182 lines
6.0 KiB
Diff
182 lines
6.0 KiB
Diff
From 9f8be4b0b83d1e0cbf1326f8cb7e077d026d9b0b Mon Sep 17 00:00:00 2001
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From: Kamil Dudka <kdudka@redhat.com>
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Date: Wed, 23 Jul 2008 11:29:21 +0200
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Subject: [PATCH] dd: iflag=fullblock now read full blocks if possible
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* src/dd.c (iread_fullblock): New function for reading full blocks.
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(scanargs): Check for new parameter iflag=fullblock.
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(skip): Use iread_fnc pointer instead of iread function.
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(dd_copy): Use iread_fnc pointer instead of iread function.
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* tests/dd/misc: Add test for dd - read full blocks.
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* doc/coretuils.texi: Mention new parameter iflag=fullblock.
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* NEWS: Mentioned the change.
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---
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NEWS | 4 ++++
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doc/coreutils.texi | 6 ++++++
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src/dd.c | 39 +++++++++++++++++++++++++++++++++++++--
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tests/dd/misc | 9 +++++++++
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4 files changed, 56 insertions(+), 2 deletions(-)
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diff --git a/doc/coreutils.texi b/doc/coreutils.texi
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index 81e3b91..b95f8dc 100644
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--- a/doc/coreutils.texi
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+++ b/doc/coreutils.texi
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@@ -7719,6 +7719,12 @@ platforms that distinguish binary from text I/O.
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Use text I/O. Like @samp{binary}, this option has no effect on
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standard platforms.
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+@item fullblock
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+@opindex fullblock
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+Read full blocks from input if possible. read() may return early
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+if a full block is not available, so retry until data is available
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+or end of file is reached. This flag can be used only for the iflag option.
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+
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@end table
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These flags are not supported on all systems, and @samp{dd} rejects
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diff --git a/src/dd.c b/src/dd.c
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index ead9574..1b620df 100644
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--- a/src/dd.c
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+++ b/src/dd.c
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@@ -225,6 +225,9 @@ static sig_atomic_t volatile interrupt_signal;
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/* A count of the number of pending info signals that have been received. */
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static sig_atomic_t volatile info_signal_count;
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+/* Function used for read (to handle iflag=fullblock parameter) */
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+static ssize_t (*iread_fnc) (int fd, char *buf, size_t size);
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+
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/* A longest symbol in the struct symbol_values tables below. */
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#define LONGEST_SYMBOL "fdatasync"
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@@ -257,6 +260,7 @@ static struct symbol_value const conversions[] =
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};
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/* Flags, for iflag="..." and oflag="...". */
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+#define O_FULLBLOCK 010000000 /* Read only full blocks from input */
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static struct symbol_value const flags[] =
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{
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{"append", O_APPEND},
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@@ -271,6 +275,7 @@ static struct symbol_value const flags[] =
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{"nonblock", O_NONBLOCK},
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{"sync", O_SYNC},
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{"text", O_TEXT},
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+ {"fullblock", O_FULLBLOCK}, /* Read only full blocks from input */
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{"", 0}
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};
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@@ -762,6 +767,27 @@ iread (int fd, char *buf, size_t size)
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}
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}
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+/* Wrapper around iread function which reads full blocks if possible */
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+static ssize_t
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+iread_fullblock (int fd, char *buf, size_t size)
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+{
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+ ssize_t nread = 0;
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+
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+ while (0 < size)
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+ {
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+ ssize_t ncurr = iread(fd, buf, size);
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+ if (ncurr < 0)
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+ return ncurr;
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+ if (ncurr == 0)
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+ break;
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+ nread += ncurr;
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+ buf += ncurr;
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+ size -= ncurr;
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+ }
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+
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+ return nread;
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+}
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+
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/* Write to FD the buffer BUF of size SIZE, processing any signals
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that arrive. Return the number of bytes written, setting errno if
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this is less than SIZE. Keep trying if there are partial
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@@ -1000,6 +1026,15 @@ scanargs (int argc, char *const *argv)
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if (input_flags & (O_DSYNC | O_SYNC))
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input_flags |= O_RSYNC;
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+ if (output_flags & O_FULLBLOCK)
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+ {
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+ error (0, 0, "%s: %s", _("invalid output flag"), "'fullblock'");
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+ usage (EXIT_FAILURE);
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+ }
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+ iread_fnc = (input_flags & O_FULLBLOCK)?
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+ iread_fullblock:
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+ iread;
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+
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if (multiple_bits_set (conversions_mask & (C_ASCII | C_EBCDIC | C_IBM)))
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error (EXIT_FAILURE, 0, _("cannot combine any two of {ascii,ebcdic,ibm}"));
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if (multiple_bits_set (conversions_mask & (C_BLOCK | C_UNBLOCK)))
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@@ -1197,7 +1232,7 @@ skip (int fdesc, char const *file, uintmax_t records, size_t blocksize,
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do
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{
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- ssize_t nread = iread (fdesc, buf, blocksize);
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+ ssize_t nread = iread_fnc (fdesc, buf, blocksize);
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if (nread < 0)
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{
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if (fdesc == STDIN_FILENO)
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@@ -1508,7 +1543,7 @@ dd_copy (void)
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(conversions_mask & (C_BLOCK | C_UNBLOCK)) ? ' ' : '\0',
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input_blocksize);
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- nread = iread (STDIN_FILENO, ibuf, input_blocksize);
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+ nread = iread_fnc (STDIN_FILENO, ibuf, input_blocksize);
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if (nread == 0)
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break; /* EOF. */
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diff --git a/tests/dd/misc b/tests/dd/misc
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index d54fbfa..24e5eba 100755
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--- a/tests/dd/misc
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+++ b/tests/dd/misc
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@@ -88,6 +88,15 @@ fi
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outbytes=`echo x | dd bs=3 ibs=10 obs=10 conv=sync 2>/dev/null | wc -c`
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test "$outbytes" -eq 3 || fail=1
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+(echo a; sleep .1; echo b) \
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+ | LC_ALL=C dd bs=4 status=noxfer iflag=fullblock >out 2>err || fail=1
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+echo "a
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+b" > out_ok
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+echo "1+0 records in
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+1+0 records out" > err_ok
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+compare out out_ok || fail=1
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+compare err err_ok || fail=1
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+
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test $fail -eq 0 && fail=$warn
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(exit $fail); exit $fail
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diff -ruN coreutils-6.12.old/doc/coreutils.info coreutils-6.12/doc/coreutils.info
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--- coreutils-6.12.old/doc/coreutils.info 2008-07-24 12:49:57.000000000 +0200
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+++ coreutils-6.12/doc/coreutils.info 2008-07-24 12:52:17.000000000 +0200
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@@ -6112,6 +6112,12 @@
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Use text I/O. Like `binary', this option has no effect on
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standard platforms.
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+ 'fullblock'
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+ Read full blocks from input if possible. read() may return
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+ early if a full block is not available, so retry until data
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+ is available or end of file is reached. This flag can be used
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+ only for the iflag option.
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+
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These flags are not supported on all systems, and `dd' rejects
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attempts to use them when they are not supported. When reading
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diff -ruN coreutils-6.12.old/man/dd.1 coreutils-6.12/man/dd.1
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--- coreutils-6.12.old/man/dd.1 2008-07-24 12:51:06.000000000 +0200
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+++ coreutils-6.12/man/dd.1 2008-07-24 12:59:06.000000000 +0200
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@@ -111,6 +111,13 @@
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.TP
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direct
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use direct I/O for data
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+.PP
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+FLAG symbols only for iflag option:
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+.TP
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+fullblock
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+Read full blocks from input if possible. read() may return early
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+if a full block is not available, so retry until data is available
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+or end of file is reached.
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.IP
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directory fail unless a directory
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dsync use synchronized I/O for data
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