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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/common.h> |
22 | #include <common/kernel-ctl/kernel-ctl.h> | |
23 | ||
24 | #include "lttng-sessiond.h" | |
25 | #include "kernel.h" | |
0dbc2034 | 26 | #include "lttng-syscall.h" |
834978fd DG |
27 | #include "utils.h" |
28 | ||
29 | /* Global syscall table. */ | |
30 | struct syscall *syscall_table; | |
31 | ||
32 | /* Number of entry in the syscall table. */ | |
33 | static size_t syscall_table_nb_entry; | |
34 | ||
35 | /* | |
36 | * Populate the system call table using the kernel tracer. | |
37 | * | |
38 | * Return 0 on success and the syscall table is allocated. On error, a negative | |
1f47715a | 39 | * value is returned. |
834978fd | 40 | */ |
7d268848 | 41 | int syscall_init_table(int tracer_fd) |
834978fd DG |
42 | { |
43 | int ret, fd, err; | |
44 | size_t nbmem; | |
45 | FILE *fp; | |
46 | /* Syscall data from the kernel. */ | |
98123e1c JR |
47 | size_t index = 0; |
48 | bool at_least_one_syscall = false; | |
834978fd DG |
49 | uint32_t bitness; |
50 | char name[SYSCALL_NAME_LEN]; | |
51 | ||
52 | DBG3("Syscall init system call table"); | |
53 | ||
7d268848 | 54 | fd = kernctl_syscall_list(tracer_fd); |
834978fd | 55 | if (fd < 0) { |
32af2c95 | 56 | ret = fd; |
834978fd DG |
57 | PERROR("kernelctl syscall list"); |
58 | goto error_ioctl; | |
59 | } | |
60 | ||
61 | fp = fdopen(fd, "r"); | |
62 | if (!fp) { | |
63 | ret = -errno; | |
64 | PERROR("syscall list fdopen"); | |
65 | goto error_fp; | |
66 | } | |
67 | ||
68 | nbmem = SYSCALL_TABLE_INIT_SIZE; | |
69 | syscall_table = zmalloc(sizeof(struct syscall) * nbmem); | |
70 | if (!syscall_table) { | |
71 | ret = -errno; | |
72 | PERROR("syscall list zmalloc"); | |
73 | goto error; | |
74 | } | |
75 | ||
76 | while (fscanf(fp, | |
97282ce2 | 77 | "syscall { index = %zu; \ |
834978fd DG |
78 | name = %" XSTR(SYSCALL_NAME_LEN) "[^;]; \ |
79 | bitness = %u; };\n", | |
80 | &index, name, &bitness) == 3) { | |
98123e1c JR |
81 | at_least_one_syscall = true; |
82 | if (index >= nbmem) { | |
834978fd DG |
83 | struct syscall *new_list; |
84 | size_t new_nbmem; | |
85 | ||
86 | /* Double memory size. */ | |
98123e1c | 87 | new_nbmem = max(index + 1, nbmem << 1); |
ec93758c | 88 | if (new_nbmem > (SIZE_MAX / sizeof(*new_list))) { |
1f47715a DG |
89 | /* Overflow, stop everything, something went really wrong. */ |
90 | ERR("Syscall listing memory size overflow. Stopping"); | |
91 | free(syscall_table); | |
92 | syscall_table = NULL; | |
93 | ret = -EINVAL; | |
94 | goto error; | |
95 | } | |
834978fd DG |
96 | |
97 | DBG("Reallocating syscall table from %zu to %zu entries", nbmem, | |
98 | new_nbmem); | |
99 | new_list = realloc(syscall_table, new_nbmem * sizeof(*new_list)); | |
100 | if (!new_list) { | |
101 | ret = -errno; | |
102 | PERROR("syscall list realloc"); | |
103 | goto error; | |
104 | } | |
105 | ||
106 | /* Zero out the new memory. */ | |
107 | memset(new_list + nbmem, 0, | |
108 | (new_nbmem - nbmem) * sizeof(*new_list)); | |
109 | nbmem = new_nbmem; | |
110 | syscall_table = new_list; | |
111 | } | |
112 | syscall_table[index].index = index; | |
113 | syscall_table[index].bitness = bitness; | |
39e3c47a MD |
114 | if (lttng_strncpy(syscall_table[index].name, name, |
115 | sizeof(syscall_table[index].name))) { | |
116 | ret = -EINVAL; | |
117 | free(syscall_table); | |
118 | syscall_table = NULL; | |
119 | goto error; | |
120 | } | |
834978fd DG |
121 | /* |
122 | DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", | |
123 | syscall_table[index].name, | |
124 | syscall_table[index].index, | |
125 | syscall_table[index].bitness); | |
126 | */ | |
127 | } | |
128 | ||
98123e1c JR |
129 | /* Index starts at 0. */ |
130 | if (at_least_one_syscall) { | |
131 | syscall_table_nb_entry = index + 1; | |
132 | } | |
834978fd DG |
133 | |
134 | ret = 0; | |
135 | ||
136 | error: | |
137 | err = fclose(fp); | |
138 | if (err) { | |
139 | PERROR("syscall list fclose"); | |
140 | } | |
141 | return ret; | |
142 | ||
143 | error_fp: | |
144 | err = close(fd); | |
145 | if (err) { | |
146 | PERROR("syscall list close"); | |
147 | } | |
148 | ||
149 | error_ioctl: | |
150 | return ret; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Helper function for the list syscalls command that empty the temporary | |
155 | * syscall hashtable used to track duplicate between 32 and 64 bit arch. | |
156 | * | |
157 | * This empty the hash table and destroys it after. After this, the pointer is | |
158 | * unsuable. RCU read side lock MUST be acquired before calling this. | |
159 | */ | |
160 | static void destroy_syscall_ht(struct lttng_ht *ht) | |
161 | { | |
162 | struct lttng_ht_iter iter; | |
163 | struct syscall *ksyscall; | |
164 | ||
165 | DBG3("Destroying syscall hash table."); | |
166 | ||
167 | if (!ht) { | |
168 | return; | |
169 | } | |
170 | ||
171 | cds_lfht_for_each_entry(ht->ht, &iter.iter, ksyscall, node.node) { | |
172 | int ret; | |
173 | ||
174 | ret = lttng_ht_del(ht, &iter); | |
175 | assert(!ret); | |
176 | free(ksyscall); | |
177 | } | |
178 | ht_cleanup_push(ht); | |
179 | } | |
180 | ||
181 | /* | |
182 | * Allocate the given hashtable pointer. | |
183 | * | |
184 | * Return 0 on success else a negative LTTNG error value. | |
185 | */ | |
186 | static int init_syscall_ht(struct lttng_ht **ht) | |
187 | { | |
188 | int ret; | |
189 | ||
190 | *ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING); | |
191 | if (!*ht) { | |
192 | ret = -LTTNG_ERR_NOMEM; | |
193 | } else { | |
194 | ret = 0; | |
195 | } | |
196 | ||
197 | return ret; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Lookup a syscall in the given hash table by name. | |
202 | * | |
203 | * Return syscall object if found or else NULL. | |
204 | */ | |
205 | static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name) | |
206 | { | |
207 | struct lttng_ht_node_str *node; | |
208 | struct lttng_ht_iter iter; | |
209 | struct syscall *ksyscall = NULL; | |
210 | ||
211 | assert(ht); | |
212 | assert(name); | |
213 | ||
214 | lttng_ht_lookup(ht, (void *) name, &iter); | |
215 | node = lttng_ht_iter_get_node_str(&iter); | |
216 | if (node) { | |
217 | ksyscall = caa_container_of(node, struct syscall, node); | |
218 | } | |
219 | ||
220 | return ksyscall; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Using the given syscall object in the events array with the bitness of the | |
225 | * syscall at index in the syscall table. | |
226 | */ | |
227 | static void update_event_syscall_bitness(struct lttng_event *events, | |
228 | unsigned int index, unsigned int syscall_index) | |
229 | { | |
230 | assert(events); | |
231 | ||
232 | if (syscall_table[index].bitness == 32) { | |
233 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_32; | |
234 | } else { | |
235 | events[syscall_index].flags |= LTTNG_EVENT_FLAG_SYSCALL_64; | |
236 | } | |
237 | } | |
238 | ||
239 | /* | |
240 | * Allocate and initialize syscall object and add it to the given hashtable. | |
241 | * | |
242 | * Return 0 on success else -LTTNG_ERR_NOMEM. | |
243 | */ | |
244 | static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, | |
245 | unsigned int syscall_index) | |
246 | { | |
247 | int ret; | |
248 | struct syscall *ksyscall; | |
249 | ||
250 | assert(ht); | |
251 | ||
252 | ksyscall = zmalloc(sizeof(*ksyscall)); | |
253 | if (!ksyscall) { | |
254 | ret = -LTTNG_ERR_NOMEM; | |
255 | goto error; | |
256 | } | |
257 | ||
258 | strncpy(ksyscall->name, syscall_table[index].name, | |
259 | sizeof(ksyscall->name)); | |
260 | ksyscall->bitness = syscall_table[index].bitness; | |
261 | ksyscall->index = syscall_index; | |
262 | lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); | |
263 | lttng_ht_add_unique_str(ht, &ksyscall->node); | |
264 | ret = 0; | |
265 | ||
266 | error: | |
267 | return ret; | |
268 | } | |
269 | ||
270 | /* | |
271 | * List syscalls present in the kernel syscall global array, allocate and | |
272 | * populate the events structure with them. Skip the empty syscall name. | |
273 | * | |
274 | * Return the number of entries in the array else a negative value. | |
275 | */ | |
276 | ssize_t syscall_table_list(struct lttng_event **_events) | |
277 | { | |
278 | int i, index = 0; | |
279 | ssize_t ret; | |
280 | struct lttng_event *events; | |
281 | /* Hash table used to filter duplicate out. */ | |
282 | struct lttng_ht *syscalls_ht = NULL; | |
283 | ||
284 | assert(_events); | |
285 | ||
286 | DBG("Syscall table listing."); | |
287 | ||
288 | rcu_read_lock(); | |
289 | ||
290 | /* | |
291 | * Allocate at least the number of total syscall we have even if some of | |
292 | * them might not be valid. The count below will make sure to return the | |
293 | * right size of the events array. | |
294 | */ | |
295 | events = zmalloc(syscall_table_nb_entry * sizeof(*events)); | |
296 | if (!events) { | |
297 | PERROR("syscall table list zmalloc"); | |
298 | ret = -LTTNG_ERR_NOMEM; | |
299 | goto error; | |
300 | } | |
301 | ||
302 | ret = init_syscall_ht(&syscalls_ht); | |
303 | if (ret < 0) { | |
304 | goto error; | |
305 | } | |
306 | ||
307 | for (i = 0; i < syscall_table_nb_entry; i++) { | |
308 | struct syscall *ksyscall; | |
309 | ||
310 | /* Skip empty syscalls. */ | |
311 | if (*syscall_table[i].name == '\0') { | |
312 | continue; | |
313 | } | |
314 | ||
315 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
316 | if (ksyscall) { | |
317 | update_event_syscall_bitness(events, i, ksyscall->index); | |
318 | continue; | |
319 | } | |
320 | ||
321 | ret = add_syscall_to_ht(syscalls_ht, i, index); | |
322 | if (ret < 0) { | |
323 | goto error; | |
324 | } | |
325 | ||
326 | /* Copy the event information in the event's array. */ | |
327 | strncpy(events[index].name, syscall_table[i].name, | |
328 | sizeof(events[index].name)); | |
329 | update_event_syscall_bitness(events, i, index); | |
330 | events[index].type = LTTNG_EVENT_SYSCALL; | |
331 | /* This makes the command line not print the enabled/disabled field. */ | |
332 | events[index].enabled = -1; | |
333 | index++; | |
334 | } | |
335 | ||
336 | destroy_syscall_ht(syscalls_ht); | |
337 | *_events = events; | |
338 | rcu_read_unlock(); | |
339 | return index; | |
340 | ||
341 | error: | |
342 | destroy_syscall_ht(syscalls_ht); | |
343 | free(events); | |
344 | rcu_read_unlock(); | |
345 | return ret; | |
346 | } |