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 |
28ab034a JG |
9 | #include "kernel.hpp" |
10 | #include "lttng-sessiond.hpp" | |
11 | #include "lttng-syscall.hpp" | |
12 | #include "utils.hpp" | |
98123e1c | 13 | |
c9e313bc SM |
14 | #include <common/common.hpp> |
15 | #include <common/kernel-ctl/kernel-ctl.hpp> | |
56047f5a | 16 | #include <common/urcu.hpp> |
834978fd | 17 | |
28ab034a | 18 | #include <stdbool.h> |
834978fd DG |
19 | |
20 | /* Global syscall table. */ | |
21 | struct syscall *syscall_table; | |
22 | ||
23 | /* Number of entry in the syscall table. */ | |
24 | static size_t syscall_table_nb_entry; | |
25 | ||
26 | /* | |
27 | * Populate the system call table using the kernel tracer. | |
28 | * | |
29 | * Return 0 on success and the syscall table is allocated. On error, a negative | |
1f47715a | 30 | * value is returned. |
834978fd | 31 | */ |
7d268848 | 32 | int syscall_init_table(int tracer_fd) |
834978fd DG |
33 | { |
34 | int ret, fd, err; | |
35 | size_t nbmem; | |
36 | FILE *fp; | |
37 | /* Syscall data from the kernel. */ | |
98123e1c JR |
38 | size_t index = 0; |
39 | bool at_least_one_syscall = false; | |
834978fd DG |
40 | uint32_t bitness; |
41 | char name[SYSCALL_NAME_LEN]; | |
42 | ||
9c7134c0 | 43 | #if (SYSCALL_NAME_LEN == 255) |
28ab034a | 44 | #define SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "254" |
9c7134c0 SM |
45 | #endif |
46 | ||
834978fd DG |
47 | DBG3("Syscall init system call table"); |
48 | ||
7d268848 | 49 | fd = kernctl_syscall_list(tracer_fd); |
834978fd | 50 | if (fd < 0) { |
32af2c95 | 51 | ret = fd; |
834978fd DG |
52 | PERROR("kernelctl syscall list"); |
53 | goto error_ioctl; | |
54 | } | |
55 | ||
56 | fp = fdopen(fd, "r"); | |
57 | if (!fp) { | |
58 | ret = -errno; | |
59 | PERROR("syscall list fdopen"); | |
60 | goto error_fp; | |
61 | } | |
62 | ||
63 | nbmem = SYSCALL_TABLE_INIT_SIZE; | |
64803277 | 64 | syscall_table = calloc<struct syscall>(nbmem); |
834978fd DG |
65 | if (!syscall_table) { |
66 | ret = -errno; | |
67 | PERROR("syscall list zmalloc"); | |
68 | goto error; | |
69 | } | |
70 | ||
71 | while (fscanf(fp, | |
28ab034a | 72 | "syscall { index = %zu; \ |
9c7134c0 | 73 | name = %" SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "[^;]; \ |
834978fd | 74 | bitness = %u; };\n", |
28ab034a JG |
75 | &index, |
76 | name, | |
77 | &bitness) == 3) { | |
98123e1c JR |
78 | at_least_one_syscall = true; |
79 | if (index >= nbmem) { | |
834978fd DG |
80 | struct syscall *new_list; |
81 | size_t new_nbmem; | |
82 | ||
83 | /* Double memory size. */ | |
7966af57 | 84 | new_nbmem = std::max(index + 1, nbmem << 1); |
ec93758c | 85 | if (new_nbmem > (SIZE_MAX / sizeof(*new_list))) { |
1f47715a DG |
86 | /* Overflow, stop everything, something went really wrong. */ |
87 | ERR("Syscall listing memory size overflow. Stopping"); | |
88 | free(syscall_table); | |
cd9adb8b | 89 | syscall_table = nullptr; |
1f47715a DG |
90 | ret = -EINVAL; |
91 | goto error; | |
92 | } | |
834978fd | 93 | |
28ab034a JG |
94 | DBG("Reallocating syscall table from %zu to %zu entries", nbmem, new_nbmem); |
95 | new_list = (struct syscall *) realloc(syscall_table, | |
96 | new_nbmem * sizeof(*new_list)); | |
834978fd DG |
97 | if (!new_list) { |
98 | ret = -errno; | |
99 | PERROR("syscall list realloc"); | |
100 | goto error; | |
101 | } | |
102 | ||
103 | /* Zero out the new memory. */ | |
28ab034a | 104 | memset(new_list + nbmem, 0, (new_nbmem - nbmem) * sizeof(*new_list)); |
834978fd DG |
105 | nbmem = new_nbmem; |
106 | syscall_table = new_list; | |
107 | } | |
108 | syscall_table[index].index = index; | |
109 | syscall_table[index].bitness = bitness; | |
28ab034a JG |
110 | if (lttng_strncpy( |
111 | syscall_table[index].name, name, sizeof(syscall_table[index].name))) { | |
39e3c47a MD |
112 | ret = -EINVAL; |
113 | free(syscall_table); | |
cd9adb8b | 114 | syscall_table = nullptr; |
39e3c47a MD |
115 | goto error; |
116 | } | |
834978fd DG |
117 | /* |
118 | DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", | |
119 | syscall_table[index].name, | |
120 | syscall_table[index].index, | |
121 | syscall_table[index].bitness); | |
122 | */ | |
123 | } | |
124 | ||
98123e1c JR |
125 | /* Index starts at 0. */ |
126 | if (at_least_one_syscall) { | |
127 | syscall_table_nb_entry = index + 1; | |
128 | } | |
834978fd DG |
129 | |
130 | ret = 0; | |
131 | ||
132 | error: | |
133 | err = fclose(fp); | |
134 | if (err) { | |
135 | PERROR("syscall list fclose"); | |
136 | } | |
137 | return ret; | |
138 | ||
139 | error_fp: | |
140 | err = close(fd); | |
141 | if (err) { | |
142 | PERROR("syscall list close"); | |
143 | } | |
144 | ||
145 | error_ioctl: | |
146 | return ret; | |
147 | } | |
148 | ||
149 | /* | |
150 | * Helper function for the list syscalls command that empty the temporary | |
151 | * syscall hashtable used to track duplicate between 32 and 64 bit arch. | |
152 | * | |
153 | * This empty the hash table and destroys it after. After this, the pointer is | |
56047f5a | 154 | * unsuable. RCU read side lock MUST NOT be acquired before calling this. |
834978fd DG |
155 | */ |
156 | static void destroy_syscall_ht(struct lttng_ht *ht) | |
157 | { | |
158 | struct lttng_ht_iter iter; | |
159 | struct syscall *ksyscall; | |
160 | ||
161 | DBG3("Destroying syscall hash table."); | |
162 | ||
163 | if (!ht) { | |
164 | return; | |
165 | } | |
166 | ||
56047f5a JG |
167 | { |
168 | lttng::urcu::read_lock_guard read_lock; | |
169 | ||
170 | cds_lfht_for_each_entry (ht->ht, &iter.iter, ksyscall, node.node) { | |
171 | int ret; | |
834978fd | 172 | |
56047f5a JG |
173 | ret = lttng_ht_del(ht, &iter); |
174 | LTTNG_ASSERT(!ret); | |
175 | free(ksyscall); | |
176 | } | |
834978fd | 177 | } |
56047f5a | 178 | |
3c339053 | 179 | lttng_ht_destroy(ht); |
834978fd DG |
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 | * | |
56047f5a JG |
204 | * RCU read lock MUST be acquired by the callers of this function. |
205 | * | |
834978fd DG |
206 | * Return syscall object if found or else NULL. |
207 | */ | |
208 | static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name) | |
209 | { | |
210 | struct lttng_ht_node_str *node; | |
211 | struct lttng_ht_iter iter; | |
cd9adb8b | 212 | struct syscall *ksyscall = nullptr; |
834978fd | 213 | |
a0377dfe FD |
214 | LTTNG_ASSERT(ht); |
215 | LTTNG_ASSERT(name); | |
834978fd DG |
216 | |
217 | lttng_ht_lookup(ht, (void *) name, &iter); | |
00d7d903 | 218 | node = lttng_ht_iter_get_node<lttng_ht_node_str>(&iter); |
834978fd | 219 | if (node) { |
0114db0e | 220 | ksyscall = lttng::utils::container_of(node, &syscall::node); |
834978fd DG |
221 | } |
222 | ||
223 | return ksyscall; | |
224 | } | |
225 | ||
226 | /* | |
227 | * Using the given syscall object in the events array with the bitness of the | |
228 | * syscall at index in the syscall table. | |
229 | */ | |
230 | static void update_event_syscall_bitness(struct lttng_event *events, | |
28ab034a JG |
231 | unsigned int index, |
232 | unsigned int syscall_index) | |
834978fd | 233 | { |
a0377dfe | 234 | LTTNG_ASSERT(events); |
834978fd DG |
235 | |
236 | if (syscall_table[index].bitness == 32) { | |
28ab034a JG |
237 | events[syscall_index].flags = (lttng_event_flag) (events[syscall_index].flags | |
238 | LTTNG_EVENT_FLAG_SYSCALL_32); | |
834978fd | 239 | } else { |
28ab034a JG |
240 | events[syscall_index].flags = (lttng_event_flag) (events[syscall_index].flags | |
241 | LTTNG_EVENT_FLAG_SYSCALL_64); | |
834978fd DG |
242 | } |
243 | } | |
244 | ||
245 | /* | |
246 | * Allocate and initialize syscall object and add it to the given hashtable. | |
247 | * | |
248 | * Return 0 on success else -LTTNG_ERR_NOMEM. | |
249 | */ | |
28ab034a | 250 | static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, unsigned int syscall_index) |
834978fd DG |
251 | { |
252 | int ret; | |
253 | struct syscall *ksyscall; | |
254 | ||
a0377dfe | 255 | LTTNG_ASSERT(ht); |
834978fd | 256 | |
64803277 | 257 | ksyscall = zmalloc<struct syscall>(); |
834978fd DG |
258 | if (!ksyscall) { |
259 | ret = -LTTNG_ERR_NOMEM; | |
260 | goto error; | |
261 | } | |
262 | ||
28ab034a | 263 | strncpy(ksyscall->name, syscall_table[index].name, sizeof(ksyscall->name)); |
834978fd DG |
264 | ksyscall->bitness = syscall_table[index].bitness; |
265 | ksyscall->index = syscall_index; | |
266 | lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); | |
267 | lttng_ht_add_unique_str(ht, &ksyscall->node); | |
268 | ret = 0; | |
269 | ||
270 | error: | |
271 | return ret; | |
272 | } | |
273 | ||
274 | /* | |
275 | * List syscalls present in the kernel syscall global array, allocate and | |
276 | * populate the events structure with them. Skip the empty syscall name. | |
277 | * | |
278 | * Return the number of entries in the array else a negative value. | |
279 | */ | |
280 | ssize_t syscall_table_list(struct lttng_event **_events) | |
281 | { | |
282 | int i, index = 0; | |
283 | ssize_t ret; | |
284 | struct lttng_event *events; | |
285 | /* Hash table used to filter duplicate out. */ | |
cd9adb8b | 286 | struct lttng_ht *syscalls_ht = nullptr; |
834978fd | 287 | |
a0377dfe | 288 | LTTNG_ASSERT(_events); |
834978fd DG |
289 | |
290 | DBG("Syscall table listing."); | |
291 | ||
834978fd DG |
292 | /* |
293 | * Allocate at least the number of total syscall we have even if some of | |
294 | * them might not be valid. The count below will make sure to return the | |
295 | * right size of the events array. | |
296 | */ | |
64803277 | 297 | events = calloc<lttng_event>(syscall_table_nb_entry); |
834978fd DG |
298 | if (!events) { |
299 | PERROR("syscall table list zmalloc"); | |
300 | ret = -LTTNG_ERR_NOMEM; | |
301 | goto error; | |
302 | } | |
303 | ||
304 | ret = init_syscall_ht(&syscalls_ht); | |
305 | if (ret < 0) { | |
306 | goto error; | |
307 | } | |
308 | ||
309 | for (i = 0; i < syscall_table_nb_entry; i++) { | |
834978fd DG |
310 | /* Skip empty syscalls. */ |
311 | if (*syscall_table[i].name == '\0') { | |
312 | continue; | |
313 | } | |
314 | ||
56047f5a JG |
315 | { |
316 | lttng::urcu::read_lock_guard read_lock; | |
317 | struct syscall *ksyscall; | |
318 | ||
319 | ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name); | |
320 | if (ksyscall) { | |
321 | update_event_syscall_bitness(events, i, ksyscall->index); | |
322 | continue; | |
323 | } | |
834978fd DG |
324 | } |
325 | ||
326 | ret = add_syscall_to_ht(syscalls_ht, i, index); | |
327 | if (ret < 0) { | |
328 | goto error; | |
329 | } | |
330 | ||
331 | /* Copy the event information in the event's array. */ | |
28ab034a | 332 | strncpy(events[index].name, syscall_table[i].name, sizeof(events[index].name)); |
834978fd DG |
333 | update_event_syscall_bitness(events, i, index); |
334 | events[index].type = LTTNG_EVENT_SYSCALL; | |
335 | /* This makes the command line not print the enabled/disabled field. */ | |
336 | events[index].enabled = -1; | |
337 | index++; | |
338 | } | |
339 | ||
340 | destroy_syscall_ht(syscalls_ht); | |
341 | *_events = events; | |
834978fd DG |
342 | return index; |
343 | ||
344 | error: | |
345 | destroy_syscall_ht(syscalls_ht); | |
346 | free(events); | |
834978fd DG |
347 | return ret; |
348 | } |