Commit | Line | Data |
---|---|---|
834978fd | 1 | /* |
ab5be9fa | 2 | * Copyright (C) 2014 David Goulet <dgoulet@efficios.com> |
834978fd | 3 | * |
ab5be9fa | 4 | * SPDX-License-Identifier: GPL-2.0-only |
834978fd | 5 | * |
834978fd DG |
6 | */ |
7 | ||
6c1c0768 | 8 | #define _LGPL_SOURCE |
98123e1c JR |
9 | #include <stdbool.h> |
10 | ||
834978fd DG |
11 | #include <common/common.h> |
12 | #include <common/kernel-ctl/kernel-ctl.h> | |
13 | ||
14 | #include "lttng-sessiond.h" | |
15 | #include "kernel.h" | |
0dbc2034 | 16 | #include "lttng-syscall.h" |
834978fd DG |
17 | #include "utils.h" |
18 | ||
19 | /* Global syscall table. */ | |
20 | struct syscall *syscall_table; | |
21 | ||
22 | /* Number of entry in the syscall table. */ | |
23 | static size_t syscall_table_nb_entry; | |
24 | ||
25 | /* | |
26 | * Populate the system call table using the kernel tracer. | |
27 | * | |
28 | * Return 0 on success and the syscall table is allocated. On error, a negative | |
1f47715a | 29 | * value is returned. |
834978fd | 30 | */ |
7d268848 | 31 | int syscall_init_table(int tracer_fd) |
834978fd DG |
32 | { |
33 | int ret, fd, err; | |
34 | size_t nbmem; | |
35 | FILE *fp; | |
36 | /* Syscall data from the kernel. */ | |
98123e1c JR |
37 | size_t index = 0; |
38 | bool at_least_one_syscall = false; | |
834978fd DG |
39 | uint32_t bitness; |
40 | char name[SYSCALL_NAME_LEN]; | |
41 | ||
9c7134c0 SM |
42 | #if (SYSCALL_NAME_LEN == 255) |
43 | #define SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "254" | |
44 | #endif | |
45 | ||
834978fd DG |
46 | DBG3("Syscall init system call table"); |
47 | ||
7d268848 | 48 | fd = kernctl_syscall_list(tracer_fd); |
834978fd | 49 | if (fd < 0) { |
32af2c95 | 50 | ret = fd; |
834978fd DG |
51 | PERROR("kernelctl syscall list"); |
52 | goto error_ioctl; | |
53 | } | |
54 | ||
55 | fp = fdopen(fd, "r"); | |
56 | if (!fp) { | |
57 | ret = -errno; | |
58 | PERROR("syscall list fdopen"); | |
59 | goto error_fp; | |
60 | } | |
61 | ||
62 | nbmem = SYSCALL_TABLE_INIT_SIZE; | |
7966af57 | 63 | syscall_table = (struct syscall *) zmalloc(sizeof(struct syscall) * nbmem); |
834978fd DG |
64 | if (!syscall_table) { |
65 | ret = -errno; | |
66 | PERROR("syscall list zmalloc"); | |
67 | goto error; | |
68 | } | |
69 | ||
70 | while (fscanf(fp, | |
97282ce2 | 71 | "syscall { index = %zu; \ |
9c7134c0 | 72 | name = %" SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "[^;]; \ |
834978fd DG |
73 | bitness = %u; };\n", |
74 | &index, name, &bitness) == 3) { | |
98123e1c JR |
75 | at_least_one_syscall = true; |
76 | if (index >= nbmem) { | |
834978fd DG |
77 | struct syscall *new_list; |
78 | size_t new_nbmem; | |
79 | ||
80 | /* Double memory size. */ | |
7966af57 | 81 | new_nbmem = std::max(index + 1, nbmem << 1); |
ec93758c | 82 | if (new_nbmem > (SIZE_MAX / sizeof(*new_list))) { |
1f47715a DG |
83 | /* Overflow, stop everything, something went really wrong. */ |
84 | ERR("Syscall listing memory size overflow. Stopping"); | |
85 | free(syscall_table); | |
86 | syscall_table = NULL; | |
87 | ret = -EINVAL; | |
88 | goto error; | |
89 | } | |
834978fd DG |
90 | |
91 | DBG("Reallocating syscall table from %zu to %zu entries", nbmem, | |
92 | new_nbmem); | |
7966af57 | 93 | new_list = (struct syscall *) realloc(syscall_table, new_nbmem * sizeof(*new_list)); |
834978fd DG |
94 | if (!new_list) { |
95 | ret = -errno; | |
96 | PERROR("syscall list realloc"); | |
97 | goto error; | |
98 | } | |
99 | ||
100 | /* Zero out the new memory. */ | |
101 | memset(new_list + nbmem, 0, | |
102 | (new_nbmem - nbmem) * sizeof(*new_list)); | |
103 | nbmem = new_nbmem; | |
104 | syscall_table = new_list; | |
105 | } | |
106 | syscall_table[index].index = index; | |
107 | syscall_table[index].bitness = bitness; | |
39e3c47a MD |
108 | if (lttng_strncpy(syscall_table[index].name, name, |
109 | sizeof(syscall_table[index].name))) { | |
110 | ret = -EINVAL; | |
111 | free(syscall_table); | |
112 | syscall_table = NULL; | |
113 | goto error; | |
114 | } | |
834978fd DG |
115 | /* |
116 | DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", | |
117 | syscall_table[index].name, | |
118 | syscall_table[index].index, | |
119 | syscall_table[index].bitness); | |
120 | */ | |
121 | } | |
122 | ||
98123e1c JR |
123 | /* Index starts at 0. */ |
124 | if (at_least_one_syscall) { | |
125 | syscall_table_nb_entry = index + 1; | |
126 | } | |
834978fd DG |
127 | |
128 | ret = 0; | |
129 | ||
130 | error: | |
131 | err = fclose(fp); | |
132 | if (err) { | |
133 | PERROR("syscall list fclose"); | |
134 | } | |
135 | return ret; | |
136 | ||
137 | error_fp: | |
138 | err = close(fd); | |
139 | if (err) { | |
140 | PERROR("syscall list close"); | |
141 | } | |
142 | ||
143 | error_ioctl: | |
144 | return ret; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Helper function for the list syscalls command that empty the temporary | |
149 | * syscall hashtable used to track duplicate between 32 and 64 bit arch. | |
150 | * | |
151 | * This empty the hash table and destroys it after. After this, the pointer is | |
152 | * unsuable. RCU read side lock MUST be acquired before calling this. | |
153 | */ | |
154 | static void destroy_syscall_ht(struct lttng_ht *ht) | |
155 | { | |
156 | struct lttng_ht_iter iter; | |
157 | struct syscall *ksyscall; | |
158 | ||
159 | DBG3("Destroying syscall hash table."); | |
160 | ||
161 | if (!ht) { | |
162 | return; | |
163 | } | |
164 | ||
165 | cds_lfht_for_each_entry(ht->ht, &iter.iter, ksyscall, node.node) { | |
166 | int ret; | |
167 | ||
168 | ret = lttng_ht_del(ht, &iter); | |
a0377dfe | 169 | LTTNG_ASSERT(!ret); |
834978fd DG |
170 | free(ksyscall); |
171 | } | |
3c339053 | 172 | lttng_ht_destroy(ht); |
834978fd DG |
173 | } |
174 | ||
175 | /* | |
176 | * Allocate the given hashtable pointer. | |
177 | * | |
178 | * Return 0 on success else a negative LTTNG error value. | |
179 | */ | |
180 | static int init_syscall_ht(struct lttng_ht **ht) | |
181 | { | |
182 | int ret; | |
183 | ||
184 | *ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING); | |
185 | if (!*ht) { | |
186 | ret = -LTTNG_ERR_NOMEM; | |
187 | } else { | |
188 | ret = 0; | |
189 | } | |
190 | ||
191 | return ret; | |
192 | } | |
193 | ||
194 | /* | |
195 | * Lookup a syscall in the given hash table by name. | |
196 | * | |
197 | * Return syscall object if found or else NULL. | |
198 | */ | |
199 | static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name) | |
200 | { | |
201 | struct lttng_ht_node_str *node; | |
202 | struct lttng_ht_iter iter; | |
203 | struct syscall *ksyscall = NULL; | |
204 | ||
a0377dfe FD |
205 | LTTNG_ASSERT(ht); |
206 | LTTNG_ASSERT(name); | |
834978fd DG |
207 | |
208 | lttng_ht_lookup(ht, (void *) name, &iter); | |
209 | node = lttng_ht_iter_get_node_str(&iter); | |
210 | if (node) { | |
211 | ksyscall = caa_container_of(node, struct syscall, node); | |
212 | } | |
213 | ||
214 | return ksyscall; | |
215 | } | |
216 | ||
217 | /* | |
218 | * Using the given syscall object in the events array with the bitness of the | |
219 | * syscall at index in the syscall table. | |
220 | */ | |
221 | static void update_event_syscall_bitness(struct lttng_event *events, | |
222 | unsigned int index, unsigned int syscall_index) | |
223 | { | |
a0377dfe | 224 | LTTNG_ASSERT(events); |
834978fd DG |
225 | |
226 | if (syscall_table[index].bitness == 32) { | |
7966af57 | 227 | events[syscall_index].flags = (lttng_event_flag) (events[syscall_index].flags | LTTNG_EVENT_FLAG_SYSCALL_32); |
834978fd | 228 | } else { |
7966af57 | 229 | events[syscall_index].flags = (lttng_event_flag) (events[syscall_index].flags | LTTNG_EVENT_FLAG_SYSCALL_64); |
834978fd DG |
230 | } |
231 | } | |
232 | ||
233 | /* | |
234 | * Allocate and initialize syscall object and add it to the given hashtable. | |
235 | * | |
236 | * Return 0 on success else -LTTNG_ERR_NOMEM. | |
237 | */ | |
238 | static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, | |
239 | unsigned int syscall_index) | |
240 | { | |
241 | int ret; | |
242 | struct syscall *ksyscall; | |
243 | ||
a0377dfe | 244 | LTTNG_ASSERT(ht); |
834978fd | 245 | |
7966af57 | 246 | ksyscall = (struct syscall *) zmalloc(sizeof(*ksyscall)); |
834978fd DG |
247 | if (!ksyscall) { |
248 | ret = -LTTNG_ERR_NOMEM; | |
249 | goto error; | |
250 | } | |
251 | ||
252 | strncpy(ksyscall->name, syscall_table[index].name, | |
253 | sizeof(ksyscall->name)); | |
254 | ksyscall->bitness = syscall_table[index].bitness; | |
255 | ksyscall->index = syscall_index; | |
256 | lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); | |
257 | lttng_ht_add_unique_str(ht, &ksyscall->node); | |
258 | ret = 0; | |
259 | ||
260 | error: | |
261 | return ret; | |
262 | } | |
263 | ||
264 | /* | |
265 | * List syscalls present in the kernel syscall global array, allocate and | |
266 | * populate the events structure with them. Skip the empty syscall name. | |
267 | * | |
268 | * Return the number of entries in the array else a negative value. | |
269 | */ | |
270 | ssize_t syscall_table_list(struct lttng_event **_events) | |
271 | { | |
272 | int i, index = 0; | |
273 | ssize_t ret; | |
274 | struct lttng_event *events; | |
275 | /* Hash table used to filter duplicate out. */ | |
276 | struct lttng_ht *syscalls_ht = NULL; | |
277 | ||
a0377dfe | 278 | LTTNG_ASSERT(_events); |
834978fd DG |
279 | |
280 | DBG("Syscall table listing."); | |
281 | ||
282 | rcu_read_lock(); | |
283 | ||
284 | /* | |
285 | * Allocate at least the number of total syscall we have even if some of | |
286 | * them might not be valid. The count below will make sure to return the | |
287 | * right size of the events array. | |
288 | */ | |
7966af57 | 289 | events = (lttng_event *) zmalloc(syscall_table_nb_entry * sizeof(*events)); |
834978fd DG |
290 | if (!events) { |
291 | PERROR("syscall table list zmalloc"); | |
292 | ret = -LTTNG_ERR_NOMEM; | |
293 | goto error; | |
294 | } | |
295 | ||
296 | ret = init_syscall_ht(&syscalls_ht); | |
297 | if (ret < 0) { | |
298 | goto error; | |
299 | } | |
300 | ||
301 | for (i = 0; i < syscall_table_nb_entry; i++) { | |
302 | struct syscall *ksyscall; | |
303 | ||
304 | /* Skip empty syscalls. */ | |
305 | if (*syscall_table[i].name == '\0') { | |
306 | continue; | |
307 | } | |
308 | ||
309 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
310 | if (ksyscall) { | |
311 | update_event_syscall_bitness(events, i, ksyscall->index); | |
312 | continue; | |
313 | } | |
314 | ||
315 | ret = add_syscall_to_ht(syscalls_ht, i, index); | |
316 | if (ret < 0) { | |
317 | goto error; | |
318 | } | |
319 | ||
320 | /* Copy the event information in the event's array. */ | |
321 | strncpy(events[index].name, syscall_table[i].name, | |
322 | sizeof(events[index].name)); | |
323 | update_event_syscall_bitness(events, i, index); | |
324 | events[index].type = LTTNG_EVENT_SYSCALL; | |
325 | /* This makes the command line not print the enabled/disabled field. */ | |
326 | events[index].enabled = -1; | |
327 | index++; | |
328 | } | |
329 | ||
330 | destroy_syscall_ht(syscalls_ht); | |
331 | *_events = events; | |
332 | rcu_read_unlock(); | |
333 | return index; | |
334 | ||
335 | error: | |
336 | destroy_syscall_ht(syscalls_ht); | |
337 | free(events); | |
338 | rcu_read_unlock(); | |
339 | return ret; | |
340 | } |