Commit | Line | Data |
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02119ee5 MD |
1 | /* |
2 | * ltt-probes.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Holds LTTng probes registry. | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/list.h> | |
11 | #include <linux/mutex.h> | |
271b6681 | 12 | #include <linux/seq_file.h> |
02119ee5 | 13 | |
85a9ca7f | 14 | #include "ltt-events.h" |
02119ee5 MD |
15 | |
16 | static LIST_HEAD(probe_list); | |
17 | static DEFINE_MUTEX(probe_mutex); | |
02119ee5 | 18 | |
85a9ca7f MD |
19 | static |
20 | const struct lttng_event_desc *find_event(const char *name) | |
02119ee5 | 21 | { |
85a9ca7f MD |
22 | struct lttng_probe_desc *probe_desc; |
23 | int i; | |
02119ee5 | 24 | |
85a9ca7f MD |
25 | list_for_each_entry(probe_desc, &probe_list, head) { |
26 | for (i = 0; i < probe_desc->nr_events; i++) { | |
27 | if (!strcmp(probe_desc->event_desc[i].name, name)) | |
28 | return &probe_desc->event_desc[i]; | |
29 | } | |
02119ee5 MD |
30 | } |
31 | return NULL; | |
32 | } | |
33 | ||
85a9ca7f | 34 | int ltt_probe_register(struct lttng_probe_desc *desc) |
02119ee5 | 35 | { |
02119ee5 | 36 | int ret = 0; |
85a9ca7f | 37 | int i; |
02119ee5 MD |
38 | |
39 | mutex_lock(&probe_mutex); | |
85a9ca7f MD |
40 | /* |
41 | * TODO: This is O(N^2). Turn into a hash table when probe registration | |
42 | * overhead becomes an issue. | |
43 | */ | |
44 | for (i = 0; i < desc->nr_events; i++) { | |
45 | if (find_event(desc->event_desc[i].name)) { | |
46 | ret = -EEXIST; | |
47 | goto end; | |
48 | } | |
02119ee5 | 49 | } |
85a9ca7f | 50 | list_add(&desc->head, &probe_list); |
02119ee5 MD |
51 | end: |
52 | mutex_unlock(&probe_mutex); | |
53 | return ret; | |
54 | } | |
55 | EXPORT_SYMBOL_GPL(ltt_probe_register); | |
56 | ||
85a9ca7f | 57 | void ltt_probe_unregister(struct lttng_probe_desc *desc) |
02119ee5 | 58 | { |
02119ee5 | 59 | mutex_lock(&probe_mutex); |
85a9ca7f | 60 | list_del(&desc->head); |
02119ee5 | 61 | mutex_unlock(&probe_mutex); |
02119ee5 MD |
62 | } |
63 | EXPORT_SYMBOL_GPL(ltt_probe_unregister); | |
64 | ||
85a9ca7f | 65 | const struct lttng_event_desc *ltt_event_get(const char *name) |
02119ee5 | 66 | { |
85a9ca7f | 67 | const struct lttng_event_desc *event; |
02119ee5 MD |
68 | int ret; |
69 | ||
70 | mutex_lock(&probe_mutex); | |
85a9ca7f | 71 | event = find_event(name); |
c099397a | 72 | mutex_unlock(&probe_mutex); |
85a9ca7f | 73 | if (!event) |
c099397a | 74 | return NULL; |
dc7f600a | 75 | ret = try_module_get(event->owner); |
02119ee5 | 76 | WARN_ON_ONCE(!ret); |
85a9ca7f | 77 | return event; |
02119ee5 | 78 | } |
85a9ca7f | 79 | EXPORT_SYMBOL_GPL(ltt_event_get); |
02119ee5 | 80 | |
85a9ca7f | 81 | void ltt_event_put(const struct lttng_event_desc *event) |
02119ee5 | 82 | { |
dc7f600a | 83 | module_put(event->owner); |
02119ee5 | 84 | } |
85a9ca7f | 85 | EXPORT_SYMBOL_GPL(ltt_event_put); |
271b6681 MD |
86 | |
87 | static | |
88 | void *tp_list_start(struct seq_file *m, loff_t *pos) | |
89 | { | |
90 | struct lttng_probe_desc *probe_desc; | |
91 | int iter = 0, i; | |
92 | ||
93 | list_for_each_entry(probe_desc, &probe_list, head) { | |
94 | for (i = 0; i < probe_desc->nr_events; i++) { | |
95 | if (iter++ >= *pos) | |
96 | return (void *) &probe_desc->event_desc[i]; | |
97 | } | |
98 | } | |
99 | /* End of list */ | |
100 | return NULL; | |
101 | } | |
102 | ||
103 | static | |
104 | void *tp_list_next(struct seq_file *m, void *p, loff_t *ppos) | |
105 | { | |
106 | struct lttng_probe_desc *probe_desc; | |
107 | int iter = 0, i; | |
108 | ||
109 | (*ppos)++; | |
110 | list_for_each_entry(probe_desc, &probe_list, head) { | |
111 | for (i = 0; i < probe_desc->nr_events; i++) { | |
112 | if (iter++ >= *ppos) | |
113 | return (void *) &probe_desc->event_desc[i]; | |
114 | } | |
115 | } | |
116 | /* End of list */ | |
117 | return NULL; | |
118 | } | |
119 | ||
120 | static | |
121 | void tp_list_stop(struct seq_file *m, void *p) | |
122 | { | |
123 | } | |
124 | ||
125 | static | |
126 | int tp_list_show(struct seq_file *m, void *p) | |
127 | { | |
128 | const struct lttng_event_desc *probe_desc = p; | |
129 | ||
130 | seq_printf(m, "event { name = %s; };\n", | |
131 | probe_desc->name); | |
132 | return 0; | |
133 | } | |
134 | ||
135 | static | |
136 | const struct seq_operations lttng_tracepoint_list_seq_ops = { | |
137 | .start = tp_list_start, | |
138 | .next = tp_list_next, | |
139 | .stop = tp_list_stop, | |
140 | .show = tp_list_show, | |
141 | }; | |
142 | ||
143 | static | |
144 | int lttng_tracepoint_list_open(struct inode *inode, struct file *file) | |
145 | { | |
146 | return seq_open(file, <tng_tracepoint_list_seq_ops); | |
147 | } | |
148 | ||
149 | const struct file_operations lttng_tracepoint_list_fops = { | |
150 | .open = lttng_tracepoint_list_open, | |
151 | .read = seq_read, | |
152 | .llseek = seq_lseek, | |
153 | .release = seq_release_private, | |
154 | }; |