[PATCH 2/3 v2] perf trace: Introduce errno_to_name()

[Hendrik Brueckner <brueckner@linux.vnet.ibm.com>]

Introduce an errno_to_name() function to return the name of a
give errno number as string.

With this change, the dependency to libaudit can be removed for
architectures that support syscall tables.  Hence, remove the
audit_errno_to_name() call in builtin-trace.c and just link
util/syscalltbl.c against libaudit.  A follow-up commit could
then clean-up this dependency with respect to the syscall table.

The errno name strings are generated by util/generate-errno-names.sh
script and saved as util/errno-names.h.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
---
 tools/perf/.gitignore                   |  1 +
 tools/perf/Makefile.config              |  2 +-
 tools/perf/Makefile.perf                | 12 ++++++++++--
 tools/perf/builtin-trace.c              | 17 ++++++++++++++---
 tools/perf/util/generate-errno-names.sh | 32 ++++++++++++++++++++++++++++++++
 5 files changed, 58 insertions(+), 6 deletions(-)
 create mode 100755 tools/perf/util/generate-errno-names.sh

diff --git a/tools/perf/.gitignore b/tools/perf/.gitignore
index 643cc4ba..4e022f9 100644
--- a/tools/perf/.gitignore
+++ b/tools/perf/.gitignore
@@ -14,6 +14,7 @@ perf*.1
 perf*.xml
 perf*.html
 common-cmds.h
+errno-names.h
 perf.data
 perf.data.old
 output.svg
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index ab16aab..d8447b1 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -251,7 +251,7 @@ INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/include/uapi
 INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/include/
 INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/
 
-# $(obj-perf)      for generated common-cmds.h
+# $(obj-perf)      for generated common-cmds.h and errno-names.h
 # $(obj-perf)/util for generated bison/flex headers
 ifneq ($(OUTPUT),)
 INC_FLAGS += -I$(obj-perf)/util
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 68cf136..82aed33d 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -518,6 +518,12 @@ $(OUTPUT)common-cmds.h: util/generate-cmdlist.sh command-list.txt
 $(OUTPUT)common-cmds.h: $(wildcard Documentation/perf-*.txt)
 	$(QUIET_GEN). util/generate-cmdlist.sh > $@+ && mv $@+ $@
 
+$(OUTPUT)util/errno-names.h: util/generate-errno-names.sh
+	$(QUIET_GEN). util/generate-errno-names.sh \
+	$(srctree)/include/uapi/asm-generic/errno-base.h \
+	$(srctree)/include/uapi/asm-generic/errno.h \
+	> $@+ && mv $@+ $@
+
 $(SCRIPTS) : % : %.sh
 	$(QUIET_GEN)$(INSTALL) '$@.sh' '$(OUTPUT)$@'
 
@@ -565,7 +571,8 @@ prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders $(drm_ioc
 	$(vhost_virtio_ioctl_array) \
 	$(madvise_behavior_array) \
 	$(perf_ioctl_array) \
-	$(prctl_option_array)
+	$(prctl_option_array) \
+	$(OUTPUT)util/errno-names.h
 
 $(OUTPUT)%.o: %.c prepare FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(build-dir) $@
@@ -847,7 +854,8 @@ clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clea
 		$(OUTPUT)$(kcmp_type_array) \
 		$(OUTPUT)$(vhost_virtio_ioctl_array) \
 		$(OUTPUT)$(perf_ioctl_array) \
-		$(OUTPUT)$(prctl_option_array)
+		$(OUTPUT)$(prctl_option_array) \
+		$(OUTPUT)util/errno-names.h
 	$(QUIET_SUBDIR0)Documentation $(QUIET_SUBDIR1) clean
 
 #
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 84debdb..04af6a1 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -42,17 +42,16 @@
 #include "string2.h"
 #include "syscalltbl.h"
 #include "rb_resort.h"
+#include "util/errno-names.h"
 
 #include <errno.h>
 #include <inttypes.h>
-#include <libaudit.h> /* FIXME: Still needed for audit_errno_to_name */
 #include <poll.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <linux/err.h>
 #include <linux/filter.h>
-#include <linux/audit.h>
 #include <linux/kernel.h>
 #include <linux/random.h>
 #include <linux/stringify.h>
@@ -1659,6 +1658,18 @@ static int trace__fprintf_callchain(struct trace *trace, struct perf_sample *sam
 	return sample__fprintf_callchain(sample, 38, print_opts, &callchain_cursor, trace->output);
 }
 
+static const char *errno_to_name(int err)
+{
+	switch (err) {
+#define ERRNO_NAME_MAP(_err, _num) case _num: return #_err;
+	ALL_ERRNO_NAME_MAPPINGS
+#undef ERRNO_NAME_MAP
+	default:
+		return "(unknown)";
+		break;
+	};
+}
+
 static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 			   union perf_event *event __maybe_unused,
 			   struct perf_sample *sample)
@@ -1729,7 +1740,7 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 errno_print: {
 		char bf[STRERR_BUFSIZE];
 		const char *emsg = str_error_r(-ret, bf, sizeof(bf)),
-			   *e = audit_errno_to_name(-ret);
+			   *e = errno_to_name(-ret);
 
 		fprintf(trace->output, ") = -1 %s %s", e, emsg);
 	}
diff --git a/tools/perf/util/generate-errno-names.sh b/tools/perf/util/generate-errno-names.sh
new file mode 100755
index 0000000..6c114a8
--- /dev/null
+++ b/tools/perf/util/generate-errno-names.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generate errno names header file
+#
+# Copyright IBM Corp. 2017
+# Author(s):  Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+
+infiles="$@"
+tmpfile=$(mktemp -t generate-errno-names.XXXXXXXXX)
+
+trap 'rm -f $tmpfile' 0
+
+grep -hE '^#define[[:blank:]]+([^[:blank:]]+)[[:blank:]]+([[:digit:]]+).*' $infiles \
+	|awk '{ print $2", "$3; }' \
+	|sort -t, -k2 -nu \
+	|sed -e 's/^/\tERRNO_NAME_MAP(/' -e 's/$/)/' \
+	>  $tmpfile
+
+cat <<EoHeader
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _UTIL_ERRNO_NAMES_H
+#define _UTIL_ERRNO_NAMES_H
+
+#define ALL_ERRNO_NAME_MAPPINGS \\
+EoHeader
+head -n -1 $tmpfile |sed -e 's/$/ \\/'
+tail -1 $tmpfile
+
+cat <<EoFooter
+#endif	/* _UTIL_ERRNO_NAMES_H */
+EoFooter
-- 
1.8.3.1