2 * Copyright (C) 2014 David Goulet <dgoulet@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
11 #include <common/common.h>
12 #include <common/kernel-ctl/kernel-ctl.h>
14 #include "lttng-sessiond.h"
16 #include "lttng-syscall.h"
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
= (struct syscall
*) zmalloc(sizeof(struct syscall
) * nbmem
);
66 PERROR("syscall list zmalloc");
71 "syscall { index = %zu; \
72 name = %" SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API
"[^;]; \
74 &index
, name
, &bitness
) == 3) {
75 at_least_one_syscall
= true;
77 struct syscall
*new_list
;
80 /* Double memory size. */
81 new_nbmem
= std::max(index
+ 1, nbmem
<< 1);
82 if (new_nbmem
> (SIZE_MAX
/ sizeof(*new_list
))) {
83 /* Overflow, stop everything, something went really wrong. */
84 ERR("Syscall listing memory size overflow. Stopping");
91 DBG("Reallocating syscall table from %zu to %zu entries", nbmem
,
93 new_list
= (struct syscall
*) realloc(syscall_table
, new_nbmem
* sizeof(*new_list
));
96 PERROR("syscall list realloc");
100 /* Zero out the new memory. */
101 memset(new_list
+ nbmem
, 0,
102 (new_nbmem
- nbmem
) * sizeof(*new_list
));
104 syscall_table
= new_list
;
106 syscall_table
[index
].index
= index
;
107 syscall_table
[index
].bitness
= bitness
;
108 if (lttng_strncpy(syscall_table
[index
].name
, name
,
109 sizeof(syscall_table
[index
].name
))) {
112 syscall_table
= NULL
;
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);
123 /* Index starts at 0. */
124 if (at_least_one_syscall
) {
125 syscall_table_nb_entry
= index
+ 1;
133 PERROR("syscall list fclose");
140 PERROR("syscall list close");
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.
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.
154 static void destroy_syscall_ht(struct lttng_ht
*ht
)
156 struct lttng_ht_iter iter
;
157 struct syscall
*ksyscall
;
159 ASSERT_RCU_READ_LOCKED();
161 DBG3("Destroying syscall hash table.");
167 cds_lfht_for_each_entry(ht
->ht
, &iter
.iter
, ksyscall
, node
.node
) {
170 ret
= lttng_ht_del(ht
, &iter
);
174 lttng_ht_destroy(ht
);
178 * Allocate the given hashtable pointer.
180 * Return 0 on success else a negative LTTNG error value.
182 static int init_syscall_ht(struct lttng_ht
**ht
)
186 *ht
= lttng_ht_new(0, LTTNG_HT_TYPE_STRING
);
188 ret
= -LTTNG_ERR_NOMEM
;
197 * Lookup a syscall in the given hash table by name.
199 * Return syscall object if found or else NULL.
201 static struct syscall
*lookup_syscall(struct lttng_ht
*ht
, const char *name
)
203 struct lttng_ht_node_str
*node
;
204 struct lttng_ht_iter iter
;
205 struct syscall
*ksyscall
= NULL
;
210 lttng_ht_lookup(ht
, (void *) name
, &iter
);
211 node
= lttng_ht_iter_get_node_str(&iter
);
213 ksyscall
= caa_container_of(node
, struct syscall
, node
);
220 * Using the given syscall object in the events array with the bitness of the
221 * syscall at index in the syscall table.
223 static void update_event_syscall_bitness(struct lttng_event
*events
,
224 unsigned int index
, unsigned int syscall_index
)
226 LTTNG_ASSERT(events
);
228 if (syscall_table
[index
].bitness
== 32) {
229 events
[syscall_index
].flags
= (lttng_event_flag
) (events
[syscall_index
].flags
| LTTNG_EVENT_FLAG_SYSCALL_32
);
231 events
[syscall_index
].flags
= (lttng_event_flag
) (events
[syscall_index
].flags
| LTTNG_EVENT_FLAG_SYSCALL_64
);
236 * Allocate and initialize syscall object and add it to the given hashtable.
238 * Return 0 on success else -LTTNG_ERR_NOMEM.
240 static int add_syscall_to_ht(struct lttng_ht
*ht
, unsigned int index
,
241 unsigned int syscall_index
)
244 struct syscall
*ksyscall
;
248 ksyscall
= (struct syscall
*) zmalloc(sizeof(*ksyscall
));
250 ret
= -LTTNG_ERR_NOMEM
;
254 strncpy(ksyscall
->name
, syscall_table
[index
].name
,
255 sizeof(ksyscall
->name
));
256 ksyscall
->bitness
= syscall_table
[index
].bitness
;
257 ksyscall
->index
= syscall_index
;
258 lttng_ht_node_init_str(&ksyscall
->node
, ksyscall
->name
);
259 lttng_ht_add_unique_str(ht
, &ksyscall
->node
);
267 * List syscalls present in the kernel syscall global array, allocate and
268 * populate the events structure with them. Skip the empty syscall name.
270 * Return the number of entries in the array else a negative value.
272 ssize_t
syscall_table_list(struct lttng_event
**_events
)
276 struct lttng_event
*events
;
277 /* Hash table used to filter duplicate out. */
278 struct lttng_ht
*syscalls_ht
= NULL
;
280 LTTNG_ASSERT(_events
);
282 DBG("Syscall table listing.");
287 * Allocate at least the number of total syscall we have even if some of
288 * them might not be valid. The count below will make sure to return the
289 * right size of the events array.
291 events
= (lttng_event
*) zmalloc(syscall_table_nb_entry
* sizeof(*events
));
293 PERROR("syscall table list zmalloc");
294 ret
= -LTTNG_ERR_NOMEM
;
298 ret
= init_syscall_ht(&syscalls_ht
);
303 for (i
= 0; i
< syscall_table_nb_entry
; i
++) {
304 struct syscall
*ksyscall
;
306 /* Skip empty syscalls. */
307 if (*syscall_table
[i
].name
== '\0') {
311 ksyscall
= lookup_syscall(syscalls_ht
, syscall_table
[i
].name
);
313 update_event_syscall_bitness(events
, i
, ksyscall
->index
);
317 ret
= add_syscall_to_ht(syscalls_ht
, i
, index
);
322 /* Copy the event information in the event's array. */
323 strncpy(events
[index
].name
, syscall_table
[i
].name
,
324 sizeof(events
[index
].name
));
325 update_event_syscall_bitness(events
, i
, index
);
326 events
[index
].type
= LTTNG_EVENT_SYSCALL
;
327 /* This makes the command line not print the enabled/disabled field. */
328 events
[index
].enabled
= -1;
332 destroy_syscall_ht(syscalls_ht
);
338 destroy_syscall_ht(syscalls_ht
);