Update documentation and adjust blocksize if larger than the device size

Signed-off-by: Mattias Andrée <maandree@kth.se>

3 files changed, 38 insertions, 4 deletions

diff --git a/README b/README
index 010786f..54ace7b 100644
--- a/README
+++ b/README
@@ -2,7 +2,8 @@ NAME
 	deadshred - override the contents of a device that may be broken
 
 SYNOPSIS
-	deadshred [-o offset] [-l length | -e postend] device [< random-source]
+	deadshred [-b blocksize] [-o offset] [-l length | -e postend]
+	          [-r] device [< random-source]
 
 DESCRIPTION
 	The deadshred utility fills a file or block devices with
@@ -14,6 +15,10 @@ DESCRIPTION
 OPTIONS
 	The following options are supported:
 
+	-b blocksize
+		Selects the initial block-size for writing on the
+		first pass over the device.
+
 	-e postend
 		Position in the device to stop writing at. The byte
 		indexed by the value postend will not be overwritten.
@@ -27,6 +32,10 @@ OPTIONS
 	-o offset
 		The index of the first byte in the device to overwrite.
 
+	-r
+		Start writing from the end instead of from the
+		beginning on the first pass over the device.
+
 OPERANDS
 	The following operand is supported:
 
diff --git a/deadshred.1 b/deadshred.1
index 5c3eb63..e445c05 100644
--- a/deadshred.1
+++ b/deadshred.1
@@ -4,6 +4,8 @@ deadshred \- override the contents of a device that may be broken
 
 .SH SYNOPSIS
 .B deadshred
+[-b
+.IR blocksize ]
 [-o
 .IR offset ]
 [-l
@@ -11,6 +13,7 @@ deadshred \- override the contents of a device that may be broken
 |
 -e
 .IR postend ]
+[-r]
 .I device
 [<
 .IR random-source ]
@@ -29,6 +32,10 @@ to override and retries it later.
 .SH OPTIONS
 The following options are supported:
 .TP
+.BR -b \ \fIblocksize\fP
+Selects the initial block-size for writing on the
+first pass over the device.
+.TP
 .BR -e \ \fIpostend\fP
 Position in the
 .I device
@@ -56,9 +63,13 @@ bytes past
 The index of the first byte in the
 .I device
 to overwrite.
+.TP
+.B -r
+Start writing from the end instead of from the
+beginning on the first pass over the device.
 .PP
 The value of the
-.B -elo
+.B -belo
 flags can be expressed a sum of terms (delimited by
 SP
 .RB (' " " '),
@@ -95,6 +106,20 @@ Unless the standard input is a terminal device, it shall be an
 unless source of either random data or a particular byte to
 fill the device with.
 
+.SH STDOUT
+If the process is terminated using either of the signals
+SIGTERM or SIGINT, the process will write to standard output
+a map of sections that has not been overwritten yet. The
+output will be the concatenation of one string per section,
+each on the format
+.PP
+.nf
+\fB\(dq%s%x-%x/%x\(dq,\fP <\fB\(dq0x\(dq\fP for the first section, \fB\(dq,\(dq\fP otherwise>\fB,\fP
+              <\fIindex of the first byte in the section\fP>\fB,\fP
+              <\fIindex of the byte after the last in the section\fP>\fB,\fP
+              <\fIthe block size that should be used when trying to overwrite\fP>
+.fi
+
 .SH NOTES
 While the
 .B deadshred
diff --git a/deadshred.c b/deadshred.c
index c471982..d7f2f5f 100644
--- a/deadshred.c
+++ b/deadshred.c
@@ -4,7 +4,6 @@
 
 
 USAGE("[-b blocksize] [-o offset] [-l length | -e postend] [-r] device [< random-source]");
-/* TODO document (also in README and man pages) options -b and -r */
 
 
 struct status status = STATUS_INIT;
@@ -417,6 +416,8 @@ main(int argc, char *argv[])
 		close(fd);
 		return 0;
 	}
+	while ((off_t)spans[0].blocksize >> 1 > total_size)
+		spans[0].blocksize >>= 1;
 
 	humansize1000(total_size, total_size_1000);
 	humansize1024(total_size, total_size_1024);
@@ -473,7 +474,6 @@ main(int argc, char *argv[])
 	print_status(1, &status);
 
 	if (nspans) {
-		/* TODO document in man page */
 		dump_map(STDOUT_FILENO, "<stdout>");
 		if (close(STDOUT_FILENO))
 			eprintf("write <stdout>");