1 /* 2 * File registry and opening functionality. 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 "directory_resource.h" 23 #include "file_object_registry.h" 24 #include "file_pager.h" 25 26 #include <systypes/fcntl.h> 27 28 29 30 /* The file object registry provides a memory page collection to the page 31 mappers it creates. */ 32 33 FileObjectRegistry::FileObjectRegistry(Pages *pages) 34 : _pages(pages) 35 { 36 } 37 38 39 40 /* Convert opening flags to map-compatible paging flags. */ 41 42 map_flags_t FileObjectRegistry::get_flags(flags_t flags) 43 { 44 return flags & (O_WRONLY | O_RDWR) ? L4RE_DS_MAP_FLAG_RW : L4RE_DS_MAP_FLAG_RO; 45 } 46 47 48 49 /* Obtain any active provider for 'fileid'. */ 50 51 long FileObjectRegistry::find_directory_provider(fileid_t fileid, 52 DirectoryProvider **directory_provider) 53 { 54 /* Obtain any registered provider. */ 55 56 Accountable *provider = get(fileid); 57 58 if (provider != NULL) 59 { 60 *directory_provider = dynamic_cast<DirectoryProvider *>(provider); 61 62 if ((*directory_provider) != NULL) 63 return L4_EOK; 64 else 65 return -L4_EIO; 66 } 67 68 return -L4_ENOENT; 69 } 70 71 /* Obtain a provider for the 'fileid' or register a new one. */ 72 73 long FileObjectRegistry::get_directory_provider(FileOpening *opening, 74 const char *path, flags_t flags, 75 fileid_t fileid, 76 DirectoryProvider **directory_provider) 77 { 78 long err = find_directory_provider(fileid, directory_provider); 79 80 if (err != -L4_ENOENT) 81 return err; 82 83 /* Make an accessor and a provider to encapsulate it. */ 84 85 DirectoryAccessor *accessor; 86 err = opening->make_directory_accessor(path, flags, fileid, &accessor); 87 88 if (err) 89 return err; 90 91 *directory_provider = new DirectoryProvider(accessor); 92 93 /* Register the provider. */ 94 95 set(fileid, *directory_provider); 96 return L4_EOK; 97 } 98 99 /* Obtain a provider for the 'fileid' or register a new one. */ 100 101 long FileObjectRegistry::get_file_provider(FileOpening *opening, 102 const char *path, flags_t flags, 103 fileid_t fileid, 104 FileProvider **file_provider) 105 { 106 /* Obtain any registered provider. */ 107 108 Accountable *provider = get(fileid); 109 110 if (provider != NULL) 111 { 112 *file_provider = dynamic_cast<FileProvider *>(provider); 113 114 if ((*file_provider) != NULL) 115 return L4_EOK; 116 else 117 return -L4_EIO; 118 } 119 120 /* Make an accessor, page mapper, and a provider to encapsulate them. */ 121 122 Accessor *accessor; 123 long err = opening->make_accessor(path, flags, fileid, &accessor); 124 125 if (err) 126 return err; 127 128 PageMapper *mapper = new PageMapper(accessor, _pages); 129 *file_provider = new FileProvider(mapper); 130 131 /* Register the provider. */ 132 133 set(fileid, *file_provider); 134 return L4_EOK; 135 } 136 137 138 139 /* Return a directory resource initialised with a provider. */ 140 141 long FileObjectRegistry::get_directory(FileOpening *opening, const char *path, 142 flags_t flags, fileid_t fileid, 143 offset_t *size, object_flags_t *object_flags, 144 Resource **resource) 145 { 146 /* Obtain any existing provider registered for the object, or make a new 147 provider. */ 148 149 DirectoryProvider *provider; 150 long err = get_directory_provider(opening, path, flags, fileid, &provider); 151 152 if (err) 153 return err; 154 155 /* Provide non-file values for certain outputs. */ 156 157 *size = 0; 158 *object_flags = 0; 159 160 /* Initialise the resource with the provider and a reference to this object 161 for detaching from the provider. */ 162 163 provider->attach(); 164 *resource = new DirectoryResource(fileid, provider, this); 165 return L4_EOK; 166 } 167 168 /* Return a file pager initialised with a provider, page mapper and accessor. */ 169 170 long FileObjectRegistry::get_file(FileOpening *opening, const char *path, 171 flags_t flags, fileid_t fileid, 172 offset_t *size, object_flags_t *object_flags, 173 Resource **resource) 174 { 175 /* Obtain any existing provider registered for the file, or make a new 176 provider. */ 177 178 FileProvider *provider; 179 long err = get_file_provider(opening, path, flags, fileid, &provider); 180 181 if (err) 182 return err; 183 184 /* Initialise the pager with the provider and a reference to this object for 185 detaching from the provider. */ 186 187 FilePager *pager = new FilePager(fileid, provider, get_flags(flags), this); 188 189 /* Obtain the size details from the pager, also providing appropriate 190 flags. */ 191 192 *size = pager->get_data_size(); 193 *object_flags = OBJECT_SUPPORTS_MMAP | OBJECT_HAS_SIZE; 194 195 provider->attach(); 196 *resource = pager; 197 return L4_EOK; 198 } 199 200 201 202 /* Return a resource for a filesystem object. */ 203 204 long FileObjectRegistry::get_resource(FileOpening *opening, const char *path, 205 flags_t flags, offset_t *size, 206 object_flags_t *object_flags, 207 Resource **resource) 208 { 209 std::lock_guard<std::mutex> guard(_lock); 210 211 /* Obtain an identifier for the file, even for new files (subject to use of 212 the appropriate flag). */ 213 214 fileid_t fileid; 215 long err = opening->get_fileid(path, flags, &fileid); 216 217 if (err) 218 return err; 219 220 /* Test for file and directory access. */ 221 222 if (opening->accessing_directory(path, flags, fileid)) 223 return get_directory(opening, path, flags, fileid, size, object_flags, resource); 224 else if (opening->accessing_file(path, flags, fileid)) 225 return get_file(opening, path, flags, fileid, size, object_flags, resource); 226 else 227 return -L4_EIO; 228 } 229 230 // vim: tabstop=4 expandtab shiftwidth=4