X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/58a740ea5c4cf2d8b1e10a3bc8bc098678be1046..296d466cd6bbf2f7e75e15bb6a01268e88c76ed0:/tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index 92b76c40..9bab8d87 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -701,6 +701,7 @@ show_remote_devices_and_exit(void)
 #define OPTION_TSTAMP_NANO		134
 #define OPTION_FP_TYPE			135
 #define OPTION_COUNT			136
+#define OPTION_TIME_T_SIZE		139
 
 static const struct option longopts[] = {
 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
@@ -748,6 +749,7 @@ static const struct option longopts[] = {
 	{ "fp-type", no_argument, NULL, OPTION_FP_TYPE },
 	{ "number", no_argument, NULL, '#' },
 	{ "print", no_argument, NULL, OPTION_PRINT },
+	{ "time-t-size", no_argument, NULL, OPTION_TIME_T_SIZE },
 	{ "version", no_argument, NULL, OPTION_VERSION },
 	{ NULL, 0, NULL, 0 }
 };
@@ -1519,6 +1521,157 @@ main(int argc, char **argv)
 	netdissect_options Ndo;
 	netdissect_options *ndo = &Ndo;
 
+#ifdef _WIN32
+	/*
+	 * We need to look for wpcap.dll in \Windows\System32\Npcap first,
+	 * as either:
+	 *
+	 *  1) WinPcap isn't installed and Npcap isn't installed in "WinPcap
+	 *     API-compatible Mode", so there's no wpcap.dll in
+	 *     \Windows\System32, only in \Windows\System32\Npcap;
+	 *
+	 *  2) WinPcap is installed and Npcap isn't installed in "WinPcap
+	 *     API-compatible Mode", so the wpcap.dll in \Windows\System32
+	 *     is a WinPcap DLL, but we'd prefer an Npcap DLL (we should
+	 *     work with either one if we're configured against WinPcap,
+	 *     and we'll probably require Npcap if we're configured againt
+	 *     it), and that's in \Windows\System32\Npcap;
+	 *
+	 *  3) Npcap is installed in "WinPcap API-compatible Mode", so both
+	 *     \Windows\System32 and \Windows\System32\Npcap have an Npcap
+	 *     wpcap.dll.
+	 *
+	 * Unfortunately, Windows has no notion of an rpath, so we can't
+	 * set the rpath to include \Windows\System32\Npcap at link time;
+	 * what we need to do is to link wpcap as a delay-load DLL and
+	 * add \Windows\System32\Npcap to the DLL search path early in
+	 * main() with a call to SetDllDirectory().
+	 *
+	 * The same applies to packet.dll.
+	 *
+	 * We add \Windows\System32\Npcap here.
+	 *
+	 * See https://npcap.com/guide/npcap-devguide.html#npcap-feature-native-dll-implicitly
+	 */
+	WCHAR *dll_directory = NULL;
+	size_t dll_directory_buf_len = 0;	/* units of bytes */
+	UINT system_directory_buf_len = 0;	/* units of WCHARs */
+	UINT system_directory_len;		/* units of WCHARs */
+	static const WCHAR npcap[] = L"\\Npcap";
+
+	/*
+	 * Get the system directory path, in UTF-16, into a buffer that's
+	 * large enough for that directory path plus "\Npcap".
+	 *
+	 * String manipulation in C, plus fetching a variable-length
+	 * string into a buffer whose size is fixed at the time of
+	 * the call, with an oddball return value (see below), is just
+	 * a huge bag of fun.
+	 *
+	 * And it's even more fun when dealing with UTF-16, so that the
+	 * buffer sizes used in GetSystemDirectoryW() are in different
+	 * units from the buffer sizes used in realloc()!   We maintain
+	 * all sizes/length in units of bytes, not WCHARs, so that our
+	 * heads don't explode.
+	 */
+	for (;;) {
+		/*
+		 * Try to fetch the system directory.
+		 *
+		 * GetSystemDirectoryW() expects a buffer size in units
+		 * of WCHARs, not bytes, and returns a directory path
+		 * length in units of WCHARs, not bytes.
+		 *
+		 * For extra fun, if GetSystemDirectoryW() succeeds,
+		 * the return value is the length of the directory
+		 * path in units of WCHARs, *not* including the
+		 * terminating '\0', but if it fails because the
+		 * path string wouldn't fit, the return value is
+		 * the length of the directory path in units of WCHARs,
+		 * *including* the terminating '\0'.
+		 */
+		system_directory_len = GetSystemDirectoryW(dll_directory,
+		    system_directory_buf_len);
+		if (system_directory_len == 0)
+			error("GetSystemDirectoryW() failed");
+
+		/*
+		 * Did the directory path fit in the buffer?
+		 *
+		 * As per the above, this means that the return value
+		 * *plus 1*, so that the terminating '\0' is counted,
+		 * is <= the buffer size.
+		 *
+		 * (If the directory path, complete with the terminating
+		 * '\0', fits *exactly*, the return value would be the
+		 * size of the buffer minus 1, as it doesn't count the
+		 * terminating '\0', so the test below would succeed.
+		 *
+		 * If everything *but* the terminating '\0' fits,
+		 * the return value would be the size of the buffer + 1,
+		 * i.e., the size that the string in question would
+		 * have required.
+		 *
+		 * The astute reader will note that returning the
+		 * size of the buffer is not one of the two cases
+		 * above, and should never happen.)
+		 */
+		if ((system_directory_len + 1) <= system_directory_buf_len) {
+			/*
+			 * No.  We have a buffer that's large enough
+			 * for our purposes.
+			 */
+			break;
+		}
+
+		/*
+		 * Yes.  Grow the buffer.
+		 *
+		 * The space we'll need in the buffer for the system
+		 * directory, in units of WCHARs, is system_directory_len,
+		 * as that's the length of the system directory path
+		 * including the terminating '\0'.
+		 */
+		system_directory_buf_len = system_directory_len;
+
+		/*
+		 * The size of the DLL directory buffer, in *bytes*, must
+		 * be the number of WCHARs taken by the system directory,
+		 * *minus* the terminating '\0' (as we'll overwrite that
+		 * with the "\" of the "\Npcap" string), multiplied by
+		 * sizeof(WCHAR) to convert it to the number of bytes,
+		 * plus the size of the "\Npcap" string, in bytes (which
+		 * will include the terminating '\0', as that will become
+		 * the DLL path's terminating '\0').
+		 */
+		dll_directory_buf_len =
+		    ((system_directory_len - 1)*sizeof(WCHAR)) + sizeof npcap;
+		dll_directory = realloc(dll_directory, dll_directory_buf_len);
+		if (dll_directory == NULL)
+			error("Can't allocate string for Npcap directory");
+	}
+
+	/*
+	 * OK, that worked.
+	 *
+	 * Now append \Npcap.  We add the length of the system directory path,
+	 * in WCHARs, *not* including the terminating '\0' (which, since
+	 * GetSystemDirectoryW() succeeded, is the return value of
+	 * GetSystemDirectoryW(), as per the above), to the pointer to the
+	 * beginning of the path, to go past the end of the system directory
+	 * to point to the terminating '\0'.
+	 */
+	memcpy(dll_directory + system_directory_len, npcap, sizeof npcap);
+
+	/*
+	 * Now add that as a system DLL directory.
+	 */
+	if (!SetDllDirectoryW(dll_directory))
+		error("SetDllDirectory failed");
+
+	free(dll_directory);
+#endif
+
 	/*
 	 * Initialize the netdissect code.
 	 */
@@ -1914,6 +2067,10 @@ main(int argc, char **argv)
 			ndo->ndo_packet_number = 1;
 			break;
 
+		case OPTION_TIME_T_SIZE:
+			printf("%zu\n", sizeof(time_t) * 8);
+			return 0;
+
 		case OPTION_VERSION:
 			print_version(stdout);
 			exit_tcpdump(S_SUCCESS);
@@ -1968,6 +2125,13 @@ main(int argc, char **argv)
 			/* NOTREACHED */
 		}
 
+	if (ndo->ndo_Aflag && ndo->ndo_xflag)
+		warning("-A and -x[x] are mutually exclusive. -A ignored.");
+	if (ndo->ndo_Aflag && ndo->ndo_Xflag)
+		warning("-A and -X[X] are mutually exclusive. -A ignored.");
+	if (ndo->ndo_xflag && ndo->ndo_Xflag)
+		warning("-x[x] and -X[X] are mutually exclusive. -x[x] ignored.");
+
 #ifdef HAVE_PCAP_FINDALLDEVS
 	if (Dflag)
 		show_devices_and_exit();
@@ -2300,7 +2464,21 @@ DIAG_ON_WARN_UNUSED_RESULT
 #endif
 	/* Cooperate with nohup(1) */
 #ifndef _WIN32
+	/*
+	 * In illumos /usr/include/sys/iso/signal_iso.h causes Clang to
+	 * generate a -Wstrict-prototypes warning here, see [1].  The
+	 * __illumos__ macro is available since at least GCC 11 and Clang 13,
+	 * see [2].
+	 * 1: https://www.illumos.org/issues/16344
+	 * 2: https://www.illumos.org/issues/13726
+	 */
+#ifdef __illumos__
+	DIAG_OFF_STRICT_PROTOTYPES
+#endif /* __illumos__ */
 	if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
+#ifdef __illumos__
+	DIAG_ON_STRICT_PROTOTYPES
+#endif /* __illumos__ */
 		(void)setsignal(SIGHUP, oldhandler);
 #endif /* _WIN32 */
 
@@ -2737,7 +2915,14 @@ static void
 		)
 		new.sa_flags = SA_RESTART;
 	if (sigaction(sig, &new, &old) < 0)
+		/* The same workaround as for SIG_DFL above. */
+#ifdef __illumos__
+		DIAG_OFF_STRICT_PROTOTYPES
+#endif /* __illumos__ */
 		return (SIG_ERR);
+#ifdef __illumos__
+		DIAG_ON_STRICT_PROTOTYPES
+#endif /* __illumos__ */
 	return (old.sa_handler);
 #endif
 }