diff options
Diffstat (limited to 'lib/libstand/ufs.c')
| -rw-r--r-- | lib/libstand/ufs.c | 123 |
1 files changed, 119 insertions, 4 deletions
diff --git a/lib/libstand/ufs.c b/lib/libstand/ufs.c index c501fe9..35af957 100644 --- a/lib/libstand/ufs.c +++ b/lib/libstand/ufs.c @@ -82,6 +82,7 @@ __FBSDID("$FreeBSD$"); #endif static int ufs_open(const char *path, struct open_file *f); +static int ufs_write(struct open_file *f, void *buf, size_t size, size_t *resid); static int ufs_close(struct open_file *f); static int ufs_read(struct open_file *f, void *buf, size_t size, size_t *resid); static off_t ufs_seek(struct open_file *f, off_t offset, int where); @@ -93,7 +94,7 @@ struct fs_ops ufs_fsops = { ufs_open, ufs_close, ufs_read, - null_write, + ufs_write, ufs_seek, ufs_stat, ufs_readdir @@ -122,6 +123,7 @@ struct file { static int read_inode(ino_t, struct open_file *); static int block_map(struct open_file *, daddr_t, daddr_t *); static int buf_read_file(struct open_file *, char **, size_t *); +static int buf_write_file(struct open_file *, char *, size_t *); static int search_directory(char *, struct open_file *, ino_t *); #ifdef COMPAT_UFS static void ffs_oldfscompat(struct fs *); @@ -288,6 +290,82 @@ block_map(f, file_block, disk_block_p) } /* + * Write a portion of a file from an internal buffer. + */ +static int +buf_write_file(f, buf_p, size_p) + struct open_file *f; + char *buf_p; + size_t *size_p; /* out */ +{ + register struct file *fp = (struct file *)f->f_fsdata; + register struct fs *fs = fp->f_fs; + long off; + register daddr_t file_block; + daddr_t disk_block; + size_t block_size; + int rc; + + /* + * Calculate the starting block address and offset. + */ + off = blkoff(fs, fp->f_seekp); + file_block = lblkno(fs, fp->f_seekp); + block_size = dblksize(fs, &fp->f_di, file_block); + + rc = block_map(f, file_block, &disk_block); + if (rc) + return (rc); + + if (disk_block == 0) + return (EFBIG); /* Because we can't allocate space on the drive */ + + /* + * Truncate buffer at end of file, and at the end of + * this block. + */ + if (*size_p > fp->f_di.di_size - fp->f_seekp) + *size_p = fp->f_di.di_size - fp->f_seekp; + if (*size_p > block_size - off) + *size_p = block_size - off; + + /* + * If we don't entirely occlude the block and it's not + * in memory already, read it in first. + */ + if (((off > 0) || (*size_p + off < block_size)) && + (file_block != fp->f_buf_blkno)) { + + if (fp->f_buf == (char *)0) + fp->f_buf = malloc(fs->fs_bsize); + + twiddle(); + rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, + fsbtodb(fs, disk_block), + block_size, fp->f_buf, &fp->f_buf_size); + if (rc) + return (rc); + + fp->f_buf_blkno = file_block; + } + + /* + * Copy the user data into the cached block. + */ + bcopy(buf_p,fp->f_buf + off,*size_p); + + /* + * Write the block out to storage. + */ + + twiddle(); + rc = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE, + fsbtodb(fs, disk_block), + block_size, fp->f_buf, &fp->f_buf_size); + return (rc); +} + +/* * Read a portion of a file into an internal buffer. Return * the location in the buffer and the amount in the buffer. */ @@ -310,13 +388,13 @@ buf_read_file(f, buf_p, size_p) block_size = dblksize(fs, &fp->f_di, file_block); if (file_block != fp->f_buf_blkno) { + if (fp->f_buf == (char *)0) + fp->f_buf = malloc(fs->fs_bsize); + rc = block_map(f, file_block, &disk_block); if (rc) return (rc); - if (fp->f_buf == (char *)0) - fp->f_buf = malloc(fs->fs_bsize); - if (disk_block == 0) { bzero(fp->f_buf, block_size); fp->f_buf_size = block_size; @@ -658,6 +736,43 @@ ufs_read(f, start, size, resid) return (rc); } +/* + * Write to a portion of an already allocated file. + * Cross block boundaries when necessary. Can not + * extend the file. + */ +static int +ufs_write(f, start, size, resid) + struct open_file *f; + void *start; + size_t size; + size_t *resid; /* out */ +{ + register struct file *fp = (struct file *)f->f_fsdata; + size_t csize; + int rc = 0; + register char *addr = start; + + csize = size; + while ((size != 0) && (csize != 0)) { + if (fp->f_seekp >= fp->f_di.di_size) + break; + + if (csize >= 512) csize = 512; /* XXX */ + + rc = buf_write_file(f, addr, &csize); + if (rc) + break; + + fp->f_seekp += csize; + addr += csize; + size -= csize; + } + if (resid) + *resid = size; + return (rc); +} + static off_t ufs_seek(f, offset, where) struct open_file *f; |
