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1// SPDX-License-Identifier: GPL-2.0
2#include "comm.h"
3#include "util.h"
4#include <errno.h>
5#include <stdlib.h>
6#include <stdio.h>
7#include <string.h>
8#include <linux/refcount.h>
9#include "rwsem.h"
10
11struct comm_str {
12 char *str;
13 struct rb_node rb_node;
14 refcount_t refcnt;
15};
16
17/* Should perhaps be moved to struct machine */
18static struct rb_root comm_str_root;
19static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
20
21static struct comm_str *comm_str__get(struct comm_str *cs)
22{
23 if (cs)
24 refcount_inc(&cs->refcnt);
25 return cs;
26}
27
28static void comm_str__put(struct comm_str *cs)
29{
30 if (cs && refcount_dec_and_test(&cs->refcnt)) {
31 down_write(&comm_str_lock);
32 rb_erase(&cs->rb_node, &comm_str_root);
33 up_write(&comm_str_lock);
34 zfree(&cs->str);
35 free(cs);
36 }
37}
38
39static struct comm_str *comm_str__alloc(const char *str)
40{
41 struct comm_str *cs;
42
43 cs = zalloc(sizeof(*cs));
44 if (!cs)
45 return NULL;
46
47 cs->str = strdup(str);
48 if (!cs->str) {
49 free(cs);
50 return NULL;
51 }
52
53 refcount_set(&cs->refcnt, 1);
54
55 return cs;
56}
57
58static
59struct comm_str *__comm_str__findnew(const char *str, struct rb_root *root)
60{
61 struct rb_node **p = &root->rb_node;
62 struct rb_node *parent = NULL;
63 struct comm_str *iter, *new;
64 int cmp;
65
66 while (*p != NULL) {
67 parent = *p;
68 iter = rb_entry(parent, struct comm_str, rb_node);
69
70 cmp = strcmp(str, iter->str);
71 if (!cmp)
72 return comm_str__get(iter);
73
74 if (cmp < 0)
75 p = &(*p)->rb_left;
76 else
77 p = &(*p)->rb_right;
78 }
79
80 new = comm_str__alloc(str);
81 if (!new)
82 return NULL;
83
84 rb_link_node(&new->rb_node, parent, p);
85 rb_insert_color(&new->rb_node, root);
86
87 return new;
88}
89
90static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
91{
92 struct comm_str *cs;
93
94 down_write(&comm_str_lock);
95 cs = __comm_str__findnew(str, root);
96 up_write(&comm_str_lock);
97
98 return cs;
99}
100
101struct comm *comm__new(const char *str, u64 timestamp, bool exec)
102{
103 struct comm *comm = zalloc(sizeof(*comm));
104
105 if (!comm)
106 return NULL;
107
108 comm->start = timestamp;
109 comm->exec = exec;
110
111 comm->comm_str = comm_str__findnew(str, &comm_str_root);
112 if (!comm->comm_str) {
113 free(comm);
114 return NULL;
115 }
116
117 return comm;
118}
119
120int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
121{
122 struct comm_str *new, *old = comm->comm_str;
123
124 new = comm_str__findnew(str, &comm_str_root);
125 if (!new)
126 return -ENOMEM;
127
128 comm_str__put(old);
129 comm->comm_str = new;
130 comm->start = timestamp;
131 if (exec)
132 comm->exec = true;
133
134 return 0;
135}
136
137void comm__free(struct comm *comm)
138{
139 comm_str__put(comm->comm_str);
140 free(comm);
141}
142
143const char *comm__str(const struct comm *comm)
144{
145 return comm->comm_str->str;
146}
1// SPDX-License-Identifier: GPL-2.0
2#include "comm.h"
3#include <errno.h>
4#include <string.h>
5#include <internal/rc_check.h>
6#include <linux/refcount.h>
7#include <linux/zalloc.h>
8#include "rwsem.h"
9
10DECLARE_RC_STRUCT(comm_str) {
11 refcount_t refcnt;
12 char str[];
13};
14
15static struct comm_strs {
16 struct rw_semaphore lock;
17 struct comm_str **strs;
18 int num_strs;
19 int capacity;
20} _comm_strs;
21
22static void comm_strs__remove_if_last(struct comm_str *cs);
23
24static void comm_strs__init(void)
25{
26 init_rwsem(&_comm_strs.lock);
27 _comm_strs.capacity = 16;
28 _comm_strs.num_strs = 0;
29 _comm_strs.strs = calloc(16, sizeof(*_comm_strs.strs));
30}
31
32static struct comm_strs *comm_strs__get(void)
33{
34 static pthread_once_t comm_strs_type_once = PTHREAD_ONCE_INIT;
35
36 pthread_once(&comm_strs_type_once, comm_strs__init);
37
38 return &_comm_strs;
39}
40
41static refcount_t *comm_str__refcnt(struct comm_str *cs)
42{
43 return &RC_CHK_ACCESS(cs)->refcnt;
44}
45
46static const char *comm_str__str(const struct comm_str *cs)
47{
48 return &RC_CHK_ACCESS(cs)->str[0];
49}
50
51static struct comm_str *comm_str__get(struct comm_str *cs)
52{
53 struct comm_str *result;
54
55 if (RC_CHK_GET(result, cs))
56 refcount_inc_not_zero(comm_str__refcnt(cs));
57
58 return result;
59}
60
61static void comm_str__put(struct comm_str *cs)
62{
63 if (!cs)
64 return;
65
66 if (refcount_dec_and_test(comm_str__refcnt(cs))) {
67 RC_CHK_FREE(cs);
68 } else {
69 if (refcount_read(comm_str__refcnt(cs)) == 1)
70 comm_strs__remove_if_last(cs);
71
72 RC_CHK_PUT(cs);
73 }
74}
75
76static struct comm_str *comm_str__new(const char *str)
77{
78 struct comm_str *result = NULL;
79 RC_STRUCT(comm_str) *cs;
80
81 cs = malloc(sizeof(*cs) + strlen(str) + 1);
82 if (ADD_RC_CHK(result, cs)) {
83 refcount_set(comm_str__refcnt(result), 1);
84 strcpy(&cs->str[0], str);
85 }
86 return result;
87}
88
89static int comm_str__search(const void *_key, const void *_member)
90{
91 const char *key = _key;
92 const struct comm_str *member = *(const struct comm_str * const *)_member;
93
94 return strcmp(key, comm_str__str(member));
95}
96
97static void comm_strs__remove_if_last(struct comm_str *cs)
98{
99 struct comm_strs *comm_strs = comm_strs__get();
100
101 down_write(&comm_strs->lock);
102 /*
103 * Are there only references from the array, if so remove the array
104 * reference under the write lock so that we don't race with findnew.
105 */
106 if (refcount_read(comm_str__refcnt(cs)) == 1) {
107 struct comm_str **entry;
108
109 entry = bsearch(comm_str__str(cs), comm_strs->strs, comm_strs->num_strs,
110 sizeof(struct comm_str *), comm_str__search);
111 comm_str__put(*entry);
112 for (int i = entry - comm_strs->strs; i < comm_strs->num_strs - 1; i++)
113 comm_strs->strs[i] = comm_strs->strs[i + 1];
114 comm_strs->num_strs--;
115 }
116 up_write(&comm_strs->lock);
117}
118
119static struct comm_str *__comm_strs__find(struct comm_strs *comm_strs, const char *str)
120{
121 struct comm_str **result;
122
123 result = bsearch(str, comm_strs->strs, comm_strs->num_strs, sizeof(struct comm_str *),
124 comm_str__search);
125
126 if (!result)
127 return NULL;
128
129 return comm_str__get(*result);
130}
131
132static struct comm_str *comm_strs__findnew(const char *str)
133{
134 struct comm_strs *comm_strs = comm_strs__get();
135 struct comm_str *result;
136
137 if (!comm_strs)
138 return NULL;
139
140 down_read(&comm_strs->lock);
141 result = __comm_strs__find(comm_strs, str);
142 up_read(&comm_strs->lock);
143 if (result)
144 return result;
145
146 down_write(&comm_strs->lock);
147 result = __comm_strs__find(comm_strs, str);
148 if (!result) {
149 if (comm_strs->num_strs == comm_strs->capacity) {
150 struct comm_str **tmp;
151
152 tmp = reallocarray(comm_strs->strs,
153 comm_strs->capacity + 16,
154 sizeof(*comm_strs->strs));
155 if (!tmp) {
156 up_write(&comm_strs->lock);
157 return NULL;
158 }
159 comm_strs->strs = tmp;
160 comm_strs->capacity += 16;
161 }
162 result = comm_str__new(str);
163 if (result) {
164 int low = 0, high = comm_strs->num_strs - 1;
165 int insert = comm_strs->num_strs; /* Default to inserting at the end. */
166
167 while (low <= high) {
168 int mid = low + (high - low) / 2;
169 int cmp = strcmp(comm_str__str(comm_strs->strs[mid]), str);
170
171 if (cmp < 0) {
172 low = mid + 1;
173 } else {
174 high = mid - 1;
175 insert = mid;
176 }
177 }
178 memmove(&comm_strs->strs[insert + 1], &comm_strs->strs[insert],
179 (comm_strs->num_strs - insert) * sizeof(struct comm_str *));
180 comm_strs->num_strs++;
181 comm_strs->strs[insert] = result;
182 }
183 }
184 up_write(&comm_strs->lock);
185 return comm_str__get(result);
186}
187
188struct comm *comm__new(const char *str, u64 timestamp, bool exec)
189{
190 struct comm *comm = zalloc(sizeof(*comm));
191
192 if (!comm)
193 return NULL;
194
195 comm->start = timestamp;
196 comm->exec = exec;
197
198 comm->comm_str = comm_strs__findnew(str);
199 if (!comm->comm_str) {
200 free(comm);
201 return NULL;
202 }
203
204 return comm;
205}
206
207int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
208{
209 struct comm_str *new, *old = comm->comm_str;
210
211 new = comm_strs__findnew(str);
212 if (!new)
213 return -ENOMEM;
214
215 comm_str__put(old);
216 comm->comm_str = new;
217 comm->start = timestamp;
218 if (exec)
219 comm->exec = true;
220
221 return 0;
222}
223
224void comm__free(struct comm *comm)
225{
226 comm_str__put(comm->comm_str);
227 free(comm);
228}
229
230const char *comm__str(const struct comm *comm)
231{
232 return comm_str__str(comm->comm_str);
233}