New option --warning=failed-read

* NEWS: Document the --warning=failed-read option.
* doc/tar.texi: Likewise.
* doc/tar.1: Likewise.
* src/common.h (WARN_FAILED_READ): New constant.
(WARNING_ENABLED): New macro.
* src/misc.c (close_diag, open_diag)
(read_diag_details, readlink_diag)
(savedir_diag, seek_diag_details)
(stat_diag): Suppress warnings if WARN_FAILED_READ is set.
* src/warning.c (failed-read): New keyword.

6 files changed, 66 insertions, 11 deletions

diff --git a/NEWS b/NEWS
index 0a173e0c..333e99ae 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,18 @@ This helps the output of 'tar' to be more deterministic.
 In some cases tar would restore the directory permissions too early,
 causing subsequent link extractions in that directory to fail.
 
+* The --warnings=failed-read option
+
+This new warning control option suppresses warning messages about
+unreadable files and directories. It has effect only if used together
+with the --ignore-failed-read option.  
+
+* The --warnings=none option now suppresses all warnings
+
+This includes warnings about unreadable files produced when
+--ignore-failed-read is in effect. To output these, use
+--warnings=none --warnings=no-failed-read.
+
 
 version 1.29 - Sergey Poznyakoff, 2016-05-16
 
diff --git a/doc/tar.1 b/doc/tar.1
index f5c1fcac..c4c990f9 100644
--- a/doc/tar.1
+++ b/doc/tar.1
@@ -13,7 +13,7 @@
 .\"
 .\" You should have received a copy of the GNU General Public License
 .\" along with this program.  If not, see <http://www.gnu.org/licenses/>.
-.TH TAR 1 "March 23, 2016" "TAR" "GNU TAR Manual"
+.TH TAR 1 "November 16, 2017" "TAR" "GNU TAR Manual"
 .SH NAME
 tar \- an archiving utility
 .SH SYNOPSIS
@@ -1163,6 +1163,12 @@ Keywords applicable for \fBtar --create\fR:
 .TP
 .B file-changed
 "%s: file changed as we read it"
+.TP
+.B failed-read
+Suppresses warnings about unreadable files or directories. This
+keyword applies only if used together with the
+.B \-\-ignore\-failed\-read
+option.
 .HP
 Keywords applicable for \fBtar --extract\fR:
 .TP
diff --git a/doc/tar.texi b/doc/tar.texi
index 09c4fbb3..572e3dd9 100644
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -4610,6 +4610,10 @@ Disable all warning messages.
 @cindex @samp{file changed as we read it}, warning message
 @item file-changed
 @samp{%s: file changed as we read it}
+@item failed-read
+Suppresses warnings about unreadable files or directories. This
+keyword applies only if used together with the @option{--ignore-failed-read}
+option. @xref{Ignore Failed Read}.
 @end table
 
 @subheading Keywords applicable for @command{tar --extract}
@@ -5726,7 +5730,7 @@ Disable SELinux context support.
 @end table
 
 @node Ignore Failed Read
-@subsection Ignore Fail Read
+@subsection Ignore Failed Read
 
 @table @option
 @item --ignore-failed-read
@@ -5734,6 +5738,13 @@ Disable SELinux context support.
 Do not exit with nonzero on unreadable files or directories.
 @end table
 
+This option has effect only during creation.  It instructs tar to
+treat as mild conditions any missing or unreadable files (directories).
+Such failures don't affect the program exit code, and the
+corresponding diagnostic messages are marked as warnings, not errors.
+These warnings can be suppressed using the
+@option{--warning=failed-read} option (@pxref{warnings}).
+
 @node extract options
 @section Options Used by @option{--extract}
 @cindex options for use with @option{--extract}
diff --git a/src/common.h b/src/common.h
index e49bd9f1..964f0b64 100644
--- a/src/common.h
+++ b/src/common.h
@@ -927,6 +927,7 @@ void checkpoint_flush_actions (void);
 #define WARN_EXISTING_FILE       0x00100000
 #define WARN_XATTR_WRITE         0x00200000
 #define WARN_RECORD_SIZE         0x00400000
+#define WARN_FAILED_READ         0x00800000
 
 /* These warnings are enabled by default in verbose mode: */
 #define WARN_VERBOSE_WARNINGS    (WARN_RENAME_DIRECTORY|WARN_NEW_DIRECTORY|\
@@ -938,10 +939,12 @@ void set_warning_option (const char *arg);
 
 extern int warning_option;
 
+#define WARNING_ENABLED(opt) (warning_option & (opt))
+
 #define WARNOPT(opt,args)			\
   do						\
     {						\
-      if (warning_option & opt) WARN (args);	\
+      if (WARNING_ENABLED(opt)) WARN (args);	\
     }						\
   while (0)
 
diff --git a/src/misc.c b/src/misc.c
index 1e5ca2aa..cd07f530 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -1044,7 +1044,10 @@ void
 close_diag (char const *name)
 {
   if (ignore_failed_read_option)
-    close_warn (name);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	close_warn (name);
+    }
   else
     close_error (name);
 }
@@ -1053,7 +1056,10 @@ void
 open_diag (char const *name)
 {
   if (ignore_failed_read_option)
-    open_warn (name);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	open_warn (name);
+    }
   else
     open_error (name);
 }
@@ -1062,7 +1068,10 @@ void
 read_diag_details (char const *name, off_t offset, size_t size)
 {
   if (ignore_failed_read_option)
-    read_warn_details (name, offset, size);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	read_warn_details (name, offset, size);
+    }
   else
     read_error_details (name, offset, size);
 }
@@ -1071,7 +1080,10 @@ void
 readlink_diag (char const *name)
 {
   if (ignore_failed_read_option)
-    readlink_warn (name);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	readlink_warn (name);
+    }
   else
     readlink_error (name);
 }
@@ -1080,7 +1092,10 @@ void
 savedir_diag (char const *name)
 {
   if (ignore_failed_read_option)
-    savedir_warn (name);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	savedir_warn (name);
+    }
   else
     savedir_error (name);
 }
@@ -1089,7 +1104,10 @@ void
 seek_diag_details (char const *name, off_t offset)
 {
   if (ignore_failed_read_option)
-    seek_warn_details (name, offset);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	seek_warn_details (name, offset);
+    }
   else
     seek_error_details (name, offset);
 }
@@ -1098,7 +1116,10 @@ void
 stat_diag (char const *name)
 {
   if (ignore_failed_read_option)
-    stat_warn (name);
+    {
+      if (WARNING_ENABLED(WARN_FAILED_READ))
+	stat_warn (name);
+    }
   else
     stat_error (name);
 }
diff --git a/src/warning.c b/src/warning.c
index 2a436d76..bfcd2d27 100644
--- a/src/warning.c
+++ b/src/warning.c
@@ -47,6 +47,7 @@ static char const *const warning_args[] = {
   "existing-file",
   "xattr-write",
   "record-size",
+  "failed-read",
   NULL
 };
 
@@ -74,7 +75,8 @@ static int warning_types[] = {
   WARN_DECOMPRESS_PROGRAM,
   WARN_EXISTING_FILE,
   WARN_XATTR_WRITE,
-  WARN_RECORD_SIZE
+  WARN_RECORD_SIZE,
+  WARN_FAILED_READ
 };
 
 ARGMATCH_VERIFY (warning_args, warning_types);