acpi4asus

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <string.h>

#define _STR(x) #x

#define STR(x) _STR(x)

#define MAX_PATH 256

const char *find_debugfs(void)

{

  static char debugfs[MAX_PATH+1];

  static int debugfs_found;

  char type[100];

  FILE *fp;

  if (debugfs_found)

    return debugfs;

  if ((fp = fopen("/proc/mounts","r")) == NULL) {

    perror("/proc/mounts");

    return NULL;

  }

  while (fscanf(fp, "%*s %"

                STR(MAX_PATH)

                "s %99s %*s %*d %*d\n",

                debugfs, type) == 2) {

    if (strcmp(type, "debugfs") == 0)

      break;

  }

  fclose(fp);

  if (strcmp(type, "debugfs") != 0) {

    fprintf(stderr, "debugfs not mounted");

    return NULL;

  }

  debugfs_found = 1;

  return debugfs;

}

const char *tracing_file(const char *file_name)

{

  static char trace_file[MAX_PATH+1];

  snprintf(trace_file, MAX_PATH, "%s/tracing/%s", find_debugfs(), file_name);

  return trace_file;

}

int main (int argc, char **argv)

{

  int fdt, fdp, fde, fdtrace;

  int status;

  char buf[1024];

  ssize_t bytes;

  if (argc < 2)

    exit(-1);

  fdt = open(tracing_file("current_tracer"), O_WRONLY);

  fdp = open(tracing_file("set_ftrace_pid"), O_WRONLY);

  fde = open(tracing_file("tracing_enabled"), O_WRONLY);

  if (fdt < 0 || fdp < 0 || fde < 0) {

    perror("open");

    exit(-1);

  }

  write(fdt, "nop", 3);

  if (fork() == 0) {

    bytes = sprintf(buf, "%d\n", getpid());

    write(fdp, buf, bytes);

    write(fdt, argv[1], strlen(argv[1]));

    write(fde, "1", 1);

    execvp(argv[2], argv+2);

  } else {

    fprintf(stderr, "Waiting child\n");

    wait(&status);

    fprintf(stderr, "Child terminated, copying trace\n");

    write(fde, "0", 1);

    fdtrace = open(tracing_file("trace"), O_RDONLY);

    while ((bytes = read(fdtrace, buf, sizeof(buf))) > 0)

      write(STDOUT_FILENO, buf, bytes);

    close(fdtrace);

    write(fdt, "nop", 3);

  }

  close(fdt);

  close(fde);

  close(fdp);

  return 0;

}