid %d error code\n", errnum);
+ break;
+ }
+
+ return 0;
+}
+
int symbol__disassemble(struct symbol *sym, struct map *map, size_t privsize)
{
struct dso *dso = map->dso;
@@ -1143,11 +1182,8 @@ int symbol__disassemble(struct symbol *sym, struct map *map, size_t privsize)
symbol__join_symfs(symfs_filename, filename);

if (filename == NULL) {
- if (dso->has_build_id) {
- pr_err("Can't annotate %s: not enough memory\n",
- sym->name);
- return -ENOMEM;
- }
+ if (dso->has_build_id)
+ return ENOMEM;
goto fallback;
} else if (dso__is_kcore(dso)) {
goto fallback;
@@ -1168,27 +1204,7 @@ fallback:

if (dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
!dso__is_kcore(dso)) {
- char bf[SBUILD_ID_SIZE + 15] = " with build id ";
- char *build_id_msg = NULL;
-
- if (dso->annotate_warned)
- goto out_free_filename;
-
- if (dso->has_build_id) {
- build_id__sprintf(dso->build_id,
- sizeof(dso->build_id), bf + 15);
- build_id_msg = bf;
- }
- err = -ENOENT;
- dso->annotate_warned = 1;
- pr_err("Can't annotate %s:\n\n"
- "No vmlinux file%s\nwas found in the path.\n\n"
- "Note that annotation using /proc/kcore requires CAP_SYS_RAWIO capability.\n\n"
- "Please use:\n\n"
- " perf buildid-cache -vu vmlinux\n\n"
- "or:\n\n"
- " --vmlinux vmlinux\n",
- sym->name, build_id_msg ?: "");
+ err = SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX;
goto out_free_filename;
}

diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index b0750d8..f67ccb0 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -157,6 +157,26 @@ void symbol__annotate_zero_histograms(struct symbol *sym);

int symbol__disassemble(struct symbol *sym, struct map *map, size_t privsize);

+enum symbol_disassemble_errno {
+ SYMBOL_ANNOTATE_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
+ */
+ __SYMBOL_ANNOTATE_ERRNO__START = -10000,
+
+ SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX = __SYMBOL_ANNOTATE_ERRNO__START,
+
+ __SYMBOL_ANNOTATE_ERRNO__END,
+};
+
+int symbol__strerror_disassemble(struct symbol *sym, struct map *map,
+ int errnum, char *buf, size_t buflen);
+
int symbol__annotate_init(struct map *map, struct symbol *sym);
int symbol__annotate_printf(struct symbol *sym, struct map *map,
struct perf_evsel *evsel, bool full_paths,