hush/libbb/copyfd.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
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#if BUFSIZ < 4096
#undef BUFSIZ
#define BUFSIZ 4096
#endif
/* Used by NOFORK applets (e.g. cat) - must not use xmalloc */
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static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
{
int status = -1;
off_t total = 0;
char buffer[BUFSIZ];
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if (src_fd < 0)
goto out;
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if (!size) {
size = BUFSIZ;
status = 1; /* copy until eof */
}
while (1) {
ssize_t rd;
rd = safe_read(src_fd, buffer, size > BUFSIZ ? BUFSIZ : size);
if (!rd) { /* eof - all done */
status = 0;
break;
}
if (rd < 0) {
bb_perror_msg(bb_msg_read_error);
break;
}
/* dst_fd == -1 is a fake, else... */
if (dst_fd >= 0) {
ssize_t wr = full_write(dst_fd, buffer, rd);
if (wr < rd) {
bb_perror_msg(bb_msg_write_error);
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break;
}
}
total += rd;
if (status < 0) { /* if we aren't copying till EOF... */
size -= rd;
if (!size) {
/* 'size' bytes copied - all done */
status = 0;
break;
}
}
}
out:
return status ? -1 : total;
}
#if 0
void complain_copyfd_and_die(off_t sz)
{
if (sz != -1)
bb_error_msg_and_die("short read");
/* if sz == -1, bb_copyfd_XX already complained */
xfunc_die();
}
#endif
off_t bb_copyfd_size(int fd1, int fd2, off_t size)
{
if (size) {
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return bb_full_fd_action(fd1, fd2, size);
}
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return 0;
}
void bb_copyfd_exact_size(int fd1, int fd2, off_t size)
{
off_t sz = bb_copyfd_size(fd1, fd2, size);
if (sz == size)
return;
if (sz != -1)
bb_error_msg_and_die("short read");
/* if sz == -1, bb_copyfd_XX already complained */
xfunc_die();
}
off_t bb_copyfd_eof(int fd1, int fd2)
{
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return bb_full_fd_action(fd1, fd2, 0);
}