1
mirror of https://github.com/mpv-player/mpv synced 2024-11-07 01:47:00 +01:00
mpv/osdep/subprocess-win.c
James Ross-Gowan 42fa954849 subprocess-win: Always quote argv[0]
If the program name isn't quoted and the .exe it refers to isn't found,
CreateProcess will add the program arguments to the program name and
continue searching, so for "program arg1 arg2", CreateProcess would try
"program.exe", "program arg1.exe", then "program arg1 arg2.exe". This
behaviour is weird and not really desirable, so prevent it by always
quoting the program name.

When quoting argv[0], escape sequences shouldn't be used. msvcrt, .NET
and CommandLineToArgvW all treat argv[0] literally and end it on the
trailing quote, without processing escape sequences.
2015-01-16 22:39:55 +11:00

377 lines
12 KiB
C

/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <windows.h>
#include <string.h>
#include "osdep/subprocess.h"
#include "osdep/io.h"
#include "osdep/atomics.h"
#include "talloc.h"
#include "common/common.h"
#include "stream/stream.h"
#include "misc/bstr.h"
static void write_arg(bstr *cmdline, char *arg)
{
// If the string doesn't have characters that need to be escaped, it's best
// to leave it alone for the sake of Windows programs that don't process
// quoted args correctly.
if (!strpbrk(arg, " \t\"")) {
bstr_xappend(NULL, cmdline, bstr0(arg));
return;
}
// If there are characters that need to be escaped, write a quoted string
bstr_xappend(NULL, cmdline, bstr0("\""));
// Escape the argument. To match the behavior of CommandLineToArgvW,
// backslashes are only escaped if they appear before a quote or the end of
// the string.
int num_slashes = 0;
for (int pos = 0; arg[pos]; pos++) {
switch (arg[pos]) {
case '\\':
// Count backslashes that appear in a row
num_slashes++;
break;
case '"':
bstr_xappend(NULL, cmdline, (struct bstr){arg, pos});
// Double preceding slashes
for (int i = 0; i < num_slashes; i++)
bstr_xappend(NULL, cmdline, bstr0("\\"));
// Escape the following quote
bstr_xappend(NULL, cmdline, bstr0("\\"));
arg += pos;
pos = 0;
num_slashes = 0;
break;
default:
num_slashes = 0;
}
}
// Write the rest of the argument
bstr_xappend(NULL, cmdline, bstr0(arg));
// Double slashes that appear at the end of the string
for (int i = 0; i < num_slashes; i++)
bstr_xappend(NULL, cmdline, bstr0("\\"));
bstr_xappend(NULL, cmdline, bstr0("\""));
}
// Convert an array of arguments to a properly escaped command-line string
static wchar_t *write_cmdline(void *ctx, char **argv)
{
// argv[0] should always be quoted. Otherwise, arguments may be interpreted
// as part of the program name. Also, it can't contain escape sequences.
bstr cmdline = {0};
bstr_xappend_asprintf(NULL, &cmdline, "\"%s\"", argv[0]);
for (int i = 1; argv[i]; i++) {
bstr_xappend(NULL, &cmdline, bstr0(" "));
write_arg(&cmdline, argv[i]);
}
wchar_t *wcmdline = mp_from_utf8(ctx, cmdline.start);
talloc_free(cmdline.start);
return wcmdline;
}
static int create_overlapped_pipe(HANDLE *read, HANDLE *write)
{
static atomic_ulong counter = ATOMIC_VAR_INIT(0);
// Generate pipe name
unsigned long id = atomic_fetch_add(&counter, 1);
unsigned pid = GetCurrentProcessId();
wchar_t buf[36];
swprintf(buf, sizeof(buf), L"\\\\?\\pipe\\mpv-anon-%08x-%08lx", pid, id);
// The function for creating anonymous pipes (CreatePipe) can't create
// overlapped pipes, so instead, use a named pipe with a unique name
*read = CreateNamedPipeW(buf, PIPE_ACCESS_INBOUND |
FILE_FLAG_FIRST_PIPE_INSTANCE | FILE_FLAG_OVERLAPPED,
PIPE_TYPE_BYTE | PIPE_WAIT, 1, 0, 4096, 0, NULL);
if (*read == INVALID_HANDLE_VALUE)
goto error;
// Open the write end of the pipe as a synchronous handle
*write = CreateFileW(buf, GENERIC_WRITE, 0, NULL, OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL, NULL);
if (*write == INVALID_HANDLE_VALUE)
goto error;
return 0;
error:
*read = *write = INVALID_HANDLE_VALUE;
return -1;
}
static void delete_handle_list(void *p)
{
LPPROC_THREAD_ATTRIBUTE_LIST list = p;
VOID (WINAPI *pDeleteProcThreadAttributeList)(LPPROC_THREAD_ATTRIBUTE_LIST);
HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
pDeleteProcThreadAttributeList =
(VOID (WINAPI*)(LPPROC_THREAD_ATTRIBUTE_LIST))
GetProcAddress(kernel32, "DeleteProcThreadAttributeList");
if (pDeleteProcThreadAttributeList)
pDeleteProcThreadAttributeList(list);
}
// Create a PROC_THREAD_ATTRIBUTE_LIST that specifies exactly which handles are
// inherited by the subprocess
static LPPROC_THREAD_ATTRIBUTE_LIST create_handle_list(void *ctx,
HANDLE *handles, int num)
{
WINBOOL (WINAPI *pInitializeProcThreadAttributeList)(
LPPROC_THREAD_ATTRIBUTE_LIST, DWORD, DWORD, PSIZE_T);
WINBOOL (WINAPI *pUpdateProcThreadAttribute)(LPPROC_THREAD_ATTRIBUTE_LIST,
DWORD, DWORD_PTR, PVOID, SIZE_T, PVOID, PSIZE_T);
// Load Windows Vista functions, if available
HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
pInitializeProcThreadAttributeList =
(WINBOOL (WINAPI*)(LPPROC_THREAD_ATTRIBUTE_LIST, DWORD, DWORD, PSIZE_T))
GetProcAddress(kernel32, "InitializeProcThreadAttributeList");
pUpdateProcThreadAttribute =
(WINBOOL (WINAPI*)(LPPROC_THREAD_ATTRIBUTE_LIST, DWORD, DWORD_PTR,
PVOID, SIZE_T, PVOID, PSIZE_T))
GetProcAddress(kernel32, "UpdateProcThreadAttribute");
if (!pInitializeProcThreadAttributeList || !pUpdateProcThreadAttribute)
return NULL;
// Get required attribute list size
SIZE_T size = 0;
if (!pInitializeProcThreadAttributeList(NULL, 1, 0, &size)) {
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return NULL;
}
// Allocate attribute list
LPPROC_THREAD_ATTRIBUTE_LIST list = talloc_size(ctx, size);
if (!pInitializeProcThreadAttributeList(list, 1, 0, &size))
goto error;
talloc_set_destructor(list, delete_handle_list);
if (!pUpdateProcThreadAttribute(list, 0, PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
handles, num * sizeof(HANDLE), NULL, NULL))
goto error;
return list;
error:
talloc_free(list);
return NULL;
}
// Helper method similar to sparse_poll, skips NULL handles
static int sparse_wait(HANDLE *handles, unsigned num_handles)
{
unsigned w_num_handles = 0;
HANDLE w_handles[num_handles];
int map[num_handles];
for (unsigned i = 0; i < num_handles; i++) {
if (!handles[i])
continue;
w_handles[w_num_handles] = handles[i];
map[w_num_handles] = i;
w_num_handles++;
}
if (w_num_handles == 0)
return -1;
DWORD i = WaitForMultipleObjects(w_num_handles, w_handles, FALSE, INFINITE);
i -= WAIT_OBJECT_0;
if (i >= w_num_handles)
return -1;
return map[i];
}
// Wrapper for ReadFile that treats ERROR_IO_PENDING as success
static int async_read(HANDLE file, void *buf, unsigned size, OVERLAPPED* ol)
{
if (!ReadFile(file, buf, size, NULL, ol))
return (GetLastError() == ERROR_IO_PENDING) ? 0 : -1;
return 0;
}
static void write_none(void *ctx, char *data, size_t size)
{
}
int mp_subprocess(char **args, struct mp_cancel *cancel, void *ctx,
subprocess_read_cb on_stdout, subprocess_read_cb on_stderr,
char **error)
{
wchar_t *tmp = talloc_new(NULL);
int status = -1;
struct {
HANDLE read;
HANDLE write;
OVERLAPPED ol;
char buf[4096];
subprocess_read_cb read_cb;
} pipes[2] = {
{ .read_cb = on_stdout ? on_stdout : write_none },
{ .read_cb = on_stderr ? on_stderr : write_none },
};
// If the function exits before CreateProcess, there was an init error
*error = "init";
for (int i = 0; i < 2; i++) {
pipes[i].ol.hEvent = CreateEventW(NULL, TRUE, FALSE, NULL);
if (!pipes[i].ol.hEvent)
goto done;
if (create_overlapped_pipe(&pipes[i].read, &pipes[i].write))
goto done;
if (!SetHandleInformation(pipes[i].write, HANDLE_FLAG_INHERIT,
HANDLE_FLAG_INHERIT))
goto done;
}
// Convert the args array to a UTF-16 Windows command-line string
wchar_t *cmdline = write_cmdline(tmp, args);
DWORD flags = CREATE_UNICODE_ENVIRONMENT;
PROCESS_INFORMATION pi = {0};
STARTUPINFOEXW si = {
.StartupInfo = {
.cb = sizeof(si),
.dwFlags = STARTF_USESTDHANDLES,
.hStdInput = NULL,
.hStdOutput = pipes[0].write,
.hStdError = pipes[1].write,
},
// Specify which handles are inherited by the subprocess. If this isn't
// specified, the subprocess inherits all inheritable handles, which
// could include handles created by other threads. See:
// http://blogs.msdn.com/b/oldnewthing/archive/2011/12/16/10248328.aspx
.lpAttributeList = create_handle_list(tmp,
(HANDLE[]){ pipes[0].write, pipes[1].write }, 2),
};
// PROC_THREAD_ATTRIBUTE_LISTs are only supported in Vista and up. If not
// supported, create_handle_list will return NULL.
if (si.lpAttributeList)
flags |= EXTENDED_STARTUPINFO_PRESENT;
// If we have a console, the subprocess will automatically attach to it so
// it can receive Ctrl+C events. If we don't have a console, prevent the
// subprocess from creating its own console window by specifying
// CREATE_NO_WINDOW. GetConsoleCP() can be used to reliably determine if we
// have a console or not (Cygwin uses it too.)
if (!GetConsoleCP())
flags |= CREATE_NO_WINDOW;
if (!CreateProcessW(NULL, cmdline, NULL, NULL, TRUE, flags, NULL, NULL,
&si.StartupInfo, &pi))
goto done;
talloc_free(cmdline);
talloc_free(si.lpAttributeList);
CloseHandle(pi.hThread);
// Init is finished
*error = NULL;
// List of handles to watch with sparse_wait
HANDLE handles[] = { pipes[0].ol.hEvent, pipes[1].ol.hEvent, pi.hProcess,
cancel ? mp_cancel_get_event(cancel) : NULL };
for (int i = 0; i < 2; i++) {
// Close our copy of the write end of the pipes
CloseHandle(pipes[i].write);
pipes[i].write = NULL;
// Do the first read operation on each pipe
if (async_read(pipes[i].read, pipes[i].buf, 4096, &pipes[i].ol)) {
CloseHandle(pipes[i].read);
handles[i] = pipes[i].read = NULL;
}
}
DWORD r;
DWORD exit_code;
while (pipes[0].read || pipes[1].read || pi.hProcess) {
int i = sparse_wait(handles, MP_ARRAY_SIZE(handles));
switch (i) {
case 0:
case 1:
// Complete the read operation on the pipe
if (!GetOverlappedResult(pipes[i].read, &pipes[i].ol, &r, TRUE)) {
CloseHandle(pipes[i].read);
handles[i] = pipes[i].read = NULL;
break;
}
pipes[i].read_cb(ctx, pipes[i].buf, r);
// Begin the next read operation on the pipe
if (async_read(pipes[i].read, pipes[i].buf, 4096, &pipes[i].ol)) {
CloseHandle(pipes[i].read);
handles[i] = pipes[i].read = NULL;
}
break;
case 2:
GetExitCodeProcess(pi.hProcess, &exit_code);
status = exit_code;
CloseHandle(pi.hProcess);
handles[i] = pi.hProcess = NULL;
break;
case 3:
if (pi.hProcess) {
TerminateProcess(pi.hProcess, 1);
*error = "killed";
goto done;
}
break;
default:
goto done;
}
}
done:
for (int i = 0; i < 2; i++) {
if (pipes[i].read) {
// Cancel any pending I/O (if the process was killed)
CancelIo(pipes[i].read);
GetOverlappedResult(pipes[i].read, &pipes[i].ol, &r, TRUE);
CloseHandle(pipes[i].read);
}
if (pipes[i].write) CloseHandle(pipes[i].write);
if (pipes[i].ol.hEvent) CloseHandle(pipes[i].ol.hEvent);
}
if (pi.hProcess) CloseHandle(pi.hProcess);
talloc_free(tmp);
return status;
}