1 /*
2  * Block device emulated in a file
3  *
4  * Copyright (c) 2022, The littlefs authors.
5  * Copyright (c) 2017, Arm Limited. All rights reserved.
6  * SPDX-License-Identifier: BSD-3-Clause
7  */
8 #include "bd/lfs_filebd.h"
9 
10 #include <fcntl.h>
11 #include <unistd.h>
12 #include <errno.h>
13 
14 #ifdef _WIN32
15 #include <windows.h>
16 #endif
17 
lfs_filebd_createcfg(const struct lfs_config * cfg,const char * path,const struct lfs_filebd_config * bdcfg)18 int lfs_filebd_createcfg(const struct lfs_config *cfg, const char *path,
19         const struct lfs_filebd_config *bdcfg) {
20     LFS_FILEBD_TRACE("lfs_filebd_createcfg(%p {.context=%p, "
21                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
22                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
23                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
24                 "\"%s\", "
25                 "%p {.erase_value=%"PRId32"})",
26             (void*)cfg, cfg->context,
27             (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
28             (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
29             cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
30             path, (void*)bdcfg, bdcfg->erase_value);
31     lfs_filebd_t *bd = cfg->context;
32     bd->cfg = bdcfg;
33 
34     // open file
35     #ifdef _WIN32
36     bd->fd = open(path, O_RDWR | O_CREAT | O_BINARY, 0666);
37     #else
38     bd->fd = open(path, O_RDWR | O_CREAT, 0666);
39     #endif
40 
41     if (bd->fd < 0) {
42         int err = -errno;
43         LFS_FILEBD_TRACE("lfs_filebd_createcfg -> %d", err);
44         return err;
45     }
46 
47     LFS_FILEBD_TRACE("lfs_filebd_createcfg -> %d", 0);
48     return 0;
49 }
50 
lfs_filebd_create(const struct lfs_config * cfg,const char * path)51 int lfs_filebd_create(const struct lfs_config *cfg, const char *path) {
52     LFS_FILEBD_TRACE("lfs_filebd_create(%p {.context=%p, "
53                 ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
54                 ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
55                 ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
56                 "\"%s\")",
57             (void*)cfg, cfg->context,
58             (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
59             (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
60             cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
61             path);
62     static const struct lfs_filebd_config defaults = {.erase_value=-1};
63     int err = lfs_filebd_createcfg(cfg, path, &defaults);
64     LFS_FILEBD_TRACE("lfs_filebd_create -> %d", err);
65     return err;
66 }
67 
lfs_filebd_destroy(const struct lfs_config * cfg)68 int lfs_filebd_destroy(const struct lfs_config *cfg) {
69     LFS_FILEBD_TRACE("lfs_filebd_destroy(%p)", (void*)cfg);
70     lfs_filebd_t *bd = cfg->context;
71     int err = close(bd->fd);
72     if (err < 0) {
73         err = -errno;
74         LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", err);
75         return err;
76     }
77     LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", 0);
78     return 0;
79 }
80 
lfs_filebd_read(const struct lfs_config * cfg,lfs_block_t block,lfs_off_t off,void * buffer,lfs_size_t size)81 int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
82         lfs_off_t off, void *buffer, lfs_size_t size) {
83     LFS_FILEBD_TRACE("lfs_filebd_read(%p, "
84                 "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
85             (void*)cfg, block, off, buffer, size);
86     lfs_filebd_t *bd = cfg->context;
87 
88     // check if read is valid
89     LFS_ASSERT(off  % cfg->read_size == 0);
90     LFS_ASSERT(size % cfg->read_size == 0);
91     LFS_ASSERT(block < cfg->block_count);
92 
93     // zero for reproducibility (in case file is truncated)
94     if (bd->cfg->erase_value != -1) {
95         memset(buffer, bd->cfg->erase_value, size);
96     }
97 
98     // read
99     off_t res1 = lseek(bd->fd,
100             (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
101     if (res1 < 0) {
102         int err = -errno;
103         LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
104         return err;
105     }
106 
107     ssize_t res2 = read(bd->fd, buffer, size);
108     if (res2 < 0) {
109         int err = -errno;
110         LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
111         return err;
112     }
113 
114     LFS_FILEBD_TRACE("lfs_filebd_read -> %d", 0);
115     return 0;
116 }
117 
lfs_filebd_prog(const struct lfs_config * cfg,lfs_block_t block,lfs_off_t off,const void * buffer,lfs_size_t size)118 int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
119         lfs_off_t off, const void *buffer, lfs_size_t size) {
120     LFS_FILEBD_TRACE("lfs_filebd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
121             (void*)cfg, block, off, buffer, size);
122     lfs_filebd_t *bd = cfg->context;
123 
124     // check if write is valid
125     LFS_ASSERT(off  % cfg->prog_size == 0);
126     LFS_ASSERT(size % cfg->prog_size == 0);
127     LFS_ASSERT(block < cfg->block_count);
128 
129     // check that data was erased? only needed for testing
130     if (bd->cfg->erase_value != -1) {
131         off_t res1 = lseek(bd->fd,
132                 (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
133         if (res1 < 0) {
134             int err = -errno;
135             LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
136             return err;
137         }
138 
139         for (lfs_off_t i = 0; i < size; i++) {
140             uint8_t c;
141             ssize_t res2 = read(bd->fd, &c, 1);
142             if (res2 < 0) {
143                 int err = -errno;
144                 LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
145                 return err;
146             }
147 
148             LFS_ASSERT(c == bd->cfg->erase_value);
149         }
150     }
151 
152     // program data
153     off_t res1 = lseek(bd->fd,
154             (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
155     if (res1 < 0) {
156         int err = -errno;
157         LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
158         return err;
159     }
160 
161     ssize_t res2 = write(bd->fd, buffer, size);
162     if (res2 < 0) {
163         int err = -errno;
164         LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
165         return err;
166     }
167 
168     LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", 0);
169     return 0;
170 }
171 
lfs_filebd_erase(const struct lfs_config * cfg,lfs_block_t block)172 int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
173     LFS_FILEBD_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
174     lfs_filebd_t *bd = cfg->context;
175 
176     // check if erase is valid
177     LFS_ASSERT(block < cfg->block_count);
178 
179     // erase, only needed for testing
180     if (bd->cfg->erase_value != -1) {
181         off_t res1 = lseek(bd->fd, (off_t)block*cfg->block_size, SEEK_SET);
182         if (res1 < 0) {
183             int err = -errno;
184             LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", err);
185             return err;
186         }
187 
188         for (lfs_off_t i = 0; i < cfg->block_size; i++) {
189             ssize_t res2 = write(bd->fd, &(uint8_t){bd->cfg->erase_value}, 1);
190             if (res2 < 0) {
191                 int err = -errno;
192                 LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", err);
193                 return err;
194             }
195         }
196     }
197 
198     LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", 0);
199     return 0;
200 }
201 
lfs_filebd_sync(const struct lfs_config * cfg)202 int lfs_filebd_sync(const struct lfs_config *cfg) {
203     LFS_FILEBD_TRACE("lfs_filebd_sync(%p)", (void*)cfg);
204     // file sync
205     lfs_filebd_t *bd = cfg->context;
206     #ifdef _WIN32
207     int err = FlushFileBuffers((HANDLE) _get_osfhandle(fd)) ? 0 : -1;
208     #else
209     int err = fsync(bd->fd);
210     #endif
211     if (err) {
212         err = -errno;
213         LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
214         return err;
215     }
216 
217     LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
218     return 0;
219 }
220