compat.c

关于tor匿名通信的源代码

    ent = gethostbyname(name);
#ifdef MS_WINDOWS
    err = WSAGetLastError();
#else
    err = h_errno;
#endif
#endif /* endif HAVE_GETHOSTBYNAME_R_6_ARG. */
    if (ent) {
      addr->family = ent->h_addrtype;
      if (ent->h_addrtype == AF_INET) {
        memcpy(&addr->addr.in_addr, ent->h_addr, sizeof(struct in_addr));
      } else if (ent->h_addrtype == AF_INET6) {
        memcpy(&addr->addr.in6_addr, ent->h_addr, sizeof(struct in6_addr));
      } else {
        tor_assert(0); /* gethostbyname() returned a bizarre addrtype */
      }
      return 0;
    }
#ifdef MS_WINDOWS
    return (err == WSATRY_AGAIN) ? 1 : -1;
#else
    return (err == TRY_AGAIN) ? 1 : -1;
#endif
#endif
  }
}

/** Hold the result of our call to <b>uname</b>. */
static char uname_result[256];
/** True iff uname_result is set. */
static int uname_result_is_set = 0;

/** Return a pointer to a description of our platform.
 */
const char *
get_uname(void)
{
#ifdef HAVE_UNAME
  struct utsname u;
#endif
  if (!uname_result_is_set) {
#ifdef HAVE_UNAME
    if (uname(&u) != -1) {
      /* (linux says 0 is success, solaris says 1 is success) */
      tor_snprintf(uname_result, sizeof(uname_result), "%s %s",
               u.sysname, u.machine);
    } else
#endif
      {
#ifdef MS_WINDOWS
        OSVERSIONINFOEX info;
        int i;
        unsigned int leftover_mask;
        const char *plat = NULL;
        const char *extra = NULL;
        static struct {
          unsigned major; unsigned minor; const char *version;
        } win_version_table[] = {
          { 6, 0, "Windows \"Longhorn\"" },
          { 5, 2, "Windows Server 2003" },
          { 5, 1, "Windows XP" },
          { 5, 0, "Windows 2000" },
          /* { 4, 0, "Windows NT 4.0" }, */
          { 4, 90, "Windows Me" },
          { 4, 10, "Windows 98" },
          /* { 4, 0, "Windows 95" } */
          { 3, 51, "Windows NT 3.51" },
          { 0, 0, NULL }
        };
#ifdef VER_SUITE_BACKOFFICE
        static struct {
          unsigned int mask; const char *str;
        } win_mask_table[] = {
          { VER_SUITE_BACKOFFICE,         " {backoffice}" },
          { VER_SUITE_BLADE,              " {\"blade\" (2003, web edition)}" },
          { VER_SUITE_DATACENTER,         " {datacenter}" },
          { VER_SUITE_ENTERPRISE,         " {enterprise}" },
          { VER_SUITE_EMBEDDEDNT,         " {embedded}" },
          { VER_SUITE_PERSONAL,           " {personal}" },
          { VER_SUITE_SINGLEUSERTS,
            " {terminal services, single user}" },
          { VER_SUITE_SMALLBUSINESS,      " {small business}" },
          { VER_SUITE_SMALLBUSINESS_RESTRICTED,
            " {small business, restricted}" },
          { VER_SUITE_TERMINAL,           " {terminal services}" },
          { 0, NULL },
        };
#endif
        memset(&info, 0, sizeof(info));
        info.dwOSVersionInfoSize = sizeof(info);
        if (! GetVersionEx((LPOSVERSIONINFO)&info)) {
          strlcpy(uname_result, "Bizarre version of Windows where GetVersionEx"
                  " doesn't work.", sizeof(uname_result));
          uname_result_is_set = 1;
          return uname_result;
        }
        if (info.dwMajorVersion == 4 && info.dwMinorVersion == 0) {
          if (info.dwPlatformId == VER_PLATFORM_WIN32_NT)
            plat = "Windows NT 4.0";
          else
            plat = "Windows 95";
          if (info.szCSDVersion[1] == 'B')
            extra = "OSR2 (B)";
          else if (info.szCSDVersion[1] == 'C')
            extra = "OSR2 (C)";
        } else {
          for (i=0; win_version_table[i].major>0; ++i) {
            if (win_version_table[i].major == info.dwMajorVersion &&
                win_version_table[i].minor == info.dwMinorVersion) {
              plat = win_version_table[i].version;
              break;
            }
          }
        }
        if (plat && !strcmp(plat, "Windows 98")) {
          if (info.szCSDVersion[1] == 'A')
            extra = "SE (A)";
          else if (info.szCSDVersion[1] == 'B')
            extra = "SE (B)";
        }
        if (plat) {
          if (!extra)
            extra = info.szCSDVersion;
          tor_snprintf(uname_result, sizeof(uname_result), "%s %s",
                       plat, extra);
        } else {
          if (info.dwMajorVersion > 6 ||
              (info.dwMajorVersion==6 && info.dwMinorVersion>0))
            tor_snprintf(uname_result, sizeof(uname_result),
                      "Very recent version of Windows [major=%d,minor=%d] %s",
                      (int)info.dwMajorVersion,(int)info.dwMinorVersion,
                      info.szCSDVersion);
          else
            tor_snprintf(uname_result, sizeof(uname_result),
                      "Unrecognized version of Windows [major=%d,minor=%d] %s",
                      (int)info.dwMajorVersion,(int)info.dwMinorVersion,
                      info.szCSDVersion);
        }
#ifdef VER_SUITE_BACKOFFICE
        if (info.wProductType == VER_NT_DOMAIN_CONTROLLER) {
          strlcat(uname_result, " [domain controller]", sizeof(uname_result));
        } else if (info.wProductType == VER_NT_SERVER) {
          strlcat(uname_result, " [server]", sizeof(uname_result));
        } else if (info.wProductType == VER_NT_WORKSTATION) {
          strlcat(uname_result, " [workstation]", sizeof(uname_result));
        }
        leftover_mask = info.wSuiteMask;
        for (i = 0; win_mask_table[i].mask; ++i) {
          if (info.wSuiteMask & win_mask_table[i].mask) {
            strlcat(uname_result, win_mask_table[i].str, sizeof(uname_result));
            leftover_mask &= ~win_mask_table[i].mask;
          }
        }
        if (leftover_mask) {
          size_t len = strlen(uname_result);
          tor_snprintf(uname_result+len, sizeof(uname_result)-len,
                       " {0x%x}", info.wSuiteMask);
        }
#endif
#else
        strlcpy(uname_result, "Unknown platform", sizeof(uname_result));
#endif
      }
    uname_result_is_set = 1;
  }
  return uname_result;
}

/*
 *   Process control
 */

#if defined(USE_PTHREADS)
/** Wraps a void (*)(void*) function and its argument so we can
 * invoke them in a way pthreads would expect.
 */
typedef struct tor_pthread_data_t {
  void (*func)(void *);
  void *data;
} tor_pthread_data_t;
/** Given a tor_pthread_data_t <b>_data</b>, call _data-&gt;func(d-&gt;data)
 * and free _data.  Used to make sure we can call functions the way pthread
 * expects. */
static void *
tor_pthread_helper_fn(void *_data)
{
  tor_pthread_data_t *data = _data;
  void (*func)(void*);
  void *arg;
  /* mask signals to worker threads to avoid SIGPIPE, etc */
  sigset_t sigs;
  /* We're in a subthread; don't handle any signals here. */
  sigfillset(&sigs);
  pthread_sigmask(SIG_SETMASK, &sigs, NULL);

  func = data->func;
  arg = data->data;
  tor_free(_data);
  func(arg);
  return NULL;
}
#endif

/** Minimalist interface to run a void function in the background.  On
 * unix calls fork, on win32 calls beginthread.  Returns -1 on failure.
 * func should not return, but rather should call spawn_exit.
 *
 * NOTE: if <b>data</b> is used, it should not be allocated on the stack,
 * since in a multithreaded environment, there is no way to be sure that
 * the caller's stack will still be around when the called function is
 * running.
 */
int
spawn_func(void (*func)(void *), void *data)
{
#if defined(USE_WIN32_THREADS)
  int rv;
  rv = (int)_beginthread(func, 0, data);
  if (rv == (int)-1)
    return -1;
  return 0;
#elif defined(USE_PTHREADS)
  pthread_t thread;
  tor_pthread_data_t *d;
  d = tor_malloc(sizeof(tor_pthread_data_t));
  d->data = data;
  d->func = func;
  if (pthread_create(&thread,NULL,tor_pthread_helper_fn,d))
    return -1;
  if (pthread_detach(thread))
    return -1;
  return 0;
#else
  pid_t pid;
  pid = fork();
  if (pid<0)
    return -1;
  if (pid==0) {
    /* Child */
    func(data);
    tor_assert(0); /* Should never reach here. */
    return 0; /* suppress "control-reaches-end-of-non-void" warning. */
  } else {
    /* Parent */
    return 0;
  }
#endif
}

/** End the current thread/process.
 */
void
spawn_exit(void)
{
#if defined(USE_WIN32_THREADS)
  _endthread();
  //we should never get here. my compiler thinks that _endthread returns, this
  //is an attempt to fool it.
  tor_assert(0);
  _exit(0);
#elif defined(USE_PTHREADS)
  pthread_exit(NULL);
#else
  /* http://www.erlenstar.demon.co.uk/unix/faq_2.html says we should
   * call _exit, not exit, from child processes. */
  _exit(0);
#endif

}

/** Set *timeval to the current time of day.  On error, log and terminate.
 * (Same as gettimeofday(timeval,NULL), but never returns -1.)
 */
void
tor_gettimeofday(struct timeval *timeval)
{
#ifdef MS_WINDOWS
  /* Epoch bias copied from perl: number of units between windows epoch and
   * unix epoch. */
#define EPOCH_BIAS U64_LITERAL(116444736000000000)
#define UNITS_PER_SEC U64_LITERAL(10000000)
#define USEC_PER_SEC U64_LITERAL(1000000)
#define UNITS_PER_USEC U64_LITERAL(10)
  union {
    uint64_t ft_64;
    FILETIME ft_ft;
  } ft;
  /* number of 100-nsec units since Jan 1, 1601 */
  GetSystemTimeAsFileTime(&ft.ft_ft);
  if (ft.ft_64 < EPOCH_BIAS) {
    log_err(LD_GENERAL,"System time is before 1970; failing.");
    exit(1);
  }
  ft.ft_64 -= EPOCH_BIAS;
  timeval->tv_sec = (unsigned) (ft.ft_64 / UNITS_PER_SEC);
  timeval->tv_usec = (unsigned) ((ft.ft_64 / UNITS_PER_USEC) % USEC_PER_SEC);
#elif defined(HAVE_GETTIMEOFDAY)
  if (gettimeofday(timeval, NULL)) {
    log_err(LD_GENERAL,"gettimeofday failed.");
    /* If gettimeofday dies, we have either given a bad timezone (we didn't),
       or segfaulted.*/
    exit(1);
  }
#elif defined(HAVE_FTIME)
  struct timeb tb;
  ftime(&tb);
  timeval->tv_sec = tb.time;
  timeval->tv_usec = tb.millitm * 1000;
#else
#error "No way to get time."
#endif
  return;
}

#if defined(TOR_IS_MULTITHREADED) && !defined(MS_WINDOWS)
/** Defined iff we need to add locks when defining fake versions of reentrant
 * versions of time-related functions. */
#define TIME_FNS_NEED_LOCKS
#endif

#ifndef HAVE_LOCALTIME_R
#ifdef TIME_FNS_NEED_LOCKS
struct tm *
tor_localtime_r(const time_t *timep, struct tm *result)
{
  struct tm *r;
  static tor_mutex_t *m=NULL;
  if (!m) { m=tor_mutex_new(); }
  tor_assert(result);
  tor_mutex_acquire(m);
  r = localtime(timep);
  memcpy(result, r, sizeof(struct tm));
  tor_mutex_release(m);
  return result;
}
#else
struct tm *
tor_localtime_r(const time_t *timep, struct tm *result)
{
  struct tm *r;
  tor_assert(result);
  r = localtime(timep);
  memcpy(result, r, sizeof(struct tm));
  return result;
}
#endif
#endif

#ifndef HAVE_GMTIME_R
#ifdef TIME_FNS_NEED_LOCKS
struct tm *
tor_gmtime_r(const time_t *timep, struct tm *result)
{
  struct tm *r;
  static tor_mutex_t *m=NULL;
  if (!m) { m=tor_mutex_new(); }
  tor_assert(result);
  tor_mutex_acquire(m);
  r = gmtime(timep);
  memcpy(result, r, sizeof(struct tm));
  tor_mutex_release(m);
  return result;
}
#else
struct tm *
tor_gmtime_r(const time_t *timep, struct tm *result)
{
  struct tm *r;
  tor_assert(result);
  r = gmtime(timep);
  memcpy(result, r, sizeof(struct tm));
  return result;
}
#endif
#endif

#if defined(USE_WIN32_THREADS) && 0
/** A generic lock structure for multithreaded builds. */
struct tor_mutex_t {
  HANDLE handle;
};
tor_mutex_t *
tor_mutex_new(void)
{
  tor_mutex_t *m;
  m = tor_malloc_zero(sizeof(tor_mutex_t));
  m->handle = CreateMutex(NULL, FALSE, NULL);
  tor_assert(m->handle != NULL);
  return m;
}
void
tor_mutex_free(tor_mutex_t *m)
{
  CloseHandle(m->handle);
  tor_free(m);
}
void
tor_mutex_acquire(tor_mutex_t *m)
{
  DWORD r;
  r = WaitForSingleObject(m->handle, INFINITE);
  switch (r) {
    case WAIT_ABANDONED: /* holding thread exited. */
    case WAIT_OBJECT_0: /* we got the mutex normally. */
      break;
    case WAIT_TIMEOUT: /* Should never happen. */
      tor_assert(0);
      break;
    case WAIT_FAILED:
      log_warn(LD_GENERAL, "Failed to acquire mutex: %d",(int) GetLastError());
  }
}
void
tor_mutex_release(tor_mutex_t *m)
{
  BOOL r;
  r = ReleaseMutex(m->handle);
  if (!r) {
    log_warn(LD_GENERAL, "Failed to release mutex: %d", (int) GetLastError());
  }
}
unsigned long
tor_get_thread_id(void)
{