53e1b68390
This follows what the kernel is doing, c.f. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5fd54ace4721fc5ce2bb5aef6318fcf17f421460.
94 lines
2.7 KiB
C
94 lines
2.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include "macro.h"
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#include "time-util.h"
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int flush_fd(int fd);
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ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll);
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int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll);
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int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll);
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int pipe_eof(int fd);
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int fd_wait_for_event(int fd, int event, usec_t timeout);
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ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length);
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static inline size_t IOVEC_TOTAL_SIZE(const struct iovec *i, unsigned n) {
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unsigned j;
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size_t r = 0;
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for (j = 0; j < n; j++)
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r += i[j].iov_len;
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return r;
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}
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static inline size_t IOVEC_INCREMENT(struct iovec *i, unsigned n, size_t k) {
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unsigned j;
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for (j = 0; j < n; j++) {
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size_t sub;
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if (_unlikely_(k <= 0))
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break;
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sub = MIN(i[j].iov_len, k);
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i[j].iov_len -= sub;
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i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
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k -= sub;
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}
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return k;
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}
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static inline bool FILE_SIZE_VALID(uint64_t l) {
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/* ftruncate() and friends take an unsigned file size, but actually cannot deal with file sizes larger than
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* 2^63 since the kernel internally handles it as signed value. This call allows checking for this early. */
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return (l >> 63) == 0;
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}
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static inline bool FILE_SIZE_VALID_OR_INFINITY(uint64_t l) {
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/* Same as above, but allows one extra value: -1 as indication for infinity. */
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if (l == (uint64_t) -1)
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return true;
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return FILE_SIZE_VALID(l);
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}
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#define IOVEC_INIT(base, len) { .iov_base = (base), .iov_len = (len) }
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#define IOVEC_MAKE(base, len) (struct iovec) IOVEC_INIT(base, len)
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#define IOVEC_INIT_STRING(string) IOVEC_INIT((char*) string, strlen(string))
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#define IOVEC_MAKE_STRING(string) (struct iovec) IOVEC_INIT_STRING(string)
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