libstdc++-v3/config/io/basic_file_stdio.cc

   1 // Wrapper of C-language FILE struct -*- C++ -*-
   2
   3 // Copyright (C) 2000, 2001, 2002, 2003, 2004 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 //
  31 // ISO C++ 14882: 27.8  File-based streams
  32 //
  33
  34 #include <bits/basic_file.h>
  35 #include <fcntl.h>
  36 #include <errno.h>
  37
  38 #ifdef _GLIBCXX_HAVE_POLL
  39 #include <poll.h>
  40 #endif
  41
  42 // Pick up ioctl on Solaris 2.8
  43 #ifdef _GLIBCXX_HAVE_UNISTD_H
  44 #include <unistd.h>
  45 #endif
  46
  47 // Pick up FIONREAD on Solaris 2
  48 #ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
  49 #define BSD_COMP
  50 #include <sys/ioctl.h>
  51 #endif
  52
  53 // Pick up FIONREAD on Solaris 2.5.
  54 #ifdef _GLIBCXX_HAVE_SYS_FILIO_H
  55 #include <sys/filio.h>
  56 #endif
  57
  58 #ifdef _GLIBCXX_HAVE_SYS_UIO_H
  59 #include <sys/uio.h>
  60 #endif
  61
  62 #if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
  63 # include <sys/stat.h>
  64 # ifdef _GLIBCXX_HAVE_S_ISREG
  65 #  define _GLIBCXX_ISREG(x) S_ISREG(x)
  66 # else
  67 #  define _GLIBCXX_ISREG(x) (((x) & S_IFMT) == S_IFREG)
  68 # endif
  69 #endif
  70
  71 #include <limits> // For <off_t>::max() and min() and <streamsize>::max()
  72
  73 namespace __gnu_internal
  74 {
  75   // Map ios_base::openmode flags to a string for use in fopen().
  76   // Table of valid combinations as given in [lib.filebuf.members]/2.
  77   static const char*
  78   fopen_mode(std::ios_base::openmode mode)
  79   {
  80     enum
  81       {
  82         in     = std::ios_base::in,
  83         out    = std::ios_base::out,
  84         trunc  = std::ios_base::trunc,
  85         app    = std::ios_base::app,
  86         binary = std::ios_base::binary
  87       };
  88
  89     switch (mode & (in|out|trunc|app|binary))
  90       {
  91       case (   out                 ): return "w";
  92       case (   out      |app       ): return "a";
  93       case (   out|trunc           ): return "w";
  94       case (in                     ): return "r";
  95       case (in|out                 ): return "r+";
  96       case (in|out|trunc           ): return "w+";
  97
  98       case (   out          |binary): return "wb";
  99       case (   out      |app|binary): return "ab";
 100       case (   out|trunc    |binary): return "wb";
 101       case (in              |binary): return "rb";
 102       case (in|out          |binary): return "r+b";
 103       case (in|out|trunc    |binary): return "w+b";
 104
 105       default: return 0; // invalid
 106       }
 107   }
 108
 109   // Wrapper handling partial write.
 110   static std::streamsize
 111   xwrite(int __fd, const char* __s, std::streamsize __n)
 112   {
 113     std::streamsize __nleft = __n;
 114
 115     for (;;)
 116       {
 117         const std::streamsize __ret = write(__fd, __s, __nleft);
 118         if (__ret == -1L && errno == EINTR)
 119           continue;
 120         if (__ret == -1L)
 121           break;
 122
 123         __nleft -= __ret;
 124         if (__nleft == 0)
 125           break;
 126
 127         __s += __ret;
 128       }
 129
 130     return __n - __nleft;
 131   }
 132
 133 #ifdef _GLIBCXX_HAVE_WRITEV
 134   // Wrapper handling partial writev.
 135   static std::streamsize
 136   xwritev(int __fd, const char* __s1, std::streamsize __n1,
 137           const char* __s2, std::streamsize __n2)
 138   {
 139     std::streamsize __nleft = __n1 + __n2;
 140     std::streamsize __n1_left = __n1;
 141
 142     struct iovec __iov[2];
 143     __iov[1].iov_base = const_cast<char*>(__s2);
 144     __iov[1].iov_len = __n2;
 145
 146     for (;;)
 147       {
 148         __iov[0].iov_base = const_cast<char*>(__s1);
 149         __iov[0].iov_len = __n1_left;
 150
 151         const std::streamsize __ret = writev(__fd, __iov, 2);
 152         if (__ret == -1L && errno == EINTR)
 153           continue;
 154         if (__ret == -1L)
 155           break;
 156
 157         __nleft -= __ret;
 158         if (__nleft == 0)
 159           break;
 160
 161         const std::streamsize __off = __ret - __n1_left;
 162         if (__off >= 0)
 163           {
 164             __nleft -= xwrite(__fd, __s2 + __off, __n2 - __off);
 165             break;
 166           }
 167
 168         __s1 += __ret;
 169         __n1_left -= __ret;
 170       }
 171
 172     return __n1 + __n2 - __nleft;
 173   }
 174 #endif
 175 } // namespace __gnu_internal
 176
 177
 178 _GLIBCXX_BEGIN_NAMESPACE(std)
 179
 180   // Definitions for __basic_file<char>.
 181   __basic_file<char>::__basic_file(__c_lock* /*__lock*/)
 182   : _M_cfile(NULL), _M_cfile_created(false) { }
 183
 184   __basic_file<char>::~__basic_file()
 185   { this->close(); }
 186
 187   __basic_file<char>*
 188   __basic_file<char>::sys_open(__c_file* __file, ios_base::openmode)
 189   {
 190     __basic_file* __ret = NULL;
 191     if (!this->is_open() && __file)
 192       {
 193         int __err;
 194         errno = 0;
 195         do
 196           __err = this->sync();
 197         while (__err && errno == EINTR);
 198         if (!__err)
 199           {
 200             _M_cfile = __file;
 201             _M_cfile_created = false;
 202             __ret = this;
 203           }
 204       }
 205     return __ret;
 206   }
 207
 208   __basic_file<char>*
 209   __basic_file<char>::sys_open(int __fd, ios_base::openmode __mode)
 210   {
 211     __basic_file* __ret = NULL;
 212     const char* __c_mode = __gnu_internal::fopen_mode(__mode);
 213     if (__c_mode && !this->is_open() && (_M_cfile = fdopen(__fd, __c_mode)))
 214       {
 215         char* __buf = NULL;
 216         _M_cfile_created = true;
 217         if (__fd == 0)
 218           setvbuf(_M_cfile, __buf, _IONBF, 0);
 219         __ret = this;
 220       }
 221     return __ret;
 222   }
 223
 224   __basic_file<char>*
 225   __basic_file<char>::open(const char* __name, ios_base::openmode __mode,
 226                            int /*__prot*/)
 227   {
 228     __basic_file* __ret = NULL;
 229     const char* __c_mode = __gnu_internal::fopen_mode(__mode);
 230     if (__c_mode && !this->is_open())
 231       {
 232 #ifdef _GLIBCXX_USE_LFS
 233         if ((_M_cfile = fopen64(__name, __c_mode)))
 234 #else
 235         if ((_M_cfile = fopen(__name, __c_mode)))
 236 #endif
 237           {
 238             _M_cfile_created = true;
 239             __ret = this;
 240           }
 241       }
 242     return __ret;
 243   }
 244
 245   bool
 246   __basic_file<char>::is_open() const
 247   { return _M_cfile != 0; }
 248
 249   int
 250   __basic_file<char>::fd()
 251   { return fileno(_M_cfile); }
 252
 253   __c_file*
 254   __basic_file<char>::file()
 255   { return _M_cfile; }
 256
 257   __basic_file<char>*
 258   __basic_file<char>::close()
 259   {
 260     __basic_file* __ret = static_cast<__basic_file*>(NULL);
 261     if (this->is_open())
 262       {
 263         int __err = 0;
 264         if (_M_cfile_created)
 265           {
 266             // In general, no need to zero errno in advance if checking
 267             // for error first. However, C89/C99 (at variance with IEEE
 268             // 1003.1, f.i.) do not mandate that fclose must set errno
 269             // upon error.
 270             errno = 0;
 271             do
 272               __err = fclose(_M_cfile);
 273             while (__err && errno == EINTR);
 274           }
 275         _M_cfile = 0;
 276         if (!__err)
 277           __ret = this;
 278       }
 279     return __ret;
 280   }
 281
 282   streamsize
 283   __basic_file<char>::xsgetn(char* __s, streamsize __n)
 284   {
 285     streamsize __ret;
 286     do
 287       __ret = read(this->fd(), __s, __n);
 288     while (__ret == -1L && errno == EINTR);
 289     return __ret;
 290   }
 291
 292   streamsize
 293   __basic_file<char>::xsputn(const char* __s, streamsize __n)
 294   { return __gnu_internal::xwrite(this->fd(), __s, __n); }
 295
 296   streamsize
 297   __basic_file<char>::xsputn_2(const char* __s1, streamsize __n1,
 298                                const char* __s2, streamsize __n2)
 299   {
 300     streamsize __ret = 0;
 301 #ifdef _GLIBCXX_HAVE_WRITEV
 302     __ret = __gnu_internal::xwritev(this->fd(), __s1, __n1, __s2, __n2);
 303 #else
 304     if (__n1)
 305       __ret = __gnu_internal::xwrite(this->fd(), __s1, __n1);
 306
 307     if (__ret == __n1)
 308       __ret += __gnu_internal::xwrite(this->fd(), __s2, __n2);
 309 #endif
 310     return __ret;
 311   }
 312
 313   streamoff
 314   __basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way)
 315   {
 316 #ifdef _GLIBCXX_USE_LFS
 317     return lseek64(this->fd(), __off, __way);
 318 #else
 319     if (__off > numeric_limits<off_t>::max()
 320         || __off < numeric_limits<off_t>::min())
 321       return -1L;
 322     return lseek(this->fd(), __off, __way);
 323 #endif
 324   }
 325
 326   int
 327   __basic_file<char>::sync()
 328   { return fflush(_M_cfile); }
 329
 330   streamsize
 331   __basic_file<char>::showmanyc()
 332   {
 333 #ifdef FIONREAD
 334     // Pipes and sockets.
 335 #ifdef _GLIBCXX_FIONREAD_TAKES_OFF_T
 336     off_t __num = 0;
 337 #else
 338     int __num = 0;
 339 #endif
 340     int __r = ioctl(this->fd(), FIONREAD, &__num);
 341     if (!__r && __num >= 0)
 342       return __num;
 343 #endif
 344
 345 #ifdef _GLIBCXX_HAVE_POLL
 346     // Cheap test.
 347     struct pollfd __pfd[1];
 348     __pfd[0].fd = this->fd();
 349     __pfd[0].events = POLLIN;
 350     if (poll(__pfd, 1, 0) <= 0)
 351       return 0;
 352 #endif
 353
 354 #if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
 355     // Regular files.
 356 #ifdef _GLIBCXX_USE_LFS
 357     struct stat64 __buffer;
 358     const int __err = fstat64(this->fd(), &__buffer);
 359     if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
 360       {
 361         const streamoff __off = __buffer.st_size - lseek64(this->fd(), 0,
 362                                                            ios_base::cur);
 363         return std::min(__off, streamoff(numeric_limits<streamsize>::max()));
 364       }
 365 #else
 366     struct stat __buffer;
 367     const int __err = fstat(this->fd(), &__buffer);
 368     if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
 369       return __buffer.st_size - lseek(this->fd(), 0, ios_base::cur);
 370 #endif
 371 #endif
 372     return 0;
 373   }
 374
 375 _GLIBCXX_END_NAMESPACE
 376