2 * Copyright (C) 2014 David Goulet <dgoulet@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
10 #include "lttng-sessiond.hpp"
11 #include "lttng-syscall.hpp"
14 #include <common/common.hpp>
15 #include <common/kernel-ctl/kernel-ctl.hpp>
19 /* Global syscall table. */
20 struct syscall
*syscall_table
;
22 /* Number of entry in the syscall table. */
23 static size_t syscall_table_nb_entry
;
26 * Populate the system call table using the kernel tracer.
28 * Return 0 on success and the syscall table is allocated. On error, a negative
31 int syscall_init_table(int tracer_fd
)
36 /* Syscall data from the kernel. */
38 bool at_least_one_syscall
= false;
40 char name
[SYSCALL_NAME_LEN
];
42 #if (SYSCALL_NAME_LEN == 255)
43 #define SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "254"
46 DBG3("Syscall init system call table");
48 fd
= kernctl_syscall_list(tracer_fd
);
51 PERROR("kernelctl syscall list");
58 PERROR("syscall list fdopen");
62 nbmem
= SYSCALL_TABLE_INIT_SIZE
;
63 syscall_table
= calloc
<struct syscall
>(nbmem
);
66 PERROR("syscall list zmalloc");
71 "syscall { index = %zu; \
72 name = %" SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API
"[^;]; \
77 at_least_one_syscall
= true;
79 struct syscall
*new_list
;
82 /* Double memory size. */
83 new_nbmem
= std::max(index
+ 1, nbmem
<< 1);
84 if (new_nbmem
> (SIZE_MAX
/ sizeof(*new_list
))) {
85 /* Overflow, stop everything, something went really wrong. */
86 ERR("Syscall listing memory size overflow. Stopping");
88 syscall_table
= nullptr;
93 DBG("Reallocating syscall table from %zu to %zu entries", nbmem
, new_nbmem
);
94 new_list
= (struct syscall
*) realloc(syscall_table
,
95 new_nbmem
* sizeof(*new_list
));
98 PERROR("syscall list realloc");
102 /* Zero out the new memory. */
103 memset(new_list
+ nbmem
, 0, (new_nbmem
- nbmem
) * sizeof(*new_list
));
105 syscall_table
= new_list
;
107 syscall_table
[index
].index
= index
;
108 syscall_table
[index
].bitness
= bitness
;
110 syscall_table
[index
].name
, name
, sizeof(syscall_table
[index
].name
))) {
113 syscall_table
= nullptr;
117 DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u",
118 syscall_table[index].name,
119 syscall_table[index].index,
120 syscall_table[index].bitness);
124 /* Index starts at 0. */
125 if (at_least_one_syscall
) {
126 syscall_table_nb_entry
= index
+ 1;
134 PERROR("syscall list fclose");
141 PERROR("syscall list close");
149 * Helper function for the list syscalls command that empty the temporary
150 * syscall hashtable used to track duplicate between 32 and 64 bit arch.
152 * This empty the hash table and destroys it after. After this, the pointer is
153 * unsuable. RCU read side lock MUST be acquired before calling this.
155 static void destroy_syscall_ht(struct lttng_ht
*ht
)
157 struct lttng_ht_iter iter
;
158 struct syscall
*ksyscall
;
160 ASSERT_RCU_READ_LOCKED();
162 DBG3("Destroying syscall hash table.");
168 cds_lfht_for_each_entry (ht
->ht
, &iter
.iter
, ksyscall
, node
.node
) {
171 ret
= lttng_ht_del(ht
, &iter
);
175 lttng_ht_destroy(ht
);
179 * Allocate the given hashtable pointer.
181 * Return 0 on success else a negative LTTNG error value.
183 static int init_syscall_ht(struct lttng_ht
**ht
)
187 *ht
= lttng_ht_new(0, LTTNG_HT_TYPE_STRING
);
189 ret
= -LTTNG_ERR_NOMEM
;
198 * Lookup a syscall in the given hash table by name.
200 * Return syscall object if found or else NULL.
202 static struct syscall
*lookup_syscall(struct lttng_ht
*ht
, const char *name
)
204 struct lttng_ht_node_str
*node
;
205 struct lttng_ht_iter iter
;
206 struct syscall
*ksyscall
= nullptr;
211 lttng_ht_lookup(ht
, (void *) name
, &iter
);
212 node
= lttng_ht_iter_get_node_str(&iter
);
214 ksyscall
= lttng::utils::container_of(node
, &syscall::node
);
221 * Using the given syscall object in the events array with the bitness of the
222 * syscall at index in the syscall table.
224 static void update_event_syscall_bitness(struct lttng_event
*events
,
226 unsigned int syscall_index
)
228 LTTNG_ASSERT(events
);
230 if (syscall_table
[index
].bitness
== 32) {
231 events
[syscall_index
].flags
= (lttng_event_flag
) (events
[syscall_index
].flags
|
232 LTTNG_EVENT_FLAG_SYSCALL_32
);
234 events
[syscall_index
].flags
= (lttng_event_flag
) (events
[syscall_index
].flags
|
235 LTTNG_EVENT_FLAG_SYSCALL_64
);
240 * Allocate and initialize syscall object and add it to the given hashtable.
242 * Return 0 on success else -LTTNG_ERR_NOMEM.
244 static int add_syscall_to_ht(struct lttng_ht
*ht
, unsigned int index
, unsigned int syscall_index
)
247 struct syscall
*ksyscall
;
251 ksyscall
= zmalloc
<struct syscall
>();
253 ret
= -LTTNG_ERR_NOMEM
;
257 strncpy(ksyscall
->name
, syscall_table
[index
].name
, sizeof(ksyscall
->name
));
258 ksyscall
->bitness
= syscall_table
[index
].bitness
;
259 ksyscall
->index
= syscall_index
;
260 lttng_ht_node_init_str(&ksyscall
->node
, ksyscall
->name
);
261 lttng_ht_add_unique_str(ht
, &ksyscall
->node
);
269 * List syscalls present in the kernel syscall global array, allocate and
270 * populate the events structure with them. Skip the empty syscall name.
272 * Return the number of entries in the array else a negative value.
274 ssize_t
syscall_table_list(struct lttng_event
**_events
)
278 struct lttng_event
*events
;
279 /* Hash table used to filter duplicate out. */
280 struct lttng_ht
*syscalls_ht
= nullptr;
282 LTTNG_ASSERT(_events
);
284 DBG("Syscall table listing.");
289 * Allocate at least the number of total syscall we have even if some of
290 * them might not be valid. The count below will make sure to return the
291 * right size of the events array.
293 events
= calloc
<lttng_event
>(syscall_table_nb_entry
);
295 PERROR("syscall table list zmalloc");
296 ret
= -LTTNG_ERR_NOMEM
;
300 ret
= init_syscall_ht(&syscalls_ht
);
305 for (i
= 0; i
< syscall_table_nb_entry
; i
++) {
306 struct syscall
*ksyscall
;
308 /* Skip empty syscalls. */
309 if (*syscall_table
[i
].name
== '\0') {
313 ksyscall
= lookup_syscall(syscalls_ht
, syscall_table
[i
].name
);
315 update_event_syscall_bitness(events
, i
, ksyscall
->index
);
319 ret
= add_syscall_to_ht(syscalls_ht
, i
, index
);
324 /* Copy the event information in the event's array. */
325 strncpy(events
[index
].name
, syscall_table
[i
].name
, sizeof(events
[index
].name
));
326 update_event_syscall_bitness(events
, i
, index
);
327 events
[index
].type
= LTTNG_EVENT_SYSCALL
;
328 /* This makes the command line not print the enabled/disabled field. */
329 events
[index
].enabled
= -1;
333 destroy_syscall_ht(syscalls_ht
);
339 destroy_syscall_ht(syscalls_ht
);