Contents of /trunk/mkinitrd-magellan/busybox/libbb/copyfd.c
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Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
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File size: 2882 byte(s)
Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 2882 byte(s)
-updated to busybox-1.17.1
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org> |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
8 | */ |
9 | |
10 | #include "libbb.h" |
11 | |
12 | /* Used by NOFORK applets (e.g. cat) - must not use xmalloc. |
13 | * size < 0 means "ignore write errors", used by tar --to-command |
14 | * size = 0 means "copy till EOF" |
15 | */ |
16 | static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) |
17 | { |
18 | int status = -1; |
19 | off_t total = 0; |
20 | bool continue_on_write_error = 0; |
21 | #if CONFIG_FEATURE_COPYBUF_KB <= 4 |
22 | char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024]; |
23 | enum { buffer_size = sizeof(buffer) }; |
24 | #else |
25 | char *buffer; |
26 | int buffer_size; |
27 | #endif |
28 | |
29 | if (size < 0) { |
30 | size = -size; |
31 | continue_on_write_error = 1; |
32 | } |
33 | |
34 | #if CONFIG_FEATURE_COPYBUF_KB > 4 |
35 | if (size > 0 && size <= 4 * 1024) |
36 | goto use_small_buf; |
37 | /* We want page-aligned buffer, just in case kernel is clever |
38 | * and can do page-aligned io more efficiently */ |
39 | buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024, |
40 | PROT_READ | PROT_WRITE, |
41 | MAP_PRIVATE | MAP_ANON, |
42 | /* ignored: */ -1, 0); |
43 | buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024; |
44 | if (buffer == MAP_FAILED) { |
45 | use_small_buf: |
46 | buffer = alloca(4 * 1024); |
47 | buffer_size = 4 * 1024; |
48 | } |
49 | #endif |
50 | |
51 | if (src_fd < 0) |
52 | goto out; |
53 | |
54 | if (!size) { |
55 | size = buffer_size; |
56 | status = 1; /* copy until eof */ |
57 | } |
58 | |
59 | while (1) { |
60 | ssize_t rd; |
61 | |
62 | rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size); |
63 | |
64 | if (!rd) { /* eof - all done */ |
65 | status = 0; |
66 | break; |
67 | } |
68 | if (rd < 0) { |
69 | bb_perror_msg(bb_msg_read_error); |
70 | break; |
71 | } |
72 | /* dst_fd == -1 is a fake, else... */ |
73 | if (dst_fd >= 0) { |
74 | ssize_t wr = full_write(dst_fd, buffer, rd); |
75 | if (wr < rd) { |
76 | if (!continue_on_write_error) { |
77 | bb_perror_msg(bb_msg_write_error); |
78 | break; |
79 | } |
80 | dst_fd = -1; |
81 | } |
82 | } |
83 | total += rd; |
84 | if (status < 0) { /* if we aren't copying till EOF... */ |
85 | size -= rd; |
86 | if (!size) { |
87 | /* 'size' bytes copied - all done */ |
88 | status = 0; |
89 | break; |
90 | } |
91 | } |
92 | } |
93 | out: |
94 | |
95 | #if CONFIG_FEATURE_COPYBUF_KB > 4 |
96 | if (buffer_size != 4 * 1024) |
97 | munmap(buffer, buffer_size); |
98 | #endif |
99 | return status ? -1 : total; |
100 | } |
101 | |
102 | |
103 | #if 0 |
104 | void FAST_FUNC complain_copyfd_and_die(off_t sz) |
105 | { |
106 | if (sz != -1) |
107 | bb_error_msg_and_die("short read"); |
108 | /* if sz == -1, bb_copyfd_XX already complained */ |
109 | xfunc_die(); |
110 | } |
111 | #endif |
112 | |
113 | off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size) |
114 | { |
115 | if (size) { |
116 | return bb_full_fd_action(fd1, fd2, size); |
117 | } |
118 | return 0; |
119 | } |
120 | |
121 | void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size) |
122 | { |
123 | off_t sz = bb_copyfd_size(fd1, fd2, size); |
124 | if (sz == (size >= 0 ? size : -size)) |
125 | return; |
126 | if (sz != -1) |
127 | bb_error_msg_and_die("short read"); |
128 | /* if sz == -1, bb_copyfd_XX already complained */ |
129 | xfunc_die(); |
130 | } |
131 | |
132 | off_t FAST_FUNC bb_copyfd_eof(int fd1, int fd2) |
133 | { |
134 | return bb_full_fd_action(fd1, fd2, 0); |
135 | } |