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"
20 #include <sys/xattr.h>
23 #define ENOATTR ENODATA
26 struct on_memory_attr {
34 void __print_on_memory_attr(struct on_memory_attr *attr)
37 char *sanitized_value = sanitize_value(attr->value, attr->value_size);
38 debug_print("--------------\n");
39 debug_print("name size: %hu\n", attr->name_size);
40 debug_print("name: '%s'\n", attr->name);
41 debug_print("value size: %zu\n", attr->value_size);
42 debug_print("sanitized_value: '%s'\n", sanitized_value);
43 debug_print("--------------\n");
44 free(sanitized_value);
48 void __free_on_memory_attr(struct on_memory_attr *attr)
50 if(attr->name != NULL)
53 if(attr->value != NULL)
59 char *__read_file(const char *path, int *buffer_size)
61 FILE *file = fopen(path, "r");
65 debug_print("file not found: %s\n", path);
66 *buffer_size = -ENOENT;
70 debug_print("file found, reading it: %s\n", path);
72 fseek(file, 0, SEEK_END);
73 *buffer_size = (int)ftell(file);
75 if (*buffer_size == -1) {
76 error_print("error: path: %s, size: %d, errno=%d\n", path, *buffer_size, errno);
82 if (*buffer_size > MAX_METADATA_SIZE) {
83 error_print("metadata file too big. path: %s, size: %d\n", path, *buffer_size);
84 *buffer_size = -ENOSPC;
89 if (*buffer_size == 0) {
90 debug_print("empty file.\n");
91 *buffer_size = -ENOENT;
95 assert(*buffer_size > 0);
96 size_t _buffer_size = (size_t) *buffer_size;
98 fseek(file, 0, SEEK_SET);
99 buffer = malloc(_buffer_size);
100 if (buffer == NULL) {
101 *buffer_size = -ENOMEM;
102 error_print("cannot allocate memory.\n");
107 memset(buffer, '\0', _buffer_size);
108 fread(buffer, 1, _buffer_size, file);
114 char *__read_file_sidecar(const char *path, int *buffer_size)
116 char *sidecar_path = get_sidecar_path(path);
117 debug_print("path=%s sidecar_path=%s\n", path, sidecar_path);
119 char *buffer = __read_file(sidecar_path, buffer_size);
124 int __cmp_name(const char *name, size_t name_length, struct on_memory_attr *attr)
126 if (attr->name_size == name_length && memcmp(attr->name, name, name_length) == 0) {
127 debug_print("match: name=%s, name_length=%zu\n", name, name_length);
128 __print_on_memory_attr(attr);
132 debug_print("doesn't match: name=%s, name_length=%zu\n", name, name_length);
133 __print_on_memory_attr(attr);
138 struct on_memory_attr *__read_on_memory_attr(size_t *offset, char *buffer, size_t buffer_size)
140 debug_print("offset=%zu\n", *offset);
141 struct on_memory_attr *attr = malloc(sizeof(struct on_memory_attr));
145 ////////////////////////////////
147 size_t data_size = sizeof(u_int16_t);
148 if (*offset + data_size > buffer_size) {
149 error_print("Error, sizes doesn't match.\n");
150 __free_on_memory_attr(attr);
153 memcpy(&attr->name_size, buffer + *offset, data_size);
154 *offset += data_size;
155 debug_print("attr->name_size=%hu\n", attr->name_size);
157 ////////////////////////////////
159 data_size = attr->name_size;
160 if (*offset + data_size > buffer_size) {
161 error_print("Error, sizes doesn't match.\n");
162 __free_on_memory_attr(attr);
165 attr->name = malloc(data_size);
166 memcpy(attr->name, buffer + *offset, data_size);
167 *offset += data_size;
169 ////////////////////////////////
171 data_size = sizeof(size_t);
172 if (*offset + data_size > buffer_size) {
173 error_print("Error, sizes doesn't match.\n");
174 __free_on_memory_attr(attr);
177 memcpy(&attr->value_size, buffer + *offset, data_size);
178 *offset += data_size;
179 debug_print("attr->value_size=%zu\n", attr->value_size);
181 ////////////////////////////////
183 data_size = attr->value_size;
184 if (*offset + data_size > buffer_size) {
185 error_print("Error, sizes doesn't match. data_size=%zu buffer_size=%zu\n",
186 data_size, buffer_size);
188 __free_on_memory_attr(attr);
191 attr->value = malloc(data_size);
192 memcpy(attr->value, buffer + *offset, data_size);
193 *offset += data_size;
198 int __write_to_file(FILE *file, const char *name, const char *value, const size_t value_size)
200 const u_int16_t name_size = (int) strlen(name) + 1;
203 char *sanitized_value = sanitize_value(value, value_size);
204 debug_print("name='%s' name_size=%hu sanitized_value='%s' value_size=%zu\n", name, name_size, sanitized_value, value_size);
205 free(sanitized_value);
209 if (fwrite(&name_size, sizeof(u_int16_t), 1, file) != 1) {
212 if (fwrite(name, name_size, 1, file) != 1) {
217 if (fwrite(&value_size, sizeof(size_t), 1, file) != 1) {
220 // write value content only if we have something to write.
221 if (value_size > 0) {
222 if (fwrite(value, value_size, 1, file) != 1) {
232 * @param path - path to file.
233 * @param name - attribute name. string null terminated. size <= XATTR_NAME_MAX bytes
234 * @param value - attribute value. size < XATTR_SIZE_MAX
236 * @param flags - XATTR_CREATE and/or XATTR_REPLACE
237 * @return On success, zero is returned. On failure, -errno is returned.
239 int binary_storage_write_key(const char *path, const char *name, const char *value, size_t size, int flags)
242 char *sanitized_value = sanitize_value(value, size);
243 debug_print("path=%s name=%s sanitized_value=%s size=%zu flags=%d\n", path, name, sanitized_value, size, flags);
244 free(sanitized_value);
248 char *buffer = __read_file_sidecar(path, &buffer_size);
250 if (buffer == NULL && buffer_size == -ENOENT && flags & XATTR_REPLACE) {
251 error_print("No xattr. (flag XATTR_REPLACE)");
255 if (buffer == NULL && buffer_size != -ENOENT) {
260 char *sidecar_path = get_sidecar_path(path);
261 FILE *file = fopen(sidecar_path, "w");
264 if (buffer == NULL) {
265 debug_print("new file, writing directly...\n");
266 status = __write_to_file(file, name, value, size);
272 assert(buffer_size >= 0);
273 size_t _buffer_size = (size_t)buffer_size;
277 size_t name_len = strlen(name) + 1; // null byte
279 while(offset < _buffer_size)
281 debug_print("replaced=%d offset=%zu buffer_size=%zu\n", replaced, offset, _buffer_size);
282 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
284 // FIXME: handle attr == NULL
285 assert(attr != NULL);
287 if (memcmp(attr->name, name, name_len) == 0) {
288 assert(replaced == 0);
289 if (flags & XATTR_CREATE) {
290 error_print("Key already exists. (flag XATTR_CREATE)");
291 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
295 status = __write_to_file(file, name, value, size);
300 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
303 __free_on_memory_attr(attr);
306 if (replaced == 0 && res == 0) {
307 if (flags & XATTR_REPLACE) {
308 error_print("Key doesn't exists. (flag XATTR_REPLACE)");
311 status = __write_to_file(file, name, value, size);
321 int binary_storage_read_key(const char *path, const char *name, char *value, size_t size)
324 char *buffer = __read_file_sidecar(path, &buffer_size);
326 if (buffer == NULL) {
327 if (buffer_size == -ENOENT) {
332 assert(buffer_size >= 0);
333 size_t _buffer_size = (size_t)buffer_size;
336 memset(value, '\0', size);
339 size_t name_len = strlen(name) + 1; // null byte \0
341 while(offset < _buffer_size)
343 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
349 if (__cmp_name(name, name_len, attr) == 1) {
350 int value_size = (int)attr->value_size;
354 } else if (attr->value_size <= size) {
355 memcpy(value, attr->value, attr->value_size);
358 error_print("error, attr->value_size=%zu > size=%zu\n", attr->value_size, size);
362 __free_on_memory_attr(attr);
365 __free_on_memory_attr(attr);
372 int binary_storage_list_keys(const char *path, char *list, size_t size)
375 char *buffer = __read_file_sidecar(path, &buffer_size);
377 if (buffer == NULL) {
378 debug_print("buffer == NULL buffer_size=%d\n", buffer_size);
379 if (buffer_size == -ENOENT) {
385 assert(buffer_size > 0);
386 size_t _buffer_size = (size_t)buffer_size;
389 memset(list, '\0', size);
394 while(offset < _buffer_size)
396 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
403 if (attr->name_size + res > size) {
404 error_print("Not enough memory allocated. allocated=%zu required=%ld\n",
405 size, attr->name_size + res);
406 __free_on_memory_attr(attr);
410 memcpy(list + res, attr->name, attr->name_size);
411 res += attr->name_size;
414 res += attr->name_size;
416 __free_on_memory_attr(attr);
420 if (size == 0 && res > XATTR_LIST_MAX) {
421 // FIXME: we should return the size or an error ?
428 int binary_storage_remove_key(const char *path, const char *name)
430 debug_print("path=%s name=%s\n", path, name);
432 char *buffer = __read_file_sidecar(path, &buffer_size);
434 if (buffer == NULL) {
437 assert(buffer_size > 0);
438 size_t _buffer_size = (size_t) buffer_size;
440 char *sidecar_path = get_sidecar_path(path);
441 FILE *file = fopen(sidecar_path, "w");
445 size_t name_len = strlen(name) + 1; // null byte \0
448 while(offset < _buffer_size)
450 debug_print("removed=%d offset=%zu buffer_size=%zu\n", removed, offset, _buffer_size);
452 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
454 error_print("error reading file. corrupted ?");
458 if (memcmp(attr->name, name, name_len) == 0) {
461 int status = __write_to_file(file, attr->name, attr->value, attr->value_size);
464 __free_on_memory_attr(attr);
469 debug_print("key removed successfully.\n");
470 } else if (removed == 0) {
471 error_print("key not found.\n");
474 debug_print("removed %d keys (was duplicated)\n", removed);