don't create empty files

git-svn-id: http://ltt.polymtl.ca/svn@1655 04897980-b3bd-0310-b5e0-8ef037075253

diff --git a/ltt-usertrace/ltt-usertrace-fast.c b/ltt-usertrace/ltt-usertrace-fast.c
index 6a287a1f73f554b77e390631a61a2e28369e014f..1364d3bb6a0a15c1fa0f15620ffccf2b104ba116 100644 (file)
--- a/ltt-usertrace/ltt-usertrace-fast.c
+++ b/ltt-usertrace/ltt-usertrace-fast.c
@@ -109,6 +109,9 @@ static void ltt_usertrace_fast_cleanup(void *arg)
 static pid_t traced_pid = 0;
 static pid_t traced_tid = 0;
 static int parent_exited = 0;
+static int fd_process = -1;
+static char outfile_name[PATH_MAX];
+static char identifier_name[PATH_MAX];
 
 /* signal handling */
 static void handler_sigusr1(int signo)
@@ -284,6 +287,45 @@ static void flush_buffer(struct ltt_buf *ltt_buf, enum force_switch_mode mode)
 
 }
 
+
+static int open_output_files(void)
+{
+       int ret;
+       int fd;
+       /* Open output files */
+       umask(00000);
+       ret = mkdir(LTT_USERTRACE_ROOT, 0777);
+       if(ret < 0 && errno != EEXIST) {
+               perror("LTT Error in creating output (mkdir)");
+               exit(-1);
+       }
+       ret = chdir(LTT_USERTRACE_ROOT);
+       if(ret < 0) {
+               perror("LTT Error in creating output (chdir)");
+               exit(-1);
+       }
+       snprintf(identifier_name, PATH_MAX-1,   "%lu.%lu.%llu",
+                       traced_tid, traced_pid, get_cycles());
+       snprintf(outfile_name, PATH_MAX-1,      "process-%s", identifier_name);
+
+#ifndef LTT_NULL_OUTPUT_TEST
+       fd = creat(outfile_name, 0644);
+#else
+       /* NULL test */
+       ret = symlink("/dev/null", outfile_name);
+       if(ret < 0) {
+               perror("error in symlink");
+               exit(-1);
+       }
+       fd = open(outfile_name, O_WRONLY);
+       if(fd_process < 0) {
+               perror("Error in open");
+               exit(-1);
+       }
+#endif //LTT_NULL_OUTPUT_TEST
+       return fd;
+}
+
 static inline int ltt_buffer_get(struct ltt_buf *ltt_buf,
                unsigned int *offset)
 {
@@ -341,6 +383,9 @@ static int read_subbuffer(struct ltt_buf *ltt_buf, int fd)
                if(err != -EAGAIN) dbg_printf("LTT Reserving sub buffer failed\n");
                goto get_error;
        }
+       if(fd_process == -1) {
+               fd_process = fd = open_output_files();
+       }
 
        err = TEMP_FAILURE_RETRY(write(fd,
                                ltt_buf->start 
@@ -380,9 +425,6 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
 {
        struct sigaction act;
        int ret;
-       int fd_process = -1;
-       char outfile_name[PATH_MAX];
-       char identifier_name[PATH_MAX];
 
        traced_pid = l_traced_pid;
        traced_tid = l_traced_tid;
@@ -410,43 +452,11 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
 
        alarm(3);
 
-       /* Open output files */
-       umask(00000);
-       ret = mkdir(LTT_USERTRACE_ROOT, 0777);
-       if(ret < 0 && errno != EEXIST) {
-               perror("LTT Error in creating output (mkdir)");
-               exit(-1);
-       }
-       ret = chdir(LTT_USERTRACE_ROOT);
-       if(ret < 0) {
-               perror("LTT Error in creating output (chdir)");
-               exit(-1);
-       }
-       snprintf(identifier_name, PATH_MAX-1,   "%lu.%lu.%llu",
-                       traced_tid, traced_pid, get_cycles());
-       snprintf(outfile_name, PATH_MAX-1,      "process-%s", identifier_name);
-
-       /* Wait for the first signal before creating files */
-       ret = sigsuspend(&oldset);
-       if(ret != -1) {
-               perror("LTT Error in sigsuspend\n");
-       }
-
-#ifndef LTT_NULL_OUTPUT_TEST
-       fd_process = creat(outfile_name, 0644);
-#else
-       /* NULL test */
-       ret = symlink("/dev/null", outfile_name);
-       if(ret < 0) {
-               perror("error in symlink");
-       }
-       fd_process = open(outfile_name, O_WRONLY);
-       if(fd_process < 0) {
-               perror("Error in open");
-       }
-#endif //LTT_NULL_OUTPUT_TEST
-       
        while(1) {
+               ret = sigsuspend(&oldset);
+               if(ret != -1) {
+                       perror("LTT Error in sigsuspend\n");
+               }
                if(traced_pid == 0) break; /* parent died */
                if(parent_exited) break;
                dbg_printf("LTT Doing a buffer switch read. pid is : %lu\n", getpid());
@@ -454,11 +464,6 @@ static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info,
                do {
                        ret = read_subbuffer(&shared_trace_info->channel.process, fd_process);
                } while(ret == 0);
-
-               ret = sigsuspend(&oldset);
-               if(ret != -1) {
-                       perror("LTT Error in sigsuspend\n");
-               }
        }
        /* The parent thread is dead and we have finished with the buffer */