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