nsz Git - musl/blob - src/passwd/nscd_query.c

   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
  10 static const struct {
  11         short sun_family;
  12         char sun_path[21];
  13 } addr = {
  14         AF_UNIX,
  15         "/var/run/nscd/socket"
  16 };
  17
  18 FILE *__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
  36         *swap = 0;
  37 retry:
  38         memset(buf, 0, len);
  39         buf[0] = NSCDVERSION;
  40
  41         fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
  42         if (fd < 0) return NULL;
  43
  44         if(!(f = fdopen(fd, "r"))) {
  45                 close(fd);
  46                 return 0;
  47         }
  48
  49         if (req_buf[2] > LOGIN_NAME_MAX)
  50                 return f;
  51
  52         if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
  53                 /* If there isn't a running nscd we return -1 to indicate that
  54                  * that is precisely what happened
  55                  */
  56                 if (errno == EACCES || errno == ECONNREFUSED || errno == ENOENT)
  57                         return f;
  58                 goto error;
  59         }
  60
  61         if (sendmsg(fd, &msg, MSG_NOSIGNAL) < 0)
  62                 goto error;
  63
  64         if (!fread(buf, len, 1, f)) {
  65                 /* If the VERSION entry mismatches nscd will disconnect. The
  66                  * most likely cause is that the endianness mismatched. So, we
  67                  * byteswap and try once more. (if we already swapped, just
  68                  * fail out)
  69                  */
  70                 if (ferror(f)) goto error;
  71                 if (!*swap) {
  72                         fclose(f);
  73                         for (i = 0; i < sizeof(req_buf)/sizeof(req_buf[0]); i++) {
  74                                 req_buf[i] = bswap_32(req_buf[i]);
  75                         }
  76                         *swap = 1;
  77                         goto retry;
  78                 } else {
  79                         errno = EIO;
  80                         goto error;
  81                 }
  82         }
  83
  84         if (*swap) {
  85                 for (i = 0; i < len/sizeof(buf[0]); i++) {
  86                         buf[i] = bswap_32(buf[i]);
  87                 }
  88         }
  89
  90         /* The first entry in every nscd response is the version number. This
  91          * really shouldn't happen, and is evidence of some form of malformed
  92          * response.
  93          */
  94         if(buf[0] != NSCDVERSION) {
  95                 errno = EIO;
  96                 goto error;
  97         }
  98
  99         return f;
 100 error:
 101         fclose(f);
 102         return 0;
 103 }