static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
int size, const void *buf)
{
struct inode_private_data *data;
errcode_t retval = 0;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if ((retval = ext2fs_file_lseek(data->file, offset,
EXT2_SEEK_SET, 0)))
return retval;
return ext2fs_file_write(data->file, buf, size, 0);
}
static errcode_t inode_write_blk64(io_channel channel,
unsigned long long block, int count, const void *buf)
{
struct inode_private_data *data;
errcode_t retval;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if ((retval = ext2fs_file_lseek(data->file,
block * channel->block_size,
EXT2_SEEK_SET, 0)))
return retval;
count = (count < 0) ? -count : (count * channel->block_size);
return ext2fs_file_write(data->file, buf, count, 0);
}
static int read_journal_block(const char *cmd, struct journal_source *source,
off_t offset, char *buf, unsigned int size)
{
int retval;
unsigned int got;
if (source->where == JOURNAL_IS_EXTERNAL) {
if (lseek(source->fd, offset, SEEK_SET) < 0) {
retval = errno;
goto seek_err;
}
retval = read(source->fd, buf, size);
if (retval < 0) {
retval = errno;
goto read_err;
}
got = retval;
retval = 0;
} else {
retval = ext2fs_file_lseek(source->file, offset,
EXT2_SEEK_SET, NULL);
if (retval) {
seek_err:
com_err(cmd, retval, "while seeking in reading journal");
return retval;
}
retval = ext2fs_file_read(source->file, buf, size, &got);
if (retval) {
read_err:
com_err(cmd, retval, "while reading journal");
return retval;
}
}
if (got != size) {
com_err(cmd, 0, "short read (read %u, expected %u) "
"while reading journal", got, size);
retval = -1;
}
return retval;
}
static int read_journal_block(const char *cmd, struct journal_source *source,
off_t offset, char *buf, int size,
unsigned int *got)
{
int retval;
if (source->where == JOURNAL_IS_EXTERNAL) {
if (lseek(source->fd, offset, SEEK_SET) < 0) {
retval = errno;
com_err(cmd, retval, "while seeking in reading journal");
return retval;
}
retval = read(source->fd, buf, size);
if (retval >= 0) {
*got = retval;
retval = 0;
} else
retval = errno;
} else {
retval = ext2fs_file_lseek(source->file, offset,
EXT2_SEEK_SET, NULL);
if (retval) {
com_err(cmd, retval, "while seeking in reading journal");
return retval;
}
retval = ext2fs_file_read(source->file, buf, size, got);
}
if (retval)
com_err(cmd, retval, "while reading journal");
else if (*got != (unsigned int) size) {
com_err(cmd, 0, "short read (read %d, expected %d) "
"while reading journal", *got, size);
retval = -1;
}
return retval;
}
/* Name: tail()
*
* Description:
*
* This function displays the last lines at the end of a file in an ext2
* file system.
*
* Algorithm:
*
* Get the directory and basename of the file
* Determine the inode number for the file
* Open the file for reading
* Skip to the last block in the file
* While we have not found the last num_lines of newline characters
* Skip backwards in the file one block and read it
* Display the contents of the block from that point on.
* Display the rest of the file if not contained in the block
* Save the current location of the file.
* If we are following the file as it grows
* While forever
* Sleep
* Re-read the inode for the file
* If the size has changed
* Display the file from the saved point on
* Save the current location of the file.
*
*
* Global Variables:
*
* None
*
* Arguments:
*
* ext2_filsys *fs; Our filesystem
* ext2_ino_t root; The root directory inode number
* char *input; The name of the input file to tail
* int num_lines; The number of lines to display
* int follow; Flag indicating if the we should follow any
* new contents to the file.
* int sleep_int; The number of seconds to sleep between checking
* for new lines
* char *cur_filesys
*
* Return Values:
*
* 0 - the last number of lines was displayed correctly.
* an error occurred.
*
* Author: Keith W. Sheffield
* Date: 08/07/2002
*
* Modification History:
*
* MM/DD/YY Name Description
*/
static long
tail(ext2_filsys *fs_ptr, ext2_ino_t root, char *input, int num_lines,
int follow, int sleep_int, char *cur_filesys)
{
ext2_filsys fs = *fs_ptr;
ext2_ino_t cwd;
ext2_ino_t tail_ino;
ext2_ino_t t_tail_ino;
char *tail_dir;
char *tail_name;
long retval;
char buf[BLK_SIZE];
unsigned int bytes_to_read;
unsigned int bytes_read;
char *ptr;
struct ext2_inode inode;
ext2_file_t tail_fd;
ext2_off_t offset;
ext2_off_t cur_pos;
if (get_file_parts(fs, root, input, &cwd, &tail_dir, &tail_name))
{
ext2fs_close(fs);
return(-1);
}
/* get the inode number for the source file */
if ((retval = ext2fs_namei(fs, cwd, cwd, tail_name, &tail_ino)))
{
fprintf(stderr, "%s: file %s\n",error_message(retval),
tail_name);
return(retval);
}
/* open the file */
if ((retval = ext2fs_file_open(fs, tail_ino, 0, &tail_fd)))
{
fputs(error_message(retval), stderr);
return retval;
}
/* get the length of the file and determine where to start reading */
inode.i_size = offset = ext2fs_file_get_size(tail_fd);
bytes_to_read = offset % BLK_SIZE;
if (bytes_to_read == 0)
bytes_to_read = BLK_SIZE;
offset -= bytes_to_read;
if (((int32_t)offset) < 0)
offset = 0;
do
{
/* seek to the start of the last block in the file */
if ((retval = ext2fs_file_lseek(tail_fd, offset, EXT2_SEEK_SET, NULL)))
{
fputs(error_message(retval), stderr);
return retval;
}
/* read the last block in the file */
if ((retval = ext2fs_file_read(tail_fd, buf, bytes_to_read,
&bytes_read)))
{
fputs(error_message(retval), stderr);
return retval;
}
if (bytes_to_read != bytes_read)
{
fputs("error reading file\n", stderr);
return(-1);
}
ptr = buf + bytes_read - 1;
while (bytes_to_read--)
{
if (*ptr == '\n' && num_lines-- == 0)
{
/* if the newline wasn't the last character in the buffer, then
* print what's remaining.
*/
if (bytes_to_read != bytes_read - 1)
{
ptr++;
if (0 > write(1, ptr, bytes_read - bytes_to_read - 1))
{
perror("writing bytes to stdout");
return -1;
}
}
offset = 0; /* make sure we break out of the main loop */
break;
}
ptr--;
}
offset -= (offset < BLK_SIZE) ? offset : BLK_SIZE;
bytes_to_read = BLK_SIZE;
}
while (offset > 0);
/* if we are here and have any lines left, we hit the beginning, so
* dump the rest of what's in memory out.
*/
if (num_lines > 0)
{
if (0 > write(1, buf, bytes_read)) {
perror("writing bytes to stdout");
return -1;
}
}
/* retreive the current position in the file */
if ((retval = ext2fs_file_lseek(tail_fd, 0, EXT2_SEEK_CUR, &cur_pos)))
{
fputs(error_message(retval), stderr);
return retval;
}
/* ok, if we are before the end of the file, then dump the rest of it */
if (cur_pos < inode.i_size)
{
if ((retval = read_to_eof(tail_fd, 1, cur_pos, &cur_pos)))
{
return retval;
}
}
if ((retval = ext2fs_file_close(tail_fd)))
{
fputs(error_message(retval), stderr);
return retval;
}
if (follow)
{
while(1)
{
sleep(sleep_int);
/* I don't know how to force a re-read of the file system info yet,
* so, just close the file system and reopen it.
*/
ext2fs_close(fs);
if ((retval = open_filesystem(cur_filesys, &fs, &root, 0)))
{
*fs_ptr = NULL;
fprintf(stderr, "%s: %s\n", error_message(retval), cur_filesys);
return retval;
}
*fs_ptr = fs;
/* if we are following the name, find the directory and file name
* again.
*/
if (follow == FOLLOW_NAME)
{
cwd = root;
if (tail_dir != NULL && *tail_dir != '\0' &&
strcmp(tail_dir, ",") != 0 &&
(retval = change_cwd(fs, root, &cwd, tail_dir)))
{
fprintf(stderr, "Error changing to directory %s\n",
tail_dir);
return(retval);
}
/* get the inode number for the source file */
if ((retval = ext2fs_namei(fs, cwd, cwd, tail_name,
&t_tail_ino)))
{
fprintf(stderr, "%s: file %s\n",error_message(retval),
tail_name);
return(retval);
}
/* if we are dealing with a new file, then start from the
* beginning.
*/
if (t_tail_ino != tail_ino)
{
tail_ino = t_tail_ino;
cur_pos = 0;
}
}
if ((retval = ext2fs_read_inode(fs, tail_ino, &inode)))
{
fputs(error_message(retval), stderr);
return retval;
}
if (inode.i_size > cur_pos)
{
if ((retval = retrieve_data(fs, tail_ino, 1, NULL, 0, cur_pos,
&cur_pos)))
{
fputs(error_message(retval), stderr);
return retval;
}
}
else if (inode.i_size < cur_pos)
{
/* the file was truncated, so bail */
return(0);
}
}
}
return(0);
}
static errcode_t copy_file(ext2_filsys fs, int fd, ext2_ino_t newfile,
int bufsize, int make_holes)
{
ext2_file_t e2_file;
errcode_t retval, close_ret;
int got;
unsigned int written;
char *buf;
char *ptr;
char *zero_buf;
int cmp;
retval = ext2fs_file_open(fs, newfile,
EXT2_FILE_WRITE, &e2_file);
if (retval)
return retval;
retval = ext2fs_get_mem(bufsize, &buf);
if (retval) {
com_err("copy_file", retval, "can't allocate buffer\n");
goto out_close;
}
/* This is used for checking whether the whole block is zero */
retval = ext2fs_get_memzero(bufsize, &zero_buf);
if (retval) {
com_err("copy_file", retval, "can't allocate zero buffer\n");
goto out_free_buf;
}
while (1) {
got = read(fd, buf, bufsize);
if (got == 0)
break;
if (got < 0) {
retval = errno;
goto fail;
}
ptr = buf;
/* Sparse copy */
if (make_holes) {
/* Check whether all is zero */
cmp = memcmp(ptr, zero_buf, got);
if (cmp == 0) {
/* The whole block is zero, make a hole */
retval = ext2fs_file_lseek(e2_file, got,
EXT2_SEEK_CUR,
NULL);
if (retval)
goto fail;
got = 0;
}
}
/* Normal copy */
while (got > 0) {
retval = ext2fs_file_write(e2_file, ptr,
got, &written);
if (retval)
goto fail;
got -= written;
ptr += written;
}
}
fail:
ext2fs_free_mem(&zero_buf);
out_free_buf:
ext2fs_free_mem(&buf);
out_close:
close_ret = ext2fs_file_close(e2_file);
if (retval == 0)
retval = close_ret;
return retval;
}
