Prevent spurious EINTR to freeze process debugging

1 files changed, 14 insertions, 3 deletions

diff --git a/linker/debugger.c b/linker/debugger.c
index 5bb065c..1bd3cc8 100644
--- a/linker/debugger.c
+++ b/linker/debugger.c
@@ -32,6 +32,7 @@
 #include <ctype.h>
 #include <signal.h>
 #include <sys/mman.h>
+#include <errno.h>
 
 #include "linker.h"
 
@@ -40,6 +41,11 @@
 
 void notify_gdb_of_libraries();
 
+#define  RETRY_ON_EINTR(ret,cond) \
+    do { \
+        ret = (cond); \
+    } while (ret < 0 && errno == EINTR)
+
 void debugger_signal_handler(int n)
 {
     unsigned tid;
@@ -58,10 +64,15 @@ void debugger_signal_handler(int n)
          * is paranoid and will verify that we are giving a tid
          * that's actually in our process
          */
-        write(s, &tid, sizeof(unsigned));
+        int  ret;
 
-        read(s, &tid, 1);
-        notify_gdb_of_libraries();
+        RETRY_ON_EINTR(ret, write(s, &tid, sizeof(unsigned)));
+        if (ret == sizeof(unsigned)) {
+            /* if the write failed, there is no point to read on
+             * the file descriptor. */
+            RETRY_ON_EINTR(ret, read(s, &tid, 1));
+            notify_gdb_of_libraries();
+        }
         close(s);
     }