| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 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 source tree. |
| 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 | } |