zhangyang-variable-monitor/source/ucli/helpfun.cc

#include "helpfun.h"

unsigned long run_in_host = 0;

enum { RUN_IN_HOST = 0, RUN_IN_CONTAINER };

int is_pid_1_has_environ(const char *field) {
  bool done = false;
  FILE *f = NULL;
  int r = 0;
  size_t l;

  assert(field);

  f = fopen("/proc/1/environ", "re");
  if (!f)
    return 0;

  (void)__fsetlocking(f, FSETLOCKING_BYCALLER);

  l = strlen(field);

  do {
    char line[BUF_LEN];
    size_t i;

    for (i = 0; i < sizeof(line) - 1; i++) {
      int c;

      c = getc(f);
      if ((c == EOF)) {
        done = true;
        break;
      } else if (c == 0)
        break;

      line[i] = c;
    }
    line[i] = 0;

    if (strneq(line, field, l) && line[l] == '=') {
      r = 1;
      goto out;
    }

  } while (!done);

out:
  fclose(f);
  return r;
}

int get_proc_field(const char *filename, const char *pattern,
                   const char *terminator, char **field) {
  char status[BUF_LEN] = {0};
  char *t, *f;
  size_t len;
  int r;

  assert(terminator);
  assert(filename);
  assert(pattern);
  assert(field);

  int fd = open(filename, O_RDONLY);
  if (fd < 0)
    return -errno;

  r = read(fd, &status, BUF_LEN - 1);
  if (r < 0)
    return r;

  t = status;

  do {
    bool pattern_ok;

    do {
      t = strstr(t, pattern);
      if (!t)
        return -ENOENT;

      /* Check that pattern occurs in beginning of line. */
      pattern_ok = (t == status || t[-1] == '\n');

      t += strlen(pattern);

    } while (!pattern_ok);

    t += strspn(t, " \t");
    if (!*t)
      return -ENOENT;

  } while (*t != ':');

  t++;

  if (*t) {
    t += strspn(t, " \t");

    /* Also skip zeros, because when this is used for
     * capabilities, we don't want the zeros. This way the
     * same capability set always maps to the same string,
     * irrespective of the total capability set size. For
     * other numbers it shouldn't matter. */
    t += strspn(t, "0");
    /* Back off one char if there's nothing but whitespace
       and zeros */
    if (!*t || isspace(*t))
      t--;
  }

  len = strcspn(t, terminator);

  f = strndup(t, len);
  if (!f)
    return -ENOMEM;

  *field = f;
  return 0;
}

static int detect_container_by_pid_2(void) {
  char *s = NULL;
  int r;

  r = get_proc_field("/proc/2/status", "PPid", WHITESPACE, &s);
  if (r >= 0) {
    if (streq(s, "0"))
      r = RUN_IN_HOST;
    else
      r = RUN_IN_CONTAINER;
  } else if (r == -ENOENT)
    r = RUN_IN_CONTAINER;
  else {
    printf("Failed to read /proc/2/status: %d\n", r);
    r = RUN_IN_HOST;
  }

  free(s);
  return r;
}

int check_in_host(void) {
  int r;

  if (is_pid_1_has_environ("container"))
    r = RUN_IN_CONTAINER;
  else
    r = detect_container_by_pid_2();

  return r == RUN_IN_HOST;
}

static const char *user_mode_str(int user_mode) {
  switch (user_mode) {
  case 1:
    return "USER MODE";
  case 0:
    return "SYSTEM MODE";
  default:
    return "UNKNOWN MODE";
  }
}

std::string state_str(int __state) {
  std::vector<std::string> states;
  if (__state == TASK_RUNNING)
    states.push_back("TASK_RUNNING");
  // if (__state & TASK_RUNNING)            states.push_back("TASK_RUNNING");
  if (__state & TASK_INTERRUPTIBLE)
    states.push_back("TASK_INTERRUPTIBLE");
  if (__state & TASK_UNINTERRUPTIBLE)
    states.push_back("TASK_UNINTERRUPTIBLE");
  if (__state & __TASK_STOPPED)
    states.push_back("__TASK_STOPPED");
  if (__state & __TASK_TRACED)
    states.push_back("__TASK_TRACED");
  if (__state & TASK_PARKED)
    states.push_back("TASK_PARKED");
  if (__state & TASK_DEAD)
    states.push_back("TASK_DEAD");
  if (__state == TASK_KILLABLE)
    states.push_back("TASK_KILLABLE");
  if (__state == TASK_STOPPED)
    states.push_back("TASK_STOPPED");
  if (__state == TASK_IDLE)
    states.push_back("TASK_IDLE");

  std::string result;
  for (const auto &state : states) {
    if (!result.empty())
      result += " | ";
    result += state;
  }

  return result;
}