forked from osmocom/wireshark
188 lines
4.1 KiB
C
188 lines
4.1 KiB
C
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/* ws_pipe.c
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*
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* Routines for handling pipes.
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#ifdef _WIN32
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#include <windows.h>
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#include <io.h>
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#else
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#include <unistd.h>
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#endif
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#include <glib.h>
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#include "wsutil/ws_pipe.h"
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gboolean
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ws_pipe_data_available(int pipe_fd)
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{
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#ifdef _WIN32 /* PeekNamedPipe */
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HANDLE hPipe = (HANDLE) _get_osfhandle(pipe_fd);
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DWORD bytes_avail;
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if (hPipe == INVALID_HANDLE_VALUE)
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{
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return FALSE;
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}
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if (! PeekNamedPipe(hPipe, NULL, 0, NULL, &bytes_avail, NULL))
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{
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return FALSE;
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}
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if (bytes_avail > 0)
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{
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return TRUE;
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}
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return FALSE;
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#else /* select */
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fd_set rfds;
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struct timeval timeout;
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FD_ZERO(&rfds);
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FD_SET(pipe_fd, &rfds);
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timeout.tv_sec = 0;
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timeout.tv_usec = 0;
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if (select(pipe_fd + 1, &rfds, NULL, NULL, &timeout) > 0)
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{
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return TRUE;
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}
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return FALSE;
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#endif
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}
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gboolean
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ws_read_string_from_pipe(ws_pipe_handle read_pipe, gchar *buffer,
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size_t buffer_size)
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{
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size_t total_bytes_read;
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size_t buffer_bytes_remaining;
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#ifdef _WIN32
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DWORD bytes_to_read;
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DWORD bytes_read;
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DWORD bytes_avail;
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#else
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size_t bytes_to_read;
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ssize_t bytes_read;
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#endif
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if (buffer_size == 0)
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{
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/* XXX - provide an error string */
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return FALSE;
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}
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if (buffer_size == 1)
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{
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/* No room for an actual string */
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buffer[0] = '\0';
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return TRUE;
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}
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/*
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* Number of bytes of string data we can actually read, leaving room
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* for the terminating NUL.
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*/
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buffer_size--;
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total_bytes_read = 0;
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for (;;)
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{
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buffer_bytes_remaining = buffer_size - total_bytes_read;
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if (buffer_bytes_remaining == 0)
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{
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/* The string won't fit in the buffer. */
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/* XXX - provide an error string */
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return FALSE;
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}
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#ifdef _WIN32
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/*
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* XXX - is there some reason why we do this before reading?
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*
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* If we're not trying to do UN*X-style non-blocking I/O,
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* where we don't block if there isn't data available to
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* read right now, I'm not sure why we do this.
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*
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* If we *are* trying to do UN*X-style non-blocking I/O,
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* 1) we're presumably in an event loop waiting for,
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* among other things, input to be available on the
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* pipe, in which case we should be doing "overlapped"
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* I/O and 2) we need to accumulate data until we have
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* a complete string, rather than just saying "OK, here's
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* the string".)
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*/
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if (!PeekNamedPipe(read_pipe, NULL, 0, NULL, &bytes_avail, NULL))
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{
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break;
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}
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if (bytes_avail <= 0)
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{
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break;
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}
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/*
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* Truncate this to whatever fits in a DWORD.
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*/
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if (buffer_bytes_remaining > 0x7fffffff)
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{
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bytes_to_read = 0x7fffffff;
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}
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else
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{
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bytes_to_read = (DWORD)buffer_bytes_remaining;
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}
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if (!ReadFile(read_pipe, &buffer[total_bytes_read], bytes_to_read,
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&bytes_read, NULL))
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{
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/* XXX - provide an error string */
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return FALSE;
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}
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#else
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bytes_to_read = buffer_bytes_remaining;
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bytes_read = read(read_pipe, buffer, bytes_to_read);
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if (bytes_read == -1)
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{
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/* XXX - provide an error string */
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return FALSE;
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}
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#endif
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if (bytes_read == 0)
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{
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break;
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}
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total_bytes_read += bytes_read;
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}
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buffer[total_bytes_read] = '\0';
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return TRUE;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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