+
+/* Determine the width of the terminal we're running on. If that's
+ not possible, return 0. */
+
+int
+determine_screen_width (void)
+{
+ /* If there's a way to get the terminal size using POSIX
+ tcgetattr(), somebody please tell me. */
+#ifndef TIOCGWINSZ
+ return 0;
+#else /* TIOCGWINSZ */
+ int fd;
+ struct winsize wsz;
+
+ if (opt.lfilename != NULL)
+ return 0;
+
+ fd = fileno (stderr);
+ if (ioctl (fd, TIOCGWINSZ, &wsz) < 0)
+ return 0; /* most likely ENOTTY */
+
+ return wsz.ws_col;
+#endif /* TIOCGWINSZ */
+}
+
+/* Return a random number between 0 and MAX-1, inclusive.
+
+ If MAX is greater than the value of RAND_MAX+1 on the system, the
+ returned value will be in the range [0, RAND_MAX]. This may be
+ fixed in a future release.
+
+ The random number generator is seeded automatically the first time
+ it is called.
+
+ This uses rand() for portability. It has been suggested that
+ random() offers better randomness, but this is not required for
+ Wget, so I chose to go for simplicity and use rand
+ unconditionally.
+
+ DO NOT use this for cryptographic purposes. It is only meant to be
+ used in situations where quality of the random numbers returned
+ doesn't really matter. */
+
+int
+random_number (int max)
+{
+ static int seeded;
+ double bounded;
+ int rnd;
+
+ if (!seeded)
+ {
+ srand (time (NULL));
+ seeded = 1;
+ }
+ rnd = rand ();
+
+ /* On systems that don't define RAND_MAX, assume it to be 2**15 - 1,
+ and enforce that assumption by masking other bits. */
+#ifndef RAND_MAX
+# define RAND_MAX 32767
+ rnd &= RAND_MAX;
+#endif
+
+ /* This is equivalent to rand() % max, but uses the high-order bits
+ for better randomness on architecture where rand() is implemented
+ using a simple congruential generator. */
+
+ bounded = (double)max * rnd / (RAND_MAX + 1.0);
+ return (int)bounded;
+}
+
+/* Return a random uniformly distributed floating point number in the
+ [0, 1) range. The precision of returned numbers is 9 digits.
+
+ Modify this to use erand48() where available! */
+
+double
+random_float (void)
+{
+ /* We can't rely on any specific value of RAND_MAX, but I'm pretty
+ sure it's greater than 1000. */
+ int rnd1 = random_number (1000);
+ int rnd2 = random_number (1000);
+ int rnd3 = random_number (1000);
+ return rnd1 / 1000.0 + rnd2 / 1000000.0 + rnd3 / 1000000000.0;
+}
+
+#if 0
+/* A debugging function for checking whether an MD5 library works. */
+
+#include "gen-md5.h"
+
+char *
+debug_test_md5 (char *buf)
+{
+ unsigned char raw[16];
+ static char res[33];
+ unsigned char *p1;
+ char *p2;
+ int cnt;
+ ALLOCA_MD5_CONTEXT (ctx);
+
+ gen_md5_init (ctx);
+ gen_md5_update ((unsigned char *)buf, strlen (buf), ctx);
+ gen_md5_finish (ctx, raw);
+
+ p1 = raw;
+ p2 = res;
+ cnt = 16;
+ while (cnt--)
+ {
+ *p2++ = XNUM_TO_digit (*p1 >> 4);
+ *p2++ = XNUM_TO_digit (*p1 & 0xf);
+ ++p1;
+ }
+ *p2 = '\0';
+
+ return res;
+}
+#endif
+\f
+/* Implementation of run_with_timeout, a generic timeout-forcing
+ routine for systems with Unix-like signal handling. */
+
+#ifdef USE_SIGNAL_TIMEOUT
+# ifdef HAVE_SIGSETJMP
+# define SETJMP(env) sigsetjmp (env, 1)
+
+static sigjmp_buf run_with_timeout_env;
+
+static RETSIGTYPE
+abort_run_with_timeout (int sig)
+{
+ assert (sig == SIGALRM);
+ siglongjmp (run_with_timeout_env, -1);
+}
+# else /* not HAVE_SIGSETJMP */
+# define SETJMP(env) setjmp (env)
+
+static jmp_buf run_with_timeout_env;
+
+static RETSIGTYPE
+abort_run_with_timeout (int sig)
+{
+ assert (sig == SIGALRM);
+ /* We don't have siglongjmp to preserve the set of blocked signals;
+ if we longjumped out of the handler at this point, SIGALRM would
+ remain blocked. We must unblock it manually. */
+ int mask = siggetmask ();
+ mask &= ~sigmask (SIGALRM);
+ sigsetmask (mask);
+
+ /* Now it's safe to longjump. */
+ longjmp (run_with_timeout_env, -1);
+}
+# endif /* not HAVE_SIGSETJMP */
+
+/* Arrange for SIGALRM to be delivered in TIMEOUT seconds. This uses
+ setitimer where available, alarm otherwise.
+
+ TIMEOUT should be non-zero. If the timeout value is so small that
+ it would be rounded to zero, it is rounded to the least legal value
+ instead (1us for setitimer, 1s for alarm). That ensures that
+ SIGALRM will be delivered in all cases. */
+
+static void
+alarm_set (double timeout)
+{
+#ifdef ITIMER_REAL
+ /* Use the modern itimer interface. */
+ struct itimerval itv;
+ xzero (itv);
+ itv.it_value.tv_sec = (long) timeout;
+ itv.it_value.tv_usec = 1000000L * (timeout - (long)timeout);
+ if (itv.it_value.tv_sec == 0 && itv.it_value.tv_usec == 0)
+ /* Ensure that we wait for at least the minimum interval.
+ Specifying zero would mean "wait forever". */
+ itv.it_value.tv_usec = 1;
+ setitimer (ITIMER_REAL, &itv, NULL);
+#else /* not ITIMER_REAL */
+ /* Use the old alarm() interface. */
+ int secs = (int) timeout;
+ if (secs == 0)
+ /* Round TIMEOUTs smaller than 1 to 1, not to zero. This is
+ because alarm(0) means "never deliver the alarm", i.e. "wait
+ forever", which is not what someone who specifies a 0.5s
+ timeout would expect. */
+ secs = 1;
+ alarm (secs);
+#endif /* not ITIMER_REAL */
+}
+
+/* Cancel the alarm set with alarm_set. */
+
+static void
+alarm_cancel (void)
+{
+#ifdef ITIMER_REAL
+ struct itimerval disable;
+ xzero (disable);
+ setitimer (ITIMER_REAL, &disable, NULL);
+#else /* not ITIMER_REAL */
+ alarm (0);
+#endif /* not ITIMER_REAL */
+}
+
+/* Call FUN(ARG), but don't allow it to run for more than TIMEOUT
+ seconds. Returns non-zero if the function was interrupted with a
+ timeout, zero otherwise.
+
+ This works by setting up SIGALRM to be delivered in TIMEOUT seconds
+ using setitimer() or alarm(). The timeout is enforced by
+ longjumping out of the SIGALRM handler. This has several
+ advantages compared to the traditional approach of relying on
+ signals causing system calls to exit with EINTR:
+
+ * The callback function is *forcibly* interrupted after the
+ timeout expires, (almost) regardless of what it was doing and
+ whether it was in a syscall. For example, a calculation that
+ takes a long time is interrupted as reliably as an IO
+ operation.
+
+ * It works with both SYSV and BSD signals because it doesn't
+ depend on the default setting of SA_RESTART.
+
+ * It doesn't special handler setup beyond a simple call to
+ signal(). (It does use sigsetjmp/siglongjmp, but they're
+ optional.)
+
+ The only downside is that, if FUN allocates internal resources that
+ are normally freed prior to exit from the functions, they will be
+ lost in case of timeout. */
+
+int
+run_with_timeout (double timeout, void (*fun) (void *), void *arg)
+{
+ int saved_errno;
+
+ if (timeout == 0)
+ {
+ fun (arg);
+ return 0;
+ }
+
+ signal (SIGALRM, abort_run_with_timeout);
+ if (SETJMP (run_with_timeout_env) != 0)
+ {
+ /* Longjumped out of FUN with a timeout. */
+ signal (SIGALRM, SIG_DFL);
+ return 1;
+ }
+ alarm_set (timeout);
+ fun (arg);
+
+ /* Preserve errno in case alarm() or signal() modifies it. */
+ saved_errno = errno;
+ alarm_cancel ();
+ signal (SIGALRM, SIG_DFL);
+ errno = saved_errno;
+
+ return 0;
+}
+
+#else /* not USE_SIGNAL_TIMEOUT */
+
+#ifndef WINDOWS
+/* A stub version of run_with_timeout that just calls FUN(ARG). Don't
+ define it under Windows, because Windows has its own version of
+ run_with_timeout that uses threads. */
+
+int
+run_with_timeout (double timeout, void (*fun) (void *), void *arg)
+{
+ fun (arg);
+ return 0;
+}
+#endif /* not WINDOWS */
+#endif /* not USE_SIGNAL_TIMEOUT */