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https://github.com/sheumann/hush.git
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136 lines
2.8 KiB
C
136 lines
2.8 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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/* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
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* size < 0 means "ignore write errors", used by tar --to-command
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* size = 0 means "copy till EOF"
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*/
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static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
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{
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int status = -1;
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off_t total = 0;
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bool continue_on_write_error = 0;
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#if CONFIG_FEATURE_COPYBUF_KB <= 4
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char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024];
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enum { buffer_size = sizeof(buffer) };
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#else
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char *buffer;
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int buffer_size;
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#endif
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if (size < 0) {
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size = -size;
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continue_on_write_error = 1;
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}
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#if CONFIG_FEATURE_COPYBUF_KB > 4
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if (size > 0 && size <= 4 * 1024)
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goto use_small_buf;
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/* We want page-aligned buffer, just in case kernel is clever
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* and can do page-aligned io more efficiently */
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buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
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PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANON,
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/* ignored: */ -1, 0);
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buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
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if (buffer == MAP_FAILED) {
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use_small_buf:
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buffer = alloca(4 * 1024);
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buffer_size = 4 * 1024;
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}
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#endif
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if (src_fd < 0)
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goto out;
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if (!size) {
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size = buffer_size;
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status = 1; /* copy until eof */
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}
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while (1) {
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ssize_t rd;
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rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size);
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if (!rd) { /* eof - all done */
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status = 0;
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break;
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}
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if (rd < 0) {
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bb_perror_msg(bb_msg_read_error);
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break;
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}
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/* dst_fd == -1 is a fake, else... */
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if (dst_fd >= 0) {
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ssize_t wr = full_write(dst_fd, buffer, rd);
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if (wr < rd) {
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if (!continue_on_write_error) {
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bb_perror_msg(bb_msg_write_error);
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break;
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}
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dst_fd = -1;
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}
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}
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total += rd;
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if (status < 0) { /* if we aren't copying till EOF... */
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size -= rd;
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if (!size) {
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/* 'size' bytes copied - all done */
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status = 0;
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break;
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}
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}
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}
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out:
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#if CONFIG_FEATURE_COPYBUF_KB > 4
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if (buffer_size != 4 * 1024)
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munmap(buffer, buffer_size);
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#endif
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return status ? -1 : total;
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}
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#if 0
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void FAST_FUNC complain_copyfd_and_die(off_t sz)
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{
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if (sz != -1)
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bb_error_msg_and_die("short read");
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/* if sz == -1, bb_copyfd_XX already complained */
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xfunc_die();
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}
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#endif
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off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size)
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{
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if (size) {
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return bb_full_fd_action(fd1, fd2, size);
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}
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return 0;
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}
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void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size)
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{
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off_t sz = bb_copyfd_size(fd1, fd2, size);
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if (sz == (size >= 0 ? size : -size))
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return;
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if (sz != -1)
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bb_error_msg_and_die("short read");
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/* if sz == -1, bb_copyfd_XX already complained */
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xfunc_die();
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}
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off_t FAST_FUNC bb_copyfd_eof(int fd1, int fd2)
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{
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return bb_full_fd_action(fd1, fd2, 0);
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}
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