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