hush/coreutils/echo.c
Denys Vlasenko 8ee2adab21 echo: do not retry on write errors
function                                             old     new   delta
echo_main                                            297     336     +39
stpcpy                                                 -      22     +22
run_pipe                                            1561    1566      +5
pseudo_exec_argv                                     187     192      +5
hush_exit                                             75      80      +5
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 4/0 up/down: 98/0)               Total: 76 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2011-02-07 02:03:51 +01:00

313 lines
8.3 KiB
C

/* 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 source tree.
*
* 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 */
/*
* NB2: we don't use stdio, we need better error handing.
* Examples include writing into non-opened stdout and error on write.
*
* 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.
* If echo is called by shell, it will try writing again later, and possibly
* will clobber future output. Not good.
*
* Solaris has fpurge which discards buffered input. glibc has __fpurge.
* But this function is not standard.
*/
int echo_main(int argc UNUSED_PARAM, char **argv)
{
char **pp;
const char *arg;
char *out;
char *buffer;
unsigned buflen;
int r;
#if !ENABLE_FEATURE_FANCY_ECHO
enum {
eflag = '\\',
nflag = 1, /* 1 -- print '\n' */
};
argv++;
#else
const char *p;
char nflag = 1;
char eflag = 0;
while ((arg = *++argv) != NULL) {
if (!arg || arg[0] != '-')
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. */
break;
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
buflen = 1;
pp = argv;
while ((arg = *pp) != NULL) {
buflen += strlen(arg) + 1;
pp++;
}
out = buffer = xmalloc(buflen);
while ((arg = *argv) != NULL) {
int c;
if (!eflag) {
/* optimization for very common case */
out = stpcpy(out, arg);
} else while ((c = *arg++)) {
if (c == eflag) { /* Check for escape seq. */
if (*arg == 'c') {
/* '\c' means cancel newline and
* ignore all subsequent chars. */
goto do_write;
}
#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);
}
}
*out++ = c;
}
if (!*++argv)
break;
*out++ = ' ';
}
if (nflag) {
*out++ = '\n';
}
do_write:
r = full_write(STDOUT_FILENO, buffer, out - buffer);
free(buffer);
if (r < 0) {
bb_perror_msg(bb_msg_write_error);
return 1;
}
return 0;
}
/*-
* 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. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
* ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
*
* 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