1 /* isatty() replacement.
2 Copyright (C) 2012-2020 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 /* Specification. */
20 #include <unistd.h>
21
22 /* This replacement is enabled on native Windows. */
23
24 #include <errno.h>
25 #include <string.h>
26
27 /* Get declarations of the Win32 API functions. */
28 #define WIN32_LEAN_AND_MEAN
29 #include <windows.h>
30
31 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
32 # include "msvc-inval.h"
33 #endif
34
35 /* Get _get_osfhandle(). */
36 #if GNULIB_MSVC_NOTHROW
37 # include "msvc-nothrow.h"
38 #else
39 # include <io.h>
40 #endif
41
42 /* Avoid warnings from gcc -Wcast-function-type. */
43 #define GetProcAddress \
44 (void *) GetProcAddress
45
46 /* GetNamedPipeClientProcessId was introduced only in Windows Vista. */
47 typedef BOOL (WINAPI * GetNamedPipeClientProcessIdFuncType) (HANDLE hPipe,
48 PULONG pClientProcessId);
49 static GetNamedPipeClientProcessIdFuncType GetNamedPipeClientProcessIdFunc = NULL;
50 /* QueryFullProcessImageName was introduced only in Windows Vista. */
51 typedef BOOL (WINAPI * QueryFullProcessImageNameFuncType) (HANDLE hProcess,
52 DWORD dwFlags,
53 LPSTR lpExeName,
54 PDWORD pdwSize);
55 static QueryFullProcessImageNameFuncType QueryFullProcessImageNameFunc = NULL;
56 static BOOL initialized = FALSE;
57
58 static void
initialize(void)59 initialize (void)
60 {
61 HMODULE kernel32 = LoadLibrary ("kernel32.dll");
62 if (kernel32 != NULL)
63 {
64 GetNamedPipeClientProcessIdFunc =
65 (GetNamedPipeClientProcessIdFuncType) GetProcAddress (kernel32, "GetNamedPipeClientProcessId");
66 QueryFullProcessImageNameFunc =
67 (QueryFullProcessImageNameFuncType) GetProcAddress (kernel32, "QueryFullProcessImageNameA");
68 }
69 initialized = TRUE;
70 }
71
IsConsoleHandle(HANDLE h)72 static BOOL IsConsoleHandle (HANDLE h)
73 {
74 DWORD mode;
75 /* GetConsoleMode
76 <https://docs.microsoft.com/en-us/windows/console/getconsolemode> */
77 return GetConsoleMode (h, &mode) != 0;
78 }
79
IsCygwinConsoleHandle(HANDLE h)80 static BOOL IsCygwinConsoleHandle (HANDLE h)
81 {
82 /* A handle to a Cygwin console is in fact a named pipe whose client process
83 and server process is <CYGWIN_INSTALL_DIR>\bin\mintty.exe. */
84 BOOL result = FALSE;
85 ULONG processId;
86
87 if (!initialized)
88 initialize ();
89
90 /* GetNamedPipeClientProcessId
91 <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getnamedpipeclientprocessid>
92 It requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher. */
93 if (GetNamedPipeClientProcessIdFunc && QueryFullProcessImageNameFunc
94 && GetNamedPipeClientProcessIdFunc (h, &processId))
95 {
96 /* OpenProcess
97 <https://docs.microsoft.com/en-us/windows/desktop/api/processthreadsapi/nf-processthreadsapi-openprocess> */
98 HANDLE processHandle =
99 OpenProcess (PROCESS_QUERY_LIMITED_INFORMATION, FALSE, processId);
100 if (processHandle != NULL)
101 {
102 char buf[1024];
103 DWORD bufsize = sizeof (buf);
104 /* The file name can be determined through
105 GetProcessImageFileName
106 <https://docs.microsoft.com/en-us/windows/desktop/api/psapi/nf-psapi-getprocessimagefilenamea>
107 or
108 QueryFullProcessImageName
109 <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-queryfullprocessimagenamea>
110 The former returns a file name in non-standard notation (it starts
111 with '\Device\') and may require linking with psapi.dll.
112 The latter is better, but requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA
113 or higher. */
114 if (QueryFullProcessImageNameFunc (processHandle, 0, buf, &bufsize))
115 {
116 if (strlen (buf) >= 11
117 && strcmp (buf + strlen (buf) - 11, "\\mintty.exe") == 0)
118 result = TRUE;
119 }
120 CloseHandle (processHandle);
121 }
122 }
123 return result;
124 }
125
126 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
127 static int
_isatty_nothrow(int fd)128 _isatty_nothrow (int fd)
129 {
130 int result;
131
132 TRY_MSVC_INVAL
133 {
134 result = _isatty (fd);
135 }
136 CATCH_MSVC_INVAL
137 {
138 result = 0;
139 }
140 DONE_MSVC_INVAL;
141
142 return result;
143 }
144 #else
145 # define _isatty_nothrow _isatty
146 #endif
147
148 /* Determine whether FD refers to a console device. Return 1 if yes.
149 Return 0 and set errno if no. (ptsname_r relies on the errno value.) */
150 int
isatty(int fd)151 isatty (int fd)
152 {
153 HANDLE h = (HANDLE) _get_osfhandle (fd);
154 if (h == INVALID_HANDLE_VALUE)
155 {
156 errno = EBADF;
157 return 0;
158 }
159 /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR.
160 But it does not set errno when it returns 0. */
161 if (_isatty_nothrow (fd))
162 {
163 if (IsConsoleHandle (h))
164 return 1;
165 }
166 if (IsCygwinConsoleHandle (h))
167 return 1;
168 errno = ENOTTY;
169 return 0;
170 }
171