In preparation to migrating RTLA to libsubcmd, build libsubcmd from the
appropriate directory next to the RTLA build proper, and link the
resulting object to RTLA.

libsubcmd uses str_error_r() and strlcpy() at several places. To support
these, also link the respective libraries from tools/lib.

For completeness, also add tools/include to include path. This will
allow other userspace function and macros shipped with the kernel to be
used in RTLA; perf and bpftool, two other users of libsubcmd, already do
that.

To prevent name conflict, rename RTLA's run_command() function to
run_tool_command(), and replace RTLA's own container_of implementation
with the one in tools/include/linux/container_of.h.

Assisted-by: Composer:composer-1
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/.gitignore  |  1 +
 tools/tracing/rtla/Makefile    | 53 +++++++++++++++++++++++++++++-----
 tools/tracing/rtla/src/rtla.c  |  8 ++---
 tools/tracing/rtla/src/utils.h |  6 ++--
 4 files changed, 53 insertions(+), 15 deletions(-)

diff --git a/tools/tracing/rtla/.gitignore b/tools/tracing/rtla/.gitignore
index 4d39d64ac08c..123c2d5ed7ac 100644
--- a/tools/tracing/rtla/.gitignore
+++ b/tools/tracing/rtla/.gitignore
@@ -9,3 +9,4 @@ custom_filename.txt
 osnoise_irq_noise_hist.txt
 osnoise_trace.txt
 timerlat_trace.txt
+libsubcmd/
diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile
index 45690ee14544..289e44c9664b 100644
--- a/tools/tracing/rtla/Makefile
+++ b/tools/tracing/rtla/Makefile
@@ -27,6 +27,24 @@ endif
 RTLA		:= $(OUTPUT)rtla
 RTLA_IN		:= $(RTLA)-in.o
 
+LIBSUBCMD_DIR = $(srctree)/tools/lib/subcmd/
+ifneq ($(OUTPUT),)
+  LIBSUBCMD_OUTPUT = $(abspath $(OUTPUT))/libsubcmd
+else
+  LIBSUBCMD_OUTPUT = $(CURDIR)/libsubcmd
+endif
+LIBSUBCMD = $(LIBSUBCMD_OUTPUT)/libsubcmd.a
+LIBSUBCMD_INCLUDES = -I$(LIBSUBCMD_OUTPUT)/include
+LIBSUBCMD_MAKEFLAGS = O=$(LIBSUBCMD_OUTPUT) DESTDIR=$(LIBSUBCMD_OUTPUT) prefix= subdir=
+
+TOOLS_INCLUDES = -I$(srctree)/tools/include
+
+LIB_STRING = $(OUTPUT)string.o
+LIB_STRING_SRC = $(srctree)/tools/lib/string.c
+
+LIB_STR_ERROR_R = $(OUTPUT)str_error_r.o
+LIB_STR_ERROR_R_SRC = $(srctree)/tools/lib/str_error_r.c
+
 VERSION		:= $(shell sh -c "make -sC ../../.. kernelversion | grep -v make")
 DOCSRC		:= ../../../Documentation/tools/rtla/
 
@@ -66,7 +84,7 @@ ifeq ($(config),1)
   include Makefile.config
 endif
 
-CFLAGS		+= $(INCLUDES) $(LIB_INCLUDES)
+CFLAGS		+= $(INCLUDES) $(LIB_INCLUDES) $(TOOLS_INCLUDES) $(LIBSUBCMD_INCLUDES)
 
 export CFLAGS OUTPUT srctree
 
@@ -93,20 +111,41 @@ tests/bpf/bpf_action_map.o: tests/bpf/bpf_action_map.c
 	$(Q)echo "BPF skeleton support is disabled, skipping tests/bpf/bpf_action_map.o"
 endif
 
-$(RTLA): $(RTLA_IN)
-	$(QUIET_LINK)$(CC) $(LDFLAGS) -o $(RTLA) $(RTLA_IN) $(EXTLIBS)
+$(RTLA): $(RTLA_IN) $(LIBSUBCMD) $(LIB_STRING) $(LIB_STR_ERROR_R)
+	$(QUIET_LINK)$(CC) $(LDFLAGS) -o $(RTLA) $(RTLA_IN) $(LIBSUBCMD) $(LIB_STRING) $(LIB_STR_ERROR_R) $(EXTLIBS)
 
-static: $(RTLA_IN)
+static: $(RTLA_IN) $(LIBSUBCMD) $(LIB_STRING) $(LIB_STR_ERROR_R)
 	$(eval LDFLAGS += -static)
-	$(QUIET_LINK)$(CC) -static $(LDFLAGS) -o $(RTLA)-static $(RTLA_IN)  $(EXTLIBS)
+	$(QUIET_LINK)$(CC) -static $(LDFLAGS) -o $(RTLA)-static $(RTLA_IN) $(LIBSUBCMD) $(LIB_STRING) $(LIB_STR_ERROR_R) $(EXTLIBS)
 
 rtla.%: fixdep FORCE
 	make -f $(srctree)/tools/build/Makefile.build dir=. $@
 
-$(RTLA_IN): fixdep FORCE src/timerlat.skel.h
+$(RTLA_IN): fixdep FORCE src/timerlat.skel.h $(LIBSUBCMD_INCLUDES)
 	make $(build)=rtla
 
-clean: doc_clean fixdep-clean
+$(LIBSUBCMD_OUTPUT):
+	$(Q)$(MKDIR) -p $@
+
+$(LIBSUBCMD_INCLUDES): $(LIBSUBCMD_OUTPUT)
+	$(Q)$(MAKE) -C $(LIBSUBCMD_DIR) $(LIBSUBCMD_MAKEFLAGS) \
+		install_headers
+
+$(LIBSUBCMD): fixdep $(LIBSUBCMD_OUTPUT)
+	$(Q)$(MAKE) -C $(LIBSUBCMD_DIR) $(LIBSUBCMD_MAKEFLAGS) \
+		$@
+
+$(LIB_STR_ERROR_R): $(LIB_STR_ERROR_R_SRC)
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -o $@ $<
+
+$(LIB_STRING): $(LIB_STRING_SRC)
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -o $@ $<
+
+$(LIBSUBCMD)-clean:
+	$(call QUIET_CLEAN, libsubcmd)
+	$(Q)$(RM) -r -- $(LIBSUBCMD_OUTPUT)
+
+clean: doc_clean fixdep-clean $(LIBSUBCMD)-clean
 	$(call QUIET_CLEAN, rtla)
 	$(Q)find . -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
 	$(Q)rm -f rtla rtla-static fixdep FEATURE-DUMP rtla-*
diff --git a/tools/tracing/rtla/src/rtla.c b/tools/tracing/rtla/src/rtla.c
index 7635c70123ab..845932f902ef 100644
--- a/tools/tracing/rtla/src/rtla.c
+++ b/tools/tracing/rtla/src/rtla.c
@@ -38,12 +38,12 @@ static void rtla_usage(int err)
 }
 
 /*
- * run_command - try to run a rtla tool command
+ * run_tool_command - try to run a rtla tool command
  *
  * It returns 0 if it fails. The tool's main will generally not
  * return as they should call exit().
  */
-int run_command(int argc, char **argv, int start_position)
+int run_tool_command(int argc, char **argv, int start_position)
 {
 	if (strcmp(argv[start_position], "osnoise") == 0) {
 		osnoise_main(argc-start_position, &argv[start_position]);
@@ -66,7 +66,7 @@ int main(int argc, char *argv[])
 	int retval;
 
 	/* is it an alias? */
-	retval = run_command(argc, argv, 0);
+	retval = run_tool_command(argc, argv, 0);
 	if (retval)
 		exit(0);
 
@@ -79,7 +79,7 @@ int main(int argc, char *argv[])
 		rtla_usage(0);
 	}
 
-	retval = run_command(argc, argv, 1);
+	retval = run_tool_command(argc, argv, 1);
 	if (retval)
 		exit(0);
 
diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h
index e794ede64b2c..96fd72042717 100644
--- a/tools/tracing/rtla/src/utils.h
+++ b/tools/tracing/rtla/src/utils.h
@@ -7,6 +7,8 @@
 #include <stdbool.h>
 #include <stdlib.h>
 
+#include <linux/container_of.h>
+
 /*
  * '18446744073709551615\0'
  */
@@ -37,10 +39,6 @@ static inline bool str_has_prefix(const char *str, const char *prefix)
 	return strncmp(str, prefix, strlen(prefix)) == 0;
 }
 
-#define container_of(ptr, type, member)({			\
-	const typeof(((type *)0)->member) *__mptr = (ptr);	\
-	(type *)((char *)__mptr - offsetof(type, member)) ; })
-
 extern int config_debug;
 void debug_msg(const char *fmt, ...);
 void err_msg(const char *fmt, ...);
-- 
2.53.0