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 <attr/xattr.h>
22 struct on_memory_attr {
30 void __print_on_memory_attr(struct on_memory_attr *attr)
33 char *sanitized_value = sanitize_value(attr->value, attr->value_size);
34 debug_print("--------------\n");
35 debug_print("name size: %hu\n", attr->name_size);
36 debug_print("name: '%s'\n", attr->name);
37 debug_print("value size: %zu\n", attr->value_size);
38 debug_print("sanitized_value: '%s'\n", sanitized_value);
39 debug_print("--------------\n");
40 free(sanitized_value);
44 void __free_on_memory_attr(struct on_memory_attr *attr)
51 char *__read_file(const char *path, int *buffer_size)
53 FILE *file = fopen(path, "r");
57 debug_print("file not found: %s\n", path);
58 *buffer_size = -ENOENT;
62 debug_print("file found, reading it: %s\n", path);
64 fseek(file, 0, SEEK_END);
65 *buffer_size = (int)ftell(file);
67 if (*buffer_size == -1) {
68 error_print("error: path: %s, size: %d, errno=%d\n", path, *buffer_size, errno);
74 if (*buffer_size > MAX_METADATA_SIZE) {
75 error_print("metadata file too big. path: %s, size: %d\n", path, *buffer_size);
76 *buffer_size = -ENOSPC;
81 if (*buffer_size == 0) {
82 debug_print("empty file.\n");
83 *buffer_size = -ENOENT;
87 assert(*buffer_size > 0);
88 size_t _buffer_size = (size_t) *buffer_size;
90 fseek(file, 0, SEEK_SET);
91 buffer = malloc(_buffer_size);
93 *buffer_size = -ENOMEM;
94 error_print("cannot allocate memory.\n");
99 memset(buffer, '\0', _buffer_size);
100 fread(buffer, 1, _buffer_size, file);
106 char *__read_file_sidecar(const char *path, int *buffer_size)
108 char *sidecar_path = get_sidecar_path(path);
109 debug_print("path=%s sidecar_path=%s\n", path, sidecar_path);
111 char *buffer = __read_file(sidecar_path, buffer_size);
116 int __cmp_name(const char *name, size_t name_length, struct on_memory_attr *attr)
118 if (attr->name_size == name_length && memcmp(attr->name, name, name_length) == 0) {
119 debug_print("match: name=%s, name_length=%zu\n", name, name_length);
120 __print_on_memory_attr(attr);
124 debug_print("doesn't match: name=%s, name_length=%zu\n", name, name_length);
125 __print_on_memory_attr(attr);
130 struct on_memory_attr *__read_on_memory_attr(size_t *offset, char *buffer, size_t buffer_size)
132 debug_print("offset=%zu\n", *offset);
133 struct on_memory_attr *attr = malloc(sizeof(struct on_memory_attr));
135 ////////////////////////////////
137 size_t data_size = sizeof(u_int16_t);
138 if (*offset + data_size > buffer_size) {
139 error_print("Error, sizes doesn't match.\n");
140 __free_on_memory_attr(attr);
143 memcpy(&attr->name_size, buffer + *offset, data_size);
144 *offset += data_size;
145 debug_print("attr->name_size=%hu\n", attr->name_size);
147 ////////////////////////////////
149 data_size = attr->name_size;
150 if (*offset + data_size > buffer_size) {
151 error_print("Error, sizes doesn't match.\n");
152 __free_on_memory_attr(attr);
155 attr->name = malloc(data_size);
156 memcpy(attr->name, buffer + *offset, data_size);
157 *offset += data_size;
159 ////////////////////////////////
161 data_size = sizeof(size_t);
162 if (*offset + data_size > buffer_size) {
163 error_print("Error, sizes doesn't match.\n");
164 __free_on_memory_attr(attr);
167 memcpy(&attr->value_size, buffer + *offset, data_size);
168 *offset += data_size;
169 debug_print("attr->value_size=%zu\n", attr->value_size);
171 ////////////////////////////////
173 data_size = attr->value_size;
174 if (*offset + data_size > buffer_size) {
175 error_print("Error, sizes doesn't match. data_size=%zu buffer_size=%zu\n",
176 data_size, buffer_size);
178 __free_on_memory_attr(attr);
181 attr->value = malloc(data_size);
182 memcpy(attr->value, buffer + *offset, data_size);
183 *offset += data_size;
188 int __write_to_file(FILE *file, const char *name, const char *value, const size_t value_size)
190 const u_int16_t name_size = (int) strlen(name) + 1;
193 char *sanitized_value = sanitize_value(value, value_size);
194 debug_print("name=%s sanitized_value=%s value_size=%zu\n", name, sanitized_value, value_size);
195 free(sanitized_value);
199 if (fwrite(&name_size, sizeof(u_int16_t), 1, file) != 1) {
202 if (fwrite(name, name_size, 1, file) != 1) {
207 if (fwrite(&value_size, sizeof(size_t), 1, file) != 1) {
210 if (fwrite(value, value_size, 1, file) != 1) {
219 * @param path - path to file.
220 * @param name - attribute name. string null terminated. size <= XATTR_NAME_MAX bytes
221 * @param value - attribute value. size < XATTR_SIZE_MAX
223 * @param flags - XATTR_CREATE and/or XATTR_REPLACE
224 * @return On success, zero is returned. On failure, -errno is returnted.
226 int binary_storage_write_key(const char *path, const char *name, const char *value, size_t size, int flags)
229 char *sanitized_value = sanitize_value(value, size);
230 debug_print("path=%s name=%s sanitized_value=%s size=%zu flags=%d\n", path, name, sanitized_value, size, flags);
231 free(sanitized_value);
235 char *buffer = __read_file_sidecar(path, &buffer_size);
237 if (buffer == NULL && buffer_size == -ENOENT && flags & XATTR_REPLACE) {
238 error_print("No xattr. (flag XATTR_REPLACE)");
242 if (buffer == NULL && buffer_size != -ENOENT) {
247 char *sidecar_path = get_sidecar_path(path);
248 FILE *file = fopen(sidecar_path, "w");
251 if (buffer == NULL) {
252 debug_print("new file, writing directly...\n");
253 status = __write_to_file(file, name, value, size);
259 assert(buffer_size >= 0);
260 size_t _buffer_size = (size_t)buffer_size;
264 size_t name_len = strlen(name) + 1; // null byte
266 while(offset < _buffer_size)
268 debug_print("replaced=%d offset=%zu buffer_size=%zu\n", replaced, offset, _buffer_size);
269 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
271 // FIXME: handle attr == NULL
272 assert(attr != NULL);
274 if (memcmp(attr->name, name, name_len) == 0) {
275 assert(replaced == 0);
276 if (flags & XATTR_CREATE) {
277 error_print("Key already exists. (flag XATTR_CREATE)");
278 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
282 status = __write_to_file(file, name, value, size);
287 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
290 __free_on_memory_attr(attr);
293 if (replaced == 0 && res == 0) {
294 if (flags & XATTR_REPLACE) {
295 error_print("Key doesn't exists. (flag XATTR_REPLACE)");
298 status = __write_to_file(file, name, value, size);
308 int binary_storage_read_key(const char *path, const char *name, char *value, size_t size)
311 char *buffer = __read_file_sidecar(path, &buffer_size);
313 if (buffer == NULL) {
314 if (buffer_size == -ENOENT) {
319 assert(buffer_size >= 0);
320 size_t _buffer_size = (size_t)buffer_size;
323 memset(value, '\0', size);
326 size_t name_len = strlen(name) + 1; // null byte \0
328 while(offset < _buffer_size)
330 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
336 if (__cmp_name(name, name_len, attr) == 1) {
337 int value_size = (int)attr->value_size;
341 } else if (attr->value_size <= size) {
342 memcpy(value, attr->value, attr->value_size);
345 error_print("error, attr->value_size=%zu > size=%zu\n", attr->value_size, size);
349 __free_on_memory_attr(attr);
352 __free_on_memory_attr(attr);
359 int binary_storage_list_keys(const char *path, char *list, size_t size)
362 char *buffer = __read_file_sidecar(path, &buffer_size);
364 if (buffer == NULL) {
365 debug_print("buffer == NULL buffer_size=%d\n", buffer_size);
366 if (buffer_size == -ENOENT) {
372 assert(buffer_size > 0);
373 size_t _buffer_size = (size_t)buffer_size;
376 memset(list, '\0', size);
381 while(offset < _buffer_size)
383 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
390 if (attr->name_size + res > size) {
391 error_print("Not enough memory allocated. allocated=%zu required=%ld\n",
392 size, attr->name_size + res);
393 __free_on_memory_attr(attr);
397 memcpy(list + res, attr->name, attr->name_size);
398 res += attr->name_size;
401 res += attr->name_size;
403 __free_on_memory_attr(attr);
407 if (size == 0 && res > XATTR_LIST_MAX) {
408 // FIXME: we should return the size or an error ?
415 int binary_storage_remove_key(const char *path, const char *name)
417 debug_print("path=%s name=%s\n", path, name);
419 char *buffer = __read_file_sidecar(path, &buffer_size);
421 if (buffer == NULL) {
424 assert(buffer_size > 0);
425 size_t _buffer_size = (size_t) buffer_size;
427 char *sidecar_path = get_sidecar_path(path);
428 FILE *file = fopen(sidecar_path, "w");
432 size_t name_len = strlen(name) + 1; // null byte \0
435 while(offset < _buffer_size)
437 debug_print("removed=%d offset=%zu buffer_size=%zu\n", removed, offset, _buffer_size);
439 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
441 error_print("error reading file. corrupted ?");
445 if (memcmp(attr->name, name, name_len) == 0) {
448 int status = __write_to_file(file, attr->name, attr->value, attr->value_size);
451 __free_on_memory_attr(attr);
456 debug_print("key removed successfully.\n");
457 } else if (removed == 0) {
458 error_print("key not found.\n");
461 debug_print("removed %d keys (was duplicated)\n", removed);