1 /* POSIX compatible FILE stream read function.
2 Copyright (C) 2008-2023 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2011.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 #include <config.h>
19
20 /* Specification. */
21 #include <stdio.h>
22
23 /* Replace these functions only if module 'nonblocking' is requested. */
24 #if GNULIB_NONBLOCKING
25
26 /* On native Windows platforms, when read() is called on a non-blocking pipe
27 with an empty buffer, ReadFile() fails with error GetLastError() =
28 ERROR_NO_DATA, and read() in consequence fails with error EINVAL. This
29 read() function is at the basis of the function which fills the buffer of
30 a FILE stream. */
31
32 # if defined _WIN32 && ! defined __CYGWIN__
33
34 # include <errno.h>
35 # include <io.h>
36
37 # define WIN32_LEAN_AND_MEAN /* avoid including junk */
38 # include <windows.h>
39
40 # if GNULIB_MSVC_NOTHROW
41 # include "msvc-nothrow.h"
42 # else
43 # include <io.h>
44 # endif
45
46 /* Don't assume that UNICODE is not defined. */
47 # undef GetNamedPipeHandleState
48 # define GetNamedPipeHandleState GetNamedPipeHandleStateA
49
50 # define CALL_WITH_ERRNO_FIX(RETTYPE, EXPRESSION, FAILED) \
51 if (ferror (stream)) \
52 return (EXPRESSION); \
53 else \
54 { \
55 RETTYPE ret; \
56 SetLastError (0); \
57 ret = (EXPRESSION); \
58 if (FAILED) \
59 { \
60 if (GetLastError () == ERROR_NO_DATA && ferror (stream)) \
61 { \
62 int fd = fileno (stream); \
63 if (fd >= 0) \
64 { \
65 HANDLE h = (HANDLE) _get_osfhandle (fd); \
66 if (GetFileType (h) == FILE_TYPE_PIPE) \
67 { \
68 /* h is a pipe or socket. */ \
69 DWORD state; \
70 if (GetNamedPipeHandleState (h, &state, NULL, NULL, \
71 NULL, NULL, 0) \
72 && (state & PIPE_NOWAIT) != 0) \
73 /* h is a pipe in non-blocking mode. \
74 Change errno from EINVAL to EAGAIN. */ \
75 errno = EAGAIN; \
76 } \
77 } \
78 } \
79 } \
80 return ret; \
81 }
82
83 /* Enable this function definition only if gnulib's <stdio.h> has prepared it.
84 Otherwise we get a function definition conflict with mingw64's <stdio.h>. */
85 # if GNULIB_SCANF
86 int
87 scanf (const char *format, ...)
88 {
89 int retval;
90 va_list args;
91
92 va_start (args, format);
93 retval = vfscanf (stdin, format, args);
94 va_end (args);
95
96 return retval;
97 }
98 # endif
99
100 /* Enable this function definition only if gnulib's <stdio.h> has prepared it.
101 Otherwise we get a function definition conflict with mingw64's <stdio.h>. */
102 # if GNULIB_FSCANF
103 int
104 fscanf (FILE *stream, const char *format, ...)
105 {
106 int retval;
107 va_list args;
108
109 va_start (args, format);
110 retval = vfscanf (stream, format, args);
111 va_end (args);
112
113 return retval;
114 }
115 # endif
116
117 /* Enable this function definition only if gnulib's <stdio.h> has prepared it.
118 Otherwise we get a function definition conflict with mingw64's <stdio.h>. */
119 # if GNULIB_VSCANF
120 int
121 vscanf (const char *format, va_list args)
122 {
123 return vfscanf (stdin, format, args);
124 }
125 # endif
126
127 /* Enable this function definition only if gnulib's <stdio.h> has prepared it.
128 Otherwise we get a function definition conflict with mingw64's <stdio.h>. */
129 # if GNULIB_VFSCANF
130 int
131 vfscanf (FILE *stream, const char *format, va_list args)
132 #undef vfscanf
133 {
134 CALL_WITH_ERRNO_FIX (int, vfscanf (stream, format, args), ret == EOF)
135 }
136 # endif
137
138 int
139 getchar (void)
140 {
141 return fgetc (stdin);
142 }
143
144 int
145 fgetc (FILE *stream)
146 #undef fgetc
147 {
148 CALL_WITH_ERRNO_FIX (int, fgetc (stream), ret == EOF)
149 }
150
151 char *
152 fgets (char *s, int n, FILE *stream)
153 #undef fgets
154 {
155 CALL_WITH_ERRNO_FIX (char *, fgets (s, n, stream), ret == NULL)
156 }
157
158 /* We intentionally don't bother to fix gets. */
159
160 size_t
161 fread (void *ptr, size_t s, size_t n, FILE *stream)
162 #undef fread
163 {
164 CALL_WITH_ERRNO_FIX (size_t, fread (ptr, s, n, stream), ret < n)
165 }
166
167 # endif
168 #endif