usertrace : make state.c ok for reused pids
[lttv.git] / usertrace-fast / ltt-usertrace-fast.c
index fc919c348452d8a52dffcdadea560daa7c462d2a..159c00df9f8a83752bda37204765b758a1a3a97a 100644 (file)
  *
  */
 
+#define inline inline __attribute__((always_inline))
+
 #define _GNU_SOURCE
+#define LTT_TRACE
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <sys/param.h>
 #include <sys/time.h>
+#include <errno.h>
 
 #include <asm/atomic.h>
 #include <asm/timex.h> //for get_cycles()
 
-#include "ltt-usertrace-fast.h"
+_syscall0(pid_t,gettid)
+
+#include <ltt/ltt-usertrace-fast.h>
+
+#ifdef LTT_SHOW_DEBUG
+#define dbg_printf(...) dbg_printf(__VA_ARGS__)
+#else
+#define dbg_printf(...)
+#endif //LTT_SHOW_DEBUG
 
+       
 enum force_switch_mode { FORCE_ACTIVE, FORCE_FLUSH };
 
 /* Writer (the traced application) */
@@ -93,28 +106,28 @@ static void ltt_usertrace_fast_cleanup(void *arg)
 /* Reader (the disk dumper daemon) */
 
 static pid_t traced_pid = 0;
-static pthread_t traced_thread = 0;
+static pid_t traced_tid = 0;
 static int parent_exited = 0;
 
 /* signal handling */
 static void handler_sigusr1(int signo)
 {
-       printf("LTT Signal %d received : parent buffer switch.\n", signo);
+       dbg_printf("LTT Signal %d received : parent buffer switch.\n", signo);
 }
 
 static void handler_sigusr2(int signo)
 {
-       printf("LTT Signal %d received : parent exited.\n", signo);
+       dbg_printf("LTT Signal %d received : parent exited.\n", signo);
        parent_exited = 1;
 }
 
 static void handler_sigalarm(int signo)
 {
-       printf("LTT Signal %d received\n", signo);
+       dbg_printf("LTT Signal %d received\n", signo);
 
        if(getppid() != traced_pid) {
                /* Parent died */
-               printf("LTT Parent %lu died, cleaning up\n", traced_pid);
+               dbg_printf("LTT Parent %lu died, cleaning up\n", traced_pid);
                traced_pid = 0;
        }
        alarm(3);
@@ -311,7 +324,7 @@ static inline int ltt_buffer_put(struct ltt_buf *ltt_buf,
                        ret = futex((unsigned long)&ltt_buf->full,
                                        FUTEX_WAKE, 1, 0, 0, 0);
                        if(ret != 1) {
-                               printf("LTT warning : race condition : writer not waiting or too many writers\n");
+                               dbg_printf("LTT warning : race condition : writer not waiting or too many writers\n");
                        }
                        atomic_set(&ltt_buf->full, 0);
                }
@@ -322,12 +335,12 @@ static int read_subbuffer(struct ltt_buf *ltt_buf, int fd)
 {
        unsigned int consumed_old;
        int err;
-       printf("LTT read buffer\n");
+       dbg_printf("LTT read buffer\n");
 
 
        err = ltt_buffer_get(ltt_buf, &consumed_old);
        if(err != 0) {
-               if(err != -EAGAIN) printf("LTT Reserving sub buffer failed\n");
+               if(err != -EAGAIN) dbg_printf("LTT Reserving sub buffer failed\n");
                goto get_error;
        }
 
@@ -353,7 +366,7 @@ write_error:
 
        if(err != 0) {
                if(err == -EIO) {
-                       printf("Reader has been pushed by the writer, last subbuffer corrupted.\n");
+                       dbg_printf("Reader has been pushed by the writer, last subbuffer corrupted.\n");
                        /* FIXME : we may delete the last written buffer if we wish. */
                }
                goto get_error;
@@ -365,7 +378,7 @@ get_error:
 
 /* This function is called by ltt_rw_init which has signals blocked */
 static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
-               sigset_t oldset, pid_t l_traced_pid, pthread_t l_traced_thread)
+               sigset_t oldset, pid_t l_traced_pid, pthread_t l_traced_tid)
 {
        struct sigaction act;
        int ret;
@@ -376,10 +389,10 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
 
 
        traced_pid = l_traced_pid;
-       traced_thread = l_traced_thread;
+       traced_tid = l_traced_tid;
 
-       printf("LTT ltt_usertrace_fast_daemon : init is %d, pid is %lu, traced_pid is %lu\n",
-                       shared_trace_info->init, getpid(), traced_pid);
+       dbg_printf("LTT ltt_usertrace_fast_daemon : init is %d, pid is %lu, traced_pid is %lu, traced_tid is %lu\n",
+                       shared_trace_info->init, getpid(), traced_pid, traced_tid);
 
        act.sa_handler = handler_sigusr1;
        act.sa_flags = 0;
@@ -402,7 +415,7 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
        /* Enable signals */
        ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL);
        if(ret) {
-               printf("LTT Error in pthread_sigmask\n");
+               dbg_printf("LTT Error in pthread_sigmask\n");
        }
 
        alarm(3);
@@ -420,7 +433,7 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
                exit(-1);
        }
        snprintf(identifier_name, PATH_MAX-1,   "%lu.%lu.%llu",
-                       traced_pid, traced_thread, get_cycles());
+                       traced_tid, traced_pid, get_cycles());
        snprintf(outfile_name, PATH_MAX-1,      "facilities-%s", identifier_name);
        fd_fac = creat(outfile_name, 0644);
 
@@ -432,7 +445,7 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
                pause();
                if(traced_pid == 0) break; /* parent died */
                if(parent_exited) break;
-               printf("LTT Doing a buffer switch read. pid is : %lu\n", getpid());
+               dbg_printf("LTT Doing a buffer switch read. pid is : %lu\n", getpid());
        
                do {
                        ret = read_subbuffer(&shared_trace_info->channel.cpu, fd_cpu);
@@ -480,12 +493,19 @@ void ltt_rw_init(void)
        int ret;
        sigset_t set, oldset;
        pid_t l_traced_pid = getpid();
-       pthread_t l_traced_thread = pthread_self();
+       pid_t l_traced_tid = gettid();
 
        /* parent : create the shared memory map */
        shared_trace_info = mmap(0, sizeof(*thread_trace_info),
                        PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, 0, 0);
-       memset(shared_trace_info, 0, sizeof(*shared_trace_info));
+       shared_trace_info->init=0;
+       shared_trace_info->filter=0;
+       shared_trace_info->daemon_id=0;
+       shared_trace_info->nesting=0;
+       memset(&shared_trace_info->channel.facilities, 0,
+                       sizeof(shared_trace_info->channel.facilities));
+       memset(&shared_trace_info->channel.cpu, 0,
+                       sizeof(shared_trace_info->channel.cpu));
        /* Tricky semaphore : is in a shared memory space, so it's ok for a fast
         * mutex (futex). */
        atomic_set(&shared_trace_info->channel.facilities.full, 0);
@@ -508,13 +528,13 @@ void ltt_rw_init(void)
        /* Disable signals */
   ret = sigfillset(&set);
   if(ret) {
-    printf("LTT Error in sigfillset\n");
+    dbg_printf("LTT Error in sigfillset\n");
   } 
        
        
   ret = pthread_sigmask(SIG_BLOCK, &set, &oldset);
   if(ret) {
-    printf("LTT Error in pthread_sigmask\n");
+    dbg_printf("LTT Error in pthread_sigmask\n");
   }
 
        pid = fork();
@@ -526,13 +546,22 @@ void ltt_rw_init(void)
                /* Enable signals */
                ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL);
                if(ret) {
-                       printf("LTT Error in pthread_sigmask\n");
+                       dbg_printf("LTT Error in pthread_sigmask\n");
                }
        } else if(pid == 0) {
+               pid_t sid;
                /* Child */
                role = LTT_ROLE_READER;
+               sid = setsid();
+               ret = nice(1);
+               if(ret < 0) {
+                       perror("Error in nice");
+               }
+               if(sid < 0) {
+                       perror("Error setting sid");
+               }
                ltt_usertrace_fast_daemon(shared_trace_info, oldset, l_traced_pid,
-                                       l_traced_thread);
+                                       l_traced_tid);
                /* Should never return */
                exit(-1);
        } else if(pid < 0) {
@@ -551,7 +580,7 @@ void ltt_thread_init(void)
        
 void __attribute__((constructor)) __ltt_usertrace_fast_init(void)
 {
-  printf("LTT usertrace-fast init\n");
+  dbg_printf("LTT usertrace-fast init\n");
 
        ltt_rw_init();
 }
@@ -559,7 +588,7 @@ void __attribute__((constructor)) __ltt_usertrace_fast_init(void)
 void __attribute__((destructor)) __ltt_usertrace_fast_fini(void)
 {
        if(role == LTT_ROLE_WRITER) {
-         printf("LTT usertrace-fast fini\n");
+         dbg_printf("LTT usertrace-fast fini\n");
                ltt_usertrace_fast_cleanup(NULL);
        }
 }
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