* Don't use sysexits.h. Just exit 1 on error and 0 otherwise.
* Don't sacrifice precision by converting the output of clock_gettime() to a
double and then comparing the results. Instead, subtract the values of
the two clock_gettime() calls, then convert to double.
* Don't use CLOCK_MONOTONIC_PRECISE. It's an unportable synonym for
CLOCK_MONOTONIC.
* Use more appropriate names for some local variables.
* In the summary message, round elapsed time to the nearest microsecond.
Reported by: bde, jilles
MFC after: 3 days
X-MFC-With: 265472
conv=sparse.
This change fixes two separate issues observed when the last output
block is all zeroes, and conv=sparse is in use. In this case, care
must be taken to roll back the last seek and write the entire last zero
block at the original offset where it should have occurred: when the
destination file is a block device, it is not possible to roll back
by just one character as the write would then not be properly aligned.
Furthermore, the buffer used to write this last all-zeroes block
needs to be properly zeroed-out. This was not the case previously,
resulting in a junk data byte appearing instead of a zero in the
output stream.
PR: bin/189174
PR: bin/189284
Reviewed by: kib
MFC after: 2 weeks
gettimeofday returns the system clock, which may jump forward or back,
especially if NTP is in use. If the time jumps backwards, then dd will see
negative elapsed time, round it up to 1usec, and print an absurdly fast
transfer rate.
The solution is to use clock_gettime(2) with CLOCK_MONOTONIC_PRECISE as the
clock_id. That clock advances steadily, regardless of changes to the system
clock.
Reviewed by: delphij
MFC after: 3 days
Sponsored by: Spectra Logic
borrowed where syntax status=noxfer means no transfer statistics
and status=none means no status information at all.
This feature is useful because the statistics information can
sometimes be annoying, and redirecting stderr to /dev/null would
mean error messages also gets silenced.
Obtained from: OpenBSD
MFC after: 2 weeks
If the bs= expr operand is specified and no conversions other than sync,
noerror, or notrunc are requested, the data returned from each input
block shall be written as a separate output block.
In particular, when both bs=size and conv=sparce were specified, the
resulted file was fully filled, instead of sparce.
PR: standards/177742
Submitted by: Matthew Rezny <mrezny@hexaneinc.com>
MFC after: 2 weeks
Introduce an explicit close of the output descriptor so that work done
on close is accounted for in the summary output triggered at exit
(implicit close()s occur after atexit() hooks).
This is useful because some devices such as cfi(4) may perform
signficant work after a close occurs (e.g. erasing and rewriting a
block of flash).
In addition to adding missing `static' keywords:
- bin/dd: Pull in `extern.h' to guarantee consistency with source file.
- libexec/rpc.rusersd: Move shared globals into an extern.h.
- libexec/talkd: Move `debug' and `hostname' into extern.h.
- usr.bin/cksum: Put counters in extern.h, as they are used by ckdist/mtree.
- usr.bin/m4: Move `end_result' into extern.h.
- usr.sbin/services_mkdb: Move shared globals into an extern.h.
This structure is not part of POSIX. According to POSIX, gettimeofday()
has the following prototype:
int gettimeofday(struct timeval *restrict tp, void *restrict tzp);
Also, POSIX states that gettimeofday() shall return 0 (as long as tzp is
not used). Remove dead error handling code. Also use NULL for a
nul-pointer instead of integer 0.
While there, change all pieces of code that only use tv_sec to use
time(3), as this provides less overhead.
This should be a bit useful for users who look at the manpage and
then try to copy data CD-ROM disks using dd. A lot of us know
that bs=2048 is required, but it still manages to cause a bit of
grief to those who haven't heard about it.
PR: bin/130857
Submitted by: Tri Brotoharsono < mail at tribrotoharsono.net >
MFC after: 3 days
to specify an alternative padding character when using a conversion
mode, or when using noerror with sync and an input error occurs. This
facilities reading old and error-prone media by allowing the user to
more effectively mark error blocks in the output stream.
Revert to using the .Tn POSIX and .Tn ANSI instead of \*[Px] and \*[Ai]
strings; using these strings is unsafe in troff mode, as they include a
change in a font size.
Approved by: re
o Old-style K&R declarations have been converted to new C89 style
o register has been removed
o prototype for main() has been removed (gcc3 makes it an error)
o int main(int argc, char *argv[]) is the preferred main definition.
o Attempt to not break style(9) conformance for declarations more than
they already are.
Approved by: arch@, new style(9)
