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.
17 #include <sys/types.h>
19 #include "binary_storage.h"
21 #include "fuse_xattrs_config.h"
22 #include "stringmem.h"
24 #include <sys/xattr.h>
27 #define ENOATTR ENODATA
30 struct on_memory_attr {
38 void __print_on_memory_attr(struct on_memory_attr *attr)
41 char *sanitized_value = sanitize_value(attr->value, attr->value_size);
42 debug_print("--------------\n");
43 debug_print("name size: %hu\n", attr->name_size);
44 debug_print("name: '%s'\n", attr->name);
45 debug_print("value size: %zu\n", attr->value_size);
46 debug_print("sanitized_value: '%s'\n", sanitized_value);
47 debug_print("--------------\n");
48 strfree(sanitized_value);
52 void __free_on_memory_attr(struct on_memory_attr *attr)
54 if(attr->name != NULL)
57 if(attr->value != NULL)
63 char *__read_file(const char *path, int *buffer_size)
65 FILE *file = fopen(path, "r");
69 debug_print("file not found: %s\n", path);
70 *buffer_size = -ENOENT;
74 debug_print("file found, reading it: %s\n", path);
76 fseek(file, 0, SEEK_END);
77 *buffer_size = (int)ftell(file);
79 if (*buffer_size == -1) {
80 error_print("error: path: %s, size: %d, errno=%d\n", path, *buffer_size, errno);
86 if (*buffer_size > MAX_METADATA_SIZE) {
87 error_print("metadata file too big. path: %s, size: %d\n", path, *buffer_size);
88 *buffer_size = -ENOSPC;
93 if (*buffer_size == 0) {
94 debug_print("empty file.\n");
95 *buffer_size = -ENOENT;
99 assert(*buffer_size > 0);
100 size_t _buffer_size = (size_t) *buffer_size;
102 fseek(file, 0, SEEK_SET);
103 buffer = malloc(_buffer_size);
104 if (buffer == NULL) {
105 *buffer_size = -ENOMEM;
106 error_print("cannot allocate memory.\n");
111 memset(buffer, '\0', _buffer_size);
112 fread(buffer, 1, _buffer_size, file);
118 char *__read_file_sidecar(const char *path, int *buffer_size)
120 char *sidecar_path = get_sidecar_path(path);
121 debug_print("path=%s sidecar_path=%s\n", path, sidecar_path);
123 char *buffer = __read_file(sidecar_path, buffer_size);
124 strfree (sidecar_path);
128 int __cmp_name(const char *name, size_t name_length, struct on_memory_attr *attr)
130 if (attr->name_size == name_length && memcmp(attr->name, name, name_length) == 0) {
131 debug_print("match: name=%s, name_length=%zu\n", name, name_length);
132 __print_on_memory_attr(attr);
136 debug_print("doesn't match: name=%s, name_length=%zu\n", name, name_length);
137 __print_on_memory_attr(attr);
142 struct on_memory_attr *__read_on_memory_attr(size_t *offset, char *buffer, size_t buffer_size)
144 debug_print("offset=%zu\n", *offset);
145 struct on_memory_attr *attr = malloc(sizeof(struct on_memory_attr));
149 ////////////////////////////////
151 size_t data_size = sizeof(u_int16_t);
152 if (*offset + data_size > buffer_size) {
153 error_print("Error, sizes doesn't match.\n");
154 __free_on_memory_attr(attr);
157 memcpy(&attr->name_size, buffer + *offset, data_size);
158 *offset += data_size;
159 debug_print("attr->name_size=%hu\n", attr->name_size);
161 ////////////////////////////////
163 data_size = attr->name_size;
164 if (*offset + data_size > buffer_size) {
165 error_print("Error, sizes doesn't match.\n");
166 __free_on_memory_attr(attr);
169 attr->name = malloc(data_size);
170 memcpy(attr->name, buffer + *offset, data_size);
171 *offset += data_size;
173 ////////////////////////////////
175 data_size = sizeof(size_t);
176 if (*offset + data_size > buffer_size) {
177 error_print("Error, sizes doesn't match.\n");
178 __free_on_memory_attr(attr);
181 memcpy(&attr->value_size, buffer + *offset, data_size);
182 *offset += data_size;
183 debug_print("attr->value_size=%zu\n", attr->value_size);
185 ////////////////////////////////
187 data_size = attr->value_size;
188 if (*offset + data_size > buffer_size) {
189 error_print("Error, sizes doesn't match. data_size=%zu buffer_size=%zu\n",
190 data_size, buffer_size);
192 __free_on_memory_attr(attr);
195 attr->value = malloc(data_size);
196 memcpy(attr->value, buffer + *offset, data_size);
197 *offset += data_size;
202 int __write_to_file(FILE *file, const char *name, const char *value, const size_t value_size)
204 const u_int16_t name_size = (int) strlen(name) + 1;
207 char *sanitized_value = sanitize_value(value, value_size);
208 debug_print("name='%s' name_size=%hu sanitized_value='%s' value_size=%zu\n", name, name_size, sanitized_value, value_size);
209 strfree(sanitized_value);
213 if (fwrite(&name_size, sizeof(u_int16_t), 1, file) != 1) {
216 if (fwrite(name, name_size, 1, file) != 1) {
221 if (fwrite(&value_size, sizeof(size_t), 1, file) != 1) {
224 // write value content only if we have something to write.
225 if (value_size > 0) {
226 if (fwrite(value, value_size, 1, file) != 1) {
234 static int ensure_dirs(char *path) {
235 int n = strlen( path );
236 char *p = stralloc( n+1 );
237 memcpy( p, path, n+1 );
240 while ( *e && *e != '/' ) e++;
243 if ( access( p, F_OK ) && mkdir( p, 0777 ) ) {
255 * @param path - path to file.
256 * @param name - attribute name. string null terminated. size <= XATTR_NAME_MAX bytes
257 * @param value - attribute value. size < XATTR_SIZE_MAX
259 * @param flags - XATTR_CREATE and/or XATTR_REPLACE
260 * @return On success, zero is returned. On failure, -errno is returned.
262 int binary_storage_write_key(const char *path, const char *name, const char *value, size_t size, int flags)
265 char *sanitized_value = sanitize_value(value, size);
266 debug_print("path=%s name=%s sanitized_value=%s size=%zu flags=%d\n", path, name, sanitized_value, size, flags);
267 strfree(sanitized_value);
271 char *buffer = __read_file_sidecar(path, &buffer_size);
273 if (buffer == NULL && buffer_size == -ENOENT && flags & XATTR_REPLACE) {
274 error_print("No xattr. (flag XATTR_REPLACE)");
278 if (buffer == NULL && buffer_size != -ENOENT) {
283 char *sidecar_path = get_sidecar_path(path);
285 if ( ensure_dirs( sidecar_path ) ) {
289 FILE *file = fopen(sidecar_path, "w");
290 strfree(sidecar_path);
292 if (buffer == NULL) {
293 debug_print("new file, writing directly...\n");
294 status = __write_to_file(file, name, value, size);
300 assert(buffer_size >= 0);
301 size_t _buffer_size = (size_t)buffer_size;
305 size_t name_len = strlen(name) + 1; // null byte
307 while(offset < _buffer_size)
309 debug_print("replaced=%d offset=%zu buffer_size=%zu\n", replaced, offset, _buffer_size);
310 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
312 // FIXME: handle attr == NULL
313 assert(attr != NULL);
315 if (memcmp(attr->name, name, name_len) == 0) {
316 assert(replaced == 0);
317 if (flags & XATTR_CREATE) {
318 error_print("Key already exists. (flag XATTR_CREATE)");
319 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
323 status = __write_to_file(file, name, value, size);
328 status = __write_to_file(file, attr->name, attr->value, attr->value_size);
331 __free_on_memory_attr(attr);
334 if (replaced == 0 && res == 0) {
335 if (flags & XATTR_REPLACE) {
336 error_print("Key doesn't exists. (flag XATTR_REPLACE)");
339 status = __write_to_file(file, name, value, size);
349 int binary_storage_read_key(const char *path, const char *name, char *value, size_t size)
352 char *buffer = __read_file_sidecar(path, &buffer_size);
354 if (buffer == NULL) {
355 if (buffer_size == -ENOENT) {
360 assert(buffer_size >= 0);
361 size_t _buffer_size = (size_t)buffer_size;
364 memset(value, '\0', size);
367 size_t name_len = strlen(name) + 1; // null byte \0
369 while(offset < _buffer_size)
371 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
377 if (__cmp_name(name, name_len, attr) == 1) {
378 int value_size = (int)attr->value_size;
382 } else if (attr->value_size <= size) {
383 memcpy(value, attr->value, attr->value_size);
386 error_print("error, attr->value_size=%zu > size=%zu\n", attr->value_size, size);
390 __free_on_memory_attr(attr);
393 __free_on_memory_attr(attr);
400 int binary_storage_list_keys(const char *path, char *list, size_t size)
403 char *buffer = __read_file_sidecar(path, &buffer_size);
405 if (buffer == NULL) {
406 debug_print("buffer == NULL buffer_size=%d\n", buffer_size);
407 if (buffer_size == -ENOENT) {
413 assert(buffer_size > 0);
414 size_t _buffer_size = (size_t)buffer_size;
417 memset(list, '\0', size);
422 while(offset < _buffer_size)
424 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
431 if (attr->name_size + res > size) {
432 error_print("Not enough memory allocated. allocated=%zu required=%ld\n",
433 size, attr->name_size + res);
434 __free_on_memory_attr(attr);
438 memcpy(list + res, attr->name, attr->name_size);
439 res += attr->name_size;
442 res += attr->name_size;
444 __free_on_memory_attr(attr);
448 if (size == 0 && res > XATTR_LIST_MAX) {
449 // FIXME: we should return the size or an error ?
456 int binary_storage_remove_key(const char *path, const char *name)
458 debug_print("path=%s name=%s\n", path, name);
460 char *buffer = __read_file_sidecar(path, &buffer_size);
462 if (buffer == NULL) {
465 assert(buffer_size > 0);
466 size_t _buffer_size = (size_t) buffer_size;
468 char *sidecar_path = get_sidecar_path(path);
469 FILE *file = fopen(sidecar_path, "w");
470 strfree(sidecar_path);
473 size_t name_len = strlen(name) + 1; // null byte \0
476 while(offset < _buffer_size)
478 debug_print("removed=%d offset=%zu buffer_size=%zu\n", removed, offset, _buffer_size);
480 struct on_memory_attr *attr = __read_on_memory_attr(&offset, buffer, _buffer_size);
482 error_print("error reading file. corrupted ?");
486 if (memcmp(attr->name, name, name_len) == 0) {
489 int status = __write_to_file(file, attr->name, attr->value, attr->value_size);
492 __free_on_memory_attr(attr);
497 debug_print("key removed successfully.\n");
498 } else if (removed == 0) {
499 error_print("key not found.\n");
502 debug_print("removed %d keys (was duplicated)\n", removed);