1 /* 2 * An opener for a "host" file provided via the C library. 3 * 4 * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program 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 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include "host_file_accessor.h" 23 #include "host_file_opener.h" 24 25 /* Return a file identifier for the given 'path'. */ 26 27 fileid_t HostFileOpener::get_fileid(const char *path, flags_t flags) 28 { 29 (void) flags; 30 31 /* Test for a valid file or an attempt to create a file. */ 32 33 FILE *fp = fopen(path, "r"); 34 35 if (fp == NULL) 36 return FILEID_INVALID; 37 38 fclose(fp); 39 40 return _get_fileid(path, true); 41 } 42 43 fileid_t HostFileOpener::_get_fileid(const char *path, bool create) 44 { 45 std::lock_guard<std::mutex> guard(_lock); 46 47 /* The inode number would be a good choice, but the L4Re read-only file 48 implementation just provides the value of a counter! 49 50 See: pkg/l4re-core/l4re_vfs/include/impl/ro_file_impl.h */ 51 52 std::string s(path); 53 54 HostFileIdentifiers::iterator it = _fileids.find(s); 55 56 if (it != _fileids.end()) 57 return it->second; 58 59 if (!create) 60 return FILEID_INVALID; 61 62 fileid_t fileid = _fileids.size(); 63 64 _fileids[s] = fileid; 65 66 return fileid; 67 } 68 69 /* Return a new accessor for 'fileid'. */ 70 71 long HostFileOpener::make_accessor(const char *path, flags_t flags, fileid_t fileid, Accessor **accessor) 72 { 73 // NOTE: Not testing for create or write flags. 74 75 (void) flags; 76 77 FILE *fp = fopen(path, "r"); 78 79 if (fp == NULL) 80 return -L4_ENOENT; 81 82 *accessor = new HostFileAccessor(fp, fileid); 83 return L4_EOK; 84 } 85 86 // vim: tabstop=4 expandtab shiftwidth=4