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>

11 files changed, 67 insertions, 12 deletions

diff --git a/tools/perf/Build b/tools/perf/Build
index 2a41217e9d88..00c4b8c3d8ca 100644
--- a/tools/perf/Build
+++ b/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/
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 59ea48c7e26c..783a3310a9d8 100644
--- a/tools/perf/perf.c
+++ b/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);
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 99b3dae57806..196beefa16a9 100644
--- a/tools/perf/util/Build
+++ b/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)
diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
index d723ecb9b959..fc6a745d2ec6 100644
--- a/tools/perf/util/cache.h
+++ b/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 *);
diff --git a/tools/perf/util/exec_cmd.c b/tools/perf/util/exec_cmd.c
index 1099e92f5ee1..b935e4ce62a2 100644
--- a/tools/perf/util/exec_cmd.c
+++ b/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;
diff --git a/tools/perf/util/exec_cmd.h b/tools/perf/util/exec_cmd.h
index 48b4175f1e11..fd4434e48d21 100644
--- a/tools/perf/util/exec_cmd.h
+++ b/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);
diff --git a/tools/perf/util/pager.c b/tools/perf/util/pager.c
index 7dcbef64b609..d5ef62eaa413 100644
--- a/tools/perf/util/pager.c
+++ b/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;
diff --git a/tools/perf/util/pager.h b/tools/perf/util/pager.h
index 2794a83b7e85..d6a591a4c017 100644
--- a/tools/perf/util/pager.h
+++ b/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);
 
diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index 0ad1384783dd..da4ba21cad21 100644
--- a/tools/perf/util/parse-options.c
+++ b/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, "|");
diff --git a/tools/perf/util/subcmd-config.c b/tools/perf/util/subcmd-config.c
new file mode 100644
index 000000000000..d017c728bd1b
--- /dev/null
+++ b/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,
+};
diff --git a/tools/perf/util/subcmd-config.h b/tools/perf/util/subcmd-config.h
new file mode 100644
index 000000000000..cc8514030b5c
--- /dev/null
+++ b/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 */