Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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}