/*
* Position input/output data streams before starting the copy. Device type
* dependent. Seekable devices use lseek, and the rest position by reading.
* Seeking past the end of file can cause null blocks to be written to the
* output.
*/
void
pos_in(void)
{
int bcnt, cnt, nr, warned;
/* If not a pipe or tape device, try to seek on it. */
if (!(in.flags & (ISPIPE|ISTAPE))) {
if (ddop_lseek(in, in.fd,
(off_t)in.offset * (off_t)in.dbsz, SEEK_CUR) == -1) {
err(EXIT_FAILURE, "%s", in.name);
/* NOTREACHED */
}
return;
/* NOTREACHED */
}
/*
* Read the data. If a pipe, read until satisfy the number of bytes
* being skipped. No differentiation for reading complete and partial
* blocks for other devices.
*/
for (bcnt = in.dbsz, cnt = in.offset, warned = 0; cnt;) {
if ((nr = ddop_read(in, in.fd, in.db, bcnt)) > 0) {
if (in.flags & ISPIPE) {
if (!(bcnt -= nr)) {
bcnt = in.dbsz;
--cnt;
}
} else
--cnt;
continue;
}
if (nr == 0) {
if (files_cnt > 1) {
--files_cnt;
continue;
}
errx(EXIT_FAILURE, "skip reached end of input");
/* NOTREACHED */
}
/*
* Input error -- either EOF with no more files, or I/O error.
* If noerror not set die. POSIX requires that the warning
* message be followed by an I/O display.
*/
if (ddflags & C_NOERROR) {
if (!warned) {
warn("%s", in.name);
warned = 1;
summary();
}
continue;
}
err(EXIT_FAILURE, "%s", in.name);
/* NOTREACHED */
}
}
void
pos_out(void)
{
struct mtop t_op;
int n;
uint64_t cnt;
/*
* If not a tape, try seeking on the file. Seeking on a pipe is
* going to fail, but don't protect the user -- they shouldn't
* have specified the seek operand.
*/
if (!(out.flags & ISTAPE)) {
if (ddop_lseek(out, out.fd,
(off_t)out.offset * (off_t)out.dbsz, SEEK_SET) == -1)
err(EXIT_FAILURE, "%s", out.name);
/* NOTREACHED */
return;
}
/* If no read access, try using mtio. */
if (out.flags & NOREAD) {
t_op.mt_op = MTFSR;
t_op.mt_count = out.offset;
if (ddop_ioctl(out, out.fd, MTIOCTOP, &t_op) < 0)
err(EXIT_FAILURE, "%s", out.name);
/* NOTREACHED */
return;
}
/* Read it. */
for (cnt = 0; cnt < out.offset; ++cnt) {
if ((n = ddop_read(out, out.fd, out.db, out.dbsz)) > 0)
continue;
if (n < 0)
err(EXIT_FAILURE, "%s", out.name);
/* NOTREACHED */
/*
* If reach EOF, fill with NUL characters; first, back up over
* the EOF mark. Note, cnt has not yet been incremented, so
* the EOF read does not count as a seek'd block.
*/
t_op.mt_op = MTBSR;
t_op.mt_count = 1;
if (ddop_ioctl(out, out.fd, MTIOCTOP, &t_op) == -1)
err(EXIT_FAILURE, "%s", out.name);
/* NOTREACHED */
while (cnt++ < out.offset)
if ((uint64_t)(n = bwrite(&out,
out.db, out.dbsz)) != out.dbsz)
err(EXIT_FAILURE, "%s", out.name);
/* NOTREACHED */
break;
}
}
static void
dd_in(void)
{
int flags;
int64_t n;
for (flags = ddflags;;) {
if (cpy_cnt && (st.in_full + st.in_part) >= cpy_cnt)
return;
/*
* Clear the buffer first if doing "sync" on input.
* If doing block operations use spaces. This will
* affect not only the C_NOERROR case, but also the
* last partial input block which should be padded
* with zero and not garbage.
*/
if (flags & C_SYNC) {
if (flags & (C_BLOCK|C_UNBLOCK))
(void)memset(in.dbp, ' ', in.dbsz);
else
(void)memset(in.dbp, 0, in.dbsz);
}
n = ddop_read(in, in.fd, in.dbp, in.dbsz);
if (n == 0) {
in.dbrcnt = 0;
return;
}
/* Read error. */
if (n < 0) {
/*
* If noerror not specified, die. POSIX requires that
* the warning message be followed by an I/O display.
*/
if (!(flags & C_NOERROR)) {
err(EXIT_FAILURE, "%s", in.name);
/* NOTREACHED */
}
warn("%s", in.name);
summary();
/*
* If it's not a tape drive or a pipe, seek past the
* error. If your OS doesn't do the right thing for
* raw disks this section should be modified to re-read
* in sector size chunks.
*/
if (!(in.flags & (ISPIPE|ISTAPE)) &&
ddop_lseek(in, in.fd, (off_t)in.dbsz, SEEK_CUR))
warn("%s", in.name);
/* If sync not specified, omit block and continue. */
if (!(ddflags & C_SYNC))
continue;
/* Read errors count as full blocks. */
in.dbcnt += in.dbrcnt = in.dbsz;
++st.in_full;
/* Handle full input blocks. */
} else if ((uint64_t)n == in.dbsz) {
in.dbcnt += in.dbrcnt = n;
++st.in_full;
/* Handle partial input blocks. */
} else {
/* If sync, use the entire block. */
if (ddflags & C_SYNC)
in.dbcnt += in.dbrcnt = in.dbsz;
else
in.dbcnt += in.dbrcnt = n;
++st.in_part;
}
/*
* POSIX states that if bs is set and no other conversions
* than noerror, notrunc or sync are specified, the block
* is output without buffering as it is read.
*/
if (ddflags & C_BS) {
out.dbcnt = in.dbcnt;
dd_out(1);
in.dbcnt = 0;
continue;
}
if (ddflags & C_SWAB) {
if ((n = in.dbrcnt) & 1) {
++st.swab;
--n;
}
swab(in.dbp, in.dbp, n);
}
in.dbp += in.dbrcnt;
(*cfunc)();
}
}
