Do not close tables on each query.
[adu.git] / user.c
1 /*
2 * Copyright (C) 2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file user.c uid User and user ID handling. */
8
9 #include "adu.h"
10 #include <dirent.h> /* readdir() */
11 #include <sys/types.h>
12 #include <pwd.h>
13 #include "cmdline.h" /* TODO: This file should be independent of command line options */
14 #include "user.h"
15 #include "fd.h"
16 #include "string.h"
17 #include "error.h"
18
19 /**
20 * Describes one range of admissible user IDs.
21 *
22 * adu converts the admissible user ids given at the command line
23 * into an array of such structs.
24 */
25 struct uid_range {
26 /** Lowest admissible user ID. */
27 uint32_t low;
28 /** Greatest admissible user ID. */
29 uint32_t high;
30 };
31
32 #define FOR_EACH_UID_RANGE(ur, urs) for (ur = urs; ur->low <= ur->high; ur++)
33
34 /** Flags for the user hash table. */
35 enum uid_info_flags {
36 /** Whether this slot of the hash table is used. */
37 UI_FL_SLOT_USED = 1,
38 /** Whether this uid should be taken into account. */
39 UI_FL_ADMISSIBLE = 2,
40 };
41 /*
42 * Contains info for each user that owns at least one regular file.
43 *
44 * Even users that are not taken into account because of the --uid
45 * option occupy a slot in this hash table. This allows to find out
46 * quicky whether a uid is admissible. And yes, this has to be fast.
47 */
48 static struct user_info *uid_hash_table;
49
50 /** This is always a power of two. It is set in create_hash_table(). */
51 static uint32_t uid_hash_table_size;
52
53 /** The number of used slots in the hash table. */
54 static uint32_t num_uids = 0;
55
56 /*
57 * The columns of the per-user tables.
58 *
59 * Adu tracks disk usage on a per-user basis. For each user, a user table is
60 * being created. The rows of the user table have three columns: The directory
61 * number that may be resolved to the path using the directory table, the
62 * number of bytes and the number of files in that directory owned by the given
63 * user.
64 */
65 static struct osl_column_description user_table_cols[] = {
66 [UT_DIR_NUM] = {
67 .storage_type = OSL_MAPPED_STORAGE,
68 .storage_flags = OSL_RBTREE | OSL_FIXED_SIZE | OSL_UNIQUE,
69 .name = "dir_num",
70 .compare_function = uint64_compare,
71 .data_size = sizeof(uint64_t)
72 },
73 [UT_BYTES] = {
74 .storage_type = OSL_MAPPED_STORAGE,
75 .storage_flags = OSL_RBTREE | OSL_FIXED_SIZE,
76 .compare_function = size_compare,
77 .name = "num_bytes",
78 .data_size = sizeof(uint64_t)
79 },
80 [UT_FILES] = {
81 .storage_type = OSL_MAPPED_STORAGE,
82 .storage_flags = OSL_RBTREE | OSL_FIXED_SIZE,
83 .compare_function = size_compare,
84 .name = "num_files",
85 .data_size = sizeof(uint64_t)
86 },
87 };
88
89 static int check_uid_arg(const char *arg, uint32_t *uid)
90 {
91 const uint32_t max = ~0U;
92 /*
93 * we need an 64-bit int for string -> uid conversion because strtoll()
94 * returns a signed value.
95 */
96 int64_t val;
97 int ret = atoi64(arg, &val);
98
99 if (ret < 0)
100 return ret;
101 if (val < 0 || val > max)
102 return -ERRNO_TO_ERROR(EINVAL);
103 *uid = val;
104 return 1;
105 }
106
107 static int parse_uid_range(const char *orig_arg, struct uid_range *ur)
108 {
109 int ret;
110 char *arg = adu_strdup(orig_arg), *p = strchr(arg, '-');
111
112 if (!p || p == arg) { /* -42 or 42 */
113 ret = check_uid_arg(p? p + 1 : arg, &ur->high);
114 if (ret < 0)
115 goto out;
116 ur->low = p? 0 : ur->high;
117 ret = 1;
118 goto out;
119 }
120 /* 42- or 42-4711 */
121 *p = '\0';
122 p++;
123 ret = check_uid_arg(arg, &ur->low);
124 if (ret < 0)
125 goto out;
126 ur->high = ~0U;
127 if (*p) { /* 42-4711 */
128 ret = check_uid_arg(p, &ur->high);
129 if (ret < 0)
130 goto out;
131 }
132 if (ur->low > ur->high)
133 ret = -ERRNO_TO_ERROR(EINVAL);
134 out:
135 if (ret < 0)
136 ERROR_LOG("bad uid option: %s\n", orig_arg);
137 else
138 INFO_LOG("admissible uid range: %u - %u\n", ur->low,
139 ur->high);
140 free(arg);
141 return ret;
142 }
143
144 int parse_uid_arg(const char *orig_arg, struct uid_range **ur)
145 {
146 char *arg, **argv;
147 unsigned n;
148 int i, ret = 1;
149
150 if (!orig_arg)
151 return 0;
152 arg = adu_strdup(orig_arg);
153 n = split_args(arg, &argv, ",");
154 if (!n)
155 return -E_SYNTAX;
156 *ur = adu_malloc((n + 1) * sizeof(struct uid_range));
157 for (i = 0; i < n; i++) {
158 ret = parse_uid_range(argv[i], *ur + i);
159 if (ret < 0)
160 break;
161 }
162 free(argv);
163 free(arg);
164 if (ret < 0) {
165 free(*ur);
166 *ur = NULL;
167 return ret;
168 }
169 /* an empty range indicates the end of the list */
170 (*ur)[n].low = 1;
171 (*ur)[n].high = 0;
172 return n;
173 }
174
175 static int uid_is_admissible(uint32_t uid, struct uid_range *urs)
176 {
177 struct uid_range *ur;
178 int ret = 1;
179
180 if (!urs) /* empty array means all uids are allowed */
181 return 1;
182 FOR_EACH_UID_RANGE(ur, urs)
183 if (ur->low <= uid && ur->high >= uid)
184 goto out;
185 ret = 0;
186 out:
187 DEBUG_LOG("uid %u is %sadmissible\n", (unsigned)uid,
188 ret? "" : "not ");
189 return ret;
190 }
191
192 int append_users(char **users, int num_users,
193 struct uid_range **admissible_uids, int num_uid_ranges)
194 {
195 int i;
196 struct uid_range *au = *admissible_uids;
197
198 for (i = 0; i < num_users; i++) {
199 char *u = users[i];
200 struct uid_range *ur;
201 struct passwd *pw = getpwnam(u);
202
203 if (!pw) {
204 ERROR_LOG("user %s not found\n", u);
205 return -ERRNO_TO_ERROR(EINVAL);
206 }
207 if (au && uid_is_admissible(pw->pw_uid, au))
208 continue; /* nothing to do */
209 /* add a range consisting of this uid only */
210 num_uid_ranges++;
211 au = adu_realloc(au, (num_uid_ranges + 1) *
212 sizeof(struct uid_range));
213 *admissible_uids = au;
214 ur = au + num_uid_ranges - 1; /* the new uid range */
215 ur->low = ur->high = pw->pw_uid;
216 /* terminate the list */
217 ur++;
218 ur->low = 1;
219 ur->high = 0;
220 }
221 return num_uid_ranges;
222 }
223
224 static inline int ui_used(struct user_info *ui)
225 {
226 return ui->flags & UI_FL_SLOT_USED;
227 }
228
229 static inline int ui_admissible(struct user_info *ui)
230 {
231 return ui->flags & UI_FL_ADMISSIBLE;
232 }
233
234 static int open_user_table(struct user_info *ui, int create)
235 {
236 int ret;
237 struct passwd *pw;
238
239 ui->desc = adu_malloc(sizeof(*ui->desc));
240 ui->desc->num_columns = NUM_UT_COLUMNS;
241 ui->desc->flags = 0;
242 ui->desc->column_descriptions = user_table_cols;
243 ui->desc->dir = adu_strdup(conf.database_dir_arg);
244 ui->desc->name = make_message("%u", (unsigned)ui->uid);
245 pw = getpwuid(ui->uid);
246 if (pw && pw->pw_name)
247 ui->pw_name = adu_strdup(pw->pw_name);
248
249 INFO_LOG("opening table for uid %u\n", (unsigned)ui->uid);
250 if (create) {
251 ret = osl(osl_create_table(ui->desc));
252 if (ret < 0)
253 goto err;
254 num_uids++;
255 }
256 ret = osl(osl_open_table(ui->desc, &ui->table));
257 if (ret < 0)
258 goto err;
259 return 1;
260 err:
261 free((char *)ui->desc->name);
262 free((char *)ui->desc->dir);
263 free(ui->pw_name);
264 free(ui->desc);
265 ui->desc->name = NULL;
266 ui->desc->dir = NULL;
267 ui->desc = NULL;
268 ui->table = NULL;
269 ui->flags = 0;
270 return ret;
271 }
272
273 #define FOR_EACH_USER(ui) for (ui = uid_hash_table; ui < \
274 uid_hash_table + uid_hash_table_size; ui++)
275
276 int for_each_admissible_user(int (*func)(struct user_info *, void *),
277 void *data)
278 {
279 struct user_info *ui;
280
281 assert(uid_hash_table);
282 FOR_EACH_USER(ui) {
283 int ret;
284
285 if (!ui_used(ui) || !ui_admissible(ui))
286 continue;
287 ret = func(ui, data);
288 if (ret < 0)
289 return ret;
290 }
291 return 1;
292 }
293
294 #define PRIME1 0xb11924e1
295 #define PRIME2 0x01000193
296
297 void create_hash_table(unsigned bits)
298 {
299 uid_hash_table_size = 1 << bits;
300 uid_hash_table = adu_calloc(uid_hash_table_size *
301 sizeof(struct user_info));
302 }
303
304 void close_user_tables(void)
305 {
306 struct user_info *ui;
307
308 FOR_EACH_USER(ui) {
309 int ret;
310
311 if (!ui_used(ui))
312 continue;
313 if (!ui->table)
314 continue;
315 INFO_LOG("closing user table for uid %u\n", (unsigned)ui->uid);
316 ret = osl(osl_close_table(ui->table, OSL_MARK_CLEAN));
317 if (ret < 0)
318 ERROR_LOG("failed to close user table %u: %s\n",
319 (unsigned)ui->uid, adu_strerror(-ret));
320 free((char *)ui->desc->name);
321 ui->desc->name = NULL;
322 free((char *)ui->desc->dir);
323 ui->desc->dir = NULL;
324 free(ui->pw_name);
325 ui->pw_name = NULL;
326 free(ui->desc);
327 ui->desc = NULL;
328 ui->table = NULL;
329 ui->flags = 0;
330 }
331 free(uid_hash_table);
332 uid_hash_table = NULL;
333 }
334
335 /*
336 * We use a hash table of size s=2^uid_hash_bits to map the uids into the
337 * interval [0..s]. Hash collisions are treated by open addressing, i.e.
338 * unused slots in the table are used to store different uids that hash to the
339 * same slot.
340 *
341 * If a hash collision occurs, different slots are successively probed in order
342 * to find an unused slot for the new uid. Probing is implemented via a second
343 * hash function that maps the uid to h=(uid * PRIME2) | 1, which is always an
344 * odd number.
345 *
346 * An odd number is sufficient to make sure each entry of the hash table gets
347 * probed for probe_num between 0 and s-1 because s is a power of two, hence
348 * the second hash value has never a common divisor with the hash table size.
349 * IOW: h is invertible in the ring [0..s].
350 */
351 static uint32_t double_hash(uint32_t uid, uint32_t probe_num)
352 {
353 return (uid * PRIME1 + ((uid * PRIME2) | 1) * probe_num)
354 % uid_hash_table_size;
355 }
356
357 static struct user_info *lookup_uid(uint32_t uid)
358 {
359 uint32_t p;
360
361 for (p = 0; p < uid_hash_table_size; p++) {
362 struct user_info *ui = uid_hash_table + double_hash(uid, p);
363 if (!ui_used(ui))
364 return ui;
365 if (ui->uid == uid)
366 return ui;
367 }
368 return NULL;
369 }
370
371 int create_user_table(uint32_t uid, struct user_info **ui_ptr)
372 {
373 struct user_info *ui = lookup_uid(uid);
374
375 if (!ui)
376 return -E_HASH_TABLE_OVERFLOW;
377 *ui_ptr = ui;
378 if (ui_used(ui))
379 return 1;
380 ui->uid = uid;
381 ui->flags |= UI_FL_SLOT_USED;
382 return open_user_table(ui, 1);
383 }
384
385 static char *get_uid_list_name(void)
386 {
387 return make_message("%s/uid_list", conf.database_dir_arg);
388 }
389
390 void sort_hash_table(int (*comp)(const void *, const void *))
391 {
392 qsort(uid_hash_table, uid_hash_table_size, sizeof(struct user_info),
393 comp);
394 }
395
396 int open_admissible_user_tables(struct uid_range *admissible_uids)
397 {
398 struct user_info *ui;
399
400 assert(uid_hash_table);
401 DEBUG_LOG("size: %d\n", uid_hash_table_size);
402 FOR_EACH_USER(ui) {
403 int ret;
404
405 if (!ui_used(ui)) {
406 continue;
407 }
408 if (!uid_is_admissible(ui->uid, admissible_uids)) {
409 DEBUG_LOG("uid %u is not admissible\n", ui->uid);
410 ui->flags &= ~UI_FL_ADMISSIBLE;
411 continue;
412 }
413 ui->flags |= UI_FL_ADMISSIBLE;
414 if (ui->table)
415 continue;
416 ret = open_user_table(ui, 0);
417 if (ret < 0)
418 return ret;
419 }
420 return 1;
421 }
422
423 int read_uid_file(void)
424 {
425 size_t size;
426 uint32_t n;
427 char *filename = get_uid_list_name(), *map;
428 int ret = mmap_full_file(filename, O_RDONLY, (void **)&map, &size, NULL);
429 unsigned bits;
430
431 if (ret < 0) {
432 ERROR_LOG("failed to map %s\n", filename);
433 free(filename);
434 return ret;
435 }
436 num_uids = size / 4;
437 INFO_LOG("found %u uids in %s\n", (unsigned)num_uids, filename);
438 free(filename);
439 /*
440 * Compute number of hash table bits. The hash table size must be a
441 * power of two and larger than the number of uids.
442 */
443 bits = 2;
444 while (1 << bits < num_uids)
445 bits++;
446 create_hash_table(bits);
447 for (n = 0; n < num_uids; n++) {
448 uint32_t uid = read_u32(map + n * sizeof(uid));
449 struct user_info *ui = lookup_uid(uid);
450 assert(ui);
451 if (ui_used(ui)) { /* impossible */
452 ERROR_LOG("duplicate user id!?\n");
453 ret = -EFAULT;
454 goto out;
455 }
456 ui->uid = uid;
457 ui->flags |= UI_FL_SLOT_USED;
458 }
459 ret = 1;
460 out:
461 adu_munmap(map, size);
462 return ret;
463 }
464
465 int write_uid_file(void)
466 {
467 char *buf, *p, *filename;
468 size_t size = num_uids * sizeof(uint32_t);
469 int ret;
470 struct user_info *ui;
471
472 if (!num_uids)
473 return 0;
474 buf = p = adu_malloc(size);
475 FOR_EACH_USER(ui) {
476 if (!ui_used(ui))
477 continue;
478 write_u32(p, ui->uid);
479 p += sizeof(uint32_t);
480 }
481 filename = get_uid_list_name();
482 ret = adu_write_file(filename, buf, size);
483 free(filename);
484 free(buf);
485 return ret;
486 }