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834978fd DG |
1 | /* |
2 | * Copyright (C) 2014 - David Goulet <dgoulet@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License, version 2 only, as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
15 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
18 | #define _GNU_SOURCE | |
19 | #include <common/bitfield.h> | |
20 | #include <common/common.h> | |
21 | #include <common/kernel-ctl/kernel-ctl.h> | |
22 | ||
23 | #include "lttng-sessiond.h" | |
24 | #include "kernel.h" | |
25 | #include "syscall.h" | |
26 | #include "utils.h" | |
27 | ||
28 | /* Global syscall table. */ | |
29 | struct syscall *syscall_table; | |
30 | ||
31 | /* Number of entry in the syscall table. */ | |
32 | static size_t syscall_table_nb_entry; | |
33 | ||
34 | /* | |
35 | * Populate the system call table using the kernel tracer. | |
36 | * | |
37 | * Return 0 on success and the syscall table is allocated. On error, a negative | |
1f47715a | 38 | * value is returned. |
834978fd DG |
39 | */ |
40 | int syscall_init_table(void) | |
41 | { | |
42 | int ret, fd, err; | |
43 | size_t nbmem; | |
44 | FILE *fp; | |
45 | /* Syscall data from the kernel. */ | |
46 | size_t index; | |
47 | uint32_t bitness; | |
48 | char name[SYSCALL_NAME_LEN]; | |
49 | ||
50 | DBG3("Syscall init system call table"); | |
51 | ||
52 | fd = kernctl_syscall_list(kernel_tracer_fd); | |
53 | if (fd < 0) { | |
54 | ret = -errno; | |
55 | PERROR("kernelctl syscall list"); | |
56 | goto error_ioctl; | |
57 | } | |
58 | ||
59 | fp = fdopen(fd, "r"); | |
60 | if (!fp) { | |
61 | ret = -errno; | |
62 | PERROR("syscall list fdopen"); | |
63 | goto error_fp; | |
64 | } | |
65 | ||
66 | nbmem = SYSCALL_TABLE_INIT_SIZE; | |
67 | syscall_table = zmalloc(sizeof(struct syscall) * nbmem); | |
68 | if (!syscall_table) { | |
69 | ret = -errno; | |
70 | PERROR("syscall list zmalloc"); | |
71 | goto error; | |
72 | } | |
73 | ||
74 | while (fscanf(fp, | |
75 | "syscall { index = %lu; \ | |
76 | name = %" XSTR(SYSCALL_NAME_LEN) "[^;]; \ | |
77 | bitness = %u; };\n", | |
78 | &index, name, &bitness) == 3) { | |
79 | if (index >= nbmem ) { | |
80 | struct syscall *new_list; | |
81 | size_t new_nbmem; | |
82 | ||
83 | /* Double memory size. */ | |
4b47b6a9 | 84 | new_nbmem = max(index, nbmem << 1); |
1f47715a DG |
85 | if (new_nbmem < nbmem) { |
86 | /* Overflow, stop everything, something went really wrong. */ | |
87 | ERR("Syscall listing memory size overflow. Stopping"); | |
88 | free(syscall_table); | |
89 | syscall_table = NULL; | |
90 | ret = -EINVAL; | |
91 | goto error; | |
92 | } | |
834978fd DG |
93 | |
94 | DBG("Reallocating syscall table from %zu to %zu entries", nbmem, | |
95 | new_nbmem); | |
96 | new_list = realloc(syscall_table, new_nbmem * sizeof(*new_list)); | |
97 | if (!new_list) { | |
98 | ret = -errno; | |
99 | PERROR("syscall list realloc"); | |
100 | goto error; | |
101 | } | |
102 | ||
103 | /* Zero out the new memory. */ | |
104 | memset(new_list + nbmem, 0, | |
105 | (new_nbmem - nbmem) * sizeof(*new_list)); | |
106 | nbmem = new_nbmem; | |
107 | syscall_table = new_list; | |
108 | } | |
109 | syscall_table[index].index = index; | |
110 | syscall_table[index].bitness = bitness; | |
111 | strncpy(syscall_table[index].name, name, | |
112 | sizeof(syscall_table[index].name)); | |
113 | /* | |
114 | DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", | |
115 | syscall_table[index].name, | |
116 | syscall_table[index].index, | |
117 | syscall_table[index].bitness); | |
118 | */ | |
119 | } | |
120 | ||
121 | syscall_table_nb_entry = index; | |
122 | ||
123 | ret = 0; | |
124 | ||
125 | error: | |
126 | err = fclose(fp); | |
127 | if (err) { | |
128 | PERROR("syscall list fclose"); | |
129 | } | |
130 | return ret; | |
131 | ||
132 | error_fp: | |
133 | err = close(fd); | |
134 | if (err) { | |
135 | PERROR("syscall list close"); | |
136 | } | |
137 | ||
138 | error_ioctl: | |
139 | return ret; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Helper function for the list syscalls command that empty the temporary | |
144 | * syscall hashtable used to track duplicate between 32 and 64 bit arch. | |
145 | * | |
146 | * This empty the hash table and destroys it after. After this, the pointer is | |
147 | * unsuable. RCU read side lock MUST be acquired before calling this. | |
148 | */ | |
149 | static void destroy_syscall_ht(struct lttng_ht *ht) | |
150 | { | |
151 | struct lttng_ht_iter iter; | |
152 | struct syscall *ksyscall; | |
153 | ||
154 | DBG3("Destroying syscall hash table."); | |
155 | ||
156 | if (!ht) { | |
157 | return; | |
158 | } | |
159 | ||
160 | cds_lfht_for_each_entry(ht->ht, &iter.iter, ksyscall, node.node) { | |
161 | int ret; | |
162 | ||
163 | ret = lttng_ht_del(ht, &iter); | |
164 | assert(!ret); | |
165 | free(ksyscall); | |
166 | } | |
167 | ht_cleanup_push(ht); | |
168 | } | |
169 | ||
170 | /* | |
171 | * Allocate the given hashtable pointer. | |
172 | * | |
173 | * Return 0 on success else a negative LTTNG error value. | |
174 | */ | |
175 | static int init_syscall_ht(struct lttng_ht **ht) | |
176 | { | |
177 | int ret; | |
178 | ||
179 | *ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING); | |
180 | if (!*ht) { | |
181 | ret = -LTTNG_ERR_NOMEM; | |
182 | } else { | |
183 | ret = 0; | |
184 | } | |
185 | ||
186 | return ret; | |
187 | } | |
188 | ||
189 | /* | |
190 | * Lookup a syscall in the given hash table by name. | |
191 | * | |
192 | * Return syscall object if found or else NULL. | |
193 | */ | |
194 | static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name) | |
195 | { | |
196 | struct lttng_ht_node_str *node; | |
197 | struct lttng_ht_iter iter; | |
198 | struct syscall *ksyscall = NULL; | |
199 | ||
200 | assert(ht); | |
201 | assert(name); | |
202 | ||
203 | lttng_ht_lookup(ht, (void *) name, &iter); | |
204 | node = lttng_ht_iter_get_node_str(&iter); | |
205 | if (node) { | |
206 | ksyscall = caa_container_of(node, struct syscall, node); | |
207 | } | |
208 | ||
209 | return ksyscall; | |
210 | } | |
211 | ||
212 | /* | |
213 | * Using the given syscall object in the events array with the bitness of the | |
214 | * syscall at index in the syscall table. | |
215 | */ | |
216 | static void update_event_syscall_bitness(struct lttng_event *events, | |
217 | unsigned int index, unsigned int syscall_index) | |
218 | { | |
219 | assert(events); | |
220 | ||
221 | if (syscall_table[index].bitness == 32) { | |
222 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_32; | |
223 | } else { | |
224 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_64; | |
225 | } | |
226 | } | |
227 | ||
228 | /* | |
229 | * Allocate and initialize syscall object and add it to the given hashtable. | |
230 | * | |
231 | * Return 0 on success else -LTTNG_ERR_NOMEM. | |
232 | */ | |
233 | static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, | |
234 | unsigned int syscall_index) | |
235 | { | |
236 | int ret; | |
237 | struct syscall *ksyscall; | |
238 | ||
239 | assert(ht); | |
240 | ||
241 | ksyscall = zmalloc(sizeof(*ksyscall)); | |
242 | if (!ksyscall) { | |
243 | ret = -LTTNG_ERR_NOMEM; | |
244 | goto error; | |
245 | } | |
246 | ||
247 | strncpy(ksyscall->name, syscall_table[index].name, | |
248 | sizeof(ksyscall->name)); | |
249 | ksyscall->bitness = syscall_table[index].bitness; | |
250 | ksyscall->index = syscall_index; | |
251 | lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); | |
252 | lttng_ht_add_unique_str(ht, &ksyscall->node); | |
253 | ret = 0; | |
254 | ||
255 | error: | |
256 | return ret; | |
257 | } | |
258 | ||
259 | /* | |
260 | * List syscalls present in the kernel syscall global array, allocate and | |
261 | * populate the events structure with them. Skip the empty syscall name. | |
262 | * | |
263 | * Return the number of entries in the array else a negative value. | |
264 | */ | |
265 | ssize_t syscall_table_list(struct lttng_event **_events) | |
266 | { | |
267 | int i, index = 0; | |
268 | ssize_t ret; | |
269 | struct lttng_event *events; | |
270 | /* Hash table used to filter duplicate out. */ | |
271 | struct lttng_ht *syscalls_ht = NULL; | |
272 | ||
273 | assert(_events); | |
274 | ||
275 | DBG("Syscall table listing."); | |
276 | ||
277 | rcu_read_lock(); | |
278 | ||
279 | /* | |
280 | * Allocate at least the number of total syscall we have even if some of | |
281 | * them might not be valid. The count below will make sure to return the | |
282 | * right size of the events array. | |
283 | */ | |
284 | events = zmalloc(syscall_table_nb_entry * sizeof(*events)); | |
285 | if (!events) { | |
286 | PERROR("syscall table list zmalloc"); | |
287 | ret = -LTTNG_ERR_NOMEM; | |
288 | goto error; | |
289 | } | |
290 | ||
291 | ret = init_syscall_ht(&syscalls_ht); | |
292 | if (ret < 0) { | |
293 | goto error; | |
294 | } | |
295 | ||
296 | for (i = 0; i < syscall_table_nb_entry; i++) { | |
297 | struct syscall *ksyscall; | |
298 | ||
299 | /* Skip empty syscalls. */ | |
300 | if (*syscall_table[i].name == '\0') { | |
301 | continue; | |
302 | } | |
303 | ||
304 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
305 | if (ksyscall) { | |
306 | update_event_syscall_bitness(events, i, ksyscall->index); | |
307 | continue; | |
308 | } | |
309 | ||
310 | ret = add_syscall_to_ht(syscalls_ht, i, index); | |
311 | if (ret < 0) { | |
312 | goto error; | |
313 | } | |
314 | ||
315 | /* Copy the event information in the event's array. */ | |
316 | strncpy(events[index].name, syscall_table[i].name, | |
317 | sizeof(events[index].name)); | |
318 | update_event_syscall_bitness(events, i, index); | |
319 | events[index].type = LTTNG_EVENT_SYSCALL; | |
320 | /* This makes the command line not print the enabled/disabled field. */ | |
321 | events[index].enabled = -1; | |
322 | index++; | |
323 | } | |
324 | ||
325 | destroy_syscall_ht(syscalls_ht); | |
326 | *_events = events; | |
327 | rcu_read_unlock(); | |
328 | return index; | |
329 | ||
330 | error: | |
331 | destroy_syscall_ht(syscalls_ht); | |
332 | free(events); | |
333 | rcu_read_unlock(); | |
334 | return ret; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Add enabled syscall to the events list using the given kernel channel. | |
339 | * | |
340 | * Return the number of entry of the events array that is different from size | |
341 | * if the array grows. On error, return negative value and events is untouched. | |
342 | */ | |
343 | ssize_t syscall_list_channel(struct ltt_kernel_channel *kchan, | |
344 | struct lttng_event **_events, size_t size) | |
345 | { | |
346 | int err, i; | |
347 | size_t new_size; | |
348 | ssize_t ret, count; | |
349 | char *mask = NULL; | |
350 | uint32_t len; | |
351 | struct lttng_event *events = NULL; | |
352 | /* Hash table used to filter duplicate out. */ | |
353 | struct lttng_ht *syscalls_ht = NULL; | |
354 | ||
355 | assert(kchan); | |
356 | ||
357 | /* Get syscall mask from the kernel tracer. */ | |
358 | err = kernel_syscall_mask(kchan->fd, &mask, &len); | |
359 | if (err < 0) { | |
360 | ret = err; | |
361 | goto error; | |
362 | } | |
363 | ||
364 | ret = init_syscall_ht(&syscalls_ht); | |
365 | if (ret < 0) { | |
366 | goto error; | |
367 | } | |
368 | ||
369 | count = new_size = size; | |
370 | events = *_events; | |
371 | ||
372 | for (i = 0; i < len; i++) { | |
373 | unsigned char val; | |
374 | struct syscall *ksyscall; | |
375 | ||
376 | bitfield_read_be(mask, unsigned char, i, 1, &val); | |
377 | if (!val) { | |
378 | /* Syscall is disabled, continue the loop. */ | |
379 | continue; | |
380 | } | |
381 | ||
382 | /* Skip empty syscall. */ | |
383 | if (*syscall_table[i].name == '\0') { | |
384 | continue; | |
385 | } | |
386 | ||
387 | /* Syscall is enabled thus add it to the events list. */ | |
388 | ||
389 | if (count >= new_size) { | |
390 | struct lttng_event *new_events; | |
391 | ||
392 | /* Get the maximum here since count can be 0. */ | |
393 | new_size = max(count << 1, 1); | |
394 | DBG3("Listing syscall realloc events array from %zu to %zu", count, | |
395 | new_size); | |
396 | new_events = realloc(events, new_size * sizeof(*new_events)); | |
397 | if (!new_events) { | |
398 | PERROR("realloc kernel events list"); | |
399 | ret = -ENOMEM; | |
400 | goto error; | |
401 | } | |
402 | memset(new_events + count, 0, | |
403 | (new_size - count) * sizeof(*new_events)); | |
404 | events = new_events; | |
405 | } | |
406 | ||
407 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
408 | if (ksyscall) { | |
409 | update_event_syscall_bitness(events, i, ksyscall->index); | |
410 | continue; | |
411 | } | |
412 | ||
413 | ret = add_syscall_to_ht(syscalls_ht, i, count); | |
414 | if (ret < 0) { | |
415 | goto error; | |
416 | } | |
417 | ||
418 | update_event_syscall_bitness(events, i, count); | |
419 | strncpy(events[count].name, syscall_table[i].name, | |
420 | sizeof(events[count].name)); | |
421 | events[count].enabled = 1; | |
422 | events[count].type = LTTNG_KERNEL_SYSCALL; | |
423 | count++; | |
424 | } | |
425 | ||
426 | *_events = events; | |
427 | ||
428 | return count; | |
429 | ||
430 | error: | |
431 | destroy_syscall_ht(syscalls_ht); | |
432 | free(events); | |
433 | return ret; | |
434 | } |