1#include <sys/socket.h>
2#include <byteswap.h>
3#include <unistd.h>
4#include <stdio.h>
5#include <string.h>
6#include <errno.h>
7#include <limits.h>
8#include "nscd.h"
9
10static const struct {
11	short sun_family;
12	char sun_path[21];
13} addr = {
14	AF_UNIX,
15	"/var/run/nscd/socket"
16};
17
18FILE *__nscd_query(int32_t req, const char *key, int32_t *buf, size_t len, int *swap)
19{
20	size_t i;
21	int fd;
22	FILE *f = 0;
23	int32_t req_buf[REQ_LEN] = {
24		NSCDVERSION,
25		req,
26		strnlen(key,LOGIN_NAME_MAX)+1
27	};
28	struct msghdr msg = {
29		.msg_iov = (struct iovec[]){
30			{&req_buf, sizeof(req_buf)},
31			{(char*)key, strlen(key)+1}
32		},
33		.msg_iovlen = 2
34	};
35	int errno_save = errno;
36
37	*swap = 0;
38retry:
39	memset(buf, 0, len);
40	buf[0] = NSCDVERSION;
41
42	fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
43	if (fd < 0) return NULL;
44
45	if(!(f = fdopen(fd, "r"))) {
46		close(fd);
47		return 0;
48	}
49
50	if (req_buf[2] > LOGIN_NAME_MAX)
51		return f;
52
53	if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
54		/* If there isn't a running nscd we simulate a "not found"
55		 * result and the caller is responsible for calling
56		 * fclose on the (unconnected) socket. The value of
57		 * errno must be left unchanged in this case.  */
58		if (errno == EACCES || errno == ECONNREFUSED || errno == ENOENT) {
59			errno = errno_save;
60			return f;
61		}
62		goto error;
63	}
64
65	if (sendmsg(fd, &msg, MSG_NOSIGNAL) < 0)
66		goto error;
67
68	if (!fread(buf, len, 1, f)) {
69		/* If the VERSION entry mismatches nscd will disconnect. The
70		 * most likely cause is that the endianness mismatched. So, we
71		 * byteswap and try once more. (if we already swapped, just
72		 * fail out)
73		 */
74		if (ferror(f)) goto error;
75		if (!*swap) {
76			fclose(f);
77			for (i = 0; i < sizeof(req_buf)/sizeof(req_buf[0]); i++) {
78				req_buf[i] = bswap_32(req_buf[i]);
79			}
80			*swap = 1;
81			goto retry;
82		} else {
83			errno = EIO;
84			goto error;
85		}
86	}
87
88	if (*swap) {
89		for (i = 0; i < len/sizeof(buf[0]); i++) {
90			buf[i] = bswap_32(buf[i]);
91		}
92	}
93
94	/* The first entry in every nscd response is the version number. This
95	 * really shouldn't happen, and is evidence of some form of malformed
96	 * response.
97	 */
98	if(buf[0] != NSCDVERSION) {
99		errno = EIO;
100		goto error;
101	}
102
103	return f;
104error:
105	fclose(f);
106	return 0;
107}
108