/* Name: get_file_parts()
*
* Description:
*
* This function returns each of the following file 'parts': directory name,
* base name, inode number of the directory
*
* Algorithm:
*
* Use the root directory as the current working directory
* Find the last / in the full pathname
* If none are found, set the basename to the full pathname,
* and the directory to NULL
* Otherwise,
* Separate the basename from the directory
* Change the working directory
* Set the return pointers.
*
* Global Variables:
*
* None.
*
* Arguments:
*
* ext2_filsys fs; the filesystem being used
* ext2_ino_t root; the root directory of the filesystem
* char *pathname; the full pathname of the file
* ext2_ino_t *dir_ino; The inode number of the directory
* char **dir_name; the directory the file is in
* char **base_name; The basename of the file
*
* Return Values:
*
* 0 - retrieved the information ok
* otherwise the error code of what went wrong
*
* Author: Keith W. Sheffield
* Date: 03/21/2002
*
* Modification History:
*
* MM/DD/YY Name Description
*
*/
long
get_file_parts(ext2_filsys fs, ext2_ino_t root, char *pathname,
ext2_ino_t *dir_ino, char **dir_name, char **base_name)
{
char *fname;
long retval;
/* move to the source directory */
*dir_name = pathname;
*dir_ino = root;
if (NULL == (fname = strrchr(pathname, '/')))
{
fname = pathname;
*dir_name = NULL;
}
else
{
*fname++ = '\0';
if ((*pathname != '\0' && strcmp(pathname, ".") != 0) &&
(retval = change_cwd(fs, root, dir_ino, pathname)))
{
fprintf(stderr, "Error changing to directory %s\n",
pathname);
return(retval);
}
}
*base_name = fname;
return(0);
} /* end of get_file_parts */
int builtin_commands(char *name, char **args, t_env **env_list)
{
int ret;
ret = 0;
if (ft_strcmp(name, "cd") == 0 && (ret = 1))
change_cwd(args, env_list);
else if (ft_strcmp(name, "env") == 0 && (ret = 1))
print_env(*env_list);
else if (ft_strcmp(name, "setenv") == 0 && (ret = 1))
ft_setenv(args[1], args[2], env_list);
else if (ft_strcmp(name, "unsetenv") == 0 && (ret = 1))
ft_unsetenv(args[1], env_list);
else if (ft_strcmp(name, "echo") == 0 && (ret = 1))
ft_echo(args, *env_list);
else if (ft_strcmp(name, "exit") == 0)
ret = 1;
if (ret == 1)
return (1);
return (0);
}
/* 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);
}
