1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 #if ENABLE_FEATURE_USE_SENDFILE
12 # include <sys/sendfile.h>
14 # define sendfile(a,b,c,d) (-1)
18 * We were using 0x7fff0000 as sendfile chunk size, but it
19 * was seen to cause largish delays when user tries to ^C a file copy.
20 * Let's use a saner size.
21 * Note: needs to be >= max(CONFIG_FEATURE_COPYBUF_KB),
22 * or else "copy to eof" code will use neddlesly short reads.
24 #define SENDFILE_BIGBUF (16*1024*1024)
26 /* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
27 * size < 0 means "ignore write errors", used by tar --to-command
28 * size = 0 means "copy till EOF"
30 static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
34 bool continue_on_write_error = 0;
36 #if CONFIG_FEATURE_COPYBUF_KB > 4
37 char *buffer = buffer; /* for compiler */
40 char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024];
41 enum { buffer_size = sizeof(buffer) };
46 continue_on_write_error = 1;
52 sendfile_sz = !ENABLE_FEATURE_USE_SENDFILE
56 size = SENDFILE_BIGBUF;
57 status = 1; /* copy until eof */
64 rd = sendfile(dst_fd, src_fd, NULL,
65 size > sendfile_sz ? sendfile_sz : size);
68 sendfile_sz = 0; /* do not try sendfile anymore */
70 #if CONFIG_FEATURE_COPYBUF_KB > 4
71 if (buffer_size == 0) {
72 if (size > 0 && size <= 4 * 1024)
74 /* We want page-aligned buffer, just in case kernel is clever
75 * and can do page-aligned io more efficiently */
76 buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
77 PROT_READ | PROT_WRITE,
78 MAP_PRIVATE | MAP_ANON,
79 /* ignored: */ -1, 0);
80 buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
81 if (buffer == MAP_FAILED) {
83 buffer = alloca(4 * 1024);
84 buffer_size = 4 * 1024;
88 rd = safe_read(src_fd, buffer,
89 size > buffer_size ? buffer_size : size);
91 bb_perror_msg(bb_msg_read_error);
95 if (!rd) { /* eof - all done */
99 /* dst_fd == -1 is a fake, else... */
100 if (dst_fd >= 0 && !sendfile_sz) {
101 ssize_t wr = full_write(dst_fd, buffer, rd);
103 if (!continue_on_write_error) {
104 bb_perror_msg(bb_msg_write_error);
111 if (status < 0) { /* if we aren't copying till EOF... */
114 /* 'size' bytes copied - all done */
122 if (buffer_size > 4 * 1024)
123 munmap(buffer, buffer_size);
124 return status ? -1 : total;
129 void FAST_FUNC complain_copyfd_and_die(off_t sz)
132 bb_error_msg_and_die("short read");
133 /* if sz == -1, bb_copyfd_XX already complained */
138 off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size)
141 return bb_full_fd_action(fd1, fd2, size);
146 void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size)
148 off_t sz = bb_copyfd_size(fd1, fd2, size);
149 if (sz == (size >= 0 ? size : -size))
152 bb_error_msg_and_die("short read");
153 /* if sz == -1, bb_copyfd_XX already complained */
157 off_t FAST_FUNC bb_copyfd_eof(int fd1, int fd2)
159 return bb_full_fd_action(fd1, fd2, 0);