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Put special pipe-handling code into libwsutil. 

Ask, in a comment, why we're doing PeekNamedPipe() when we're trying
to read everyting in the pipe, up to the EOF, into a string.

On UN*X, do the same "read up to an EOF and then NUL-terminate the
result" stuff that we did on Windows; nothing guarantees that, on all
UN*Xes, in all circumstances, until the end of time, world without end,
amen, we can do one read and get the entire string.

Change-Id: I578802b23fec1051139eaefd9a09fe2a6de06a11
Reviewed-on: https://code.wireshark.org/review/24959
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>
This commit is contained in:
Guy Harris 2017-12-23 00:05:21 -08:00
parent 13a9c636a5
commit 6a949ed155
8 changed files with 237 additions and 120 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
capchild/capture_sync.c
View File

@ -100,7 +100,7 @@
#include <process.h> /* For spawning child process */
#endif
#include <wsutil/ws_pipe.h>
#ifdef _WIN32
static void create_dummy_signal_pipe();
@ -1524,37 +1524,12 @@ pipe_read_bytes(int pipe_fd, char *bytes, int required, char **msg)
return offset;
}
static gboolean pipe_data_available(int pipe_fd) {
#ifdef _WIN32 /* PeekNamedPipe */
HANDLE hPipe = (HANDLE) _get_osfhandle(pipe_fd);
DWORD bytes_avail;
if (hPipe == INVALID_HANDLE_VALUE)
return FALSE;
if (! PeekNamedPipe(hPipe, NULL, 0, NULL, &bytes_avail, NULL))
return FALSE;
if (bytes_avail > 0)
return TRUE;
return FALSE;
#else /* select */
fd_set rfds;
struct timeval timeout;
FD_ZERO(&rfds);
FD_SET(pipe_fd, &rfds);
timeout.tv_sec = 0;
timeout.tv_usec = 0;
if (select(pipe_fd+1, &rfds, NULL, NULL, &timeout) > 0)
return TRUE;
return FALSE;
#endif
}
/* Read a line from a pipe, similar to fgets */
/*
* Read a line from a pipe; similar to fgets, but doesn't block.
*
* XXX - just stops reading if there's nothing to be read right now;
* that could conceivably mean that you don't get a complete line.
*/
int
sync_pipe_gets_nonblock(int pipe_fd, char *bytes, int max) {
ssize_t newly;
@ -1562,7 +1537,7 @@ sync_pipe_gets_nonblock(int pipe_fd, char *bytes, int max) {
while(offset < max - 1) {
offset++;
if (! pipe_data_available(pipe_fd))
if (! ws_pipe_data_available(pipe_fd))
break;
newly = ws_read(pipe_fd, &bytes[offset], 1);
if (newly == 0) {

60
extcap.c
View File

@ -42,6 +42,7 @@
#include <wsutil/glib-compat.h>
#include <wsutil/file_util.h>
#include <wsutil/filesystem.h>
#include <wsutil/ws_pipe.h>
#include <wsutil/tempfile.h>
#include "capture_opts.h"
@ -944,46 +945,6 @@ extcap_has_toolbar(const char *ifname)
return FALSE;
}
/* taken from capchild/capture_sync.c */
static gboolean pipe_data_available(int pipe_fd)
{
#ifdef _WIN32 /* PeekNamedPipe */
HANDLE hPipe = (HANDLE) _get_osfhandle(pipe_fd);
DWORD bytes_avail;
if (hPipe == INVALID_HANDLE_VALUE)
{
return FALSE;
}
if (! PeekNamedPipe(hPipe, NULL, 0, NULL, &bytes_avail, NULL))
{
return FALSE;
}
if (bytes_avail > 0)
{
return TRUE;
}
return FALSE;
#else /* select */
fd_set rfds;
struct timeval timeout;
FD_ZERO(&rfds);
FD_SET(pipe_fd, &rfds);
timeout.tv_sec = 0;
timeout.tv_usec = 0;
if (select(pipe_fd + 1, &rfds, NULL, NULL, &timeout) > 0)
{
return TRUE;
}
return FALSE;
#endif
}
void extcap_if_cleanup(capture_options *capture_opts, gchar **errormsg)
{
interface_options *interface_opts;
@ -1064,23 +1025,10 @@ void extcap_if_cleanup(capture_options *capture_opts, gchar **errormsg)
userdata = (extcap_userdata *) interface_opts->extcap_userdata;
if (userdata)
{
if (userdata->extcap_stderr_rd > 0 && pipe_data_available(userdata->extcap_stderr_rd))
if (userdata->extcap_stderr_rd > 0 && ws_pipe_data_available(userdata->extcap_stderr_rd))
{
buffer = (gchar *)g_malloc0(sizeof(gchar) * STDERR_BUFFER_SIZE + 1);
#ifdef _WIN32
win32_readfrompipe((HANDLE)_get_osfhandle(userdata->extcap_stderr_rd), STDERR_BUFFER_SIZE, buffer);
#else
ssize_t buffer_len;
buffer_len = read(userdata->extcap_stderr_rd, buffer, sizeof(gchar) * STDERR_BUFFER_SIZE);
if (buffer_len <= 0)
{
buffer[0] = '\0';
}
else
{
buffer[buffer_len] = '\0';
}
#endif
buffer = (gchar *)g_malloc0(STDERR_BUFFER_SIZE + 1);
ws_read_string_from_pipe(ws_get_pipe_handle(userdata->extcap_stderr_rd), buffer, STDERR_BUFFER_SIZE + 1);
if (strlen(buffer) > 0)
{
userdata->extcap_stderr = g_strdup_printf("%s", buffer);

32
extcap_spawn.c
View File

@ -18,6 +18,7 @@
#include <wsutil/file_util.h>
#include <wsutil/filesystem.h>
#include <wsutil/ws_pipe.h>
#ifdef _WIN32
#include <wsutil/win32-utils.h>
#endif
@ -27,35 +28,6 @@
#include "extcap.h"
#include "extcap_spawn.h"
#ifdef _WIN32
void win32_readfrompipe(HANDLE read_pipe, gint32 max_buffer, gchar *buffer)
{
gboolean bSuccess = FALSE;
gint32 bytes_written = 0;
gint32 max_bytes = 0;
DWORD dwRead;
DWORD bytes_avail = 0;
for (;;)
{
if (!PeekNamedPipe(read_pipe, NULL, 0, NULL, &bytes_avail, NULL)) break;
if (bytes_avail <= 0) break;
max_bytes = max_buffer - bytes_written - 1;
bSuccess = ReadFile(read_pipe, &buffer[bytes_written], max_bytes, &dwRead, NULL);
if (!bSuccess || dwRead == 0) break;
bytes_written += dwRead;
if ((bytes_written + 1) >= max_buffer) break;
}
buffer[bytes_written] = '\0';
}
#endif
gboolean extcap_spawn_sync(gchar *dirname, gchar *command, gint argc, gchar **args, gchar **command_output)
{
gboolean status = FALSE;
@ -148,7 +120,7 @@ gboolean extcap_spawn_sync(gchar *dirname, gchar *command, gint argc, gchar **ar
if (CreateProcess(NULL, wcommandline, NULL, NULL, TRUE, CREATE_NEW_CONSOLE, NULL, NULL, &info, &processInfo))
{
WaitForSingleObject(processInfo.hProcess, INFINITE);
win32_readfrompipe(child_stdout_rd, BUFFER_SIZE, buffer);
ws_read_string_from_pipe(child_stdout_rd, buffer, BUFFER_SIZE);
local_output = g_strdup_printf("%s", buffer);
CloseHandle(child_stdout_rd);

1
extcap_spawn.h
View File

@ -36,7 +36,6 @@ GPid extcap_spawn_async ( extcap_userdata * userdata, GPtrArray * args );
#ifdef _WIN32
gboolean extcap_wait_for_pipe(HANDLE * pipe_handles, int num_pipe_handles, HANDLE pid);
void win32_readfrompipe(HANDLE read_pipe, gint32 max_buffer, gchar * buffer);
#endif
#endif

2
wsutil/CMakeLists.txt
View File

@ -78,6 +78,7 @@ set(WSUTIL_PUBLIC_HEADERS
ws_cpuid.h
ws_mempbrk.h
ws_mempbrk_int.h
ws_pipe.h
ws_printf.h
wsjsmn.h
xtea.h
@ -127,6 +128,7 @@ set(WSUTIL_COMMON_FILES
type_util.c
unicode-utils.c
ws_mempbrk.c
ws_pipe.c
wsgcrypt.c
wsjsmn.c
xtea.c

2
wsutil/Makefile.am
View File

@ -86,6 +86,7 @@ WSUTIL_PUBLIC_INCLUDES = \
ws_cpuid.h \
ws_mempbrk.h \
ws_mempbrk_int.h \
ws_pipe.h \
ws_printf.h \
wsjsmn.h \
wsgcrypt.h \
@ -164,6 +165,7 @@ libwsutil_la_SOURCES = \
type_util.c \
unicode-utils.c \
ws_mempbrk.c \
ws_pipe.c \
wsgcrypt.c \
wsjsmn.c \
xtea.c

187
wsutil/ws_pipe.c Normal file
View File

@ -0,0 +1,187 @@
/* ws_pipe.c
*
* Routines for handling pipes.
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#include <io.h>
#else
#include <unistd.h>
#endif
#include <glib.h>
#include "wsutil/ws_pipe.h"
gboolean
ws_pipe_data_available(int pipe_fd)
{
#ifdef _WIN32 /* PeekNamedPipe */
HANDLE hPipe = (HANDLE) _get_osfhandle(pipe_fd);
DWORD bytes_avail;
if (hPipe == INVALID_HANDLE_VALUE)
{
return FALSE;
}
if (! PeekNamedPipe(hPipe, NULL, 0, NULL, &bytes_avail, NULL))
{
return FALSE;
}
if (bytes_avail > 0)
{
return TRUE;
}
return FALSE;
#else /* select */
fd_set rfds;
struct timeval timeout;
FD_ZERO(&rfds);
FD_SET(pipe_fd, &rfds);
timeout.tv_sec = 0;
timeout.tv_usec = 0;
if (select(pipe_fd + 1, &rfds, NULL, NULL, &timeout) > 0)
{
return TRUE;
}
return FALSE;
#endif
}
gboolean
ws_read_string_from_pipe(ws_pipe_handle read_pipe, gchar *buffer,
size_t buffer_size)
{
size_t total_bytes_read;
size_t buffer_bytes_remaining;
#ifdef _WIN32
DWORD bytes_to_read;
DWORD bytes_read;
DWORD bytes_avail;
#else
size_t bytes_to_read;
ssize_t bytes_read;
#endif
if (buffer_size == 0)
{
/* XXX - provide an error string */
return FALSE;
}
if (buffer_size == 1)
{
/* No room for an actual string */
buffer[0] = '\0';
return TRUE;
}
/*
* Number of bytes of string data we can actually read, leaving room
* for the terminating NUL.
*/
buffer_size--;
total_bytes_read = 0;
for (;;)
{
buffer_bytes_remaining = buffer_size - total_bytes_read;
if (buffer_bytes_remaining == 0)
{
/* The string won't fit in the buffer. */
/* XXX - provide an error string */
return FALSE;
}
#ifdef _WIN32
/*
* XXX - is there some reason why we do this before reading?
*
* If we're not trying to do UN*X-style non-blocking I/O,
* where we don't block if there isn't data available to
* read right now, I'm not sure why we do this.
*
* If we *are* trying to do UN*X-style non-blocking I/O,
* 1) we're presumably in an event loop waiting for,
* among other things, input to be available on the
* pipe, in which case we should be doing "overlapped"
* I/O and 2) we need to accumulate data until we have
* a complete string, rather than just saying "OK, here's
* the string".)
*/
if (!PeekNamedPipe(read_pipe, NULL, 0, NULL, &bytes_avail, NULL))
{
break;
}
if (bytes_avail <= 0)
{
break;
}
/*
* Truncate this to whatever fits in a DWORD.
*/
if (buffer_bytes_remaining > 0x7fffffff)
{
bytes_to_read = 0x7fffffff;
}
else
{
bytes_to_read = (DWORD)buffer_bytes_remaining;
}
if (!ReadFile(read_pipe, &buffer[total_bytes_read], bytes_to_read,
&bytes_read, NULL))
{
/* XXX - provide an error string */
return FALSE;
}
#else
bytes_to_read = buffer_bytes_remaining;
bytes_read = read(read_pipe, buffer, bytes_to_read);
if (bytes_read == -1)
{
/* XXX - provide an error string */
return FALSE;
}
#endif
if (bytes_read == 0)
{
break;
}
total_bytes_read += bytes_read;
}
buffer[total_bytes_read] = '\0';
return TRUE;
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/

32
wsutil/ws_pipe.h Normal file
View File

@ -0,0 +1,32 @@
/* ws_pipe.h
*
* Routines for handling pipes.
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef __WS_PIPE_H__
#define __WS_PIPE_H__
#include "ws_symbol_export.h"
#ifdef _WIN32
#include <windows.h>
#include <io.h>
#define ws_pipe_handle HANDLE
#define ws_get_pipe_handle(pipe_fd) ((HANDLE)_get_osfhandle(pipe_fd))
#else
#define ws_pipe_handle int
#define ws_get_pipe_handle(pipe_fd) (pipe_fd)
#endif
WS_DLL_PUBLIC gboolean ws_pipe_data_available(int pipe_fd);
WS_DLL_PUBLIC gboolean ws_read_string_from_pipe(ws_pipe_handle read_pipe,
gchar *buffer, size_t buffer_size);
#endif /* __WS_PIPE_H__ */