1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
55 	n = io->offset;  in seek_offset()
56 	sz = io->dbsz;  in seek_offset()
58 	_Static_assert(sizeof(io->offset) == sizeof(int64_t), "64-bit off_t");  in seek_offset()
65 	 * Bail out if the calculation of a file offset would overflow.  in seek_offset()
67 	if ((io->flags & ISCHR) == 0 && (n < 0 || n > OFF_MAX / (ssize_t)sz))  in seek_offset()
70 	else if ((io->flags & ISCHR) != 0 && (uint64_t)n > UINT64_MAX / sz)  in seek_offset()
94 		if (lseek(in.fd, seek_offset(&in), SEEK_CUR) == -1 &&  in pos_in()
100 	/* Don't try to read a really weird amount (like negative). */  in pos_in()
105 	 * Read the data.  If a pipe, read until satisfy the number of bytes  in pos_in()
110 		if ((nr = read(in.fd, in.db, bcnt)) > 0) {  in pos_in()
112 				if (!(bcnt -= nr)) {  in pos_in()
114 					--cnt;  in pos_in()
117 				--cnt;  in pos_in()
127 				--files_cnt;  in pos_in()
134 		 * Input error -- either EOF with no more files, or I/O error.  in pos_in()
159 	 * going to fail, but don't protect the user -- they shouldn't  in pos_out()
162 	if (out.flags & (ISSEEK | ISPIPE)) {  in pos_out()
164 		if (lseek(out.fd, seek_offset(&out), SEEK_CUR) == -1 &&  in pos_out()
166 			err(1, "%s", out.name);  in pos_out()
170 	/* Don't try to read a really weird amount (like negative). */  in pos_out()
171 	if (out.offset < 0)  in pos_out()
174 	/* If no read access, try using mtio. */  in pos_out()
175 	if (out.flags & NOREAD) {  in pos_out()
177 		t_op.mt_count = out.offset;  in pos_out()
179 		if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)  in pos_out()
180 			err(1, "%s", out.name);  in pos_out()
184 	/* Read it. */  in pos_out()
185 	for (cnt = 0; cnt < out.offset; ++cnt) {  in pos_out()
187 		n = read(out.fd, out.db, out.dbsz);  in pos_out()
191 		if (n == -1)  in pos_out()
192 			err(1, "%s", out.name);  in pos_out()
197 		 * the EOF read does not count as a seek'd block.  in pos_out()
201 		if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)  in pos_out()
202 			err(1, "%s", out.name);  in pos_out()
204 		while (cnt++ < out.offset) {  in pos_out()
206 			n = write(out.fd, out.db, out.dbsz);  in pos_out()
208 			if (n == -1)  in pos_out()
209 				err(1, "%s", out.name);  in pos_out()
210 			if (n != out.dbsz)  in pos_out()
211 				errx(1, "%s: write failure", out.name);  in pos_out()