Added code for calculating crc of erofs blocks (4K size).for now it calculates checksum of first block. but can modified to calculate crc for any no. of blocks.
Signed-off-by: Pratik Shinde <[email protected]> --- include/erofs/config.h | 3 +++ include/erofs/io.h | 8 ++++++ lib/config.c | 2 ++ lib/io.c | 27 +++++++++++++++++++ mkfs/main.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 113 insertions(+) diff --git a/include/erofs/config.h b/include/erofs/config.h index 9711638..e167cd4 100644 --- a/include/erofs/config.h +++ b/include/erofs/config.h @@ -16,6 +16,8 @@ enum { FORCE_INODE_EXTENDED, }; +#define EROFS_FEATURE_BLK_CKSUM 1 + struct erofs_configure { const char *c_version; int c_dbg_lvl; @@ -29,6 +31,7 @@ struct erofs_configure { int c_compr_level_master; int c_force_inodeversion; u64 c_unix_timestamp; + int c_blk_cksum; }; extern struct erofs_configure cfg; diff --git a/include/erofs/io.h b/include/erofs/io.h index 9775047..e0ca8d9 100644 --- a/include/erofs/io.h +++ b/include/erofs/io.h @@ -19,6 +19,7 @@ int dev_open(const char *devname); void dev_close(void); int dev_write(const void *buf, u64 offset, size_t len); +int dev_read(void *buf, u64 offset, size_t len); int dev_fillzero(u64 offset, size_t len, bool padding); int dev_fsync(void); int dev_resize(erofs_blk_t nblocks); @@ -31,5 +32,12 @@ static inline int blk_write(const void *buf, erofs_blk_t blkaddr, blknr_to_addr(nblocks)); } +static inline int blk_read(void *buf, erofs_blk_t start, + u32 nblocks) +{ + return dev_read(buf, blknr_to_addr(start), + blknr_to_addr(nblocks)); +} + #endif diff --git a/lib/config.c b/lib/config.c index 46625d7..b5ddff8 100644 --- a/lib/config.c +++ b/lib/config.c @@ -9,6 +9,7 @@ #include <string.h> #include "erofs/print.h" #include "erofs/internal.h" +#include "erofs/config.h" struct erofs_configure cfg; @@ -22,6 +23,7 @@ void erofs_init_configure(void) cfg.c_compr_level_master = -1; cfg.c_force_inodeversion = 0; cfg.c_unix_timestamp = -1; + cfg.c_blk_cksum = EROFS_FEATURE_BLK_CKSUM; } void erofs_show_config(void) diff --git a/lib/io.c b/lib/io.c index 7f5f94d..52f9424 100644 --- a/lib/io.c +++ b/lib/io.c @@ -207,3 +207,30 @@ int dev_resize(unsigned int blocks) return dev_fillzero(st.st_size, length, true); } +int dev_read(void *buf, u64 offset, size_t len) +{ + int ret; + + if (cfg.c_dry_run) + return 0; + + if (!buf) { + erofs_err("buf is NULL"); + return -EINVAL; + } + if (offset >= erofs_devsz || len > erofs_devsz || + offset > erofs_devsz - len) { + erofs_err("read posion[%" PRIu64 ", %zd] is too large beyond" + "the end of device(%" PRIu64 ").", + offset, len, erofs_devsz); + return -EINVAL; + } + + ret = pread64(erofs_devfd, buf, len, (off64_t)offset); + if (ret != (int)len) { + erofs_err("Failed to read data from device - %s:[%" PRIu64 ", %zd].", + erofs_devname, offset, len); + return -errno; + } + return 0; +} diff --git a/mkfs/main.c b/mkfs/main.c index 91a018f..239d6e7 100644 --- a/mkfs/main.c +++ b/mkfs/main.c @@ -22,6 +22,9 @@ #define EROFS_SUPER_END (EROFS_SUPER_OFFSET + sizeof(struct erofs_super_block)) +// number of blocks for calculating checksum +#define EROFS_CKSUM_BLOCKS 1 + static void usage(void) { fprintf(stderr, "usage: [options] FILE DIRECTORY\n\n"); @@ -85,6 +88,10 @@ static int parse_extended_opts(const char *opts) return -EINVAL; cfg.c_force_inodeversion = FORCE_INODE_EXTENDED; } + + if (MATCH_EXTENTED_OPT("nocrc", token, keylen)) { + cfg.c_blk_cksum = ~EROFS_FEATURE_BLK_CKSUM; + } } return 0; } @@ -180,6 +187,7 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh, .meta_blkaddr = sbi.meta_blkaddr, .xattr_blkaddr = 0, .feature_incompat = cpu_to_le32(sbi.feature_incompat), + .checksum = 0 }; const unsigned int sb_blksize = round_up(EROFS_SUPER_END, EROFS_BLKSIZ); @@ -202,6 +210,68 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh, return 0; } +#define CRCPOLY 0x82F63B78 +static inline u32 crc32c(u32 seed, unsigned char const *in, size_t len) +{ + int i; + u32 crc = seed; + + while (len--) { + crc ^= *in++; + for (i = 0; i < 8; i++) { + crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY : 0); + } + } + return crc; +} + +// calculate checksum for first n blocks +u32 erofs_blk_checksum(erofs_blk_t nblks, u32 *crc) { + char *buf; + int err = 0; + + buf = malloc(nblks * EROFS_BLKSIZ); + err = blk_read(buf, 0, nblks); + if (err) { + erofs_err("Failed to calculate erofs checksum - %s", + erofs_strerror(err)); + return err; + } + *crc = crc32c(0, (const unsigned char *)buf, nblks * EROFS_BLKSIZ); + free(buf); + return 0; +} + +void erofs_set_checksum() { + struct erofs_super_block *sb; + char buf[EROFS_BLKSIZ]; + int ret = 0; + u32 crc; + + ret = erofs_blk_checksum(EROFS_CKSUM_BLOCKS, &crc); + if (ret) { + return; + } + ret = blk_read(buf, 0, 1); + if (ret) { + erofs_err("error reading super-block structure"); + return; + } + + sb = (struct erofs_super_block *)((u8 *)buf + EROFS_SUPER_OFFSET); + if (le32_to_cpu(sb->magic) != EROFS_SUPER_MAGIC_V1) { + erofs_err("not an erofs image"); + return; + } + sb->checksum = cpu_to_le32(crc); + ret = blk_write(buf, 0, 1); + if (ret) { + erofs_err("error writing 0th block to disk - %s", + erofs_strerror(ret)); + return; + } +} + int main(int argc, char **argv) { int err = 0; @@ -301,6 +371,9 @@ int main(int argc, char **argv) err = -EIO; else err = dev_resize(nblocks); + if (cfg.c_blk_cksum & EROFS_FEATURE_BLK_CKSUM) { + erofs_set_checksum(); + } exit: z_erofs_compress_exit(); dev_close(); -- 2.9.3
