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1 | |
2 | /* LTTng user-space tracing code |
3 | * |
4 | * Copyright 2006 Mathieu Desnoyers |
5 | * |
6 | */ |
7 | |
8 | |
9 | #include <sys/types.h> |
10 | #include <sys/wait.h> |
11 | #include <unistd.h> |
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12 | #include <stdlib.h> |
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13 | #include <stdio.h> |
14 | #include <signal.h> |
15 | #include <syscall.h> |
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16 | #include <features.h> |
17 | #include <pthread.h> |
18 | #include <malloc.h> |
19 | #include <string.h> |
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20 | |
21 | #include "lttng_usertrace.h" |
22 | |
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23 | #define MAX_TRACES 16 |
24 | |
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25 | |
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26 | /* TLS for the trace info |
27 | * http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html |
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28 | * |
29 | * Add after paragraph 4 |
30 | * |
31 | * The storage for an object of thread storage duration shall be statically |
32 | * initialized before the first statement of the thread startup function. An |
33 | * object of thread storage duration shall not require dynamic |
34 | * initialization. |
35 | * GCC extention permits init of a range. |
36 | */ |
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37 | |
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38 | static __thread struct lttng_trace_info lttng_trace_info[MAX_TRACES] = |
39 | { [ 0 ... MAX_TRACES-1 ].active = 0, |
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40 | [ 0 ... MAX_TRACES-1 ].filter = 0, |
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41 | [ 0 ... MAX_TRACES-1 ].nesting = ATOMIC_INIT(0), |
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42 | [ 0 ... MAX_TRACES-1 ].channel = |
43 | { NULL, |
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44 | 0, |
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45 | ATOMIC_INIT(0), |
46 | ATOMIC_INIT(0), |
47 | ATOMIC_INIT(0), |
48 | ATOMIC_INIT(0), |
49 | ATOMIC_INIT(0) |
50 | } |
51 | }; |
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52 | |
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53 | |
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54 | /* Must be called we sure nobody else is using the info. |
55 | * It implies that the trace should have been previously stopped |
56 | * and that every writer has finished. |
57 | * |
58 | * Writers should always check if the trace must be destroyed when they |
59 | * finish writing and the nesting level is 0. |
60 | */ |
61 | void lttng_free_trace_info(struct lttng_trace_info *info) |
62 | { |
63 | int ret; |
64 | |
65 | if(info->active) { |
66 | printf( |
67 | "LTTng ERROR : lttng_free_trace_info should be called on inactive trace\n"); |
68 | exit(1); |
69 | } |
70 | if(!info->destroy) { |
71 | printf( |
72 | "LTTng ERROR : lttng_free_trace_info should be called on destroyed trace\n"); |
73 | exit(1); |
74 | } |
75 | if(atomic_read(&info->nesting) > 0) { |
76 | printf( |
77 | "LTTng ERROR : lttng_free_trace_info should not be nested on tracing\n"); |
78 | exit(1); |
79 | } |
80 | |
81 | /* Remove the maps */ |
82 | ret = munmap(info->channel.cpu.start, info->channel.cpu.length); |
83 | if(ret) { |
84 | perror("LTTNG : error in munmap"); |
85 | } |
86 | ret = munmap(info->channel.facilities.start, info->channel.facilities.length); |
87 | if(ret) { |
88 | perror("LTTNG : error in munmap"); |
89 | } |
90 | |
91 | /* Zero the structure */ |
92 | memset(info, 0, sizeof(struct lttng_trace_info)); |
93 | } |
94 | |
95 | |
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96 | static void lttng_get_new_info(void) |
97 | { |
98 | unsigned long cpu_addr, fac_addr; |
99 | unsigned int i, first_empty; |
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100 | int active, filter, destroy; |
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101 | int ret; |
102 | |
103 | /* Get all the new traces */ |
104 | while(1) { |
105 | cpu_addr = fac_addr = 0; |
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106 | active = filter = destroy = 0; |
107 | ret = ltt_update(&cpu_addr, &fac_addr, &active, &filter, &destroy); |
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108 | if(ret) { |
109 | printf("LTTng : error in ltt_update\n"); |
110 | exit(1); |
111 | } |
112 | |
113 | if(!cpu_addr || !fac_addr) break; |
114 | |
115 | first_empty = MAX_TRACES; |
116 | /* Try to find the trace */ |
117 | for(i=0;i<MAX_TRACES;i++) { |
118 | if(i<first_empty && !lttng_trace_info[i].channel.cpu.start) |
119 | first_empty = i; |
120 | if(cpu_addr == |
121 | (unsigned long)lttng_trace_info[i].channel.cpu.start && |
122 | fac_addr == |
123 | (unsigned long)lttng_trace_info[i].channel.facilities.start) { |
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124 | /* Found */ |
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125 | lttng_trace_info[i].filter = filter; |
126 | lttng_trace_info[i].active = active; |
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127 | lttng_trace_info[i].destroy = destroy; |
128 | if(destroy && !atomic_read(<tng_trace_info[i].nesting)) { |
129 | lttng_free_trace_info(<tng_trace_info[i]); |
130 | } |
131 | break; |
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132 | } |
133 | |
134 | } |
135 | if(i == MAX_TRACES) { |
136 | /* Not found. Must take an empty slot */ |
137 | if(first_empty == MAX_TRACES) { |
138 | printf( |
139 | "LTTng WARNING : too many traces requested for pid %d by the kernel.\n" |
140 | " Compilation defined maximum is %u\n", |
141 | getpid(), MAX_TRACES); |
142 | |
143 | } else { |
144 | lttng_trace_info[first_empty].channel.cpu.start = (void*)cpu_addr; |
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145 | lttng_trace_info[first_empty].channel.cpu.length = PAGE_SIZE; |
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146 | lttng_trace_info[first_empty].channel.facilities.start = |
147 | (void*)fac_addr; |
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148 | lttng_trace_info[first_empty].channel.facilities.length = PAGE_SIZE; |
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149 | lttng_trace_info[first_empty].filter = filter; |
150 | lttng_trace_info[first_empty].active = active; |
151 | } |
152 | } |
153 | } |
154 | } |
155 | |
156 | |
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157 | /* signal handler */ |
158 | void __lttng_sig_trace_handler(int signo) |
159 | { |
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160 | int ret; |
161 | sigset_t set, oldset; |
162 | |
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163 | printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid()); |
164 | #if 0 |
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165 | /* Disable signals */ |
166 | ret = sigfillset(&set); |
167 | if(ret) { |
168 | printf("Error in sigfillset\n"); |
169 | exit(1); |
170 | } |
171 | |
172 | ret = sigprocmask(SIG_BLOCK, &set, &oldset); |
173 | if(ret) { |
174 | printf("Error in sigprocmask\n"); |
175 | exit(1); |
176 | } |
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177 | #endif //0 |
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178 | #if 0 |
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179 | /* Enable signals */ |
180 | ret = sigprocmask(SIG_SETMASK, &oldset, NULL); |
181 | if(ret) { |
182 | printf("Error in sigprocmask\n"); |
183 | exit(1); |
184 | } |
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185 | #endif //0 |
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186 | } |
187 | |
188 | |
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189 | static void thread_init(void) |
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190 | { |
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191 | lttng_get_new_info(); |
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192 | int err; |
193 | |
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194 | /* Make some ltt_switch syscalls */ |
195 | err = ltt_switch((unsigned long)NULL); |
196 | if(err) { |
197 | printf("Error in ltt_switch system call\n"); |
198 | exit(1); |
199 | } |
1a1e2a8c |
200 | } |
201 | |
202 | void __attribute__((constructor)) __lttng_user_init(void) |
203 | { |
204 | static struct sigaction act; |
205 | int err; |
206 | |
207 | printf("LTTng user init\n"); |
208 | |
209 | /* Activate the signal */ |
210 | act.sa_handler = __lttng_sig_trace_handler; |
211 | err = sigemptyset(&(act.sa_mask)); |
212 | if(err) perror("Error with sigemptyset"); |
213 | err = sigaddset(&(act.sa_mask), SIGRTMIN+3); |
214 | if(err) perror("Error with sigaddset"); |
215 | err = sigaction(SIGRTMIN+3, &act, NULL); |
216 | if(err) perror("Error with sigaction"); |
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217 | |
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218 | thread_init(); |
219 | } |
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220 | |
221 | |
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222 | void lttng_thread_init(void) |
223 | { |
224 | thread_init(); |
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225 | } |
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226 | |
227 | |
228 | |
229 | |
230 | |