| 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> |
| 12 | #include <stdlib.h> |
| 13 | #include <stdio.h> |
| 14 | #include <signal.h> |
| 15 | #include <syscall.h> |
| 16 | #include <features.h> |
| 17 | #include <pthread.h> |
| 18 | #include <malloc.h> |
| 19 | #include <string.h> |
| 20 | |
| 21 | #include <asm/atomic.h> |
| 22 | #include "lttng_usertrace.h" |
| 23 | |
| 24 | #define MAX_TRACES 16 |
| 25 | |
| 26 | struct ltt_buf { |
| 27 | void *start; |
| 28 | atomic_t offset; |
| 29 | atomic_t reserve_count; |
| 30 | atomic_t commit_count; |
| 31 | |
| 32 | atomic_t events_lost; |
| 33 | }; |
| 34 | |
| 35 | struct lttng_trace_info { |
| 36 | int active:1; |
| 37 | int filter; |
| 38 | struct { |
| 39 | struct ltt_buf facilities; |
| 40 | struct ltt_buf cpu; |
| 41 | } channel; |
| 42 | }; |
| 43 | |
| 44 | |
| 45 | /* TLS for the trace info |
| 46 | * http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html |
| 47 | * |
| 48 | * Add after paragraph 4 |
| 49 | * |
| 50 | * The storage for an object of thread storage duration shall be statically |
| 51 | * initialized before the first statement of the thread startup function. An |
| 52 | * object of thread storage duration shall not require dynamic |
| 53 | * initialization. |
| 54 | * GCC extention permits init of a range. |
| 55 | */ |
| 56 | |
| 57 | static __thread struct lttng_trace_info lttng_trace_info[MAX_TRACES] = |
| 58 | { [ 0 ... MAX_TRACES-1 ].active = 0, |
| 59 | [ 0 ... MAX_TRACES-1 ].filter = 0, |
| 60 | [ 0 ... MAX_TRACES-1 ].channel = |
| 61 | { NULL, |
| 62 | ATOMIC_INIT(0), |
| 63 | ATOMIC_INIT(0), |
| 64 | ATOMIC_INIT(0), |
| 65 | ATOMIC_INIT(0), |
| 66 | ATOMIC_INIT(0) |
| 67 | } |
| 68 | }; |
| 69 | |
| 70 | |
| 71 | static void lttng_get_new_info(void) |
| 72 | { |
| 73 | unsigned long cpu_addr, fac_addr; |
| 74 | unsigned int i, first_empty; |
| 75 | int active, filter; |
| 76 | int ret; |
| 77 | |
| 78 | /* Get all the new traces */ |
| 79 | while(1) { |
| 80 | cpu_addr = fac_addr = 0; |
| 81 | active = filter = 0; |
| 82 | ret = ltt_update(&cpu_addr, &fac_addr, &active, &filter); |
| 83 | if(ret) { |
| 84 | printf("LTTng : error in ltt_update\n"); |
| 85 | exit(1); |
| 86 | } |
| 87 | |
| 88 | if(!cpu_addr || !fac_addr) break; |
| 89 | |
| 90 | first_empty = MAX_TRACES; |
| 91 | /* Try to find the trace */ |
| 92 | for(i=0;i<MAX_TRACES;i++) { |
| 93 | if(i<first_empty && !lttng_trace_info[i].channel.cpu.start) |
| 94 | first_empty = i; |
| 95 | if(cpu_addr == |
| 96 | (unsigned long)lttng_trace_info[i].channel.cpu.start && |
| 97 | fac_addr == |
| 98 | (unsigned long)lttng_trace_info[i].channel.facilities.start) { |
| 99 | |
| 100 | lttng_trace_info[i].filter = filter; |
| 101 | lttng_trace_info[i].active = active; |
| 102 | } |
| 103 | |
| 104 | } |
| 105 | if(i == MAX_TRACES) { |
| 106 | /* Not found. Must take an empty slot */ |
| 107 | if(first_empty == MAX_TRACES) { |
| 108 | printf( |
| 109 | "LTTng WARNING : too many traces requested for pid %d by the kernel.\n" |
| 110 | " Compilation defined maximum is %u\n", |
| 111 | getpid(), MAX_TRACES); |
| 112 | |
| 113 | } else { |
| 114 | lttng_trace_info[first_empty].channel.cpu.start = (void*)cpu_addr; |
| 115 | lttng_trace_info[first_empty].channel.facilities.start = |
| 116 | (void*)fac_addr; |
| 117 | lttng_trace_info[first_empty].filter = filter; |
| 118 | lttng_trace_info[first_empty].active = active; |
| 119 | } |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | |
| 125 | /* signal handler */ |
| 126 | void __lttng_sig_trace_handler(int signo) |
| 127 | { |
| 128 | int ret; |
| 129 | sigset_t set, oldset; |
| 130 | |
| 131 | printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid()); |
| 132 | #if 0 |
| 133 | /* Disable signals */ |
| 134 | ret = sigfillset(&set); |
| 135 | if(ret) { |
| 136 | printf("Error in sigfillset\n"); |
| 137 | exit(1); |
| 138 | } |
| 139 | |
| 140 | ret = sigprocmask(SIG_BLOCK, &set, &oldset); |
| 141 | if(ret) { |
| 142 | printf("Error in sigprocmask\n"); |
| 143 | exit(1); |
| 144 | } |
| 145 | #endif //0 |
| 146 | #if 0 |
| 147 | /* Enable signals */ |
| 148 | ret = sigprocmask(SIG_SETMASK, &oldset, NULL); |
| 149 | if(ret) { |
| 150 | printf("Error in sigprocmask\n"); |
| 151 | exit(1); |
| 152 | } |
| 153 | #endif //0 |
| 154 | } |
| 155 | |
| 156 | |
| 157 | static void thread_init(void) |
| 158 | { |
| 159 | lttng_get_new_info(); |
| 160 | int err; |
| 161 | |
| 162 | /* Make some ltt_switch syscalls */ |
| 163 | err = ltt_switch((unsigned long)NULL); |
| 164 | if(err) { |
| 165 | printf("Error in ltt_switch system call\n"); |
| 166 | exit(1); |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | void __attribute__((constructor)) __lttng_user_init(void) |
| 171 | { |
| 172 | static struct sigaction act; |
| 173 | int err; |
| 174 | |
| 175 | printf("LTTng user init\n"); |
| 176 | |
| 177 | /* Activate the signal */ |
| 178 | act.sa_handler = __lttng_sig_trace_handler; |
| 179 | err = sigemptyset(&(act.sa_mask)); |
| 180 | if(err) perror("Error with sigemptyset"); |
| 181 | err = sigaddset(&(act.sa_mask), SIGRTMIN+3); |
| 182 | if(err) perror("Error with sigaddset"); |
| 183 | err = sigaction(SIGRTMIN+3, &act, NULL); |
| 184 | if(err) perror("Error with sigaction"); |
| 185 | |
| 186 | thread_init(); |
| 187 | } |
| 188 | |
| 189 | |
| 190 | void lttng_thread_init(void) |
| 191 | { |
| 192 | thread_init(); |
| 193 | } |
| 194 | |
| 195 | |
| 196 | |
| 197 | |
| 198 | |