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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 | ||
6c1c0768 | 18 | #define _LGPL_SOURCE |
98123e1c JR |
19 | #include <stdbool.h> |
20 | ||
834978fd DG |
21 | #include <common/bitfield.h> |
22 | #include <common/common.h> | |
23 | #include <common/kernel-ctl/kernel-ctl.h> | |
24 | ||
25 | #include "lttng-sessiond.h" | |
26 | #include "kernel.h" | |
27 | #include "syscall.h" | |
28 | #include "utils.h" | |
29 | ||
30 | /* Global syscall table. */ | |
31 | struct syscall *syscall_table; | |
32 | ||
33 | /* Number of entry in the syscall table. */ | |
34 | static size_t syscall_table_nb_entry; | |
35 | ||
36 | /* | |
37 | * Populate the system call table using the kernel tracer. | |
38 | * | |
39 | * Return 0 on success and the syscall table is allocated. On error, a negative | |
1f47715a | 40 | * value is returned. |
834978fd DG |
41 | */ |
42 | int syscall_init_table(void) | |
43 | { | |
44 | int ret, fd, err; | |
45 | size_t nbmem; | |
46 | FILE *fp; | |
47 | /* Syscall data from the kernel. */ | |
98123e1c JR |
48 | size_t index = 0; |
49 | bool at_least_one_syscall = false; | |
834978fd DG |
50 | uint32_t bitness; |
51 | char name[SYSCALL_NAME_LEN]; | |
52 | ||
53 | DBG3("Syscall init system call table"); | |
54 | ||
55 | fd = kernctl_syscall_list(kernel_tracer_fd); | |
56 | if (fd < 0) { | |
32af2c95 | 57 | ret = fd; |
834978fd DG |
58 | PERROR("kernelctl syscall list"); |
59 | goto error_ioctl; | |
60 | } | |
61 | ||
62 | fp = fdopen(fd, "r"); | |
63 | if (!fp) { | |
64 | ret = -errno; | |
65 | PERROR("syscall list fdopen"); | |
66 | goto error_fp; | |
67 | } | |
68 | ||
69 | nbmem = SYSCALL_TABLE_INIT_SIZE; | |
70 | syscall_table = zmalloc(sizeof(struct syscall) * nbmem); | |
71 | if (!syscall_table) { | |
72 | ret = -errno; | |
73 | PERROR("syscall list zmalloc"); | |
74 | goto error; | |
75 | } | |
76 | ||
77 | while (fscanf(fp, | |
97282ce2 | 78 | "syscall { index = %zu; \ |
834978fd DG |
79 | name = %" XSTR(SYSCALL_NAME_LEN) "[^;]; \ |
80 | bitness = %u; };\n", | |
81 | &index, name, &bitness) == 3) { | |
98123e1c JR |
82 | at_least_one_syscall = true; |
83 | if (index >= nbmem) { | |
834978fd DG |
84 | struct syscall *new_list; |
85 | size_t new_nbmem; | |
86 | ||
87 | /* Double memory size. */ | |
98123e1c | 88 | new_nbmem = max(index + 1, nbmem << 1); |
ec93758c | 89 | if (new_nbmem > (SIZE_MAX / sizeof(*new_list))) { |
1f47715a DG |
90 | /* Overflow, stop everything, something went really wrong. */ |
91 | ERR("Syscall listing memory size overflow. Stopping"); | |
92 | free(syscall_table); | |
93 | syscall_table = NULL; | |
94 | ret = -EINVAL; | |
95 | goto error; | |
96 | } | |
834978fd DG |
97 | |
98 | DBG("Reallocating syscall table from %zu to %zu entries", nbmem, | |
99 | new_nbmem); | |
100 | new_list = realloc(syscall_table, new_nbmem * sizeof(*new_list)); | |
101 | if (!new_list) { | |
102 | ret = -errno; | |
103 | PERROR("syscall list realloc"); | |
104 | goto error; | |
105 | } | |
106 | ||
107 | /* Zero out the new memory. */ | |
108 | memset(new_list + nbmem, 0, | |
109 | (new_nbmem - nbmem) * sizeof(*new_list)); | |
110 | nbmem = new_nbmem; | |
111 | syscall_table = new_list; | |
112 | } | |
113 | syscall_table[index].index = index; | |
114 | syscall_table[index].bitness = bitness; | |
39e3c47a MD |
115 | if (lttng_strncpy(syscall_table[index].name, name, |
116 | sizeof(syscall_table[index].name))) { | |
117 | ret = -EINVAL; | |
118 | free(syscall_table); | |
119 | syscall_table = NULL; | |
120 | goto error; | |
121 | } | |
834978fd DG |
122 | /* |
123 | DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", | |
124 | syscall_table[index].name, | |
125 | syscall_table[index].index, | |
126 | syscall_table[index].bitness); | |
127 | */ | |
128 | } | |
129 | ||
98123e1c JR |
130 | /* Index starts at 0. */ |
131 | if (at_least_one_syscall) { | |
132 | syscall_table_nb_entry = index + 1; | |
133 | } | |
834978fd DG |
134 | |
135 | ret = 0; | |
136 | ||
137 | error: | |
138 | err = fclose(fp); | |
139 | if (err) { | |
140 | PERROR("syscall list fclose"); | |
141 | } | |
142 | return ret; | |
143 | ||
144 | error_fp: | |
145 | err = close(fd); | |
146 | if (err) { | |
147 | PERROR("syscall list close"); | |
148 | } | |
149 | ||
150 | error_ioctl: | |
151 | return ret; | |
152 | } | |
153 | ||
154 | /* | |
155 | * Helper function for the list syscalls command that empty the temporary | |
156 | * syscall hashtable used to track duplicate between 32 and 64 bit arch. | |
157 | * | |
158 | * This empty the hash table and destroys it after. After this, the pointer is | |
159 | * unsuable. RCU read side lock MUST be acquired before calling this. | |
160 | */ | |
161 | static void destroy_syscall_ht(struct lttng_ht *ht) | |
162 | { | |
163 | struct lttng_ht_iter iter; | |
164 | struct syscall *ksyscall; | |
165 | ||
166 | DBG3("Destroying syscall hash table."); | |
167 | ||
168 | if (!ht) { | |
169 | return; | |
170 | } | |
171 | ||
172 | cds_lfht_for_each_entry(ht->ht, &iter.iter, ksyscall, node.node) { | |
173 | int ret; | |
174 | ||
175 | ret = lttng_ht_del(ht, &iter); | |
176 | assert(!ret); | |
177 | free(ksyscall); | |
178 | } | |
179 | ht_cleanup_push(ht); | |
180 | } | |
181 | ||
182 | /* | |
183 | * Allocate the given hashtable pointer. | |
184 | * | |
185 | * Return 0 on success else a negative LTTNG error value. | |
186 | */ | |
187 | static int init_syscall_ht(struct lttng_ht **ht) | |
188 | { | |
189 | int ret; | |
190 | ||
191 | *ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING); | |
192 | if (!*ht) { | |
193 | ret = -LTTNG_ERR_NOMEM; | |
194 | } else { | |
195 | ret = 0; | |
196 | } | |
197 | ||
198 | return ret; | |
199 | } | |
200 | ||
201 | /* | |
202 | * Lookup a syscall in the given hash table by name. | |
203 | * | |
204 | * Return syscall object if found or else NULL. | |
205 | */ | |
206 | static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name) | |
207 | { | |
208 | struct lttng_ht_node_str *node; | |
209 | struct lttng_ht_iter iter; | |
210 | struct syscall *ksyscall = NULL; | |
211 | ||
212 | assert(ht); | |
213 | assert(name); | |
214 | ||
215 | lttng_ht_lookup(ht, (void *) name, &iter); | |
216 | node = lttng_ht_iter_get_node_str(&iter); | |
217 | if (node) { | |
218 | ksyscall = caa_container_of(node, struct syscall, node); | |
219 | } | |
220 | ||
221 | return ksyscall; | |
222 | } | |
223 | ||
224 | /* | |
225 | * Using the given syscall object in the events array with the bitness of the | |
226 | * syscall at index in the syscall table. | |
227 | */ | |
228 | static void update_event_syscall_bitness(struct lttng_event *events, | |
229 | unsigned int index, unsigned int syscall_index) | |
230 | { | |
231 | assert(events); | |
232 | ||
233 | if (syscall_table[index].bitness == 32) { | |
234 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_32; | |
235 | } else { | |
236 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_64; | |
237 | } | |
238 | } | |
239 | ||
240 | /* | |
241 | * Allocate and initialize syscall object and add it to the given hashtable. | |
242 | * | |
243 | * Return 0 on success else -LTTNG_ERR_NOMEM. | |
244 | */ | |
245 | static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, | |
246 | unsigned int syscall_index) | |
247 | { | |
248 | int ret; | |
249 | struct syscall *ksyscall; | |
250 | ||
251 | assert(ht); | |
252 | ||
253 | ksyscall = zmalloc(sizeof(*ksyscall)); | |
254 | if (!ksyscall) { | |
255 | ret = -LTTNG_ERR_NOMEM; | |
256 | goto error; | |
257 | } | |
258 | ||
259 | strncpy(ksyscall->name, syscall_table[index].name, | |
260 | sizeof(ksyscall->name)); | |
261 | ksyscall->bitness = syscall_table[index].bitness; | |
262 | ksyscall->index = syscall_index; | |
263 | lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); | |
264 | lttng_ht_add_unique_str(ht, &ksyscall->node); | |
265 | ret = 0; | |
266 | ||
267 | error: | |
268 | return ret; | |
269 | } | |
270 | ||
271 | /* | |
272 | * List syscalls present in the kernel syscall global array, allocate and | |
273 | * populate the events structure with them. Skip the empty syscall name. | |
274 | * | |
275 | * Return the number of entries in the array else a negative value. | |
276 | */ | |
277 | ssize_t syscall_table_list(struct lttng_event **_events) | |
278 | { | |
279 | int i, index = 0; | |
280 | ssize_t ret; | |
281 | struct lttng_event *events; | |
282 | /* Hash table used to filter duplicate out. */ | |
283 | struct lttng_ht *syscalls_ht = NULL; | |
284 | ||
285 | assert(_events); | |
286 | ||
287 | DBG("Syscall table listing."); | |
288 | ||
289 | rcu_read_lock(); | |
290 | ||
291 | /* | |
292 | * Allocate at least the number of total syscall we have even if some of | |
293 | * them might not be valid. The count below will make sure to return the | |
294 | * right size of the events array. | |
295 | */ | |
296 | events = zmalloc(syscall_table_nb_entry * sizeof(*events)); | |
297 | if (!events) { | |
298 | PERROR("syscall table list zmalloc"); | |
299 | ret = -LTTNG_ERR_NOMEM; | |
300 | goto error; | |
301 | } | |
302 | ||
303 | ret = init_syscall_ht(&syscalls_ht); | |
304 | if (ret < 0) { | |
305 | goto error; | |
306 | } | |
307 | ||
308 | for (i = 0; i < syscall_table_nb_entry; i++) { | |
309 | struct syscall *ksyscall; | |
310 | ||
311 | /* Skip empty syscalls. */ | |
312 | if (*syscall_table[i].name == '\0') { | |
313 | continue; | |
314 | } | |
315 | ||
316 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
317 | if (ksyscall) { | |
318 | update_event_syscall_bitness(events, i, ksyscall->index); | |
319 | continue; | |
320 | } | |
321 | ||
322 | ret = add_syscall_to_ht(syscalls_ht, i, index); | |
323 | if (ret < 0) { | |
324 | goto error; | |
325 | } | |
326 | ||
327 | /* Copy the event information in the event's array. */ | |
328 | strncpy(events[index].name, syscall_table[i].name, | |
329 | sizeof(events[index].name)); | |
330 | update_event_syscall_bitness(events, i, index); | |
331 | events[index].type = LTTNG_EVENT_SYSCALL; | |
332 | /* This makes the command line not print the enabled/disabled field. */ | |
333 | events[index].enabled = -1; | |
334 | index++; | |
335 | } | |
336 | ||
337 | destroy_syscall_ht(syscalls_ht); | |
338 | *_events = events; | |
339 | rcu_read_unlock(); | |
340 | return index; | |
341 | ||
342 | error: | |
343 | destroy_syscall_ht(syscalls_ht); | |
344 | free(events); | |
345 | rcu_read_unlock(); | |
346 | return ret; | |
347 | } |