1 files changed, 143 insertions, 0 deletions
diff --git a/stdio-common/tst-rndseek.c b/stdio-common/tst-rndseek.c
new file mode 100644
index 0000000000..82a4cfd83e
--- /dev/null
+++ b/stdio-common/tst-rndseek.c
@@ -0,0 +1,143 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+
+static char fname[] = "/tmp/rndseek.XXXXXX";
+static char tempdata[65 * 1024];
+
+
+static int do_test (void);
+#define TEST_FUNCTION do_test ()
+
+#include "../test-skeleton.c"
+
+
+static int
+fp_test (FILE *fp)
+{
+  int result = 0;
+  int rounds = 10000;
+
+  do
+    {
+      int idx = random () % (sizeof (tempdata) - 2);
+      char ch1;
+      char ch2;
+
+      if (fseek (fp, idx, SEEK_SET) != 0)
+	{
+	  printf ("%d: fseek failed: %m\n", rounds);
+	  result = 1;
+	  break;
+	}
+
+      ch1 = fgetc_unlocked (fp);
+      ch2 = tempdata[idx];
+      if (ch1 != ch2)
+	{
+	  printf ("%d: character at index %d not what is expected ('%c' vs '%c')\n",
+		  rounds, idx, ch1, ch2);
+	  result = 1;
+	  break;
+	}
+
+      ch1 = fgetc (fp);
+      ch2 = tempdata[idx + 1];
+      if (ch1 != ch2)
+	{
+	  printf ("%d: character at index %d not what is expected ('%c' vs '%c')\n",
+		  rounds, idx + 1, ch1, ch2);
+	  result = 1;
+	  break;
+	}
+    }
+  while (--rounds > 0);
+
+  fclose (fp);
+
+  return result;
+}
+
+
+static int
+do_test (void)
+{
+  int fd;
+  FILE *fp;
+  int i;
+  int result;
+
+  fd = mkstemp (fname);
+  if (fd == -1)
+    {
+      printf ("cannot open temporary file: %m\n");
+      return 1;
+    }
+  /* Make sure the file gets removed.  */
+  add_temp_file (fname);
+
+  /* Repeatability demands this.  */
+  srandom (42);
+
+  /* First create some temporary data.  */
+  for (i = 0; i < sizeof (tempdata); ++i)
+    tempdata[i] = (char) random ();
+
+  /* Write this data to a file.  */
+  if (TEMP_FAILURE_RETRY (write (fd, tempdata, sizeof (tempdata)))
+      != sizeof (tempdata))
+    {
+      printf ("cannot wrote data to temporary file: %m\n");
+      return 1;
+    }
+
+  /* Now try reading the data.  */
+  fp = fdopen (dup (fd), "r");
+  if (fp == NULL)
+    {
+      printf ("cannot duplicate temporary file descriptor: %m\n");
+      return 1;
+    }
+
+  rewind (fp);
+  for (i = 0; i < sizeof (tempdata); ++i)
+    {
+      int ch0 = fgetc (fp);
+      char ch1 = ch0;
+      char ch2 = tempdata[i];
+
+      if (ch0 == EOF)
+	{
+	  puts ("premature end of file while reading data");
+	  return 1;
+	}
+
+      if (ch1 != ch2)
+	{
+	  printf ("%d: '%c' vs '%c'\n", i, ch1, ch2);
+	  return 1;
+	}
+    }
+
+  result = fp_test (fp);
+
+  fp = fopen (fname, "r");
+  result |= fp_test (fp);
+
+  fp = fopen64 (fname, "r");
+  result |= fp_test (fp);
+
+  /* The "rw" mode will prevent the mmap-using code from being used.  */
+  fp = fdopen (fd, "rw");
+  result = fp_test (fp);
+
+  fp = fopen (fname, "rw");
+  result |= fp_test (fp);
+
+  fp = fopen64 (fname, "rw");
+  result |= fp_test (fp);
+
+  return result;
+}