[ccache] [PATCH] handle EAGAIN during copy_fd

[Alfred Landrum]

In util.c, write may return EAGAIN if the file descriptor is a full pipe.  Currently, if this occurs, the log message "ccache: FATAL: Failed to copy fd" is printed and ccache exits.  We've seen this locally when the recorded stderr output was exceptionally large due to many compilation warnings.  

diff -u -r ccache-3.1.8/util.c ccache-3.1.8-eagain-patch/util.c
--- ccache-3.1.8/util.c 2012-08-11 02:03:17.000000000 -0700
+++ ccache-3.1.8-eagain-patch/util.c    2012-08-30 12:54:42.992117460 -0700
@@ -149,10 +149,13 @@
                ssize_t count, written = 0;
                do {
                        count = write(fd_out, buf + written, n - written);
-                       if (count == -1 && errno != EINTR) {
-                               fatal("Failed to copy fd");
+                       if (count == -1) {
+                               if (errno != EAGAIN && errno != EINTR) {
+                                       fatal("Failed to copy fd");
+                               }
+                       } else {
+                               written += count;
                        }
-                       written += count;
                } while (written < n);
        }