| /* 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" |
| |
| /* Used by NOFORK applets (e.g. cat) - must not use xmalloc. |
| * size < 0 means "ignore write errors", used by tar --to-command |
| * size = 0 means "copy till EOF" |
| */ |
| static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) |
| { |
| int status = -1; |
| off_t total = 0; |
| bool continue_on_write_error = 0; |
| #if CONFIG_FEATURE_COPYBUF_KB <= 4 |
| char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024]; |
| enum { buffer_size = sizeof(buffer) }; |
| #else |
| char *buffer; |
| int buffer_size; |
| #endif |
| |
| if (size < 0) { |
| size = -size; |
| continue_on_write_error = 1; |
| } |
| |
| #if CONFIG_FEATURE_COPYBUF_KB > 4 |
| if (size > 0 && size <= 4 * 1024) |
| goto use_small_buf; |
| /* We want page-aligned buffer, just in case kernel is clever |
| * and can do page-aligned io more efficiently */ |
| buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024, |
| PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANON, |
| /* ignored: */ -1, 0); |
| buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024; |
| if (buffer == MAP_FAILED) { |
| use_small_buf: |
| buffer = alloca(4 * 1024); |
| buffer_size = 4 * 1024; |
| } |
| #endif |
| |
| if (src_fd < 0) |
| goto out; |
| |
| if (!size) { |
| size = buffer_size; |
| status = 1; /* copy until eof */ |
| } |
| |
| while (1) { |
| ssize_t rd; |
| |
| rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : 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) { |
| if (!continue_on_write_error) { |
| bb_perror_msg(bb_msg_write_error); |
| break; |
| } |
| dst_fd = -1; |
| } |
| } |
| 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: |
| |
| #if CONFIG_FEATURE_COPYBUF_KB > 4 |
| if (buffer_size != 4 * 1024) |
| munmap(buffer, buffer_size); |
| #endif |
| return status ? -1 : total; |
| } |
| |
| |
| #if 0 |
| void FAST_FUNC 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 FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size) |
| { |
| if (size) { |
| return bb_full_fd_action(fd1, fd2, size); |
| } |
| return 0; |
| } |
| |
| void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size) |
| { |
| off_t sz = bb_copyfd_size(fd1, fd2, size); |
| if (sz == (size >= 0 ? size : -size)) |
| return; |
| if (sz != -1) |
| bb_error_msg_and_die("short read"); |
| /* if sz == -1, bb_copyfd_XX already complained */ |
| xfunc_die(); |
| } |
| |
| off_t FAST_FUNC bb_copyfd_eof(int fd1, int fd2) |
| { |
| return bb_full_fd_action(fd1, fd2, 0); |
| } |