diff options
| -rw-r--r-- | block/Makefile.objs | 1 | ||||
| -rw-r--r-- | block/tar.c | 386 |
2 files changed, 387 insertions, 0 deletions
diff --git a/block/Makefile.objs b/block/Makefile.objs index 080fd26e2..0790d1995 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -25,6 +25,7 @@ common-obj-y += stream.o common-obj-y += commit.o common-obj-y += backup.o common-obj-y += dictzip.o +common-obj-y += tar.o iscsi.o-cflags := $(LIBISCSI_CFLAGS) iscsi.o-libs := $(LIBISCSI_LIBS) diff --git a/block/tar.c b/block/tar.c new file mode 100644 index 000000000..2f42d20ab --- /dev/null +++ b/block/tar.c @@ -0,0 +1,386 @@ +/* + * Tar block driver + * + * Copyright (c) 2009 Alexander Graf <agraf@suse.de> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu-common.h" +#include "block/block_int.h" + +// #define DEBUG + +#ifdef DEBUG +#define dprintf(fmt, ...) do { printf("tar: " fmt, ## __VA_ARGS__); } while (0) +#else +#define dprintf(fmt, ...) do { } while (0) +#endif + +#define SECTOR_SIZE 512 + +#define POSIX_TAR_MAGIC "ustar" +#define OFFS_LENGTH 0x7c +#define OFFS_TYPE 0x9c +#define OFFS_MAGIC 0x101 + +#define OFFS_S_SP 0x182 +#define OFFS_S_EXT 0x1e2 +#define OFFS_S_LENGTH 0x1e3 +#define OFFS_SX_EXT 0x1f8 + +typedef struct SparseCache { + uint64_t start; + uint64_t end; +} SparseCache; + +typedef struct BDRVTarState { + BlockDriverState *hd; + size_t file_sec; + uint64_t file_len; + SparseCache *sparse; + int sparse_num; + uint64_t last_end; + char longfile[2048]; +} BDRVTarState; + +static int tar_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + if (buf_size < OFFS_MAGIC + 5) + return 0; + + /* we only support newer tar */ + if (!strncmp((char*)buf + OFFS_MAGIC, POSIX_TAR_MAGIC, 5)) + return 100; + + return 0; +} + +static int str_ends(char *str, const char *end) +{ + int end_len = strlen(end); + int str_len = strlen(str); + + if (str_len < end_len) + return 0; + + return !strncmp(str + str_len - end_len, end, end_len); +} + +static int is_target_file(BlockDriverState *bs, char *filename) +{ + int retval = 0; + + if (str_ends(filename, ".raw")) + retval = 1; + + if (str_ends(filename, ".qcow")) + retval = 1; + + if (str_ends(filename, ".qcow2")) + retval = 1; + + if (str_ends(filename, ".vmdk")) + retval = 1; + + dprintf("does filename %s match? %s\n", filename, retval ? "yes" : "no"); + + /* make sure we're not using this name again */ + filename[0] = '\0'; + return retval; +} + +static uint64_t tar2u64(char *ptr) +{ + uint64_t retval; + char oldend = ptr[12]; + + ptr[12] = '\0'; + if (*ptr & 0x80) { + /* XXX we only support files up to 64 bit length */ + retval = be64_to_cpu(*(uint64_t *)(ptr+4)); + dprintf("Convert %lx -> %#lx\n", *(uint64_t*)(ptr+4), retval); + } else { + retval = strtol(ptr, NULL, 8); + dprintf("Convert %s -> %#lx\n", ptr, retval); + } + + ptr[12] = oldend; + + return retval; +} + +static void tar_sparse(BDRVTarState *s, uint64_t offs, uint64_t len) +{ + SparseCache *sparse; + + if (!len) + return; + if (!(offs - s->last_end)) { + s->last_end += len; + return; + } + if (s->last_end > offs) + return; + + dprintf("Last chunk until %lx new chunk at %lx\n", s->last_end, offs); + + s->sparse = g_realloc(s->sparse, (s->sparse_num + 1) * sizeof(SparseCache)); + sparse = &s->sparse[s->sparse_num]; + sparse->start = s->last_end; + sparse->end = offs; + s->last_end = offs + len; + s->sparse_num++; + dprintf("Sparse at %lx end=%lx\n", sparse->start, + sparse->end); +} + +static QemuOptsList runtime_opts = { + .name = "tar", + .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head), + .desc = { + { + .name = "filename", + .type = QEMU_OPT_STRING, + .help = "URL to the tar file", + }, + { /* end of list */ } + }, +}; + +static int tar_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) +{ + BDRVTarState *s = bs->opaque; + char header[SECTOR_SIZE]; + char *real_file = header; + char *magic; + size_t header_offs = 0; + int ret; + QemuOpts *opts; + Error *local_err = NULL; + const char *filename; + + opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort); + qemu_opts_absorb_qdict(opts, options, &local_err); + if (local_err != NULL) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto fail; + } + + filename = qemu_opt_get(opts, "filename"); + + if (!strncmp(filename, "tar://", 6)) + filename += 6; + else if (!strncmp(filename, "tar:", 4)) + filename += 4; + + ret = bdrv_open(&s->hd, filename, NULL, NULL, flags | BDRV_O_PROTOCOL, NULL, &local_err); + if (ret < 0) { + error_propagate(errp, local_err); + qemu_opts_del(opts); + return ret; + } + + /* Search the file for an image */ + + do { + /* tar header */ + if (bdrv_pread(s->hd, header_offs, header, SECTOR_SIZE) != SECTOR_SIZE) + goto fail; + + if ((header_offs > 1) && !header[0]) { + fprintf(stderr, "Tar: No image file found in archive\n"); + goto fail; + } + + magic = &header[OFFS_MAGIC]; + if (strncmp(magic, POSIX_TAR_MAGIC, 5)) { + fprintf(stderr, "Tar: Invalid magic: %s\n", magic); + goto fail; + } + + dprintf("file type: %c\n", header[OFFS_TYPE]); + + /* file length*/ + s->file_len = (tar2u64(&header[OFFS_LENGTH]) + (SECTOR_SIZE - 1)) & + ~(SECTOR_SIZE - 1); + s->file_sec = (header_offs / SECTOR_SIZE) + 1; + + header_offs += s->file_len + SECTOR_SIZE; + + if (header[OFFS_TYPE] == 'L') { + bdrv_pread(s->hd, header_offs - s->file_len, s->longfile, + sizeof(s->longfile)); + s->longfile[sizeof(s->longfile)-1] = '\0'; + } else if (s->longfile[0]) { + real_file = s->longfile; + } else { + real_file = header; + } + } while(!is_target_file(bs, real_file)); + + /* We found an image! */ + + if (header[OFFS_TYPE] == 'S') { + uint8_t isextended; + int i; + + for (i = OFFS_S_SP; i < (OFFS_S_SP + (4 * 24)); i += 24) + tar_sparse(s, tar2u64(&header[i]), tar2u64(&header[i+12])); + + s->file_len = tar2u64(&header[OFFS_S_LENGTH]); + isextended = header[OFFS_S_EXT]; + + while (isextended) { + if (bdrv_pread(s->hd, s->file_sec * SECTOR_SIZE, header, + SECTOR_SIZE) != SECTOR_SIZE) + goto fail; + + for (i = 0; i < (21 * 24); i += 24) + tar_sparse(s, tar2u64(&header[i]), tar2u64(&header[i+12])); + isextended = header[OFFS_SX_EXT]; + s->file_sec++; + } + tar_sparse(s, s->file_len, 1); + } + qemu_opts_del(opts); + + return 0; + +fail: + fprintf(stderr, "Tar: Error opening file\n"); + bdrv_unref(s->hd); + qemu_opts_del(opts); + return -EINVAL; +} + +typedef struct TarAIOCB { + BlockAIOCB common; + QEMUBH *bh; +} TarAIOCB; + +/* This callback gets invoked when we have pure sparseness */ +static void tar_sparse_cb(void *opaque) +{ + TarAIOCB *acb = (TarAIOCB *)opaque; + + acb->common.cb(acb->common.opaque, 0); + qemu_bh_delete(acb->bh); + qemu_aio_unref(acb); +} + +static void tar_aio_cancel(BlockAIOCB *blockacb) +{ +} + +static AIOCBInfo tar_aiocb_info = { + .aiocb_size = sizeof(TarAIOCB), + .cancel_async = tar_aio_cancel, +}; + +/* This is where we get a request from a caller to read something */ +static BlockAIOCB *tar_aio_readv(BlockDriverState *bs, + int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, + BlockCompletionFunc *cb, void *opaque) +{ + BDRVTarState *s = bs->opaque; + SparseCache *sparse; + int64_t sec_file = sector_num + s->file_sec; + int64_t start = sector_num * SECTOR_SIZE; + int64_t end = start + (nb_sectors * SECTOR_SIZE); + int i; + TarAIOCB *acb; + + for (i = 0; i < s->sparse_num; i++) { + sparse = &s->sparse[i]; + if (sparse->start > end) { + /* We expect the cache to be start increasing */ + break; + } else if ((sparse->start < start) && (sparse->end <= start)) { + /* sparse before our offset */ + sec_file -= (sparse->end - sparse->start) / SECTOR_SIZE; + } else if ((sparse->start <= start) && (sparse->end >= end)) { + /* all our sectors are sparse */ + char *buf = g_malloc0(nb_sectors * SECTOR_SIZE); + + acb = qemu_aio_get(&tar_aiocb_info, bs, cb, opaque); + qemu_iovec_from_buf(qiov, 0, buf, nb_sectors * SECTOR_SIZE); + g_free(buf); + acb->bh = qemu_bh_new(tar_sparse_cb, acb); + qemu_bh_schedule(acb->bh); + + return &acb->common; + } else if (((sparse->start >= start) && (sparse->start < end)) || + ((sparse->end >= start) && (sparse->end < end))) { + /* we're semi-sparse (worst case) */ + /* let's go synchronous and read all sectors individually */ + char *buf = g_malloc(nb_sectors * SECTOR_SIZE); + uint64_t offs; + + for (offs = 0; offs < (nb_sectors * SECTOR_SIZE); + offs += SECTOR_SIZE) { + bdrv_pread(bs, (sector_num * SECTOR_SIZE) + offs, + buf + offs, SECTOR_SIZE); + } + + qemu_iovec_from_buf(qiov, 0, buf, nb_sectors * SECTOR_SIZE); + acb = qemu_aio_get(&tar_aiocb_info, bs, cb, opaque); + acb->bh = qemu_bh_new(tar_sparse_cb, acb); + qemu_bh_schedule(acb->bh); + + return &acb->common; + } + } + + return bdrv_aio_readv(s->hd, sec_file, qiov, nb_sectors, + cb, opaque); +} + +static void tar_close(BlockDriverState *bs) +{ + dprintf("Close\n"); +} + +static int64_t tar_getlength(BlockDriverState *bs) +{ + BDRVTarState *s = bs->opaque; + dprintf("getlength -> %ld\n", s->file_len); + return s->file_len; +} + +static BlockDriver bdrv_tar = { + .format_name = "tar", + .protocol_name = "tar", + + .instance_size = sizeof(BDRVTarState), + .bdrv_file_open = tar_open, + .bdrv_close = tar_close, + .bdrv_getlength = tar_getlength, + .bdrv_probe = tar_probe, + + .bdrv_aio_readv = tar_aio_readv, +}; + +static void tar_block_init(void) +{ + bdrv_register(&bdrv_tar); +} + +block_init(tar_block_init); |