X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Ftests%2Ffilesys%2Fextended%2Fchild-syn-rw.c;h=d456a3a5ec49991d44530f192fe064230a96b154;hb=520ff4dd2a106a4d4a21468a72ba820c8ea7d242;hp=6334bda0b1077d97707df098c44a9f30b87d277c;hpb=615bf3b3d2a8573ed6fb9ddc0055745e163ac999;p=pintos-anon

diff --git a/src/tests/filesys/extended/child-syn-rw.c b/src/tests/filesys/extended/child-syn-rw.c
index 6334bda..d456a3a 100644
--- a/src/tests/filesys/extended/child-syn-rw.c
+++ b/src/tests/filesys/extended/child-syn-rw.c
@@ -1,11 +1,18 @@
+/* Child process for syn-rw.
+   Reads from a file created by our parent process, which is
+   growing it.  We loop until we've read the whole file
+   successfully.  Many iterations through the loop will return 0
+   bytes, because the file has not grown in the meantime.  That
+   is, we are "busy waiting" for the file to grow.
+   (This test could be improved by adding a "yield" system call
+   and calling yield whenever we receive a 0-byte read.) */
+
 #include <random.h>
 #include <stdlib.h>
 #include <syscall.h>
 #include "tests/filesys/extended/syn-rw.h"
 #include "tests/lib.h"
 
-const char *test_name = "child-syn-rw";
-
 static char buf1[BUF_SIZE];
 static char buf2[BUF_SIZE];
 
@@ -16,6 +23,7 @@ main (int argc, const char *argv[])
   int fd;
   size_t ofs;
 
+  test_name = "child-syn-rw";
   quiet = true;
   
   CHECK (argc == 2, "argc must be 2, actually %d", argc);
@@ -24,17 +32,17 @@ main (int argc, const char *argv[])
   random_init (0);
   random_bytes (buf1, sizeof buf1);
 
-  CHECK ((fd = open (filename)) > 1, "open \"%s\"", filename);
+  CHECK ((fd = open (file_name)) > 1, "open \"%s\"", file_name);
   ofs = 0;
   while (ofs < sizeof buf2)
     {
       int bytes_read = read (fd, buf2 + ofs, sizeof buf2 - ofs);
       CHECK (bytes_read >= -1 && bytes_read <= (int) (sizeof buf2 - ofs),
              "%zu-byte read on \"%s\" returned invalid value of %d",
-             sizeof buf2 - ofs, filename, bytes_read);
+             sizeof buf2 - ofs, file_name, bytes_read);
       if (bytes_read > 0) 
         {
-          compare_bytes (buf2 + ofs, buf1 + ofs, bytes_read, ofs, filename);
+          compare_bytes (buf2 + ofs, buf1 + ofs, bytes_read, ofs, file_name);
           ofs += bytes_read;
         }
     }