perf tools: Provide subcmd configuration at runtime

Create init functions for exec_cmd.c and pager.c.  This allows their
configuration to be specified at runtime so they can be split out into a
separate library which can be used by other programs.  Their
configuration is stored in a shared subcmd_config struct.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/21f5f6b38da72c985a8dcfa185700d03e7eecd1d.1450193761.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Build

@@ -36,7 +36,10 @@ paths += -DPERF_MAN_PATH="BUILD_STR($(mandir_SQ))"
 
 CFLAGS_builtin-help.o      += $(paths)
 CFLAGS_builtin-timechart.o += $(paths)
-CFLAGS_perf.o              += -DPERF_HTML_PATH="BUILD_STR($(htmldir_SQ))" -include $(OUTPUT)PERF-VERSION-FILE
+CFLAGS_perf.o              += -DPERF_HTML_PATH="BUILD_STR($(htmldir_SQ))"	\
+			      -DPERF_EXEC_PATH="BUILD_STR($(perfexecdir_SQ))"	\
+			      -DPREFIX="BUILD_STR($(prefix_SQ))"		\
+			      -include $(OUTPUT)PERF-VERSION-FILE
 CFLAGS_builtin-trace.o	   += -DSTRACE_GROUPS_DIR="BUILD_STR($(STRACE_GROUPS_DIR_SQ))"
 
 libperf-y += util/

tools/perf/perf.c

@@ -119,7 +119,7 @@ static void commit_pager_choice(void)
 {
 	switch (use_pager) {
 	case 0:
-		setenv("PERF_PAGER", "cat", 1);
+		setenv(PERF_PAGER_ENVIRONMENT, "cat", 1);
 		break;
 	case 1:
 		/* setup_pager(); */
@@ -530,6 +530,10 @@ int main(int argc, const char **argv)
 	const char *cmd;
 	char sbuf[STRERR_BUFSIZE];
 
+	/* libsubcmd init */
+	exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
+	pager_init(PERF_PAGER_ENVIRONMENT);
+
 	/* The page_size is placed in util object. */
 	page_size = sysconf(_SC_PAGE_SIZE);
 	cacheline_size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);

tools/perf/util/Build

@@ -88,6 +88,7 @@ libperf-y += parse-branch-options.o
 libperf-y += parse-regs-options.o
 libperf-y += term.o
 libperf-y += help-unknown-cmd.o
+libperf-y += subcmd-config.o
 
 libperf-$(CONFIG_LIBBPF) += bpf-loader.o
 libperf-$(CONFIG_BPF_PROLOGUE) += bpf-prologue.o
@@ -113,7 +114,6 @@ libperf-$(CONFIG_ZLIB) += zlib.o
 libperf-$(CONFIG_LZMA) += lzma.o
 
 CFLAGS_config.o   += -DETC_PERFCONFIG="BUILD_STR($(ETC_PERFCONFIG_SQ))"
-CFLAGS_exec_cmd.o += -DPERF_EXEC_PATH="BUILD_STR($(perfexecdir_SQ))" -DPREFIX="BUILD_STR($(prefix_SQ))"
 
 $(OUTPUT)util/parse-events-flex.c: util/parse-events.l $(OUTPUT)util/parse-events-bison.c
 	$(call rule_mkdir)

tools/perf/util/cache.h

@@ -21,6 +21,7 @@
 #define DEFAULT_PERF_DIR_ENVIRONMENT ".perf"
 #define PERF_DEBUGFS_ENVIRONMENT "PERF_DEBUGFS_DIR"
 #define PERF_TRACEFS_ENVIRONMENT "PERF_TRACEFS_DIR"
+#define PERF_PAGER_ENVIRONMENT "PERF_PAGER"
 
 typedef int (*config_fn_t)(const char *, const char *, void *);
 extern int perf_default_config(const char *, const char *, void *);

tools/perf/util/exec_cmd.c

@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "exec_cmd.h"
 #include "quote.h"
+#include "subcmd-config.h"
 
 #include <string.h>
 
@@ -9,15 +10,23 @@
 static const char *argv_exec_path;
 static const char *argv0_path;
 
+void exec_cmd_init(const char *exec_name, const char *prefix,
+		   const char *exec_path, const char *exec_path_env)
+{
+	subcmd_config.exec_name		= exec_name;
+	subcmd_config.prefix		= prefix;
+	subcmd_config.exec_path		= exec_path;
+	subcmd_config.exec_path_env	= exec_path_env;
+}
+
 char *system_path(const char *path)
 {
-	static const char *prefix = PREFIX;
 	struct strbuf d = STRBUF_INIT;
 
 	if (is_absolute_path(path))
 		return strdup(path);
 
-	strbuf_addf(&d, "%s/%s", prefix, path);
+	strbuf_addf(&d, "%s/%s", subcmd_config.prefix, path);
 	path = strbuf_detach(&d, NULL);
 	return (char *)path;
 }
@@ -47,7 +56,7 @@ void perf_set_argv_exec_path(const char *exec_path)
 	/*
 	 * Propagate this setting to external programs.
 	 */
-	setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
+	setenv(subcmd_config.exec_path_env, exec_path, 1);
 }
 
 
@@ -59,11 +68,11 @@ char *perf_exec_path(void)
 	if (argv_exec_path)
 		return strdup(argv_exec_path);
 
-	env = getenv(EXEC_PATH_ENVIRONMENT);
+	env = getenv(subcmd_config.exec_path_env);
 	if (env && *env)
 		return strdup(env);
 
-	return system_path(PERF_EXEC_PATH);
+	return system_path(subcmd_config.exec_path);
 }
 
 static void add_path(struct strbuf *out, const char *path)
@@ -107,7 +116,7 @@ static const char **prepare_perf_cmd(const char **argv)
 		; /* just counting */
 	nargv = malloc(sizeof(*nargv) * (argc + 2));
 
-	nargv[0] = "perf";
+	nargv[0] = subcmd_config.exec_name;
 	for (argc = 0; argv[argc]; argc++)
 		nargv[argc + 1] = argv[argc];
 	nargv[argc + 1] = NULL;
@@ -118,7 +127,7 @@ int execv_perf_cmd(const char **argv) {
 	const char **nargv = prepare_perf_cmd(argv);
 
 	/* execvp() can only ever return if it fails */
-	execvp("perf", (char **)nargv);
+	execvp(subcmd_config.exec_name, (char **)nargv);
 
 	free(nargv);
 	return -1;

tools/perf/util/exec_cmd.h

@@ -1,6 +1,9 @@
 #ifndef __PERF_EXEC_CMD_H
 #define __PERF_EXEC_CMD_H
 
+extern void exec_cmd_init(const char *exec_name, const char *prefix,
+			  const char *exec_path, const char *exec_path_env);
+
 extern void perf_set_argv_exec_path(const char *exec_path);
 extern const char *perf_extract_argv0_path(const char *path);
 extern void setup_path(void);

tools/perf/util/pager.c

@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "run-command.h"
 #include "sigchain.h"
+#include "subcmd-config.h"
 
 /*
  * This is split up from the rest of git so that we can do
@@ -9,6 +10,11 @@
 
 static int spawned_pager;
 
+void pager_init(const char *pager_env)
+{
+	subcmd_config.pager_env = pager_env;
+}
+
 static void pager_preexec(void)
 {
 	/*
@@ -46,7 +52,7 @@ static void wait_for_pager_signal(int signo)
 
 void setup_pager(void)
 {
-	const char *pager = getenv("PERF_PAGER");
+	const char *pager = getenv(subcmd_config.pager_env);
 
 	if (!isatty(1))
 		return;

tools/perf/util/pager.h

@@ -1,6 +1,8 @@
 #ifndef __PERF_PAGER_H
 #define __PERF_PAGER_H
 
+extern void pager_init(const char *pager_env);
+
 extern void setup_pager(void);
 extern int pager_in_use(void);
 

tools/perf/util/parse-options.c

@@ -2,6 +2,7 @@
 #include "parse-options.h"
 #include "cache.h"
 #include "header.h"
+#include "subcmd-config.h"
 #include <linux/string.h>
 
 #define OPT_SHORT 1
@@ -577,7 +578,8 @@ int parse_options_subcommand(int argc, const char **argv, const struct option *o
 	if (subcommands && !usagestr[0]) {
 		struct strbuf buf = STRBUF_INIT;
 
-		strbuf_addf(&buf, "perf %s [<options>] {", argv[0]);
+		strbuf_addf(&buf, "%s %s [<options>] {",
+			    subcmd_config.exec_name, argv[0]);
 		for (int i = 0; subcommands[i]; i++) {
 			if (i)
 				strbuf_addstr(&buf, "|");

tools/perf/util/subcmd-config.c

@@ -0,0 +1,11 @@
+#include "subcmd-config.h"
+
+#define UNDEFINED "SUBCMD_HAS_NOT_BEEN_INITIALIZED"
+
+struct subcmd_config subcmd_config = {
+	.exec_name	= UNDEFINED,
+	.prefix		= UNDEFINED,
+	.exec_path	= UNDEFINED,
+	.exec_path_env	= UNDEFINED,
+	.pager_env	= UNDEFINED,
+};

tools/perf/util/subcmd-config.h

@@ -0,0 +1,14 @@
+#ifndef __PERF_SUBCMD_CONFIG_H
+#define __PERF_SUBCMD_CONFIG_H
+
+struct subcmd_config {
+	const char *exec_name;
+	const char *prefix;
+	const char *exec_path;
+	const char *exec_path_env;
+	const char *pager_env;
+};
+
+extern struct subcmd_config subcmd_config;
+
+#endif /* __PERF_SUBCMD_CONFIG_H */