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 /* Make a directory provider. */ 50 51 long FileObjectRegistry::make_directory_provider(FileOpening *opening, 52 const char *path, flags_t flags, 53 fileid_t fileid, 54 Provider **provider) 55 { 56 /* Make an accessor and a provider to encapsulate it. */ 57 58 DirectoryAccessor *accessor; 59 long err = opening->make_directory_accessor(path, flags, fileid, &accessor); 60 61 if (err) 62 return err; 63 64 *provider = new DirectoryProvider(accessor); 65 66 /* Register the provider. */ 67 68 set(fileid, *provider); 69 return L4_EOK; 70 } 71 72 /* Make a file provider. */ 73 74 long FileObjectRegistry::make_file_provider(FileOpening *opening, 75 const char *path, flags_t flags, 76 fileid_t fileid, 77 Provider **provider) 78 { 79 /* Make an accessor, page mapper, and a provider to encapsulate them. */ 80 81 Accessor *accessor; 82 long err = opening->make_accessor(path, flags, fileid, &accessor); 83 84 if (err) 85 return err; 86 87 PageMapper *mapper = new PageMapper(accessor, _pages); 88 *provider = new FileProvider(mapper); 89 90 /* Register the provider. */ 91 92 set(fileid, *provider); 93 return L4_EOK; 94 } 95 96 /* Make a provider of the appropriate type. */ 97 98 long FileObjectRegistry::make_provider(FileOpening *opening, 99 const char *path, flags_t flags, 100 fileid_t fileid, 101 Provider **provider) 102 { 103 if (opening->accessing_directory(path, flags, fileid)) 104 return make_directory_provider(opening, path, flags, fileid, provider); 105 else if (opening->accessing_file(path, flags, fileid)) 106 return make_file_provider(opening, path, flags, fileid, provider); 107 else 108 return -L4_EIO; 109 } 110 111 112 113 /* Return a directory resource initialised with a provider. */ 114 115 long FileObjectRegistry::make_directory_resource(fileid_t fileid, offset_t *size, 116 object_flags_t *object_flags, 117 DirectoryProvider *provider, 118 Resource **resource) 119 { 120 /* Provide non-file values for certain outputs. */ 121 122 *size = 0; 123 *object_flags = 0; 124 125 /* Initialise the resource with the provider and a reference to this object 126 for detaching from the provider. */ 127 128 provider->attach(); 129 *resource = new DirectoryResource(fileid, provider, this); 130 return L4_EOK; 131 } 132 133 /* Return a file pager initialised with a provider, page mapper and accessor. */ 134 135 long FileObjectRegistry::make_file_resource(flags_t flags, fileid_t fileid, 136 offset_t *size, 137 object_flags_t *object_flags, 138 FileProvider *provider, 139 Resource **resource) 140 { 141 /* Initialise the pager with the provider and a reference to this object for 142 detaching from the provider. */ 143 144 FilePager *pager = new FilePager(fileid, provider, get_flags(flags), this); 145 146 /* Obtain the size details from the pager, also providing appropriate 147 flags. */ 148 149 *size = pager->get_data_size(); 150 *object_flags = OBJECT_SUPPORTS_MMAP | OBJECT_HAS_SIZE; 151 152 provider->attach(); 153 *resource = pager; 154 return L4_EOK; 155 } 156 157 /* Make a resource of the appropriate type. */ 158 159 long FileObjectRegistry::make_resource(flags_t flags, fileid_t fileid, 160 offset_t *size, 161 object_flags_t *object_flags, 162 Provider *provider, Resource **resource) 163 { 164 DirectoryProvider *dp = dynamic_cast<DirectoryProvider *>(provider); 165 166 if (dp != NULL) 167 return make_directory_resource(fileid, size, object_flags, dp, resource); 168 169 FileProvider *fp = dynamic_cast<FileProvider *>(provider); 170 171 if (fp != NULL) 172 return make_file_resource(flags, fileid, size, object_flags, fp, resource); 173 174 return -L4_EIO; 175 } 176 177 178 179 /* Return a resource for a filesystem object. */ 180 181 long FileObjectRegistry::get_resource(FileOpening *opening, const char *path, 182 flags_t flags, offset_t *size, 183 object_flags_t *object_flags, 184 Resource **resource) 185 { 186 std::lock_guard<std::mutex> guard(_lock); 187 188 /* Obtain an identifier for the object, even for new files (subject to use 189 of the appropriate flag). */ 190 191 fileid_t fileid; 192 long err = opening->get_fileid(path, flags, &fileid); 193 194 if (err) 195 return err; 196 197 /* Obtain a provider for the object. */ 198 199 Provider *provider; 200 err = find_provider(fileid, &provider); 201 202 /* Make a new provider if necessary. */ 203 204 if (err == -L4_ENOENT) 205 err = make_provider(opening, path, flags, fileid, &provider); 206 207 if (err) 208 return err; 209 210 /* Make a resource for the provider. */ 211 212 return make_resource(flags, fileid, size, object_flags, provider, resource); 213 } 214 215 216 217 /* Obtain any active provider for the given 'fileid'. */ 218 219 long FileObjectRegistry::find_provider(fileid_t fileid, Provider **provider) 220 { 221 /* Obtain any registered provider. */ 222 223 Accountable *accountable = get(fileid); 224 225 if (accountable != NULL) 226 { 227 *provider = dynamic_cast<Provider *>(accountable); 228 229 if ((*provider) != NULL) 230 return L4_EOK; 231 else 232 return -L4_EIO; 233 } 234 235 return -L4_ENOENT; 236 } 237 238 // vim: tabstop=4 expandtab shiftwidth=4