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 <sys/stat.h> 23 24 #include "host_file_accessor.h" 25 #include "host_file_opener.h" 26 27 HostFileOpener::~HostFileOpener() 28 { 29 } 30 31 bool HostFileOpener::accessing_directory(const char *path, flags_t flags, fileid_t fileid) 32 { 33 (void) flags; (void) fileid; 34 struct stat st; 35 36 if (stat(path, &st)) 37 return false; 38 39 return (st.st_mode & S_IFDIR) ? true : false; 40 } 41 42 bool HostFileOpener::accessing_file(const char *path, flags_t flags, fileid_t fileid) 43 { 44 (void) flags; (void) fileid; 45 struct stat st; 46 47 if (stat(path, &st)) 48 return false; 49 50 return (st.st_mode & S_IFREG) ? true : false; 51 } 52 53 /* Return a file identifier for the given 'path'. */ 54 55 long HostFileOpener::get_fileid(const char *path, flags_t flags, fileid_t *fileid) 56 { 57 (void) flags; 58 59 /* Test for a valid file. */ 60 61 FILE *fp = fopen(path, "r"); 62 63 if (fp == NULL) 64 return -L4_ENOENT; 65 66 fclose(fp); 67 68 *fileid = _get_fileid(path, true); 69 return L4_EOK; 70 } 71 72 fileid_t HostFileOpener::_get_fileid(const char *path, bool create) 73 { 74 std::lock_guard<std::mutex> guard(_lock); 75 76 /* The inode number would be a good choice, but the L4Re read-only file 77 implementation just provides the value of a counter! 78 79 See: pkg/l4re-core/l4re_vfs/include/impl/ro_file_impl.h */ 80 81 std::string s(path); 82 83 HostFileIdentifiers::iterator it = _fileids.find(s); 84 85 if (it != _fileids.end()) 86 return it->second; 87 88 if (!create) 89 return FILEID_INVALID; 90 91 fileid_t fileid = _fileids.size(); 92 93 _fileids[s] = fileid; 94 95 return fileid; 96 } 97 98 /* Return a new accessor for 'fileid'. */ 99 100 long HostFileOpener::make_accessor(const char *path, flags_t flags, fileid_t fileid, Accessor **accessor) 101 { 102 // NOTE: Not testing for create or write flags. 103 104 (void) flags; 105 106 FILE *fp = fopen(path, "r"); 107 108 if (fp == NULL) 109 return -L4_ENOENT; 110 111 *accessor = new HostFileAccessor(fp, fileid); 112 return L4_EOK; 113 } 114 115 // vim: tabstop=4 expandtab shiftwidth=4