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) {
44 if (errno == EAFNOSUPPORT) {
45 f = fopen("/dev/null", "re");
46 if (f)
47 errno = errno_save;
48 return f;
49 }
50 return 0;
51 }
52
53 if(!(f = fdopen(fd, "r"))) {
54 close(fd);
55 return 0;
56 }
57
58 if (req_buf[2] > LOGIN_NAME_MAX)
59 return f;
60
61 if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
62 /* If there isn't a running nscd we simulate a "not found"
63 * result and the caller is responsible for calling
64 * fclose on the (unconnected) socket. The value of
65 * errno must be left unchanged in this case. */
66 if (errno == EACCES || errno == ECONNREFUSED || errno == ENOENT) {
67 errno = errno_save;
68 return f;
69 }
70 goto error;
71 }
72
73 if (sendmsg(fd, &msg, MSG_NOSIGNAL) < 0)
74 goto error;
75
76 if (!fread(buf, len, 1, f)) {
77 /* If the VERSION entry mismatches nscd will disconnect. The
78 * most likely cause is that the endianness mismatched. So, we
79 * byteswap and try once more. (if we already swapped, just
80 * fail out)
81 */
82 if (ferror(f)) goto error;
83 if (!*swap) {
84 fclose(f);
85 for (i = 0; i < sizeof(req_buf)/sizeof(req_buf[0]); i++) {
86 req_buf[i] = bswap_32(req_buf[i]);
87 }
88 *swap = 1;
89 goto retry;
90 } else {
91 errno = EIO;
92 goto error;
93 }
94 }
95
96 if (*swap) {
97 for (i = 0; i < len/sizeof(buf[0]); i++) {
98 buf[i] = bswap_32(buf[i]);
99 }
100 }
101
102 /* The first entry in every nscd response is the version number. This
103 * really shouldn't happen, and is evidence of some form of malformed
104 * response.
105 */
106 if(buf[0] != NSCDVERSION) {
107 errno = EIO;
108 goto error;
109 }
110
111 return f;
112error:
113 fclose(f);
114 return 0;
115}