/* 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); }