1 // Wrapper of C-language FILE struct -*- C++ -*- 2 3 // Copyright (C) 2000-2017 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 68 namespace 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* fopen_mode(std::ios_base::openmode mode)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 xwrite(int __fd,const char * __s,std::streamsize __n)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 xwritev(int __fd,const char * __s1,std::streamsize __n1,const char * __s2,std::streamsize __n2)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 179 180 181 namespace std _GLIBCXX_VISIBILITY(default) 182 { 183 _GLIBCXX_BEGIN_NAMESPACE_VERSION 184 185 // Definitions for __basic_file<char>. __basic_file(__c_lock *)186 __basic_file<char>::__basic_file(__c_lock* /*__lock*/) throw() 187 : _M_cfile(NULL), _M_cfile_created(false) { } 188 ~__basic_file()189 __basic_file<char>::~__basic_file() 190 { this->close(); } 191 192 __basic_file<char>* sys_open(__c_file * __file,ios_base::openmode)193 __basic_file<char>::sys_open(__c_file* __file, ios_base::openmode) 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 = 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>* sys_open(int __fd,ios_base::openmode __mode)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>* open(const char * __name,ios_base::openmode __mode,int)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 bool is_open() const253 __basic_file<char>::is_open() const throw () 254 { return _M_cfile != 0; } 255 256 int fd()257 __basic_file<char>::fd() throw () 258 { return fileno(_M_cfile); } 259 260 __c_file* file()261 __basic_file<char>::file() throw () 262 { return _M_cfile; } 263 264 __basic_file<char>* close()265 __basic_file<char>::close() 266 { 267 __basic_file* __ret = static_cast<__basic_file*>(NULL); 268 if (this->is_open()) 269 { 270 int __err = 0; 271 if (_M_cfile_created) 272 __err = fclose(_M_cfile); 273 _M_cfile = 0; 274 if (!__err) 275 __ret = this; 276 } 277 return __ret; 278 } 279 280 streamsize xsgetn(char * __s,streamsize __n)281 __basic_file<char>::xsgetn(char* __s, streamsize __n) 282 { 283 streamsize __ret; 284 do 285 __ret = read(this->fd(), __s, __n); 286 while (__ret == -1L && errno == EINTR); 287 return __ret; 288 } 289 290 streamsize xsputn(const char * __s,streamsize __n)291 __basic_file<char>::xsputn(const char* __s, streamsize __n) 292 { return xwrite(this->fd(), __s, __n); } 293 294 streamsize xsputn_2(const char * __s1,streamsize __n1,const char * __s2,streamsize __n2)295 __basic_file<char>::xsputn_2(const char* __s1, streamsize __n1, 296 const char* __s2, streamsize __n2) 297 { 298 streamsize __ret = 0; 299 #ifdef _GLIBCXX_HAVE_WRITEV 300 __ret = xwritev(this->fd(), __s1, __n1, __s2, __n2); 301 #else 302 if (__n1) 303 __ret = xwrite(this->fd(), __s1, __n1); 304 305 if (__ret == __n1) 306 __ret += xwrite(this->fd(), __s2, __n2); 307 #endif 308 return __ret; 309 } 310 311 streamoff seekoff(streamoff __off,ios_base::seekdir __way)312 __basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way) throw () 313 { 314 #ifdef _GLIBCXX_USE_LFS 315 return lseek64(this->fd(), __off, __way); 316 #else 317 if (__off > numeric_limits<off_t>::max() 318 || __off < numeric_limits<off_t>::min()) 319 return -1L; 320 return lseek(this->fd(), __off, __way); 321 #endif 322 } 323 324 int sync()325 __basic_file<char>::sync() 326 { return fflush(_M_cfile); } 327 328 streamsize showmanyc()329 __basic_file<char>::showmanyc() 330 { 331 #ifndef _GLIBCXX_NO_IOCTL 332 #ifdef FIONREAD 333 // Pipes and sockets. 334 int __num = 0; 335 int __r = ioctl(this->fd(), FIONREAD, &__num); 336 if (!__r && __num >= 0) 337 return __num; 338 #endif 339 #endif 340 341 #ifdef _GLIBCXX_HAVE_POLL 342 // Cheap test. 343 struct pollfd __pfd[1]; 344 __pfd[0].fd = this->fd(); 345 __pfd[0].events = POLLIN; 346 if (poll(__pfd, 1, 0) <= 0) 347 return 0; 348 #endif 349 350 #if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG) 351 // Regular files. 352 #ifdef _GLIBCXX_USE_LFS 353 struct stat64 __buffer; 354 const int __err = fstat64(this->fd(), &__buffer); 355 if (!__err && _GLIBCXX_ISREG(__buffer.st_mode)) 356 { 357 const streamoff __off = __buffer.st_size - lseek64(this->fd(), 0, 358 ios_base::cur); 359 return std::min(__off, streamoff(numeric_limits<streamsize>::max())); 360 } 361 #else 362 struct stat __buffer; 363 const int __err = fstat(this->fd(), &__buffer); 364 if (!__err && _GLIBCXX_ISREG(__buffer.st_mode)) 365 return __buffer.st_size - lseek(this->fd(), 0, ios_base::cur); 366 #endif 367 #endif 368 return 0; 369 } 370 371 _GLIBCXX_END_NAMESPACE_VERSION 372 } // namespace 373 374