1 /*
2 * Unix SMB/CIFS implementation.
3 * Samba system utilities
4 * Copyright (C) Volker Lendecke 2014
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "replace.h"
21 #include "system/filesys.h"
22 #include "iov_buf.h"
23 #include <talloc.h>
24
iov_buflen(const struct iovec * iov,int iovcnt)25 ssize_t iov_buflen(const struct iovec *iov, int iovcnt)
26 {
27 return iov_buf(iov, iovcnt, NULL, 0);
28 }
29
iov_buf(const struct iovec * iov,int iovcnt,uint8_t * buf,size_t buflen)30 ssize_t iov_buf(const struct iovec *iov, int iovcnt,
31 uint8_t *buf, size_t buflen)
32 {
33 size_t needed = 0;
34 uint8_t *p = buf;
35 int i;
36
37 for (i=0; i<iovcnt; i++) {
38 size_t thislen = iov[i].iov_len;
39 size_t tmp;
40
41 tmp = needed + thislen;
42
43 if (tmp < needed) {
44 /* wrap */
45 return -1;
46 }
47 needed = tmp;
48
49 if ((p != NULL) && needed <= buflen && thislen > 0) {
50 memcpy(p, iov[i].iov_base, thislen);
51 p += thislen;
52 }
53 }
54
55 return needed;
56 }
57
iov_advance(struct iovec ** iov,int * iovcnt,size_t n)58 bool iov_advance(struct iovec **iov, int *iovcnt, size_t n)
59 {
60 struct iovec *v = *iov;
61 int cnt = *iovcnt;
62
63 while (n > 0) {
64 if (cnt == 0) {
65 return false;
66 }
67 if (n < v->iov_len) {
68 v->iov_base = (char *)v->iov_base + n;
69 v->iov_len -= n;
70 break;
71 }
72 n -= v->iov_len;
73 v += 1;
74 cnt -= 1;
75 }
76
77 /*
78 * Skip 0-length iovec's
79 *
80 * There might be empty buffers at the end of iov. Next time we do a
81 * readv/writev based on this iov would give 0 transferred bytes, also
82 * known as EPIPE. So we need to be careful discarding them.
83 */
84
85 while ((cnt > 0) && (v->iov_len == 0)) {
86 v += 1;
87 cnt -= 1;
88 }
89
90 *iov = v;
91 *iovcnt = cnt;
92 return true;
93 }
94
iov_concat(TALLOC_CTX * mem_ctx,const struct iovec * iov,int count)95 uint8_t *iov_concat(TALLOC_CTX *mem_ctx, const struct iovec *iov, int count)
96 {
97 ssize_t buflen;
98 uint8_t *buf;
99
100 buflen = iov_buflen(iov, count);
101 if (buflen == -1) {
102 return NULL;
103 }
104
105 buf = talloc_array(mem_ctx, uint8_t, buflen);
106 if (buf == NULL) {
107 return NULL;
108 }
109
110 iov_buf(iov, count, buf, buflen);
111
112 return buf;
113 }
114