maint: update copyright

[gnulib.git] / lib / fwriteerror.c

diff --git a/lib/fwriteerror.c b/lib/fwriteerror.c
index 3ea3ecc..9d62e5c 100644 (file)
--- a/lib/fwriteerror.c
+++ b/lib/fwriteerror.c
@@ -1,5 +1,5 @@
 /* Detect write error on a stream.
-   Copyright (C) 2003-2006 Free Software Foundation, Inc.
+   Copyright (C) 2003-2006, 2008-2014 Free Software Foundation, Inc.
    Written by Bruno Haible <bruno@clisp.org>, 2003.
 
    This program is free software: you can redistribute it and/or modify
@@ -32,13 +32,25 @@ do_fwriteerror (FILE *fp, bool ignore_ebadf)
   if (fp == stdout)
     {
       if (stdout_closed)
-       return 0;
+        return 0;
 
       /* If we are closing stdout, don't attempt to do it later again.  */
       stdout_closed = true;
     }
 
-  /* Need to
+  /* This function returns an error indication if there was a previous failure
+     or if fclose failed, with two exceptions:
+       - Ignore an fclose failure if there was no previous error, no data
+         remains to be flushed, and fclose failed with EBADF.  That can
+         happen when a program like cp is invoked like this 'cp a b >&-'
+         (i.e., with standard output closed) and doesn't generate any
+         output (hence no previous error and nothing to be flushed).
+       - Ignore an fclose failure due to EPIPE.  That can happen when a
+         program blocks or ignores SIGPIPE, and the output pipe or socket
+         has no readers now.  The EPIPE tells us that we should stop writing
+         to this output.  That's what we are doing anyway here.
+
+     Need to
      1. test the error indicator of the stream,
      2. flush the buffers both in userland and in the kernel, through fclose,
         testing for error again.  */
@@ -50,15 +62,15 @@ do_fwriteerror (FILE *fp, bool ignore_ebadf)
   if (ferror (fp))
     {
       if (fflush (fp))
-       goto close_preserving_errno; /* errno is set here */
+        goto close_preserving_errno; /* errno is set here */
       /* The stream had an error earlier, but its errno was lost.  If the
-        error was not temporary, we can get the same errno by writing and
-        flushing one more byte.  We can do so because at this point the
-        stream's contents is garbage anyway.  */
+         error was not temporary, we can get the same errno by writing and
+         flushing one more byte.  We can do so because at this point the
+         stream's contents is garbage anyway.  */
       if (fputc ('\0', fp) == EOF)
-       goto close_preserving_errno; /* errno is set here */
+        goto close_preserving_errno; /* errno is set here */
       if (fflush (fp))
-       goto close_preserving_errno; /* errno is set here */
+        goto close_preserving_errno; /* errno is set here */
       /* Give up on errno.  */
       errno = 0;
       goto close_preserving_errno;
@@ -67,16 +79,16 @@ do_fwriteerror (FILE *fp, bool ignore_ebadf)
   if (ignore_ebadf)
     {
       /* We need an explicit fflush to tell whether some output was already
-        done on FP.  */
+         done on FP.  */
       if (fflush (fp))
-       goto close_preserving_errno; /* errno is set here */
+        goto close_preserving_errno; /* errno is set here */
       if (fclose (fp) && errno != EBADF)
-       return -1; /* errno is set here */
+        goto got_errno; /* errno is set here */
     }
   else
     {
       if (fclose (fp))
-       return -1; /* errno is set here */
+        goto got_errno; /* errno is set here */
     }
 
   return 0;
@@ -88,8 +100,13 @@ do_fwriteerror (FILE *fp, bool ignore_ebadf)
     int saved_errno = errno;
     fclose (fp);
     errno = saved_errno;
-    return -1;
   }
+ got_errno:
+  /* There's an error.  Ignore EPIPE.  */
+  if (errno == EPIPE)
+    return 0;
+  else
+    return -1;
 }
 
 int
@@ -108,7 +125,7 @@ fwriteerror_no_ebadf (FILE *fp)
 #if TEST
 
 /* Name of a file on which writing fails.  On systems without /dev/full,
-   you can choose a filename on a full filesystem.  */
+   you can choose a filename on a full file system.  */
 #define UNWRITABLE_FILE "/dev/full"
 
 int
@@ -130,32 +147,32 @@ main ()
       size_t size = sizes[i];
 
       for (j = 0; j < 2; j++)
-       {
-         /* Run a test depending on i and j:
-            Write size bytes and then calls fflush if j==1.  */
-         FILE *stream = fopen (UNWRITABLE_FILE, "w");
-
-         if (stream == NULL)
-           {
-             fprintf (stderr, "Test %u:%u: could not open file\n", i, j);
-             continue;
-           }
-
-         fwrite (dummy, 347, 1, stream);
-         fwrite (dummy, size - 347, 1, stream);
-         if (j)
-           fflush (stream);
-
-         if (fwriteerror (stream) == -1)
-           {
-             if (errno != ENOSPC)
-               fprintf (stderr, "Test %u:%u: fwriteerror ok, errno = %d\n",
-                        i, j, errno);
-           }
-         else
-           fprintf (stderr, "Test %u:%u: fwriteerror found no error!\n",
-                    i, j);
-       }
+        {
+          /* Run a test depending on i and j:
+             Write size bytes and then calls fflush if j==1.  */
+          FILE *stream = fopen (UNWRITABLE_FILE, "w");
+
+          if (stream == NULL)
+            {
+              fprintf (stderr, "Test %u:%u: could not open file\n", i, j);
+              continue;
+            }
+
+          fwrite (dummy, 347, 1, stream);
+          fwrite (dummy, size - 347, 1, stream);
+          if (j)
+            fflush (stream);
+
+          if (fwriteerror (stream) == -1)
+            {
+              if (errno != ENOSPC)
+                fprintf (stderr, "Test %u:%u: fwriteerror ok, errno = %d\n",
+                         i, j, errno);
+            }
+          else
+            fprintf (stderr, "Test %u:%u: fwriteerror found no error!\n",
+                     i, j);
+        }
     }
 
   return 0;