exec_cmd.c

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#include "cache.h"
#include "exec_cmd.h"
#include "quote.h"

#include <string.h>

#define MAX_ARGS    32

static const char *argv_exec_path;
static const char *argv0_path;

const char *system_path(const char *path)
{
    static const char *prefix = PREFIX;
    struct strbuf d = STRBUF_INIT;

    if (is_absolute_path(path))
        return path;

    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 argv0_path ? slash + 1 : NULL;
    }

    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);
}

static 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);
}