busybox/libbb/copyfd.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2003 by Erik Andersen <andersen@codepoet.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <errno.h>
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#include <stdlib.h>
#include <string.h>
#include <unistd.h>
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#include "busybox.h"
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#if BUFSIZ < 4096
#undef BUFSIZ
#define BUFSIZ 4096
#endif
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/* If size is 0 copy until EOF */
static size_t bb_full_fd_action(int src_fd, int dst_fd, const size_t size)
{
size_t read_total = 0;
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RESERVE_CONFIG_BUFFER(buffer,BUFSIZ);
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while ((size == 0) || (read_total < size)) {
size_t read_try;
ssize_t read_actual;
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if ((size == 0) || (size - read_total > BUFSIZ)) {
read_try = BUFSIZ;
} else {
read_try = size - read_total;
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}
read_actual = safe_read(src_fd, buffer, read_try);
if (read_actual > 0) {
if ((dst_fd >= 0) && (bb_full_write(dst_fd, buffer, (size_t) read_actual) != read_actual)) {
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bb_perror_msg(bb_msg_write_error); /* match Read error below */
break;
}
}
else if (read_actual == 0) {
if (size) {
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bb_error_msg("Unable to read all data");
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}
break;
} else {
/* read_actual < 0 */
bb_perror_msg("Read error");
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break;
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}
read_total += read_actual;
}
RELEASE_CONFIG_BUFFER(buffer);
return(read_total);
}
extern int bb_copyfd_size(int fd1, int fd2, const off_t size)
{
if (size) {
return(bb_full_fd_action(fd1, fd2, size));
}
return(0);
}
extern int bb_copyfd_eof(int fd1, int fd2)
{
return(bb_full_fd_action(fd1, fd2, 0));
}