/* * This file is part of the libpayload project. * * Copyright (C) 2008 coresystems GmbH * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /** * @file libc/readline.c * Simple readline implementation */ #include <libpayload.h> static char *readline_buffer; static int readline_bufferlen; /** * Read a line from the terminal and return it. * * This readline implementation is rather simple, but it does more than the * original readline() because it allows us to have a pre-filled buffer. * To pre-fill the buffer, use the getline() function. * * @param prompt A prompt to display on the line. * @return A pointer to the input string. */ char *readline(const char *prompt) { char *buffer; int current, ch, nonspace_seen; if (!readline_buffer || !readline_bufferlen) { #define READLINE_BUFFERSIZE 256 readline_buffer = malloc(READLINE_BUFFERSIZE); if (!readline_buffer) return NULL; readline_bufferlen = READLINE_BUFFERSIZE; memset(readline_buffer, 0, readline_bufferlen); } buffer = readline_buffer; /* print prompt */ if (prompt) { current = 0; while (prompt[current]) { putchar(prompt[current]); current++; } } /* print existing buffer, if there is one */ current = 0; while (buffer[current]) { putchar(buffer[current]); current++; } while (1) { ch = getchar(); switch (ch) { case '\r': case '\n': /* newline */ putchar('\n'); goto out; case '\b': case '\x7f': /* backspace */ if (current > 0) { putchar('\b'); putchar(' '); putchar('\b'); current--; } break; case 'W' & 0x1f: /* CTRL-W */ /* word erase */ nonspace_seen = 0; while (current) { if (buffer[current - 1] != ' ') nonspace_seen = 1; putchar('\b'); putchar(' '); putchar('\b'); current--; if (nonspace_seen && (current < readline_bufferlen - 1) && (current > 0) && (buffer[current - 1] == ' ')) break; } break; case 'U' & 0x1f: /* CTRL-U */ /* line erase */ while (current) { putchar('\b'); putchar(' '); putchar('\b'); current--; } current = 0; break; default: /* all other characters */ /* ignore control characters */ if (ch < 0x20) break; /* ignore unprintables */ if (ch >= 0x7f) break; if (current + 1 < readline_bufferlen) { /* print new character */ putchar(ch); /* and add it to the array */ buffer[current] = ch; current++; } } } out: if (current >= readline_bufferlen) current = readline_bufferlen - 1; buffer[current] = '\0'; return buffer; } /** * Read a line from the input and store it in a buffer. * * This function allows the user to pass a predefined buffer to readline(). * The buffer may be filled with a default value which will be displayed by * readline() and can be edited as normal. * The final input string returned by readline() will be returned in * the buffer and the function will return the length of the string. * * @param buffer Pointer to a buffer to store the line in. * @param len Length of the buffer. * @return The final length of the string. */ int getline(char *buffer, int len) { readline_buffer = buffer; readline_bufferlen = len; readline(NULL); return strlen(buffer); }