267 lines
6.9 KiB
C
267 lines
6.9 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2010 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <poll.h>
|
|
#include <stdio.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
#include "io-util.h"
|
|
#include "time-util.h"
|
|
|
|
int flush_fd(int fd) {
|
|
struct pollfd pollfd = {
|
|
.fd = fd,
|
|
.events = POLLIN,
|
|
};
|
|
|
|
for (;;) {
|
|
char buf[LINE_MAX];
|
|
ssize_t l;
|
|
int r;
|
|
|
|
r = poll(&pollfd, 1, 0);
|
|
if (r < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
return -errno;
|
|
|
|
} else if (r == 0)
|
|
return 0;
|
|
|
|
l = read(fd, buf, sizeof(buf));
|
|
if (l < 0) {
|
|
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
if (errno == EAGAIN)
|
|
return 0;
|
|
|
|
return -errno;
|
|
} else if (l == 0)
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
|
|
uint8_t *p = buf;
|
|
ssize_t n = 0;
|
|
|
|
assert(fd >= 0);
|
|
assert(buf);
|
|
|
|
/* If called with nbytes == 0, let's call read() at least
|
|
* once, to validate the operation */
|
|
|
|
if (nbytes > (size_t) SSIZE_MAX)
|
|
return -EINVAL;
|
|
|
|
do {
|
|
ssize_t k;
|
|
|
|
k = read(fd, p, nbytes);
|
|
if (k < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
if (errno == EAGAIN && do_poll) {
|
|
|
|
/* We knowingly ignore any return value here,
|
|
* and expect that any error/EOF is reported
|
|
* via read() */
|
|
|
|
(void) fd_wait_for_event(fd, POLLIN, USEC_INFINITY);
|
|
continue;
|
|
}
|
|
|
|
return n > 0 ? n : -errno;
|
|
}
|
|
|
|
if (k == 0)
|
|
return n;
|
|
|
|
assert((size_t) k <= nbytes);
|
|
|
|
p += k;
|
|
nbytes -= k;
|
|
n += k;
|
|
} while (nbytes > 0);
|
|
|
|
return n;
|
|
}
|
|
|
|
int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
|
|
ssize_t n;
|
|
|
|
n = loop_read(fd, buf, nbytes, do_poll);
|
|
if (n < 0)
|
|
return (int) n;
|
|
if ((size_t) n != nbytes)
|
|
return -EIO;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
|
|
const uint8_t *p = buf;
|
|
|
|
assert(fd >= 0);
|
|
assert(buf);
|
|
|
|
if (nbytes > (size_t) SSIZE_MAX)
|
|
return -EINVAL;
|
|
|
|
do {
|
|
ssize_t k;
|
|
|
|
k = write(fd, p, nbytes);
|
|
if (k < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
if (errno == EAGAIN && do_poll) {
|
|
/* We knowingly ignore any return value here,
|
|
* and expect that any error/EOF is reported
|
|
* via write() */
|
|
|
|
(void) fd_wait_for_event(fd, POLLOUT, USEC_INFINITY);
|
|
continue;
|
|
}
|
|
|
|
return -errno;
|
|
}
|
|
|
|
if (_unlikely_(nbytes > 0 && k == 0)) /* Can't really happen */
|
|
return -EIO;
|
|
|
|
assert((size_t) k <= nbytes);
|
|
|
|
p += k;
|
|
nbytes -= k;
|
|
} while (nbytes > 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int pipe_eof(int fd) {
|
|
struct pollfd pollfd = {
|
|
.fd = fd,
|
|
.events = POLLIN|POLLHUP,
|
|
};
|
|
|
|
int r;
|
|
|
|
r = poll(&pollfd, 1, 0);
|
|
if (r < 0)
|
|
return -errno;
|
|
|
|
if (r == 0)
|
|
return 0;
|
|
|
|
return pollfd.revents & POLLHUP;
|
|
}
|
|
|
|
int fd_wait_for_event(int fd, int event, usec_t t) {
|
|
|
|
struct pollfd pollfd = {
|
|
.fd = fd,
|
|
.events = event,
|
|
};
|
|
|
|
struct timespec ts;
|
|
int r;
|
|
|
|
r = ppoll(&pollfd, 1, t == USEC_INFINITY ? NULL : timespec_store(&ts, t), NULL);
|
|
if (r < 0)
|
|
return -errno;
|
|
|
|
if (r == 0)
|
|
return 0;
|
|
|
|
return pollfd.revents;
|
|
}
|
|
|
|
static size_t nul_length(const uint8_t *p, size_t sz) {
|
|
size_t n = 0;
|
|
|
|
while (sz > 0) {
|
|
if (*p != 0)
|
|
break;
|
|
|
|
n++;
|
|
p++;
|
|
sz--;
|
|
}
|
|
|
|
return n;
|
|
}
|
|
|
|
ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
|
|
const uint8_t *q, *w, *e;
|
|
ssize_t l;
|
|
|
|
q = w = p;
|
|
e = q + sz;
|
|
while (q < e) {
|
|
size_t n;
|
|
|
|
n = nul_length(q, e - q);
|
|
|
|
/* If there are more than the specified run length of
|
|
* NUL bytes, or if this is the beginning or the end
|
|
* of the buffer, then seek instead of write */
|
|
if ((n > run_length) ||
|
|
(n > 0 && q == p) ||
|
|
(n > 0 && q + n >= e)) {
|
|
if (q > w) {
|
|
l = write(fd, w, q - w);
|
|
if (l < 0)
|
|
return -errno;
|
|
if (l != q -w)
|
|
return -EIO;
|
|
}
|
|
|
|
if (lseek(fd, n, SEEK_CUR) == (off_t) -1)
|
|
return -errno;
|
|
|
|
q += n;
|
|
w = q;
|
|
} else if (n > 0)
|
|
q += n;
|
|
else
|
|
q ++;
|
|
}
|
|
|
|
if (q > w) {
|
|
l = write(fd, w, q - w);
|
|
if (l < 0)
|
|
return -errno;
|
|
if (l != q - w)
|
|
return -EIO;
|
|
}
|
|
|
|
return q - (const uint8_t*) p;
|
|
}
|