diff options
Diffstat (limited to 'lib/sqfs/write_xattr.c')
| -rw-r--r-- | lib/sqfs/write_xattr.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/sqfs/write_xattr.c b/lib/sqfs/write_xattr.c new file mode 100644 index 0000000..b6198b4 --- /dev/null +++ b/lib/sqfs/write_xattr.c @@ -0,0 +1,205 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +#include "meta_writer.h" +#include "highlevel.h" +#include "util.h" + +#include <assert.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +static const struct { + const char *prefix; + E_SQFS_XATTR_TYPE type; +} xattr_types[] = { + { "user.", SQUASHFS_XATTR_USER }, + { "trusted.", SQUASHFS_XATTR_TRUSTED }, + { "security.", SQUASHFS_XATTR_SECURITY }, +}; + +static int get_prefix(const char *key) +{ + size_t i, len; + + for (i = 0; i < sizeof(xattr_types) / sizeof(xattr_types[0]); ++i) { + len = strlen(xattr_types[i].prefix); + + if (strncmp(key, xattr_types[i].prefix, len) == 0 && + strlen(key) > len) { + return xattr_types[i].type; + } + } + + fprintf(stderr, "unknown xattr key '%s'\n", key); + return -1; +} + +static int write_pair(meta_writer_t *mw, const char *key, const char *value) +{ + sqfs_xattr_entry_t kent; + sqfs_xattr_value_t vent; + int type; + + type = get_prefix(key); + if (type < 0) + return -1; + + key = strchr(key, '.'); + assert(key != NULL); + ++key; + + kent.type = htole16(type); + kent.size = htole16(strlen(key)); + + if (meta_writer_append(mw, &kent, sizeof(kent))) + return -1; + if (meta_writer_append(mw, key, strlen(key))) + return -1; + + vent.size = htole32(strlen(value)); + + if (meta_writer_append(mw, &vent, sizeof(vent))) + return -1; + if (meta_writer_append(mw, value, strlen(value))) + return -1; + + return 0; +} + +static int write_kv_pairs(fstree_t *fs, meta_writer_t *mw, tree_xattr_t *xattr) +{ + uint32_t key_idx, val_idx; + const char *key, *value; + size_t i; + + for (i = 0; i < xattr->num_attr; ++i) { + key_idx = (xattr->ref[i] >> 32) & 0xFFFFFFFF; + val_idx = xattr->ref[i] & 0xFFFFFFFF; + + key = str_table_get_string(&fs->xattr_keys, key_idx); + value = str_table_get_string(&fs->xattr_values, val_idx); + + if (write_pair(mw, key, value)) + return -1; + + xattr->size += sizeof(sqfs_xattr_entry_t) + strlen(key); + xattr->size += sizeof(sqfs_xattr_value_t) + strlen(value); + } + + return 0; +} + +int write_xattr(int outfd, fstree_t *fs, sqfs_super_t *super, + compressor_t *cmp) +{ + uint64_t kv_start, id_start, block, *tbl; + size_t i = 0, count = 0, blocks; + sqfs_xattr_id_table_t idtbl; + sqfs_xattr_id_t id_ent; + meta_writer_t *mw; + tree_xattr_t *it; + uint32_t offset; + ssize_t ret; + + if (fs->xattr == NULL) + return 0; + + mw = meta_writer_create(outfd, cmp); + if (mw == NULL) + return -1; + + /* write xattr key-value pairs */ + kv_start = super->bytes_used; + + for (it = fs->xattr; it != NULL; it = it->next) { + meta_writer_get_position(mw, &it->block, &it->offset); + it->size = 0; + + if (write_kv_pairs(fs, mw, it)) + goto fail_mw; + + ++count; + } + + if (meta_writer_flush(mw)) + goto fail_mw; + + meta_writer_get_position(mw, &block, &offset); + meta_writer_reset(mw); + + super->bytes_used += block; + + /* allocate location table */ + blocks = (count * sizeof(id_ent)) / SQFS_META_BLOCK_SIZE; + + if ((count * sizeof(id_ent)) % SQFS_META_BLOCK_SIZE) + ++blocks; + + tbl = calloc(sizeof(uint64_t), blocks); + + if (tbl == NULL) { + perror("generating xattr ID table"); + goto fail_mw; + } + + /* write ID table referring to key value pairs, record offsets */ + id_start = 0; + tbl[i++] = htole64(super->bytes_used); + + for (it = fs->xattr; it != NULL; it = it->next) { + id_ent.xattr = htole64((it->block << 16) | it->offset); + id_ent.count = htole32(it->num_attr); + id_ent.size = htole32(it->size); + + if (meta_writer_append(mw, &id_ent, sizeof(id_ent))) + goto fail_tbl; + + meta_writer_get_position(mw, &block, &offset); + + if (block != id_start) { + id_start = block; + tbl[i++] = htole64(super->bytes_used + id_start); + } + } + + if (meta_writer_flush(mw)) + goto fail_tbl; + + meta_writer_get_position(mw, &block, &offset); + super->bytes_used += block; + + /* write offset table */ + idtbl.xattr_table_start = htole64(kv_start); + idtbl.xattr_ids = htole32(count); + idtbl.unused = 0; + + ret = write_retry(outfd, &idtbl, sizeof(idtbl)); + if (ret < 0) + goto fail_wr; + if ((size_t)ret < sizeof(idtbl)) + goto fail_trunc; + + write_retry(outfd, tbl, sizeof(tbl[0]) * blocks); + if (ret < 0) + goto fail_wr; + if ((size_t)ret < sizeof(tbl[0]) * blocks) + goto fail_trunc; + + super->xattr_id_table_start = super->bytes_used; + super->bytes_used += sizeof(idtbl) + sizeof(tbl[0]) * blocks; + + free(tbl); + meta_writer_destroy(mw); + return 0; +fail_wr: + perror("writing xattr ID table"); + goto fail_tbl; +fail_trunc: + fputs("writing xattr ID table: truncated write\n", stderr); + goto fail_tbl; +fail_tbl: + free(tbl); +fail_mw: + meta_writer_destroy(mw); + return -1; +} |