fix concurrent writing to trace file

1 files changed, 4 insertions, 2 deletions

diff --git a/src/libtrace/libtrace.c b/src/libtrace/libtrace.c
index 3798cb998..9a944d0f6 100644
--- a/src/libtrace/libtrace.c
+++ b/src/libtrace/libtrace.c
@@ -55,7 +55,7 @@ static orig_access_t orig_access = NULL;
 // Using fprintf to /dev/tty instead of printf in order to fix #561
 static FILE *ftty = NULL;
 static pid_t mypid = 0;
-#define MAXNAME 16
+#define MAXNAME 16 // 8 or larger
 static char myname[MAXNAME] = "unknown";
 
 static void init(void) __attribute__((constructor));
@@ -85,6 +85,8 @@ void init(void) {
                 }
                 sleep(1);
         }
+        // unbuffered stream
+        setvbuf(ftty, NULL, _IONBF, 0);
 
         // pid
         mypid = getpid();
@@ -96,7 +98,7 @@ void init(void) {
                 free(fname);
                 if (fp) {
                         if (fgets(myname, MAXNAME, fp) == NULL)
-                                strncpy(myname, "unknown", MAXNAME-1);
+                                strcpy(myname, "unknown");
                         fclose(fp);
                 }
         }