/* vi: set sw=4 ts=4: */ /* * echo implementation for busybox * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. * * Original copyright notice is retained at the end of this file. */ /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */ /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */ /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) * * Because of behavioral differences, implemented configurable SUSv3 * or 'fancy' gnu-ish behaviors. Also, reduced size and fixed bugs. * 1) In handling '\c' escape, the previous version only suppressed the * trailing newline. SUSv3 specifies _no_ output after '\c'. * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}. * The previous version did not allow 4-digit octals. */ #include "libbb.h" /* This is a NOFORK applet. Be very careful! */ /* NB: can be used by shell even if not enabled as applet */ int echo_main(int argc UNUSED_PARAM, char **argv) { const char *arg; #if !ENABLE_FEATURE_FANCY_ECHO enum { eflag = '\\', nflag = 1, /* 1 -- print '\n' */ }; /* We must check that stdout is not closed. * The reason for this is highly non-obvious. * echo_main is used from shell. Shell must correctly handle "echo foo" * if stdout is closed. With stdio, output gets shoveled into * stdout buffer, and even fflush cannot clear it out. It seems that * even if libc receives EBADF on write attempts, it feels determined * to output data no matter what. So it will try later, * and possibly will clobber future output. Not good. */ // TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR? if (fcntl(1, F_GETFL) == -1) return 1; /* match coreutils 6.10 (sans error msg to stderr) */ //if (dup2(1, 1) != 1) - old way // return 1; arg = *++argv; if (!arg) goto newline_ret; #else const char *p; char nflag = 1; char eflag = 0; /* We must check that stdout is not closed. */ if (fcntl(1, F_GETFL) == -1) return 1; while (1) { arg = *++argv; if (!arg) goto newline_ret; if (*arg != '-') break; /* If it appears that we are handling options, then make sure * that all of the options specified are actually valid. * Otherwise, the string should just be echoed. */ p = arg + 1; if (!*p) /* A single '-', so echo it. */ goto just_echo; do { if (!strrchr("neE", *p)) goto just_echo; } while (*++p); /* All of the options in this arg are valid, so handle them. */ p = arg + 1; do { if (*p == 'n') nflag = 0; if (*p == 'e') eflag = '\\'; } while (*++p); } just_echo: #endif while (1) { /* arg is already == *argv and isn't NULL */ int c; if (!eflag) { /* optimization for very common case */ fputs(arg, stdout); } else while ((c = *arg++)) { if (c == eflag) { /* Check for escape seq. */ if (*arg == 'c') { /* '\c' means cancel newline and * ignore all subsequent chars. */ goto ret; } #if !ENABLE_FEATURE_FANCY_ECHO /* SUSv3 specifies that octal escapes must begin with '0'. */ if ( ((int)(unsigned char)(*arg) - '0') >= 8) /* '8' or bigger */ #endif { /* Since SUSv3 mandates a first digit of 0, 4-digit octals * of the form \0### are accepted. */ if (*arg == '0') { /* NB: don't turn "...\0" into "...\" */ if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) { arg++; } } /* bb_process_escape_sequence handles NUL correctly * ("...\" case). */ c = bb_process_escape_sequence(&arg); } } bb_putchar(c); } arg = *++argv; if (!arg) break; bb_putchar(' '); } newline_ret: if (nflag) { bb_putchar('\n'); } ret: return fflush(stdout); } /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * 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. * * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)echo.c 8.1 (Berkeley) 5/31/93 */ #ifdef VERSION_WITH_WRITEV /* We can't use stdio. * The reason for this is highly non-obvious. * echo_main is used from shell. Shell must correctly handle "echo foo" * if stdout is closed. With stdio, output gets shoveled into * stdout buffer, and even fflush cannot clear it out. It seems that * even if libc receives EBADF on write attempts, it feels determined * to output data no matter what. So it will try later, * and possibly will clobber future output. Not good. * * Using writev instead, with 'direct' conversion of argv vector. */ int echo_main(int argc, char **argv) { struct iovec io[argc]; struct iovec *cur_io = io; char *arg; char *p; #if !ENABLE_FEATURE_FANCY_ECHO enum { eflag = '\\', nflag = 1, /* 1 -- print '\n' */ }; arg = *++argv; if (!arg) goto newline_ret; #else char nflag = 1; char eflag = 0; while (1) { arg = *++argv; if (!arg) goto newline_ret; if (*arg != '-') break; /* If it appears that we are handling options, then make sure * that all of the options specified are actually valid. * Otherwise, the string should just be echoed. */ p = arg + 1; if (!*p) /* A single '-', so echo it. */ goto just_echo; do { if (!strrchr("neE", *p)) goto just_echo; } while (*++p); /* All of the options in this arg are valid, so handle them. */ p = arg + 1; do { if (*p == 'n') nflag = 0; if (*p == 'e') eflag = '\\'; } while (*++p); } just_echo: #endif while (1) { /* arg is already == *argv and isn't NULL */ int c; cur_io->iov_base = p = arg; if (!eflag) { /* optimization for very common case */ p += strlen(arg); } else while ((c = *arg++)) { if (c == eflag) { /* Check for escape seq. */ if (*arg == 'c') { /* '\c' means cancel newline and * ignore all subsequent chars. */ cur_io->iov_len = p - (char*)cur_io->iov_base; cur_io++; goto ret; } #if !ENABLE_FEATURE_FANCY_ECHO /* SUSv3 specifies that octal escapes must begin with '0'. */ if ( (((unsigned char)*arg) - '1') >= 7) #endif { /* Since SUSv3 mandates a first digit of 0, 4-digit octals * of the form \0### are accepted. */ if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) { arg++; } /* bb_process_escape_sequence can handle nul correctly */ c = bb_process_escape_sequence( (void*) &arg); } } *p++ = c; } arg = *++argv; if (arg) *p++ = ' '; cur_io->iov_len = p - (char*)cur_io->iov_base; cur_io++; if (!arg) break; } newline_ret: if (nflag) { cur_io->iov_base = (char*)"\n"; cur_io->iov_len = 1; cur_io++; } ret: /* TODO: implement and use full_writev? */ return writev(1, io, (cur_io - io)) >= 0; } #endif