| 1 | /* |
| 2 | * Copyright 2020 Google LLC |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style |
| 5 | * license that can be found in the LICENSE file or at |
| 6 | * https://developers.google.com/open-source/licenses/bsd |
| 7 | */ |
| 8 | |
| 9 | #include "system.h" |
| 10 | |
| 11 | #include "basics.h" |
| 12 | #include "blocksource.h" |
| 13 | #include "reftable-blocksource.h" |
| 14 | #include "reftable-error.h" |
| 15 | |
| 16 | void block_source_release_data(struct reftable_block_data *data) |
| 17 | { |
| 18 | struct reftable_block_source source = data->source; |
| 19 | if (data && source.ops) |
| 20 | source.ops->release_data(source.arg, data); |
| 21 | data->data = NULL; |
| 22 | data->len = 0; |
| 23 | data->source.ops = NULL; |
| 24 | data->source.arg = NULL; |
| 25 | } |
| 26 | |
| 27 | void block_source_close(struct reftable_block_source *source) |
| 28 | { |
| 29 | if (!source->ops) { |
| 30 | return; |
| 31 | } |
| 32 | |
| 33 | source->ops->close(source->arg); |
| 34 | source->ops = NULL; |
| 35 | } |
| 36 | |
| 37 | ssize_t block_source_read_data(struct reftable_block_source *source, |
| 38 | struct reftable_block_data *dest, uint64_t off, |
| 39 | uint32_t size) |
| 40 | { |
| 41 | ssize_t result = source->ops->read_data(source->arg, dest, off, size); |
| 42 | dest->source = *source; |
| 43 | return result; |
| 44 | } |
| 45 | |
| 46 | uint64_t block_source_size(struct reftable_block_source *source) |
| 47 | { |
| 48 | return source->ops->size(source->arg); |
| 49 | } |
| 50 | |
| 51 | static void reftable_buf_release_data(void *b REFTABLE_UNUSED, struct reftable_block_data *dest) |
| 52 | { |
| 53 | if (dest->len) |
| 54 | memset(dest->data, 0xff, dest->len); |
| 55 | reftable_free(dest->data); |
| 56 | } |
| 57 | |
| 58 | static void reftable_buf_close(void *b REFTABLE_UNUSED) |
| 59 | { |
| 60 | } |
| 61 | |
| 62 | static ssize_t reftable_buf_read_data(void *v, struct reftable_block_data *dest, |
| 63 | uint64_t off, uint32_t size) |
| 64 | { |
| 65 | struct reftable_buf *b = v; |
| 66 | assert(off + size <= b->len); |
| 67 | REFTABLE_CALLOC_ARRAY(dest->data, size); |
| 68 | if (!dest->data) |
| 69 | return -1; |
| 70 | memcpy(dest->data, b->buf + off, size); |
| 71 | dest->len = size; |
| 72 | return size; |
| 73 | } |
| 74 | |
| 75 | static uint64_t reftable_buf_size(void *b) |
| 76 | { |
| 77 | return ((struct reftable_buf *)b)->len; |
| 78 | } |
| 79 | |
| 80 | static struct reftable_block_source_vtable reftable_buf_vtable = { |
| 81 | .size = &reftable_buf_size, |
| 82 | .read_data = &reftable_buf_read_data, |
| 83 | .release_data = &reftable_buf_release_data, |
| 84 | .close = &reftable_buf_close, |
| 85 | }; |
| 86 | |
| 87 | void block_source_from_buf(struct reftable_block_source *bs, |
| 88 | struct reftable_buf *buf) |
| 89 | { |
| 90 | assert(!bs->ops); |
| 91 | bs->ops = &reftable_buf_vtable; |
| 92 | bs->arg = buf; |
| 93 | } |
| 94 | |
| 95 | struct file_block_source { |
| 96 | struct reftable_mmap mmap; |
| 97 | }; |
| 98 | |
| 99 | static uint64_t file_size(void *b) |
| 100 | { |
| 101 | return ((struct file_block_source *)b)->mmap.size; |
| 102 | } |
| 103 | |
| 104 | static void file_release_data(void *b REFTABLE_UNUSED, struct reftable_block_data *dest REFTABLE_UNUSED) |
| 105 | { |
| 106 | } |
| 107 | |
| 108 | static void file_close(void *v) |
| 109 | { |
| 110 | struct file_block_source *b = v; |
| 111 | reftable_munmap(&b->mmap); |
| 112 | reftable_free(b); |
| 113 | } |
| 114 | |
| 115 | static ssize_t file_read_data(void *v, struct reftable_block_data *dest, uint64_t off, |
| 116 | uint32_t size) |
| 117 | { |
| 118 | struct file_block_source *b = v; |
| 119 | assert(off + size <= b->mmap.size); |
| 120 | dest->data = (unsigned char *) b->mmap.data + off; |
| 121 | dest->len = size; |
| 122 | return size; |
| 123 | } |
| 124 | |
| 125 | static struct reftable_block_source_vtable file_vtable = { |
| 126 | .size = &file_size, |
| 127 | .read_data = &file_read_data, |
| 128 | .release_data = &file_release_data, |
| 129 | .close = &file_close, |
| 130 | }; |
| 131 | |
| 132 | int reftable_block_source_from_file(struct reftable_block_source *bs, |
| 133 | const char *name) |
| 134 | { |
| 135 | struct file_block_source *p = NULL; |
| 136 | struct stat st; |
| 137 | int fd, err; |
| 138 | |
| 139 | fd = open(name, O_RDONLY); |
| 140 | if (fd < 0) { |
| 141 | if (errno == ENOENT) |
| 142 | return REFTABLE_NOT_EXIST_ERROR; |
| 143 | err = -1; |
| 144 | goto out; |
| 145 | } |
| 146 | |
| 147 | if (fstat(fd, &st) < 0) { |
| 148 | err = REFTABLE_IO_ERROR; |
| 149 | goto out; |
| 150 | } |
| 151 | |
| 152 | REFTABLE_CALLOC_ARRAY(p, 1); |
| 153 | if (!p) { |
| 154 | err = REFTABLE_OUT_OF_MEMORY_ERROR; |
| 155 | goto out; |
| 156 | } |
| 157 | |
| 158 | err = reftable_mmap(&p->mmap, fd, st.st_size); |
| 159 | if (err < 0) |
| 160 | goto out; |
| 161 | |
| 162 | assert(!bs->ops); |
| 163 | bs->ops = &file_vtable; |
| 164 | bs->arg = p; |
| 165 | |
| 166 | err = 0; |
| 167 | |
| 168 | out: |
| 169 | if (fd >= 0) |
| 170 | close(fd); |
| 171 | if (err < 0) |
| 172 | reftable_free(p); |
| 173 | return err; |
| 174 | } |