1// Wrapper of C-language FILE struct -*- C++ -*-
2
3// Copyright (C) 2000-2020 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25//
26// ISO C++ 14882: 27.8  File-based streams
27//
28
29#include <bits/basic_file.h>
30#include <fcntl.h>
31#include <errno.h>
32
33#ifdef _GLIBCXX_HAVE_POLL
34#include <poll.h>
35#endif
36
37// Pick up ioctl on Solaris 2.8
38#ifdef _GLIBCXX_HAVE_UNISTD_H
39#include <unistd.h>
40#endif
41
42// Pick up FIONREAD on Solaris 2
43#ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
44#define BSD_COMP
45#include <sys/ioctl.h>
46#endif
47
48// Pick up FIONREAD on Solaris 2.5.
49#ifdef _GLIBCXX_HAVE_SYS_FILIO_H
50#include <sys/filio.h>
51#endif
52
53#ifdef _GLIBCXX_HAVE_SYS_UIO_H
54#include <sys/uio.h>
55#endif
56
57#if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
58# include <sys/stat.h>
59# ifdef _GLIBCXX_HAVE_S_ISREG
60#  define _GLIBCXX_ISREG(x) S_ISREG(x)
61# else
62#  define _GLIBCXX_ISREG(x) (((x) & S_IFMT) == S_IFREG)
63# endif
64#endif
65
66#include <limits> // For <off_t>::max() and min() and <streamsize>::max()
67
68namespace
69{
70  // Map ios_base::openmode flags to a string for use in fopen().
71  // Table of valid combinations as given in [lib.filebuf.members]/2.
72  static const char*
73  fopen_mode(std::ios_base::openmode mode)
74  {
75    enum
76      {
77	in     = std::ios_base::in,
78	out    = std::ios_base::out,
79	trunc  = std::ios_base::trunc,
80	app    = std::ios_base::app,
81	binary = std::ios_base::binary
82      };
83
84    // _GLIBCXX_RESOLVE_LIB_DEFECTS
85    // 596. 27.8.1.3 Table 112 omits "a+" and "a+b" modes.
86    switch (mode & (in|out|trunc|app|binary))
87      {
88      case (   out                 ): return "w";
89      case (   out      |app       ): return "a";
90      case (             app       ): return "a";
91      case (   out|trunc           ): return "w";
92      case (in                     ): return "r";
93      case (in|out                 ): return "r+";
94      case (in|out|trunc           ): return "w+";
95      case (in|out      |app       ): return "a+";
96      case (in          |app       ): return "a+";
97
98      case (   out          |binary): return "wb";
99      case (   out      |app|binary): return "ab";
100      case (             app|binary): return "ab";
101      case (   out|trunc    |binary): return "wb";
102      case (in              |binary): return "rb";
103      case (in|out          |binary): return "r+b";
104      case (in|out|trunc    |binary): return "w+b";
105      case (in|out      |app|binary): return "a+b";
106      case (in          |app|binary): return "a+b";
107
108      default: return 0; // invalid
109      }
110  }
111
112  // Wrapper handling partial write.
113  static std::streamsize
114  xwrite(int __fd, const char* __s, std::streamsize __n)
115  {
116    std::streamsize __nleft = __n;
117
118    for (;;)
119      {
120	const std::streamsize __ret = write(__fd, __s, __nleft);
121	if (__ret == -1L && errno == EINTR)
122	  continue;
123	if (__ret == -1L)
124	  break;
125
126	__nleft -= __ret;
127	if (__nleft == 0)
128	  break;
129
130	__s += __ret;
131      }
132
133    return __n - __nleft;
134  }
135
136#ifdef _GLIBCXX_HAVE_WRITEV
137  // Wrapper handling partial writev.
138  static std::streamsize
139  xwritev(int __fd, const char* __s1, std::streamsize __n1,
140	  const char* __s2, std::streamsize __n2)
141  {
142    std::streamsize __nleft = __n1 + __n2;
143    std::streamsize __n1_left = __n1;
144
145    struct iovec __iov[2];
146    __iov[1].iov_base = const_cast<char*>(__s2);
147    __iov[1].iov_len = __n2;
148
149    for (;;)
150      {
151	__iov[0].iov_base = const_cast<char*>(__s1);
152	__iov[0].iov_len = __n1_left;
153
154	const std::streamsize __ret = writev(__fd, __iov, 2);
155	if (__ret == -1L && errno == EINTR)
156	  continue;
157	if (__ret == -1L)
158	  break;
159
160	__nleft -= __ret;
161	if (__nleft == 0)
162	  break;
163
164	const std::streamsize __off = __ret - __n1_left;
165	if (__off >= 0)
166	  {
167	    __nleft -= xwrite(__fd, __s2 + __off, __n2 - __off);
168	    break;
169	  }
170
171	__s1 += __ret;
172	__n1_left -= __ret;
173      }
174
175    return __n1 + __n2 - __nleft;
176  }
177#endif
178} // anonymous namespace
179
180
181namespace std _GLIBCXX_VISIBILITY(default)
182{
183_GLIBCXX_BEGIN_NAMESPACE_VERSION
184
185  // Definitions for __basic_file<char>.
186  __basic_file<char>::__basic_file(__c_lock* /*__lock*/) throw()
187  : _M_cfile(NULL), _M_cfile_created(false) { }
188
189  __basic_file<char>::~__basic_file()
190  { this->close(); }
191
192  __basic_file<char>*
193  __basic_file<char>::sys_open(__c_file* __file, ios_base::openmode __mode)
194  {
195    __basic_file* __ret = NULL;
196    if (!this->is_open() && __file)
197      {
198	int __err, __save_errno = errno;
199	// POSIX guarantees that fflush sets errno on error, but C doesn't.
200	errno = 0;
201	do
202	  __err = (__mode == std::ios_base::in ? 0 : fflush(__file));
203	while (__err && errno == EINTR);
204	errno = __save_errno;
205	if (!__err)
206	  {
207	    _M_cfile = __file;
208	    _M_cfile_created = false;
209	    __ret = this;
210	  }
211      }
212    return __ret;
213  }
214
215  __basic_file<char>*
216  __basic_file<char>::sys_open(int __fd, ios_base::openmode __mode) throw ()
217  {
218    __basic_file* __ret = NULL;
219    const char* __c_mode = fopen_mode(__mode);
220    if (__c_mode && !this->is_open() && (_M_cfile = fdopen(__fd, __c_mode)))
221      {
222	char* __buf = NULL;
223	_M_cfile_created = true;
224	if (__fd == 0)
225	  setvbuf(_M_cfile, __buf, _IONBF, 0);
226	__ret = this;
227      }
228    return __ret;
229  }
230
231  __basic_file<char>*
232  __basic_file<char>::open(const char* __name, ios_base::openmode __mode,
233			   int /*__prot*/)
234  {
235    __basic_file* __ret = NULL;
236    const char* __c_mode = fopen_mode(__mode);
237    if (__c_mode && !this->is_open())
238      {
239#ifdef _GLIBCXX_USE_LFS
240	if ((_M_cfile = fopen64(__name, __c_mode)))
241#else
242	if ((_M_cfile = fopen(__name, __c_mode)))
243#endif
244	  {
245	    _M_cfile_created = true;
246	    __ret = this;
247	  }
248      }
249    return __ret;
250  }
251
252#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
253  __basic_file<char>*
254  __basic_file<char>::open(const wchar_t* __name, ios_base::openmode __mode)
255  {
256    __basic_file* __ret = NULL;
257    const char* __c_mode = fopen_mode(__mode);
258    if (__c_mode && !this->is_open())
259      {
260	wchar_t __wc_mode[4] = { };
261	int __i = 0;
262	do
263	  {
264	    switch(__c_mode[__i]) {
265	    case 'a': __wc_mode[__i] = L'a'; break;
266	    case 'b': __wc_mode[__i] = L'b'; break;
267	    case 'r': __wc_mode[__i] = L'r'; break;
268	    case 'w': __wc_mode[__i] = L'w'; break;
269	    case '+': __wc_mode[__i] = L'+'; break;
270	    default: return __ret;
271	    }
272	  }
273	while (__c_mode[++__i]);
274
275	if ((_M_cfile = _wfopen(__name, __wc_mode)))
276	  {
277	    _M_cfile_created = true;
278	    __ret = this;
279	  }
280      }
281    return __ret;
282  }
283#endif
284
285  bool
286  __basic_file<char>::is_open() const throw ()
287  { return _M_cfile != 0; }
288
289  int
290  __basic_file<char>::fd() throw ()
291  { return fileno(_M_cfile); }
292
293  __c_file*
294  __basic_file<char>::file() throw ()
295  { return _M_cfile; }
296
297  __basic_file<char>*
298  __basic_file<char>::close()
299  {
300    __basic_file* __ret = static_cast<__basic_file*>(NULL);
301    if (this->is_open())
302      {
303	int __err = 0;
304	if (_M_cfile_created)
305	  __err = fclose(_M_cfile);
306	_M_cfile = 0;
307	if (!__err)
308	  __ret = this;
309      }
310    return __ret;
311  }
312
313  streamsize
314  __basic_file<char>::xsgetn(char* __s, streamsize __n)
315  {
316    streamsize __ret;
317    do
318      __ret = read(this->fd(), __s, __n);
319    while (__ret == -1L && errno == EINTR);
320    return __ret;
321  }
322
323  streamsize
324  __basic_file<char>::xsputn(const char* __s, streamsize __n)
325  { return xwrite(this->fd(), __s, __n); }
326
327  streamsize
328  __basic_file<char>::xsputn_2(const char* __s1, streamsize __n1,
329			       const char* __s2, streamsize __n2)
330  {
331    streamsize __ret = 0;
332#ifdef _GLIBCXX_HAVE_WRITEV
333    __ret = xwritev(this->fd(), __s1, __n1, __s2, __n2);
334#else
335    if (__n1)
336      __ret = xwrite(this->fd(), __s1, __n1);
337
338    if (__ret == __n1)
339      __ret += xwrite(this->fd(), __s2, __n2);
340#endif
341    return __ret;
342  }
343
344  streamoff
345  __basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way) throw ()
346  {
347#ifdef _GLIBCXX_USE_LFS
348    return lseek64(this->fd(), __off, __way);
349#else
350    if (__off > numeric_limits<off_t>::max()
351	|| __off < numeric_limits<off_t>::min())
352      return -1L;
353    return lseek(this->fd(), __off, __way);
354#endif
355  }
356
357  int
358  __basic_file<char>::sync()
359  { return fflush(_M_cfile); }
360
361  streamsize
362  __basic_file<char>::showmanyc()
363  {
364#ifndef _GLIBCXX_NO_IOCTL
365#ifdef FIONREAD
366    // Pipes and sockets.
367    int __num = 0;
368    int __r = ioctl(this->fd(), FIONREAD, &__num);
369    if (!__r && __num >= 0)
370      return __num;
371#endif
372#endif
373
374#ifdef _GLIBCXX_HAVE_POLL
375    // Cheap test.
376    struct pollfd __pfd[1];
377    __pfd[0].fd = this->fd();
378    __pfd[0].events = POLLIN;
379    if (poll(__pfd, 1, 0) <= 0)
380      return 0;
381#endif
382
383#if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
384    // Regular files.
385#ifdef _GLIBCXX_USE_LFS
386    struct stat64 __buffer;
387    const int __err = fstat64(this->fd(), &__buffer);
388    if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
389      {
390	const streamoff __off = __buffer.st_size - lseek64(this->fd(), 0,
391							   ios_base::cur);
392	return std::min(__off, streamoff(numeric_limits<streamsize>::max()));
393      }
394#else
395    struct stat __buffer;
396    const int __err = fstat(this->fd(), &__buffer);
397    if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
398      return __buffer.st_size - lseek(this->fd(), 0, ios_base::cur);
399#endif
400#endif
401    return 0;
402  }
403
404_GLIBCXX_END_NAMESPACE_VERSION
405} // namespace
406
407