dd: implement conv=notrunc support - ubase - suckless linux base utils
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---
DIR commit e0dc3f9546b3cd839aef8e58376c6295679a5ed5
DIR parent 596663c1b1f140c10ba1facede783201d6a876a7
HTML Author: Eivind Uggedal <eivind@uggedal.com>
Date: Wed, 16 Mar 2016 09:23:50 +0000
dd: implement conv=notrunc support
Diffstat:
M dd.1 | 2 ++
M dd.c | 11 +++++++----
2 files changed, 9 insertions(+), 4 deletions(-)
---
DIR diff --git a/dd.1 b/dd.1
@@ -61,4 +61,6 @@ blocks from the beginning of the output before copying.
Skip
.Ar N
blocks from the beginning of the input before copying.
+.It Ar conv=notrunc
+Do not truncate the output file.
.El
DIR diff --git a/dd.c b/dd.c
@@ -32,7 +32,7 @@ struct dd_config {
uint64_t skip, seek, count, b_in, b_out, rec_in, rec_out;
off_t fsize;
blksize_t bs;
- char quiet, nosync, direct;
+ char quiet, nosync, notrunc, direct;
time_t t_start, t_end;
};
@@ -99,7 +99,7 @@ prepare_copy(struct dd_config *ddc, int *ifd, int *ofd)
return -1;
}
- if (!ddc->seek)
+ if (!ddc->seek && !ddc->notrunc)
flo |= O_TRUNC;
if (!ddc->out) *ofd = 1;
@@ -108,7 +108,7 @@ prepare_copy(struct dd_config *ddc, int *ifd, int *ofd)
return -1;
}
- if (ddc->seek) {
+ if (ddc->seek && !ddc->notrunc) {
if (fstat(*ofd, &st) < 0)
return -1;
if (!S_ISREG(st.st_mode))
@@ -238,7 +238,8 @@ static void
usage(void)
{
eprintf("usage: %s [-h] [if=infile] [of=outfile] [bs[=N]] [seek=N] "
- "[skip=N] [count=N] [direct] [quiet] [nosync]\n", argv0);
+ "[skip=N] [count=N] [direct] [quiet] [nosync]"
+ "[conv=notrunc]\n", argv0);
}
int
@@ -278,6 +279,8 @@ main(int argc, char *argv[])
config.quiet = 1;
else if (strcmp(argv[i], "nosync") == 0)
config.nosync = 1;
+ else if (strcmp(argv[i], "conv=notrunc") == 0)
+ config.notrunc = 1;
else if (strcmp(argv[i], "-h") == 0)
usage();
}