diff options
| -rw-r--r-- | fs/romfs/internal.h | 4 | ||||
| -rw-r--r-- | fs/romfs/storage.c | 67 | ||||
| -rw-r--r-- | fs/romfs/super.c | 4 |
3 files changed, 53 insertions, 22 deletions
diff --git a/fs/romfs/internal.h b/fs/romfs/internal.h index 06044a9..95217b8 100644 --- a/fs/romfs/internal.h +++ b/fs/romfs/internal.h @@ -43,5 +43,5 @@ extern int romfs_dev_read(struct super_block *sb, unsigned long pos, void *buf, size_t buflen); extern ssize_t romfs_dev_strnlen(struct super_block *sb, unsigned long pos, size_t maxlen); -extern int romfs_dev_strncmp(struct super_block *sb, unsigned long pos, - const char *str, size_t size); +extern int romfs_dev_strcmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size); diff --git a/fs/romfs/storage.c b/fs/romfs/storage.c index 7e3e1e1..66ce9dd 100644 --- a/fs/romfs/storage.c +++ b/fs/romfs/storage.c @@ -67,26 +67,35 @@ static ssize_t romfs_mtd_strnlen(struct super_block *sb, * compare a string to one in a romfs image on MTD * - return 1 if matched, 0 if differ, -ve if error */ -static int romfs_mtd_strncmp(struct super_block *sb, unsigned long pos, - const char *str, size_t size) +static int romfs_mtd_strcmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) { - u_char buf[16]; + u_char buf[17]; size_t len, segment; int ret; - /* scan the string up to 16 bytes at a time */ + /* scan the string up to 16 bytes at a time, and attempt to grab the + * trailing NUL whilst we're at it */ + buf[0] = 0xff; + while (size > 0) { - segment = min_t(size_t, size, 16); + segment = min_t(size_t, size + 1, 17); ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf); if (ret < 0) return ret; + len--; if (memcmp(buf, str, len) != 0) return 0; + buf[0] = buf[len]; size -= len; pos += len; str += len; } + /* check the trailing NUL was */ + if (buf[0]) + return 0; + return 1; } #endif /* CONFIG_ROMFS_ON_MTD */ @@ -154,28 +163,48 @@ static ssize_t romfs_blk_strnlen(struct super_block *sb, * compare a string to one in a romfs image on a block device * - return 1 if matched, 0 if differ, -ve if error */ -static int romfs_blk_strncmp(struct super_block *sb, unsigned long pos, - const char *str, size_t size) +static int romfs_blk_strcmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) { struct buffer_head *bh; unsigned long offset; size_t segment; - bool x; + bool matched, terminated = false; - /* scan the string up to 16 bytes at a time */ + /* compare string up to a block at a time */ while (size > 0) { offset = pos & (ROMBSIZE - 1); segment = min_t(size_t, size, ROMBSIZE - offset); bh = sb_bread(sb, pos >> ROMBSBITS); if (!bh) return -EIO; - x = (memcmp(bh->b_data + offset, str, segment) != 0); - brelse(bh); - if (x) - return 0; + matched = (memcmp(bh->b_data + offset, str, segment) == 0); + size -= segment; pos += segment; str += segment; + if (matched && size == 0 && offset + segment < ROMBSIZE) { + if (!bh->b_data[offset + segment]) + terminated = true; + else + matched = false; + } + brelse(bh); + if (!matched) + return 0; + } + + if (!terminated) { + /* the terminating NUL must be on the first byte of the next + * block */ + BUG_ON((pos & (ROMBSIZE - 1)) != 0); + bh = sb_bread(sb, pos >> ROMBSBITS); + if (!bh) + return -EIO; + matched = !bh->b_data[0]; + brelse(bh); + if (!matched) + return 0; } return 1; @@ -234,10 +263,12 @@ ssize_t romfs_dev_strnlen(struct super_block *sb, /* * compare a string to one in romfs + * - the string to be compared to, str, may not be NUL-terminated; instead the + * string is of the specified size * - return 1 if matched, 0 if differ, -ve if error */ -int romfs_dev_strncmp(struct super_block *sb, unsigned long pos, - const char *str, size_t size) +int romfs_dev_strcmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) { size_t limit; @@ -246,16 +277,16 @@ int romfs_dev_strncmp(struct super_block *sb, unsigned long pos, return -EIO; if (size > ROMFS_MAXFN) return -ENAMETOOLONG; - if (size > limit - pos) + if (size + 1 > limit - pos) return -EIO; #ifdef CONFIG_ROMFS_ON_MTD if (sb->s_mtd) - return romfs_mtd_strncmp(sb, pos, str, size); + return romfs_mtd_strcmp(sb, pos, str, size); #endif #ifdef CONFIG_ROMFS_ON_BLOCK if (sb->s_bdev) - return romfs_blk_strncmp(sb, pos, str, size); + return romfs_blk_strcmp(sb, pos, str, size); #endif return -EIO; } diff --git a/fs/romfs/super.c b/fs/romfs/super.c index 10ca7d9..c53b5ef 100644 --- a/fs/romfs/super.c +++ b/fs/romfs/super.c @@ -240,8 +240,8 @@ static struct dentry *romfs_lookup(struct inode *dir, struct dentry *dentry, goto error; /* try to match the first 16 bytes of name */ - ret = romfs_dev_strncmp(dir->i_sb, offset + ROMFH_SIZE, name, - len); + ret = romfs_dev_strcmp(dir->i_sb, offset + ROMFH_SIZE, name, + len); if (ret < 0) goto error; if (ret == 1) |
