Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 1 | /* |
| 2 | * iovec manipulation routines. |
| 3 | * |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * Fixes: |
| 11 | * Andrew Lunn : Errors in iovec copying. |
| 12 | * Pedro Roque : Added memcpy_fromiovecend and |
| 13 | * csum_..._fromiovecend. |
| 14 | * Andi Kleen : fixed error handling for 2.1 |
| 15 | * Alexey Kuznetsov: 2.1 optimisations |
| 16 | * Andi Kleen : Fix csum*fromiovecend for IPv6. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/errno.h> |
Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 20 | #include <linux/kernel.h> |
| 21 | #include <linux/compiler.h> |
| 22 | #include <sys/uio.h> |
| 23 | #include <kvm/iovec.h> |
| 24 | #include <string.h> |
| 25 | |
| 26 | /* |
| 27 | * Copy kernel to iovec. Returns -EFAULT on error. |
| 28 | * |
| 29 | * Note: this modifies the original iovec. |
| 30 | */ |
| 31 | |
| 32 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len) |
| 33 | { |
| 34 | while (len > 0) { |
| 35 | if (iov->iov_len) { |
| 36 | int copy = min_t(unsigned int, iov->iov_len, len); |
| 37 | memcpy(iov->iov_base, kdata, copy); |
| 38 | kdata += copy; |
| 39 | len -= copy; |
| 40 | iov->iov_len -= copy; |
| 41 | iov->iov_base += copy; |
| 42 | } |
| 43 | iov++; |
| 44 | } |
| 45 | |
| 46 | return 0; |
| 47 | } |
Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Copy kernel to iovec. Returns -EFAULT on error. |
| 51 | */ |
| 52 | |
| 53 | int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata, |
| 54 | size_t offset, int len) |
| 55 | { |
| 56 | int copy; |
| 57 | for (; len > 0; ++iov) { |
| 58 | /* Skip over the finished iovecs */ |
| 59 | if (unlikely(offset >= iov->iov_len)) { |
| 60 | offset -= iov->iov_len; |
| 61 | continue; |
| 62 | } |
| 63 | copy = min_t(unsigned int, iov->iov_len - offset, len); |
| 64 | memcpy(iov->iov_base + offset, kdata, copy); |
| 65 | offset = 0; |
| 66 | kdata += copy; |
| 67 | len -= copy; |
| 68 | } |
| 69 | |
| 70 | return 0; |
| 71 | } |
Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 72 | |
| 73 | /* |
| 74 | * Copy iovec to kernel. Returns -EFAULT on error. |
| 75 | * |
| 76 | * Note: this modifies the original iovec. |
| 77 | */ |
| 78 | |
| 79 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) |
| 80 | { |
| 81 | while (len > 0) { |
| 82 | if (iov->iov_len) { |
| 83 | int copy = min_t(unsigned int, len, iov->iov_len); |
| 84 | memcpy(kdata, iov->iov_base, copy); |
| 85 | len -= copy; |
| 86 | kdata += copy; |
| 87 | iov->iov_base += copy; |
| 88 | iov->iov_len -= copy; |
| 89 | } |
| 90 | iov++; |
| 91 | } |
| 92 | |
| 93 | return 0; |
| 94 | } |
Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 95 | |
| 96 | /* |
Jean-Philippe Brucker | c492534 | 2022-06-07 18:02:25 +0100 | [diff] [blame] | 97 | * Copy at most @len bytes from iovec to buffer. |
| 98 | * Returns the remaining len. |
| 99 | * |
| 100 | * Note: this modifies the original iovec, the iov pointer, and the |
| 101 | * iovcount to describe the remaining buffer. |
| 102 | */ |
| 103 | ssize_t memcpy_fromiovec_safe(void *buf, struct iovec **iov, size_t len, |
| 104 | size_t *iovcount) |
| 105 | { |
| 106 | size_t copy; |
| 107 | |
| 108 | while (len && *iovcount) { |
| 109 | copy = min(len, (*iov)->iov_len); |
| 110 | memcpy(buf, (*iov)->iov_base, copy); |
| 111 | buf += copy; |
| 112 | len -= copy; |
| 113 | |
| 114 | /* Move iov cursor */ |
| 115 | (*iov)->iov_base += copy; |
| 116 | (*iov)->iov_len -= copy; |
| 117 | |
| 118 | if (!(*iov)->iov_len) { |
| 119 | (*iov)++; |
| 120 | (*iovcount)--; |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | return len; |
| 125 | } |
| 126 | |
| 127 | /* |
Sasha Levin | d8f3617 | 2013-05-03 16:29:15 -0400 | [diff] [blame] | 128 | * Copy iovec from kernel. Returns -EFAULT on error. |
| 129 | */ |
| 130 | |
| 131 | int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, |
| 132 | size_t offset, int len) |
| 133 | { |
| 134 | /* Skip over the finished iovecs */ |
| 135 | while (offset >= iov->iov_len) { |
| 136 | offset -= iov->iov_len; |
| 137 | iov++; |
| 138 | } |
| 139 | |
| 140 | while (len > 0) { |
| 141 | char *base = iov->iov_base + offset; |
| 142 | int copy = min_t(unsigned int, len, iov->iov_len - offset); |
| 143 | |
| 144 | offset = 0; |
| 145 | memcpy(kdata, base, copy); |
| 146 | len -= copy; |
| 147 | kdata += copy; |
| 148 | iov++; |
| 149 | } |
| 150 | |
| 151 | return 0; |
| 152 | } |