[mirror_lxcfs.git] / utils.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#ifndef FUSE_USE_VERSION
#define FUSE_USE_VERSION 26
#endif

#define _FILE_OFFSET_BITS 64

#include <errno.h>
#include <fcntl.h>
#include <fuse.h>
#include <inttypes.h>
#include <sched.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include "bindings.h"
#include "config.h"
#include "macro.h"
#include "memory_utils.h"
#include "utils.h"

/*
 * append the given formatted string to *src.
 * src: a pointer to a char* in which to append the formatted string.
 * sz: the number of characters printed so far, minus trailing \0.
 * asz: the allocated size so far
 * format: string format. See printf for details.
 * ...: varargs. See printf for details.
 */
/*
 * append the given formatted string to *src.
 * src: a pointer to a char* in which to append the formatted string.
 * sz: the number of characters printed so far, minus trailing \0.
 * asz: the allocated size so far
 * format: string format. See printf for details.
 * ...: varargs. See printf for details.
 */
char *must_strcat(char **src, size_t *sz, size_t *asz, const char *format, ...)
{
	char tmp[BUF_RESERVE_SIZE];
	va_list args;
	int tmplen;

	va_start (args, format);
	tmplen = vsnprintf(tmp, BUF_RESERVE_SIZE, format, args);
	va_end(args);

	if (!*src || tmplen + *sz + 1 >= *asz) {
		char *str;
		do {
			str = realloc(*src, *asz + BUF_RESERVE_SIZE);
		} while (!str);
		*src = str;
		*asz += BUF_RESERVE_SIZE;
	}
	memcpy((*src) +*sz , tmp, tmplen+1); /* include the \0 */
	*sz += tmplen;

	return *src;
}

/**
 * in_same_namespace - Check whether two processes are in the same namespace.
 * @pid1 - PID of the first process.
 * @pid2 - PID of the second process.
 * @ns   - Name of the namespace to check. Must correspond to one of the names
 *         for the namespaces as shown in /proc/<pid/ns/
 *
 * If the two processes are not in the same namespace returns an fd to the
 * namespace of the second process identified by @pid2. If the two processes are
 * in the same namespace returns -EINVAL, -1 if an error occurred.
 */
static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
{
	__do_close_prot_errno int ns_fd1 = -1, ns_fd2 = -1;
	int ret = -1;
	struct stat ns_st1, ns_st2;

	ns_fd1 = preserve_ns(pid1, ns);
	if (ns_fd1 < 0) {
		/* The kernel does not support this namespace. This is not an
		 * error.
		 */
		if (errno == ENOENT)
			return -EINVAL;

		return -1;
	}

	ns_fd2 = preserve_ns(pid2, ns);
	if (ns_fd2 < 0)
		return -1;

	ret = fstat(ns_fd1, &ns_st1);
	if (ret < 0)
		return -1;

	ret = fstat(ns_fd2, &ns_st2);
	if (ret < 0)
		return -1;

	/* processes are in the same namespace */
	if ((ns_st1.st_dev == ns_st2.st_dev) && (ns_st1.st_ino == ns_st2.st_ino))
		return -EINVAL;

	/* processes are in different namespaces */
	return move_fd(ns_fd2);
}

bool is_shared_pidns(pid_t pid)
{
	if (pid != 1)
		return false;

	if (in_same_namespace(pid, getpid(), "pid") == -EINVAL)
		return true;

	return false;
}

int preserve_ns(const int pid, const char *ns)
{
	int ret;
/* 5 /proc + 21 /int_as_str + 3 /ns + 20 /NS_NAME + 1 \0 */
#define __NS_PATH_LEN 50
	char path[__NS_PATH_LEN];

	/* This way we can use this function to also check whether namespaces
	 * are supported by the kernel by passing in the NULL or the empty
	 * string.
	 */
	ret = snprintf(path, __NS_PATH_LEN, "/proc/%d/ns%s%s", pid,
		       !ns || strcmp(ns, "") == 0 ? "" : "/",
		       !ns || strcmp(ns, "") == 0 ? "" : ns);
	if (ret < 0 || (size_t)ret >= __NS_PATH_LEN) {
		errno = EFBIG;
		return -1;
	}

	return open(path, O_RDONLY | O_CLOEXEC);
}

void do_release_file_info(struct fuse_file_info *fi)
{
	struct file_info *f;

	f = INTTYPE_TO_PTR(fi->fh);
	if (!f)
		return;

	fi->fh = 0;

	free_disarm(f->controller);
	free_disarm(f->cgroup);
	free_disarm(f->file);
	free_disarm(f->buf);
	free_disarm(f);
}

#define POLLIN_SET ( EPOLLIN | EPOLLHUP | EPOLLRDHUP )

bool wait_for_sock(int sock, int timeout)
{
	struct epoll_event ev;
	int epfd, ret, now, starttime, deltatime, saved_errno;

	if ((starttime = time(NULL)) < 0)
		return false;

	if ((epfd = epoll_create(1)) < 0) {
		lxcfs_error("%s\n", "Failed to create epoll socket: %m.");
		return false;
	}

	ev.events = POLLIN_SET;
	ev.data.fd = sock;
	if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
		lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
		close(epfd);
		return false;
	}

again:
	if ((now = time(NULL)) < 0) {
		close(epfd);
		return false;
	}

	deltatime = (starttime + timeout) - now;
	if (deltatime < 0) { // timeout
		errno = 0;
		close(epfd);
		return false;
	}
	ret = epoll_wait(epfd, &ev, 1, 1000*deltatime + 1);
	if (ret < 0 && errno == EINTR)
		goto again;
	saved_errno = errno;
	close(epfd);

	if (ret <= 0) {
		errno = saved_errno;
		return false;
	}
	return true;
}

bool recv_creds(int sock, struct ucred *cred, char *v)
{
	struct msghdr msg = { 0 };
	struct iovec iov;
	struct cmsghdr *cmsg;
	char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
	char buf[1];
	int ret;
	int optval = 1;

	*v = '1';

	cred->pid = -1;
	cred->uid = -1;
	cred->gid = -1;

	if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
		lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
		return false;
	}
	buf[0] = '1';
	if (write(sock, buf, 1) != 1) {
		lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
		return false;
	}

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_control = cmsgbuf;
	msg.msg_controllen = sizeof(cmsgbuf);

	iov.iov_base = buf;
	iov.iov_len = sizeof(buf);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;

	if (!wait_for_sock(sock, 2)) {
		lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
		return false;
	}
	ret = recvmsg(sock, &msg, MSG_DONTWAIT);
	if (ret < 0) {
		lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
		return false;
	}

	cmsg = CMSG_FIRSTHDR(&msg);

	if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)) &&
			cmsg->cmsg_level == SOL_SOCKET &&
			cmsg->cmsg_type == SCM_CREDENTIALS) {
		memcpy(cred, CMSG_DATA(cmsg), sizeof(*cred));
	}
	*v = buf[0];

	return true;
}

static int msgrecv(int sockfd, void *buf, size_t len)
{
	if (!wait_for_sock(sockfd, 2))
		return -1;
	return recv(sockfd, buf, len, MSG_DONTWAIT);
}

int send_creds(int sock, struct ucred *cred, char v, bool pingfirst)
{
	struct msghdr msg = { 0 };
	struct iovec iov;
	struct cmsghdr *cmsg;
	char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
	char buf[1];
	buf[0] = 'p';

	if (pingfirst) {
		if (msgrecv(sock, buf, 1) != 1) {
			lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
			return SEND_CREDS_FAIL;
		}
	}

	msg.msg_control = cmsgbuf;
	msg.msg_controllen = sizeof(cmsgbuf);

	cmsg = CMSG_FIRSTHDR(&msg);
	cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SCM_CREDENTIALS;
	memcpy(CMSG_DATA(cmsg), cred, sizeof(*cred));

	msg.msg_name = NULL;
	msg.msg_namelen = 0;

	buf[0] = v;
	iov.iov_base = buf;
	iov.iov_len = sizeof(buf);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;

	if (sendmsg(sock, &msg, 0) < 0) {
		lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
		if (errno == 3)
			return SEND_CREDS_NOTSK;
		return SEND_CREDS_FAIL;
	}

	return SEND_CREDS_OK;
}

int read_file_fuse(const char *path, char *buf, size_t size, struct file_info *d)
{
	__do_free char *line = NULL;
	__do_fclose FILE *f = NULL;
	size_t linelen = 0, total_len = 0;
	char *cache = d->buf;
	size_t cache_size = d->buflen;

	f = fopen(path, "re");
	if (!f)
		return 0;

	while (getline(&line, &linelen, f) != -1) {
		ssize_t l = snprintf(cache, cache_size, "%s", line);
		if (l < 0) {
			perror("Error writing to cache");
			return 0;
		}
		if (l >= cache_size) {
			lxcfs_error("%s\n", "Internal error: truncated write to cache.");
			return 0;
		}
		cache += l;
		cache_size -= l;
		total_len += l;
	}

	d->size = total_len;
	if (total_len > size)
		total_len = size;

	/* read from off 0 */
	memcpy(buf, d->buf, total_len);

	if (d->size > total_len)
		d->cached = d->size - total_len;
	return total_len;
}

#define INITSCOPE "/init.scope"
void prune_init_slice(char *cg)
{
	char *point;
	size_t cg_len = strlen(cg), initscope_len = strlen(INITSCOPE);

	if (cg_len < initscope_len)
		return;

	point = cg + cg_len - initscope_len;
	if (strcmp(point, INITSCOPE) == 0) {
		if (point == cg)
			*(point + 1) = '\0';
		else
			*point = '\0';
	}
}

int wait_for_pid(pid_t pid)
{
	int status, ret;

	if (pid <= 0)
		return -1;

again:
	ret = waitpid(pid, &status, 0);
	if (ret == -1) {
		if (errno == EINTR)
			goto again;
		return -1;
	}
	if (ret != pid)
		goto again;
	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
		return -1;
	return 0;
}

static ssize_t read_nointr(int fd, void *buf, size_t count)
{
	ssize_t ret;
again:
	ret = read(fd, buf, count);
	if (ret < 0 && errno == EINTR)
		goto again;

	return ret;
}

static void *must_realloc(void *orig, size_t sz)
{
	void *ret;

	do {
		ret = realloc(orig, sz);
	} while (!ret);

	return ret;
}

static char *file_to_buf(const char *path, size_t *length)
{
	__do_close_prot_errno int fd = -EBADF;
	__do_free char *copy = NULL;
	char buf[PATH_MAX];

	if (!length)
		return NULL;

	fd = open(path, O_RDONLY | O_CLOEXEC);
	if (fd < 0)
		return NULL;

	*length = 0;
	for (;;) {
		int n;
		char *old = copy;

		n = read_nointr(fd, buf, sizeof(buf));
		if (n < 0)
			return NULL;
		if (!n)
			break;

		copy = must_realloc(old, (*length + n) * sizeof(*old));
		memcpy(copy + *length, buf, n);
		*length += n;
	}

	return move_ptr(copy);
}

FILE *fopen_cached(const char *path, const char *mode, void **caller_freed_buffer)
{
	__do_free char *buf = NULL;
	size_t len = 0;
	FILE *f;

	buf = file_to_buf(path, &len);
	if (!buf)
		return NULL;

	f = fmemopen(buf, len, mode);
	if (!f)
		return NULL;
	*caller_freed_buffer = move_ptr(buf);
	return f;
}
Commit	Line	Data
1f5596dd CB	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
	2
	3	#ifndef _GNU_SOURCE
	4	#define _GNU_SOURCE
	5	#endif
	6
	7	#ifndef FUSE_USE_VERSION
	8	#define FUSE_USE_VERSION 26
	9	#endif
	10
	11	#define _FILE_OFFSET_BITS 64
	12
1d81c6a6 CB	13	#include <errno.h>
1d81c6a6 CB	14	#include <fcntl.h>
1f5596dd	15	#include <fuse.h>
1d81c6a6 CB	16	#include <inttypes.h>
	17	#include <sched.h>
	18	#include <stdarg.h>
4ec5c9da	19	#include <stdio.h>
1d81c6a6 CB	20	#include <stdbool.h>
	21	#include <stdint.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <string.h>
1f5596dd	25	#include <sys/epoll.h>
1d81c6a6 CB	26	#include <sys/stat.h>
1d81c6a6 CB	27	#include <sys/types.h>
4ec5c9da	28	#include <sys/wait.h>
1d81c6a6 CB	29	#include <unistd.h>
1d81c6a6 CB	30
1f5596dd	31	#include "bindings.h"
1d81c6a6 CB	32	#include "config.h"
	33	#include "macro.h"
	34	#include "memory_utils.h"
	35	#include "utils.h"
	36
	37	/*
	38	* append the given formatted string to *src.
	39	* src: a pointer to a char* in which to append the formatted string.
	40	* sz: the number of characters printed so far, minus trailing \0.
	41	* asz: the allocated size so far
	42	* format: string format. See printf for details.
	43	* ...: varargs. See printf for details.
	44	*/
87f7558b CB	45	/*
	46	* append the given formatted string to *src.
	47	* src: a pointer to a char* in which to append the formatted string.
	48	* sz: the number of characters printed so far, minus trailing \0.
	49	* asz: the allocated size so far
	50	* format: string format. See printf for details.
	51	* ...: varargs. See printf for details.
	52	*/
	53	char must_strcat(char src, size_t sz, size_t asz, const char format, ...)
1d81c6a6 CB	54	{
1d81c6a6 CB	55	char tmp[BUF_RESERVE_SIZE];
87f7558b CB	56	va_list args;
87f7558b CB	57	int tmplen;
1d81c6a6 CB	58
1d81c6a6 CB	59	va_start (args, format);
87f7558b	60	tmplen = vsnprintf(tmp, BUF_RESERVE_SIZE, format, args);
1d81c6a6 CB	61	va_end(args);
	62
	63	if (!src \|\| tmplen + sz + 1 >= *asz) {
87f7558b	64	char *str;
1d81c6a6	65	do {
87f7558b CB	66	str = realloc(src, asz + BUF_RESERVE_SIZE);
	67	} while (!str);
	68	*src = str;
1d81c6a6 CB	69	*asz += BUF_RESERVE_SIZE;
	70	}
	71	memcpy((src) +sz , tmp, tmplen+1); /* include the \0 */
	72	*sz += tmplen;
87f7558b CB	73
87f7558b CB	74	return *src;
1d81c6a6 CB	75	}
	76
	77	/**
	78	* in_same_namespace - Check whether two processes are in the same namespace.
	79	* @pid1 - PID of the first process.
	80	* @pid2 - PID of the second process.
	81	* @ns - Name of the namespace to check. Must correspond to one of the names
	82	* for the namespaces as shown in /proc/<pid/ns/
	83	*
	84	* If the two processes are not in the same namespace returns an fd to the
	85	* namespace of the second process identified by @pid2. If the two processes are
	86	* in the same namespace returns -EINVAL, -1 if an error occurred.
	87	*/
	88	static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
	89	{
	90	__do_close_prot_errno int ns_fd1 = -1, ns_fd2 = -1;
	91	int ret = -1;
	92	struct stat ns_st1, ns_st2;
	93
	94	ns_fd1 = preserve_ns(pid1, ns);
	95	if (ns_fd1 < 0) {
	96	/* The kernel does not support this namespace. This is not an
	97	* error.
	98	*/
	99	if (errno == ENOENT)
	100	return -EINVAL;
	101
	102	return -1;
	103	}
	104
	105	ns_fd2 = preserve_ns(pid2, ns);
	106	if (ns_fd2 < 0)
	107	return -1;
	108
	109	ret = fstat(ns_fd1, &ns_st1);
	110	if (ret < 0)
	111	return -1;
	112
	113	ret = fstat(ns_fd2, &ns_st2);
	114	if (ret < 0)
	115	return -1;
	116
	117	/* processes are in the same namespace */
	118	if ((ns_st1.st_dev == ns_st2.st_dev) && (ns_st1.st_ino == ns_st2.st_ino))
	119	return -EINVAL;
	120
	121	/* processes are in different namespaces */
	122	return move_fd(ns_fd2);
	123	}
	124
	125	bool is_shared_pidns(pid_t pid)
	126	{
	127	if (pid != 1)
	128	return false;
	129
	130	if (in_same_namespace(pid, getpid(), "pid") == -EINVAL)
	131	return true;
	132
	133	return false;
	134	}
	135
	136	int preserve_ns(const int pid, const char *ns)
	137	{
	138	int ret;
139	/* 5 /proc + 21 /int_as_str + 3 /ns + 20 /NS_NAME + 1 \0 */
140	#define __NS_PATH_LEN 50
141	char path[__NS_PATH_LEN];
142
143	/* This way we can use this function to also check whether namespaces
144	* are supported by the kernel by passing in the NULL or the empty
145	* string.
146	*/
147	ret = snprintf(path, __NS_PATH_LEN, "/proc/%d/ns%s%s", pid,
148	!ns \|\| strcmp(ns, "") == 0 ? "" : "/",
149	!ns \|\| strcmp(ns, "") == 0 ? "" : ns);
150	if (ret < 0 \|\| (size_t)ret >= __NS_PATH_LEN) {
151	errno = EFBIG;
152	return -1;
153	}
154
155	return open(path, O_RDONLY \| O_CLOEXEC);
156	}
580fe4df CB	157
	158	void do_release_file_info(struct fuse_file_info *fi)
	159	{
99b183fb	160	struct file_info *f;
580fe4df	161
99b183fb	162	f = INTTYPE_TO_PTR(fi->fh);
580fe4df CB	163	if (!f)
	164	return;
	165
	166	fi->fh = 0;
	167
	168	free_disarm(f->controller);
	169	free_disarm(f->cgroup);
	170	free_disarm(f->file);
	171	free_disarm(f->buf);
	172	free_disarm(f);
	173	}
1f5596dd CB	174
	175	#define POLLIN_SET ( EPOLLIN \| EPOLLHUP \| EPOLLRDHUP )
	176
	177	bool wait_for_sock(int sock, int timeout)
	178	{
	179	struct epoll_event ev;
	180	int epfd, ret, now, starttime, deltatime, saved_errno;
	181
	182	if ((starttime = time(NULL)) < 0)
	183	return false;
	184
	185	if ((epfd = epoll_create(1)) < 0) {
	186	lxcfs_error("%s\n", "Failed to create epoll socket: %m.");
	187	return false;
	188	}
	189
	190	ev.events = POLLIN_SET;
	191	ev.data.fd = sock;
	192	if (epoll_ctl(epfd, EPOLL_CTL_ADD, sock, &ev) < 0) {
	193	lxcfs_error("%s\n", "Failed adding socket to epoll: %m.");
	194	close(epfd);
	195	return false;
	196	}
	197
	198	again:
	199	if ((now = time(NULL)) < 0) {
	200	close(epfd);
	201	return false;
	202	}
	203
	204	deltatime = (starttime + timeout) - now;
	205	if (deltatime < 0) { // timeout
	206	errno = 0;
	207	close(epfd);
	208	return false;
	209	}
	210	ret = epoll_wait(epfd, &ev, 1, 1000*deltatime + 1);
	211	if (ret < 0 && errno == EINTR)
	212	goto again;
	213	saved_errno = errno;
	214	close(epfd);
	215
	216	if (ret <= 0) {
	217	errno = saved_errno;
	218	return false;
	219	}
	220	return true;
	221	}
	222
	223	bool recv_creds(int sock, struct ucred cred, char v)
	224	{
	225	struct msghdr msg = { 0 };
	226	struct iovec iov;
	227	struct cmsghdr *cmsg;
	228	char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
	229	char buf[1];
	230	int ret;
	231	int optval = 1;
	232
	233	*v = '1';
	234
	235	cred->pid = -1;
	236	cred->uid = -1;
	237	cred->gid = -1;
238
239	if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &optval, sizeof(optval)) == -1) {
240	lxcfs_error("Failed to set passcred: %s\n", strerror(errno));
241	return false;
242	}
243	buf[0] = '1';
244	if (write(sock, buf, 1) != 1) {
245	lxcfs_error("Failed to start write on scm fd: %s\n", strerror(errno));
246	return false;
247	}
248
249	msg.msg_name = NULL;
250	msg.msg_namelen = 0;
251	msg.msg_control = cmsgbuf;
252	msg.msg_controllen = sizeof(cmsgbuf);
253
254	iov.iov_base = buf;
255	iov.iov_len = sizeof(buf);
256	msg.msg_iov = &iov;
257	msg.msg_iovlen = 1;
258
259	if (!wait_for_sock(sock, 2)) {
260	lxcfs_error("Timed out waiting for scm_cred: %s\n", strerror(errno));
261	return false;
262	}
263	ret = recvmsg(sock, &msg, MSG_DONTWAIT);
264	if (ret < 0) {
265	lxcfs_error("Failed to receive scm_cred: %s\n", strerror(errno));
266	return false;
267	}
268
269	cmsg = CMSG_FIRSTHDR(&msg);
270
271	if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)) &&
272	cmsg->cmsg_level == SOL_SOCKET &&
273	cmsg->cmsg_type == SCM_CREDENTIALS) {
274	memcpy(cred, CMSG_DATA(cmsg), sizeof(*cred));
275	}
276	*v = buf[0];
277
278	return true;
279	}
280
281	static int msgrecv(int sockfd, void *buf, size_t len)
282	{
283	if (!wait_for_sock(sockfd, 2))
284	return -1;
285	return recv(sockfd, buf, len, MSG_DONTWAIT);
286	}
287
288	int send_creds(int sock, struct ucred *cred, char v, bool pingfirst)
289	{
290	struct msghdr msg = { 0 };
291	struct iovec iov;
292	struct cmsghdr *cmsg;
293	char cmsgbuf[CMSG_SPACE(sizeof(*cred))];
294	char buf[1];
295	buf[0] = 'p';
296
297	if (pingfirst) {
298	if (msgrecv(sock, buf, 1) != 1) {
299	lxcfs_error("%s\n", "Error getting reply from server over socketpair.");
300	return SEND_CREDS_FAIL;
301	}
302	}
303
304	msg.msg_control = cmsgbuf;
305	msg.msg_controllen = sizeof(cmsgbuf);
306
307	cmsg = CMSG_FIRSTHDR(&msg);
308	cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
309	cmsg->cmsg_level = SOL_SOCKET;
310	cmsg->cmsg_type = SCM_CREDENTIALS;
311	memcpy(CMSG_DATA(cmsg), cred, sizeof(*cred));
312
313	msg.msg_name = NULL;
314	msg.msg_namelen = 0;
315
316	buf[0] = v;
317	iov.iov_base = buf;
318	iov.iov_len = sizeof(buf);
319	msg.msg_iov = &iov;
320	msg.msg_iovlen = 1;
321
322	if (sendmsg(sock, &msg, 0) < 0) {
323	lxcfs_error("Failed at sendmsg: %s.\n",strerror(errno));
324	if (errno == 3)
325	return SEND_CREDS_NOTSK;
326	return SEND_CREDS_FAIL;
327	}
328
329	return SEND_CREDS_OK;
330	}
331
332	int read_file_fuse(const char path, char buf, size_t size, struct file_info *d)
333	{
334	__do_free char *line = NULL;
335	__do_fclose FILE *f = NULL;
336	size_t linelen = 0, total_len = 0;
337	char *cache = d->buf;
338	size_t cache_size = d->buflen;
339
dbb1f822	340	f = fopen(path, "re");
1f5596dd CB	341	if (!f)
	342	return 0;
	343
	344	while (getline(&line, &linelen, f) != -1) {
	345	ssize_t l = snprintf(cache, cache_size, "%s", line);
	346	if (l < 0) {
	347	perror("Error writing to cache");
	348	return 0;
	349	}
	350	if (l >= cache_size) {
	351	lxcfs_error("%s\n", "Internal error: truncated write to cache.");
	352	return 0;
	353	}
	354	cache += l;
	355	cache_size -= l;
	356	total_len += l;
	357	}
	358
	359	d->size = total_len;
	360	if (total_len > size)
	361	total_len = size;
	362
	363	/* read from off 0 */
	364	memcpy(buf, d->buf, total_len);
	365
	366	if (d->size > total_len)
	367	d->cached = d->size - total_len;
	368	return total_len;
	369	}
4ec5c9da CB	370
	371	#define INITSCOPE "/init.scope"
	372	void prune_init_slice(char *cg)
	373	{
	374	char *point;
	375	size_t cg_len = strlen(cg), initscope_len = strlen(INITSCOPE);
	376
	377	if (cg_len < initscope_len)
	378	return;
	379
	380	point = cg + cg_len - initscope_len;
	381	if (strcmp(point, INITSCOPE) == 0) {
	382	if (point == cg)
700dd417	383	*(point + 1) = '\0';
4ec5c9da CB	384	else
	385	*point = '\0';
	386	}
	387	}
	388
	389	int wait_for_pid(pid_t pid)
	390	{
	391	int status, ret;
	392
	393	if (pid <= 0)
	394	return -1;
	395
	396	again:
	397	ret = waitpid(pid, &status, 0);
	398	if (ret == -1) {
	399	if (errno == EINTR)
	400	goto again;
	401	return -1;
	402	}
	403	if (ret != pid)
	404	goto again;
	405	if (!WIFEXITED(status) \|\| WEXITSTATUS(status) != 0)
	406	return -1;
	407	return 0;
	408	}
757a63e7 CB	409
	410	static ssize_t read_nointr(int fd, void *buf, size_t count)
	411	{
	412	ssize_t ret;
	413	again:
	414	ret = read(fd, buf, count);
	415	if (ret < 0 && errno == EINTR)
	416	goto again;
	417
	418	return ret;
	419	}
	420
	421	static void must_realloc(void orig, size_t sz)
	422	{
	423	void *ret;
	424
	425	do {
	426	ret = realloc(orig, sz);
	427	} while (!ret);
	428
	429	return ret;
	430	}
	431
	432	static char file_to_buf(const char path, size_t *length)
	433	{
	434	__do_close_prot_errno int fd = -EBADF;
	435	__do_free char *copy = NULL;
	436	char buf[PATH_MAX];
	437
	438	if (!length)
	439	return NULL;
	440
	441	fd = open(path, O_RDONLY \| O_CLOEXEC);
	442	if (fd < 0)
	443	return NULL;
	444
	445	*length = 0;
	446	for (;;) {
	447	int n;
	448	char *old = copy;
	449
	450	n = read_nointr(fd, buf, sizeof(buf));
	451	if (n < 0)
	452	return NULL;
	453	if (!n)
	454	break;
	455
	456	copy = must_realloc(old, (length + n) sizeof(*old));
	457	memcpy(copy + *length, buf, n);
	458	*length += n;
	459	}
	460
	461	return move_ptr(copy);
	462	}
	463
	464	FILE fopen_cached(const char path, const char mode, void *caller_freed_buffer)
	465	{
	466	__do_free char *buf = NULL;
	467	size_t len = 0;
	468	FILE *f;
	469
	470	buf = file_to_buf(path, &len);
	471	if (!buf)
	472	return NULL;
473
474	f = fmemopen(buf, len, mode);
475	if (!f)
476	return NULL;
477	*caller_freed_buffer = move_ptr(buf);
478	return f;
479	}