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, 411 insertions, 0 deletions

diff --git a/Documentation/perf_counter/perf.c b/Documentation/perf_counter/perf.c
new file mode 100644
index 000000000000..9256f6a16446
--- /dev/null
+++ b/Documentation/perf_counter/perf.c
@@ -0,0 +1,411 @@
+#include "builtin.h"
+#include "exec_cmd.h"
+#include "cache.h"
+//#include "quote.h"
+#include "run-command.h"
+
+const char perf_usage_string[] =
+        "perf [--version] [--exec-path[=PERF_EXEC_PATH]] [--html-path] [-p|--paginate|--no-pager] [--bare] [--perf-dir=PERF_DIR] [--work-tree=PERF_WORK_TREE] [--help] COMMAND [ARGS]";
+
+const char perf_more_info_string[] =
+        "See 'perf help COMMAND' for more information on a specific command.";
+
+static int use_pager = -1;
+struct pager_config {
+        const char *cmd;
+        int val;
+};
+
+static int pager_command_config(const char *var, const char *value, void *data)
+{
+        struct pager_config *c = data;
+        if (!prefixcmp(var, "pager.") && !strcmp(var + 6, c->cmd))
+                c->val = perf_config_bool(var, value);
+        return 0;
+}
+
+/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
+int check_pager_config(const char *cmd)
+{
+        struct pager_config c;
+        c.cmd = cmd;
+        c.val = -1;
+        perf_config(pager_command_config, &c);
+        return c.val;
+}
+
+static void commit_pager_choice(void) {
+        switch (use_pager) {
+        case 0:
+                setenv("PERF_PAGER", "cat", 1);
+                break;
+        case 1:
+                /* setup_pager(); */
+                break;
+        default:
+                break;
+        }
+}
+
+static int handle_options(const char*** argv, int* argc, int* envchanged)
+{
+        int handled = 0;
+
+        while (*argc > 0) {
+                const char *cmd = (*argv)[0];
+                if (cmd[0] != '-')
+                        break;
+
+                /*
+                 * For legacy reasons, the "version" and "help"
+                 * commands can be written with "--" prepended
+                 * to make them look like flags.
+                 */
+                if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
+                        break;
+
+                /*
+                 * Check remaining flags.
+                 */
+                if (!prefixcmp(cmd, "--exec-path")) {
+                        cmd += 11;
+                        if (*cmd == '=')
+                                perf_set_argv_exec_path(cmd + 1);
+                        else {
+                                puts(perf_exec_path());
+                                exit(0);
+                        }
+                } else if (!strcmp(cmd, "--html-path")) {
+                        puts(system_path(PERF_HTML_PATH));
+                        exit(0);
+                } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
+                        use_pager = 1;
+                } else if (!strcmp(cmd, "--no-pager")) {
+                        use_pager = 0;
+                        if (envchanged)
+                                *envchanged = 1;
+                } else if (!strcmp(cmd, "--perf-dir")) {
+                        if (*argc < 2) {
+                                fprintf(stderr, "No directory given for --perf-dir.\n" );
+                                usage(perf_usage_string);
+                        }
+                        setenv(PERF_DIR_ENVIRONMENT, (*argv)[1], 1);
+                        if (envchanged)
+                                *envchanged = 1;
+                        (*argv)++;
+                        (*argc)--;
+                        handled++;
+                } else if (!prefixcmp(cmd, "--perf-dir=")) {
+                        setenv(PERF_DIR_ENVIRONMENT, cmd + 10, 1);
+                        if (envchanged)
+                                *envchanged = 1;
+                } else if (!strcmp(cmd, "--work-tree")) {
+                        if (*argc < 2) {
+                                fprintf(stderr, "No directory given for --work-tree.\n" );
+                                usage(perf_usage_string);
+                        }
+                        setenv(PERF_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
+                        if (envchanged)
+                                *envchanged = 1;
+                        (*argv)++;
+                        (*argc)--;
+                } else if (!prefixcmp(cmd, "--work-tree=")) {
+                        setenv(PERF_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
+                        if (envchanged)
+                                *envchanged = 1;
+                } else {
+                        fprintf(stderr, "Unknown option: %s\n", cmd);
+                        usage(perf_usage_string);
+                }
+
+                (*argv)++;
+                (*argc)--;
+                handled++;
+        }
+        return handled;
+}
+
+static int handle_alias(int *argcp, const char ***argv)
+{
+        int envchanged = 0, ret = 0, saved_errno = errno;
+        int count, option_count;
+        const char** new_argv;
+        const char *alias_command;
+        char *alias_string;
+        int unused_nonperf;
+
+        alias_command = (*argv)[0];
+        alias_string = alias_lookup(alias_command);
+        if (alias_string) {
+                if (alias_string[0] == '!') {
+                        if (*argcp > 1) {
+                                struct strbuf buf;
+
+                                strbuf_init(&buf, PATH_MAX);
+                                strbuf_addstr(&buf, alias_string);
+                                sq_quote_argv(&buf, (*argv) + 1, PATH_MAX);
+                                free(alias_string);
+                                alias_string = buf.buf;
+                        }
+                        ret = system(alias_string + 1);
+                        if (ret >= 0 && WIFEXITED(ret) &&
+                            WEXITSTATUS(ret) != 127)
+                                exit(WEXITSTATUS(ret));
+                        die("Failed to run '%s' when expanding alias '%s'",
+                            alias_string + 1, alias_command);
+                }
+                count = split_cmdline(alias_string, &new_argv);
+                if (count < 0)
+                        die("Bad alias.%s string", alias_command);
+                option_count = handle_options(&new_argv, &count, &envchanged);
+                if (envchanged)
+                        die("alias '%s' changes environment variables\n"
+                                 "You can use '!perf' in the alias to do this.",
+                                 alias_command);
+                memmove(new_argv - option_count, new_argv,
+                                count * sizeof(char *));
+                new_argv -= option_count;
+
+                if (count < 1)
+                        die("empty alias for %s", alias_command);
+
+                if (!strcmp(alias_command, new_argv[0]))
+                        die("recursive alias: %s", alias_command);
+
+                new_argv = realloc(new_argv, sizeof(char*) *
+                                    (count + *argcp + 1));
+                /* insert after command name */
+                memcpy(new_argv + count, *argv + 1, sizeof(char*) * *argcp);
+                new_argv[count+*argcp] = NULL;
+
+                *argv = new_argv;
+                *argcp += count - 1;
+
+                ret = 1;
+        }
+
+        errno = saved_errno;
+
+        return ret;
+}
+
+const char perf_version_string[] = PERF_VERSION;
+
+#define RUN_SETUP       (1<<0)
+#define USE_PAGER       (1<<1)
+/*
+ * require working tree to be present -- anything uses this needs
+ * RUN_SETUP for reading from the configuration file.
+ */
+#define NEED_WORK_TREE  (1<<2)
+
+struct cmd_struct {
+        const char *cmd;
+        int (*fn)(int, const char **, const char *);
+        int option;
+};
+
+static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
+{
+        int status;
+        struct stat st;
+        const char *prefix;
+
+        prefix = NULL;
+        if (p->option & RUN_SETUP)
+                prefix = NULL; /* setup_perf_directory(); */
+
+        if (use_pager == -1 && p->option & RUN_SETUP)
+                use_pager = check_pager_config(p->cmd);
+        if (use_pager == -1 && p->option & USE_PAGER)
+                use_pager = 1;
+        commit_pager_choice();
+
+        if (p->option & NEED_WORK_TREE)
+                /* setup_work_tree() */;
+
+        status = p->fn(argc, argv, prefix);
+        if (status)
+                return status & 0xff;
+
+        /* Somebody closed stdout? */
+        if (fstat(fileno(stdout), &st))
+                return 0;
+        /* Ignore write errors for pipes and sockets.. */
+        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
+                return 0;
+
+        /* Check for ENOSPC and EIO errors.. */
+        if (fflush(stdout))
+                die("write failure on standard output: %s", strerror(errno));
+        if (ferror(stdout))
+                die("unknown write failure on standard output");
+        if (fclose(stdout))
+                die("close failed on standard output: %s", strerror(errno));
+        return 0;
+}
+
+static void handle_internal_command(int argc, const char **argv)
+{
+        const char *cmd = argv[0];
+        static struct cmd_struct commands[] = {
+                { "top", cmd_top, 0 },
+        };
+        int i;
+        static const char ext[] = STRIP_EXTENSION;
+
+        if (sizeof(ext) > 1) {
+                i = strlen(argv[0]) - strlen(ext);
+                if (i > 0 && !strcmp(argv[0] + i, ext)) {
+                        char *argv0 = strdup(argv[0]);
+                        argv[0] = cmd = argv0;
+                        argv0[i] = '\0';
+                }
+        }
+
+        /* Turn "perf cmd --help" into "perf help cmd" */
+        if (argc > 1 && !strcmp(argv[1], "--help")) {
+                argv[1] = argv[0];
+                argv[0] = cmd = "help";
+        }
+
+        for (i = 0; i < ARRAY_SIZE(commands); i++) {
+                struct cmd_struct *p = commands+i;
+                if (strcmp(p->cmd, cmd))
+                        continue;
+                exit(run_builtin(p, argc, argv));
+        }
+}
+
+static void execv_dashed_external(const char **argv)
+{
+        struct strbuf cmd = STRBUF_INIT;
+        const char *tmp;
+        int status;
+
+        strbuf_addf(&cmd, "perf-%s", argv[0]);
+
+        /*
+         * argv[0] must be the perf command, but the argv array
+         * belongs to the caller, and may be reused in
+         * subsequent loop iterations. Save argv[0] and
+         * restore it on error.
+         */
+        tmp = argv[0];
+        argv[0] = cmd.buf;
+
+        /*
+         * if we fail because the command is not found, it is
+         * OK to return. Otherwise, we just pass along the status code.
+         */
+        status = run_command_v_opt(argv, 0);
+        if (status != -ERR_RUN_COMMAND_EXEC) {
+                if (IS_RUN_COMMAND_ERR(status))
+                        die("unable to run '%s'", argv[0]);
+                exit(-status);
+        }
+        errno = ENOENT; /* as if we called execvp */
+
+        argv[0] = tmp;
+
+        strbuf_release(&cmd);
+}
+
+static int run_argv(int *argcp, const char ***argv)
+{
+        int done_alias = 0;
+
+        while (1) {
+                /* See if it's an internal command */
+                handle_internal_command(*argcp, *argv);
+
+                /* .. then try the external ones */
+                execv_dashed_external(*argv);
+
+                /* It could be an alias -- this works around the insanity
+                 * of overriding "perf log" with "perf show" by having
+                 * alias.log = show
+                 */
+                if (done_alias || !handle_alias(argcp, argv))
+                        break;
+                done_alias = 1;
+        }
+
+        return done_alias;
+}
+
+
+int main(int argc, const char **argv)
+{
+        const char *cmd;
+
+        cmd = perf_extract_argv0_path(argv[0]);
+        if (!cmd)
+                cmd = "perf-help";
+
+        /*
+         * "perf-xxxx" is the same as "perf xxxx", but we obviously:
+         *
+         *  - cannot take flags in between the "perf" and the "xxxx".
+         *  - cannot execute it externally (since it would just do
+         *    the same thing over again)
+         *
+         * So we just directly call the internal command handler, and
+         * die if that one cannot handle it.
+         */
+        if (!prefixcmp(cmd, "perf-")) {
+                cmd += 4;
+                argv[0] = cmd;
+                handle_internal_command(argc, argv);
+                die("cannot handle %s internally", cmd);
+        }
+
+        /* Look for flags.. */
+        argv++;
+        argc--;
+        handle_options(&argv, &argc, NULL);
+        commit_pager_choice();
+        if (argc > 0) {
+                if (!prefixcmp(argv[0], "--"))
+                        argv[0] += 2;
+        } else {
+                /* The user didn't specify a command; give them help */
+                printf("usage: %s\n\n", perf_usage_string);
+                list_common_cmds_help();
+                printf("\n%s\n", perf_more_info_string);
+                exit(1);
+        }
+        cmd = argv[0];
+
+        /*
+         * We use PATH to find perf commands, but we prepend some higher
+         * precidence paths: the "--exec-path" option, the PERF_EXEC_PATH
+         * environment, and the $(perfexecdir) from the Makefile at build
+         * time.
+         */
+        setup_path();
+
+        while (1) {
+                static int done_help = 0;
+                static int was_alias = 0;
+                was_alias = run_argv(&argc, &argv);
+                if (errno != ENOENT)
+                        break;
+                if (was_alias) {
+                        fprintf(stderr, "Expansion of alias '%s' failed; "
+                                "'%s' is not a perf-command\n",
+                                cmd, argv[0]);
+                        exit(1);
+                }
+                if (!done_help) {
+                        cmd = argv[0] = help_unknown_cmd(cmd);
+                        done_help = 1;
+                } else
+                        break;
+        }
+
+        fprintf(stderr, "Failed to run command '%s': %s\n",
+                cmd, strerror(errno));
+
+        return 1;
+}