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0c0686ee NC |
1 | /* |
2 | * Copyright (C) 2010 Nils Carlson | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
f37142a4 MD |
6 | * License as published by the Free Software Foundation; |
7 | * version 2.1 of the License. | |
0c0686ee NC |
8 | * |
9 | * This library is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with this library; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | * | |
18 | */ | |
19 | ||
b0c4126f | 20 | #define _LGPL_SOURCE |
0c0686ee NC |
21 | #include <errno.h> |
22 | #include <ust/tracepoint.h> | |
81614639 | 23 | #include <ust/tracepoint-internal.h> |
0c0686ee NC |
24 | #include <ust/core.h> |
25 | #include <ust/kcompat/kcompat.h> | |
0c0686ee NC |
26 | #include <urcu-bp.h> |
27 | ||
b0c4126f MD |
28 | #include "usterr_signal_safe.h" |
29 | ||
0c0686ee | 30 | /* libraries that contain trace_events (struct trace_event_lib) */ |
0222e121 | 31 | static CDS_LIST_HEAD(libs); |
c7292295 MD |
32 | /* |
33 | * Nested mutex is not required here, but provide the same guaranteed | |
34 | * for start/stop iteration vs nested ops as markers and tracepoints. | |
35 | */ | |
36 | static __thread int nested_mutex; | |
0c0686ee NC |
37 | static DEFINE_MUTEX(trace_events_mutex); |
38 | ||
c7292295 MD |
39 | static |
40 | int trace_event_get_iter_range(struct trace_event * const **trace_event, | |
41 | struct trace_event * const *begin, | |
42 | struct trace_event * const *end); | |
43 | ||
44 | static | |
0c0686ee NC |
45 | void lock_trace_events(void) |
46 | { | |
c7292295 MD |
47 | if (!(nested_mutex++)) |
48 | pthread_mutex_lock(&trace_events_mutex); | |
0c0686ee NC |
49 | } |
50 | ||
c7292295 | 51 | static |
0c0686ee NC |
52 | void unlock_trace_events(void) |
53 | { | |
c7292295 MD |
54 | if (!(--nested_mutex)) |
55 | pthread_mutex_unlock(&trace_events_mutex); | |
0c0686ee NC |
56 | } |
57 | ||
c7292295 | 58 | static |
0c0686ee NC |
59 | int lib_get_iter_trace_events(struct trace_event_iter *iter) |
60 | { | |
61 | struct trace_event_lib *iter_lib; | |
62 | int found = 0; | |
63 | ||
0222e121 | 64 | cds_list_for_each_entry(iter_lib, &libs, list) { |
0c0686ee NC |
65 | if (iter_lib < iter->lib) |
66 | continue; | |
67 | else if (iter_lib > iter->lib) | |
68 | iter->trace_event = NULL; | |
69 | found = trace_event_get_iter_range(&iter->trace_event, | |
70 | iter_lib->trace_events_start, | |
71 | iter_lib->trace_events_start + iter_lib->trace_events_count); | |
72 | if (found) { | |
73 | iter->lib = iter_lib; | |
74 | break; | |
75 | } | |
76 | } | |
77 | return found; | |
78 | } | |
79 | ||
80 | /** | |
81 | * trace_event_get_iter_range - Get a next trace_event iterator given a range. | |
82 | * @trace_event: current trace_events (in), next trace_event (out) | |
83 | * @begin: beginning of the range | |
84 | * @end: end of the range | |
85 | * | |
86 | * Returns whether a next trace_event has been found (1) or not (0). | |
87 | * Will return the first trace_event in the range if the input trace_event is NULL. | |
c7292295 | 88 | * Called with trace event mutex held. |
0c0686ee | 89 | */ |
c7292295 | 90 | static |
fc1caebc MD |
91 | int trace_event_get_iter_range(struct trace_event * const **trace_event, |
92 | struct trace_event * const *begin, | |
93 | struct trace_event * const *end) | |
0c0686ee | 94 | { |
f08ebbe2 | 95 | if (!*trace_event && begin != end) |
0c0686ee | 96 | *trace_event = begin; |
f08ebbe2 MD |
97 | while (*trace_event >= begin && *trace_event < end) { |
98 | if (!**trace_event) | |
99 | (*trace_event)++; /* skip dummy */ | |
100 | else | |
101 | return 1; | |
0c0686ee | 102 | } |
0c0686ee NC |
103 | return 0; |
104 | } | |
105 | ||
106 | static void trace_event_get_iter(struct trace_event_iter *iter) | |
107 | { | |
108 | int found = 0; | |
109 | ||
110 | found = lib_get_iter_trace_events(iter); | |
e2b46575 | 111 | |
0c0686ee NC |
112 | if (!found) |
113 | trace_event_iter_reset(iter); | |
114 | } | |
115 | ||
116 | void trace_event_iter_start(struct trace_event_iter *iter) | |
117 | { | |
c7292295 | 118 | lock_trace_events(); |
0c0686ee NC |
119 | trace_event_get_iter(iter); |
120 | } | |
121 | ||
c7292295 MD |
122 | /* |
123 | * Called with trace event mutex held. | |
124 | */ | |
0c0686ee NC |
125 | void trace_event_iter_next(struct trace_event_iter *iter) |
126 | { | |
127 | iter->trace_event++; | |
128 | /* | |
129 | * iter->trace_event may be invalid because we blindly incremented it. | |
130 | * Make sure it is valid by marshalling on the trace_events, getting the | |
131 | * trace_events from following modules if necessary. | |
132 | */ | |
133 | trace_event_get_iter(iter); | |
134 | } | |
135 | ||
c7292295 MD |
136 | void trace_event_iter_stop(struct trace_event_iter *iter) |
137 | { | |
138 | unlock_trace_events(); | |
139 | } | |
140 | ||
0c0686ee NC |
141 | void trace_event_iter_reset(struct trace_event_iter *iter) |
142 | { | |
143 | iter->lib = NULL; | |
144 | iter->trace_event = NULL; | |
145 | } | |
146 | ||
fc1caebc | 147 | int trace_event_register_lib(struct trace_event * const *trace_events_start, |
0c0686ee NC |
148 | int trace_events_count) |
149 | { | |
b467f7a7 | 150 | struct trace_event_lib *pl, *iter; |
0c0686ee NC |
151 | |
152 | pl = (struct trace_event_lib *) malloc(sizeof(struct trace_event_lib)); | |
153 | ||
154 | pl->trace_events_start = trace_events_start; | |
155 | pl->trace_events_count = trace_events_count; | |
156 | ||
c7292295 | 157 | lock_trace_events(); |
b467f7a7 MD |
158 | /* |
159 | * We sort the libs by struct lib pointer address. | |
160 | */ | |
161 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
162 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
163 | if (iter < pl) { | |
164 | /* We belong to the location right after iter. */ | |
165 | cds_list_add(&pl->list, &iter->list); | |
166 | goto lib_added; | |
167 | } | |
168 | } | |
169 | /* We should be added at the head of the list */ | |
0222e121 | 170 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 171 | lib_added: |
c7292295 | 172 | unlock_trace_events(); |
0c0686ee | 173 | |
f08ebbe2 | 174 | /* trace_events_count - 1: skip dummy */ |
3b297856 | 175 | DBG("just registered a trace_events section from %p and having %d trace_events (minus dummy trace_event)", trace_events_start, trace_events_count); |
0c0686ee NC |
176 | |
177 | return 0; | |
178 | } | |
179 | ||
fc1caebc | 180 | int trace_event_unregister_lib(struct trace_event * const *trace_events_start) |
0c0686ee NC |
181 | { |
182 | struct trace_event_lib *lib; | |
183 | ||
c7292295 | 184 | unlock_trace_events(); |
0222e121 | 185 | cds_list_for_each_entry(lib, &libs, list) { |
0c0686ee NC |
186 | if(lib->trace_events_start == trace_events_start) { |
187 | struct trace_event_lib *lib2free = lib; | |
0222e121 | 188 | cds_list_del(&lib->list); |
0c0686ee NC |
189 | free(lib2free); |
190 | break; | |
191 | } | |
192 | } | |
c7292295 | 193 | unlock_trace_events(); |
0c0686ee NC |
194 | |
195 | return 0; | |
196 | } |