perf_counter tools: add in basic glue from Git

First very raw version at having a central 'perf' command and
a list of subcommands:

  perf top
  perf stat
  perf record
  perf report
  ...

This is done by picking up Git's collection of utility functions,
and hacking them to build fine in this new environment.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 165 insertions, 0 deletions

diff --git a/Documentation/perf_counter/exec_cmd.c b/Documentation/perf_counter/exec_cmd.c
new file mode 100644
index 000000000000..d39292263153
--- /dev/null
+++ b/Documentation/perf_counter/exec_cmd.c
@@ -0,0 +1,165 @@
+#include "cache.h"
+#include "exec_cmd.h"
+#include "quote.h"
+#define MAX_ARGS        32
+
+extern char **environ;
+static const char *argv_exec_path;
+static const char *argv0_path;
+
+const char *system_path(const char *path)
+{
+#ifdef RUNTIME_PREFIX
+        static const char *prefix;
+#else
+        static const char *prefix = PREFIX;
+#endif
+        struct strbuf d = STRBUF_INIT;
+
+        if (is_absolute_path(path))
+                return path;
+
+#ifdef RUNTIME_PREFIX
+        assert(argv0_path);
+        assert(is_absolute_path(argv0_path));
+
+        if (!prefix &&
+            !(prefix = strip_path_suffix(argv0_path, PERF_EXEC_PATH)) &&
+            !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
+            !(prefix = strip_path_suffix(argv0_path, "perf"))) {
+                prefix = PREFIX;
+                fprintf(stderr, "RUNTIME_PREFIX requested, "
+                                "but prefix computation failed.  "
+                                "Using static fallback '%s'.\n", prefix);
+        }
+#endif
+
+        strbuf_addf(&d, "%s/%s", prefix, path);
+        path = strbuf_detach(&d, NULL);
+        return path;
+}
+
+const char *perf_extract_argv0_path(const char *argv0)
+{
+        const char *slash;
+
+        if (!argv0 || !*argv0)
+                return NULL;
+        slash = argv0 + strlen(argv0);
+
+        while (argv0 <= slash && !is_dir_sep(*slash))
+                slash--;
+
+        if (slash >= argv0) {
+                argv0_path = strndup(argv0, slash - argv0);
+                return slash + 1;
+        }
+
+        return argv0;
+}
+
+void perf_set_argv_exec_path(const char *exec_path)
+{
+        argv_exec_path = exec_path;
+        /*
+         * Propagate this setting to external programs.
+         */
+        setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
+}
+
+
+/* Returns the highest-priority, location to look for perf programs. */
+const char *perf_exec_path(void)
+{
+        const char *env;
+
+        if (argv_exec_path)
+                return argv_exec_path;
+
+        env = getenv(EXEC_PATH_ENVIRONMENT);
+        if (env && *env) {
+                return env;
+        }
+
+        return system_path(PERF_EXEC_PATH);
+}
+
+static void add_path(struct strbuf *out, const char *path)
+{
+        if (path && *path) {
+                if (is_absolute_path(path))
+                        strbuf_addstr(out, path);
+                else
+                        strbuf_addstr(out, make_nonrelative_path(path));
+
+                strbuf_addch(out, PATH_SEP);
+        }
+}
+
+void setup_path(void)
+{
+        const char *old_path = getenv("PATH");
+        struct strbuf new_path = STRBUF_INIT;
+
+        add_path(&new_path, perf_exec_path());
+        add_path(&new_path, argv0_path);
+
+        if (old_path)
+                strbuf_addstr(&new_path, old_path);
+        else
+                strbuf_addstr(&new_path, "/usr/local/bin:/usr/bin:/bin");
+
+        setenv("PATH", new_path.buf, 1);
+
+        strbuf_release(&new_path);
+}
+
+const char **prepare_perf_cmd(const char **argv)
+{
+        int argc;
+        const char **nargv;
+
+        for (argc = 0; argv[argc]; argc++)
+                ; /* just counting */
+        nargv = malloc(sizeof(*nargv) * (argc + 2));
+
+        nargv[0] = "perf";
+        for (argc = 0; argv[argc]; argc++)
+                nargv[argc + 1] = argv[argc];
+        nargv[argc + 1] = NULL;
+        return nargv;
+}
+
+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);
+
+        free(nargv);
+        return -1;
+}
+
+
+int execl_perf_cmd(const char *cmd,...)
+{
+        int argc;
+        const char *argv[MAX_ARGS + 1];
+        const char *arg;
+        va_list param;
+
+        va_start(param, cmd);
+        argv[0] = cmd;
+        argc = 1;
+        while (argc < MAX_ARGS) {
+                arg = argv[argc++] = va_arg(param, char *);
+                if (!arg)
+                        break;
+        }
+        va_end(param);
+        if (MAX_ARGS <= argc)
+                return error("too many args to run %s", cmd);
+
+        argv[argc] = NULL;
+        return execv_perf_cmd(argv);
+}