2 fuse_xattrs - Add xattrs support using sidecar files
4 Copyright (C) 2016 Felipe Barriga Richards <felipe {at} felipebarriga.cl>
6 This program can be distributed under the terms of the GNU GPL.
16 #include "binary_storage.h"
18 #include "fuse_xattrs_config.h"
19 #include "stringmem.h"
21 #include <sys/xattr.h>
24 #define ENOATTR ENODATA
27 struct on_memory_attr {
35 void __print_on_memory_attr(struct on_memory_attr *attr)
38 char *sanitized_value = sanitize_value(attr->value, attr->value_size);
39 debug_print("--------------\n");
40 debug_print("name size: %hu\n", attr->name_size);
41 debug_print("name: '%s'\n", attr->name);
42 debug_print("value size: %zu\n", attr->value_size);
43 debug_print("sanitized_value: '%s'\n", sanitized_value);
44 debug_print("--------------\n");
45 strfree(sanitized_value);
49 void __free_on_memory_attr(struct on_memory_attr *attr)
51 if(attr->name != NULL)
54 if(attr->value != NULL)
60 char *__read_file(const char *path, int *buffer_size)
62 FILE *file = fopen(path, "r");
66 debug_print("file not found: %s\n", path);
67 *buffer_size = -ENOENT;
71 debug_print("file found, reading it: %s\n", path);
73 fseek(file, 0, SEEK_END);
74 *buffer_size = (int)ftell(file);
76 if (*buffer_size == -1) {
77 error_print("error: path: %s, size: %d, errno=%d\n", path, *buffer_size, errno);
83 if (*buffer_size > MAX_METADATA_SIZE) {
84 error_print("metadata file too big. path: %s, size: %d\n", path, *buffer_size);
85 *buffer_size = -ENOSPC;
90 if (*buffer_size == 0) {
91 debug_print("empty file.\n");
92 *buffer_size = -ENOENT;
96 assert(*buffer_size > 0);
97 size_t _buffer_size = (size_t) *buffer_size;
99 fseek(file, 0, SEEK_SET);
100 buffer = malloc(_buffer_size);
101 if (buffer == NULL) {
102 *buffer_size = -ENOMEM;
103 error_print("cannot allocate memory.\n");
108 memset(buffer, '\0', _buffer_size);
109 fread(buffer, 1, _buffer_size, file);
115 char *__read_file_sidecar(const char *path, int *buffer_size)
117 char *sidecar_path = get_sidecar_path(path);
118 debug_print("path=%s sidecar_path=%s\n", path, sidecar_path);
120 char *buffer = __read_file(sidecar_path, buffer_size);
121 strfree (sidecar_path);
125 int __cmp_name(const char *name, size_t name_length, struct on_memory_attr *attr)
127 if (attr->name_size == name_length && memcmp(attr->name, name, name_length) == 0) {
128 debug_print("match: name=%s, name_length=%zu\n", name, name_length);
129 __print_on_memory_attr(attr);
133 debug_print("doesn't match: name=%s, name_length=%zu\n", name, name_length);
134 __print_on_memory_attr(attr);
139 struct on_memory_attr *__read_on_memory_attr(size_t *offset, char *buffer, size_t buffer_size)
141 debug_print("offset=%zu\n", *offset);
142 struct on_memory_attr *attr = malloc(sizeof(struct on_memory_attr));
146 ////////////////////////////////
148 size_t data_size = sizeof(u_int16_t);
149 if (*offset + data_size > buffer_size) {
150 error_print("Error, sizes doesn't match.\n");
151 __free_on_memory_attr(attr);
154 memcpy(&attr->name_size, buffer + *offset, data_size);
155 *offset += data_size;
156 debug_print("attr->name_size=%hu\n", attr->name_size);
158 ////////////////////////////////
160 data_size = attr->name_size;
161 if (*offset + data_size > buffer_size) {
162 error_print("Error, sizes doesn't match.\n");
163 __free_on_memory_attr(attr);
166 attr->name = malloc(data_size);
167 memcpy(attr->name, buffer + *offset, data_size);
168 *offset += data_size;
170 ////////////////////////////////
172 data_size = sizeof(size_t);
173 if (*offset + data_size > buffer_size) {
174 error_print("Error, sizes doesn't match.\n");
175 __free_on_memory_attr(attr);
178 memcpy(&attr->value_size, buffer + *offset, data_size);
179 *offset += data_size;
180 debug_print("attr->value_size=%zu\n", attr->value_size);
182 ////////////////////////////////
184 data_size = attr->value_size;
185 if (*offset + data_size > buffer_size) {
186 error_print("Error, sizes doesn't match. data_size=%zu buffer_size=%zu\n",
187 data_size, buffer_size);
189 __free_on_memory_attr(attr);
192 attr->value = malloc(data_size);
193 memcpy(attr->value, buffer + *offset, data_size);
194 *offset += data_size;
199 int __write_to_file(FILE *file, const char *name, const char *value, const size_t value_size)
201 const u_int16_t name_size = (int) strlen(name) + 1;
204 char *sanitized_value = sanitize_value(value, value_size);
205 debug_print("name='%s' name_size=%hu sanitized_value='%s' value_size=%zu\n", name, name_size, sanitized_value, value_size);
206 strfree(sanitized_value);
210 if (fwrite(&name_size, sizeof(u_int16_t), 1, file) != 1) {
213 if (fwrite(name, name_size, 1, file) != 1) {
218 if (fwrite(&value_size, sizeof(size_t), 1, file) != 1) {
221 // write value content only if we have something to write.
222 if (value_size > 0) {
223 if (fwrite(value, value_size, 1, file) != 1) {
233 * @param path - path to file.
234 * @param name - attribute name. string null terminated. size <= XATTR_NAME_MAX bytes
235 * @param value - attribute value. size < XATTR_SIZE_MAX
237 * @param flags - XATTR_CREATE and/or XATTR_REPLACE
238 * @return On success, zero is returned. On failure, -errno is returned.
240 int binary_storage_write_key(const char *path, const char *name, const char *value, size_t size, int flags)
243 char *sanitized_value = sanitize_value(value, size);
244 debug_print("path=%s name=%s sanitized_value=%s size=%zu flags=%d\n", path, name, sanitized_value, size, flags);
245 strfree(sanitized_value);
249 char *buffer = __read_file_sidecar(path, &buffer_size);
251 if (buffer == NULL && buffer_size == -ENOENT && flags & XATTR_REPLACE) {
252 error_print("No xattr. (flag XATTR_REPLACE)");
256 if (buffer == NULL && buffer_size != -ENOENT) {
261 char *sidecar_path = get_sidecar_path(path);
262 FILE *file = fopen(sidecar_path, "w");
263 strfree(sidecar_path);
265 if (buffer == NULL) {
266 debug_print("new file, writing directly...\n");
267 status = __write_to_file(file, name, value, size);
273 assert(buffer_size >= 0);
274 size_t _buffer_size = (size_t)buffer_size;
278 size_t name_len = strlen(name) + 1; // null byte
280 while(offset < _buffer_size)
282 debug_print("replaced=%d offset=%zu buffer_size=%zu\n", replaced, offset, _buffer_size);
283 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
285 // FIXME: handle attr == NULL
286 assert(attr != NULL);
288 if (memcmp(attr->name, name, name_len) == 0) {
289 assert(replaced == 0);
290 if (flags & XATTR_CREATE) {
291 error_print("Key already exists. (flag XATTR_CREATE)");
292 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
296 status = __write_to_file(file, name, value, size);
301 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
304 __free_on_memory_attr(attr);
307 if (replaced == 0 && res == 0) {
308 if (flags & XATTR_REPLACE) {
309 error_print("Key doesn't exists. (flag XATTR_REPLACE)");
312 status = __write_to_file(file, name, value, size);
322 int binary_storage_read_key(const char *path, const char *name, char *value, size_t size)
325 char *buffer = __read_file_sidecar(path, &buffer_size);
327 if (buffer == NULL) {
328 if (buffer_size == -ENOENT) {
333 assert(buffer_size >= 0);
334 size_t _buffer_size = (size_t)buffer_size;
337 memset(value, '\0', size);
340 size_t name_len = strlen(name) + 1; // null byte \0
342 while(offset < _buffer_size)
344 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
350 if (__cmp_name(name, name_len, attr) == 1) {
351 int value_size = (int)attr->value_size;
355 } else if (attr->value_size <= size) {
356 memcpy(value, attr->value, attr->value_size);
359 error_print("error, attr->value_size=%zu > size=%zu\n", attr->value_size, size);
363 __free_on_memory_attr(attr);
366 __free_on_memory_attr(attr);
373 int binary_storage_list_keys(const char *path, char *list, size_t size)
376 char *buffer = __read_file_sidecar(path, &buffer_size);
378 if (buffer == NULL) {
379 debug_print("buffer == NULL buffer_size=%d\n", buffer_size);
380 if (buffer_size == -ENOENT) {
386 assert(buffer_size > 0);
387 size_t _buffer_size = (size_t)buffer_size;
390 memset(list, '\0', size);
395 while(offset < _buffer_size)
397 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
404 if (attr->name_size + res > size) {
405 error_print("Not enough memory allocated. allocated=%zu required=%ld\n",
406 size, attr->name_size + res);
407 __free_on_memory_attr(attr);
411 memcpy(list + res, attr->name, attr->name_size);
412 res += attr->name_size;
415 res += attr->name_size;
417 __free_on_memory_attr(attr);
421 if (size == 0 && res > XATTR_LIST_MAX) {
422 // FIXME: we should return the size or an error ?
429 int binary_storage_remove_key(const char *path, const char *name)
431 debug_print("path=%s name=%s\n", path, name);
433 char *buffer = __read_file_sidecar(path, &buffer_size);
435 if (buffer == NULL) {
438 assert(buffer_size > 0);
439 size_t _buffer_size = (size_t) buffer_size;
441 char *sidecar_path = get_sidecar_path(path);
442 FILE *file = fopen(sidecar_path, "w");
443 strfree(sidecar_path);
446 size_t name_len = strlen(name) + 1; // null byte \0
449 while(offset < _buffer_size)
451 debug_print("removed=%d offset=%zu buffer_size=%zu\n", removed, offset, _buffer_size);
453 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
455 error_print("error reading file. corrupted ?");
459 if (memcmp(attr->name, name, name_len) == 0) {
462 int status = __write_to_file(file, attr->name, attr->value, attr->value_size);
465 __free_on_memory_attr(attr);
470 debug_print("key removed successfully.\n");
471 } else if (removed == 0) {
472 error_print("key not found.\n");
475 debug_print("removed %d keys (was duplicated)\n", removed);