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contrib/dhcpcd/src/control.c

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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2019 Roy Marples <roy@marples.name>
* All rights reserved
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "config.h"
#include "common.h"
#include "dhcpcd.h"
#include "control.h"
#include "eloop.h"
#include "if.h"
#include "logerr.h"
#ifndef SUN_LEN
#define SUN_LEN(su) \
(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
#endif
static void
control_queue_free(struct fd_list *fd)
{
struct fd_data *fdp;
while ((fdp = TAILQ_FIRST(&fd->queue))) {
TAILQ_REMOVE(&fd->queue, fdp, next);
if (fdp->data_size != 0)
free(fdp->data);
free(fdp);
}
fd->queue_len = 0;
#ifdef CTL_FREE_LIST
while ((fdp = TAILQ_FIRST(&fd->free_queue))) {
TAILQ_REMOVE(&fd->free_queue, fdp, next);
if (fdp->data_size != 0)
free(fdp->data);
free(fdp);
}
#endif
}
static void
control_delete(struct fd_list *fd)
{
TAILQ_REMOVE(&fd->ctx->control_fds, fd, next);
eloop_event_delete(fd->ctx->eloop, fd->fd);
close(fd->fd);
control_queue_free(fd);
free(fd);
}
static void
control_handle_data(void *arg)
{
struct fd_list *fd = arg;
char buffer[1024], *e, *p, *argvp[255], **ap, *a;
ssize_t bytes;
size_t len;
int argc;
bytes = read(fd->fd, buffer, sizeof(buffer) - 1);
if (bytes == -1 || bytes == 0) {
/* Control was closed or there was an error.
* Remove it from our list. */
control_delete(fd);
return;
}
buffer[bytes] = '\0';
p = buffer;
e = buffer + bytes;
/* Each command is \n terminated
* Each argument is NULL separated */
while (p < e) {
argc = 0;
ap = argvp;
while (p < e) {
argc++;
if ((size_t)argc >= sizeof(argvp) / sizeof(argvp[0])) {
errno = ENOBUFS;
return;
}
a = *ap++ = p;
len = strlen(p);
p += len + 1;
if (len && a[len - 1] == '\n') {
a[len - 1] = '\0';
break;
}
}
*ap = NULL;
if (dhcpcd_handleargs(fd->ctx, fd, argc, argvp) == -1) {
logerr(__func__);
if (errno != EINTR && errno != EAGAIN) {
control_delete(fd);
return;
}
}
}
}
static void
control_handle1(struct dhcpcd_ctx *ctx, int lfd, unsigned int fd_flags)
{
struct sockaddr_un run;
socklen_t len;
struct fd_list *l;
int fd, flags;
len = sizeof(run);
if ((fd = accept(lfd, (struct sockaddr *)&run, &len)) == -1)
goto error;
if ((flags = fcntl(fd, F_GETFD, 0)) == -1 ||
fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
goto error;
if ((flags = fcntl(fd, F_GETFL, 0)) == -1 ||
fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
goto error;
l = malloc(sizeof(*l));
if (l == NULL)
goto error;
l->ctx = ctx;
l->fd = fd;
l->flags = fd_flags;
TAILQ_INIT(&l->queue);
l->queue_len = 0;
#ifdef CTL_FREE_LIST
TAILQ_INIT(&l->free_queue);
#endif
TAILQ_INSERT_TAIL(&ctx->control_fds, l, next);
eloop_event_add(ctx->eloop, l->fd, control_handle_data, l);
return;
error:
logerr(__func__);
if (fd != -1)
close(fd);
}
static void
control_handle(void *arg)
{
struct dhcpcd_ctx *ctx = arg;
control_handle1(ctx, ctx->control_fd, 0);
}
static void
control_handle_unpriv(void *arg)
{
struct dhcpcd_ctx *ctx = arg;
control_handle1(ctx, ctx->control_unpriv_fd, FD_UNPRIV);
}
static int
make_sock(struct sockaddr_un *sa, const char *ifname, int unpriv)
{
int fd;
#define SOCK_FLAGS SOCK_CLOEXEC | SOCK_NONBLOCK
if ((fd = xsocket(AF_UNIX, SOCK_STREAM | SOCK_FLAGS, 0)) == -1)
return -1;
#undef SOCK_FLAGS
memset(sa, 0, sizeof(*sa));
sa->sun_family = AF_UNIX;
if (unpriv)
strlcpy(sa->sun_path, UNPRIVSOCKET, sizeof(sa->sun_path));
else {
snprintf(sa->sun_path, sizeof(sa->sun_path), CONTROLSOCKET,
ifname ? "-" : "", ifname ? ifname : "");
}
return fd;
}
#define S_PRIV (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP)
#define S_UNPRIV (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
static int
control_start1(struct dhcpcd_ctx *ctx, const char *ifname, mode_t fmode)
{
struct sockaddr_un sa;
int fd;
socklen_t len;
if ((fd = make_sock(&sa, ifname, (fmode & S_UNPRIV) == S_UNPRIV)) == -1)
return -1;
len = (socklen_t)SUN_LEN(&sa);
unlink(sa.sun_path);
if (bind(fd, (struct sockaddr *)&sa, len) == -1 ||
chmod(sa.sun_path, fmode) == -1 ||
(ctx->control_group &&
chown(sa.sun_path, geteuid(), ctx->control_group) == -1) ||
listen(fd, sizeof(ctx->control_fds)) == -1)
{
close(fd);
unlink(sa.sun_path);
return -1;
}
if ((fmode & S_UNPRIV) != S_UNPRIV)
strlcpy(ctx->control_sock, sa.sun_path,
sizeof(ctx->control_sock));
return fd;
}
int
control_start(struct dhcpcd_ctx *ctx, const char *ifname)
{
int fd;
if ((fd = control_start1(ctx, ifname, S_PRIV)) == -1)
return -1;
ctx->control_fd = fd;
eloop_event_add(ctx->eloop, fd, control_handle, ctx);
if (ifname == NULL && (fd = control_start1(ctx, NULL, S_UNPRIV)) != -1){
/* We must be in master mode, so create an unpriviledged socket
* to allow normal users to learn the status of dhcpcd. */
ctx->control_unpriv_fd = fd;
eloop_event_add(ctx->eloop, fd, control_handle_unpriv, ctx);
}
return ctx->control_fd;
}
int
control_stop(struct dhcpcd_ctx *ctx)
{
int retval = 0;
struct fd_list *l;
if (ctx->options & DHCPCD_FORKED)
goto freeit;
if (ctx->control_fd == -1)
return 0;
eloop_event_delete(ctx->eloop, ctx->control_fd);
close(ctx->control_fd);
ctx->control_fd = -1;
if (unlink(ctx->control_sock) == -1)
retval = -1;
if (ctx->control_unpriv_fd != -1) {
eloop_event_delete(ctx->eloop, ctx->control_unpriv_fd);
close(ctx->control_unpriv_fd);
ctx->control_unpriv_fd = -1;
if (unlink(UNPRIVSOCKET) == -1)
retval = -1;
}
freeit:
while ((l = TAILQ_FIRST(&ctx->control_fds))) {
TAILQ_REMOVE(&ctx->control_fds, l, next);
eloop_event_delete(ctx->eloop, l->fd);
close(l->fd);
control_queue_free(l);
free(l);
}
return retval;
}
int
control_open(const char *ifname)
{
struct sockaddr_un sa;
int fd;
if ((fd = make_sock(&sa, ifname, 0)) != -1) {
socklen_t len;
len = (socklen_t)SUN_LEN(&sa);
if (connect(fd, (struct sockaddr *)&sa, len) == -1) {
close(fd);
fd = -1;
}
}
return fd;
}
ssize_t
control_send(struct dhcpcd_ctx *ctx, int argc, char * const *argv)
{
char buffer[1024];
int i;
size_t len, l;
if (argc > 255) {
errno = ENOBUFS;
return -1;
}
len = 0;
for (i = 0; i < argc; i++) {
l = strlen(argv[i]) + 1;
if (len + l > sizeof(buffer)) {
errno = ENOBUFS;
return -1;
}
memcpy(buffer + len, argv[i], l);
len += l;
}
return write(ctx->control_fd, buffer, len);
}
static void
control_writeone(void *arg)
{
struct fd_list *fd;
struct iovec iov[2];
struct fd_data *data;
fd = arg;
data = TAILQ_FIRST(&fd->queue);
iov[0].iov_base = &data->data_len;
iov[0].iov_len = sizeof(size_t);
iov[1].iov_base = data->data;
iov[1].iov_len = data->data_len;
if (writev(fd->fd, iov, 2) == -1) {
logerr(__func__);
if (errno != EINTR && errno != EAGAIN)
control_delete(fd);
return;
}
TAILQ_REMOVE(&fd->queue, data, next);
fd->queue_len--;
#ifdef CTL_FREE_LIST
TAILQ_INSERT_TAIL(&fd->free_queue, data, next);
#else
if (data->data_size != 0)
free(data->data);
free(data);
#endif
if (TAILQ_FIRST(&fd->queue) == NULL)
eloop_event_remove_writecb(fd->ctx->eloop, fd->fd);
}
int
control_queue(struct fd_list *fd, void *data, size_t data_len, bool fit)
{
struct fd_data *d;
if (data_len == 0)
return 0;
#ifdef CTL_FREE_LIST
struct fd_data *df;
d = NULL;
TAILQ_FOREACH(df, &fd->free_queue, next) {
if (!fit) {
if (df->data_size == 0) {
d = df;
break;
}
continue;
}
if (d == NULL || d->data_size < df->data_size) {
d = df;
if (d->data_size <= data_len)
break;
}
}
if (d != NULL)
TAILQ_REMOVE(&fd->free_queue, d, next);
else
#endif
{
if (fd->queue_len == CONTROL_QUEUE_MAX) {
errno = ENOBUFS;
return -1;
}
fd->queue_len++;
d = calloc(1, sizeof(*d));
if (d == NULL)
return -1;
}
if (!fit) {
#ifdef CTL_FREE_LIST
if (d->data_size != 0) {
free(d->data);
d->data_size = 0;
}
#endif
d->data = data;
d->data_len = data_len;
goto queue;
}
if (d->data_size == 0)
d->data = NULL;
if (d->data_size < data_len) {
void *nbuf = realloc(d->data, data_len);
if (nbuf == NULL) {
free(d->data);
free(d);
return -1;
}
d->data = nbuf;
d->data_size = data_len;
}
memcpy(d->data, data, data_len);
d->data_len = data_len;
queue:
TAILQ_INSERT_TAIL(&fd->queue, d, next);
eloop_event_add_w(fd->ctx->eloop, fd->fd, control_writeone, fd);
return 0;
}
void
control_close(struct dhcpcd_ctx *ctx)
{
if (ctx->control_fd != -1) {
close(ctx->control_fd);
ctx->control_fd = -1;
}
}