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#include <sys/socket.h>
#include <byteswap.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include "nscd.h"
static const struct {
short sun_family;
char sun_path[21];
} addr = {
AF_UNIX,
"/var/run/nscd/socket"
};
FILE *__nscd_query(int32_t req, const char *key, int32_t *buf, size_t len, int *swap)
{
size_t i;
int fd;
FILE *f = 0;
int32_t req_buf[REQ_LEN] = {
NSCDVERSION,
req,
strnlen(key,LOGIN_NAME_MAX)+1
};
struct msghdr msg = {
.msg_iov = (struct iovec[]){
{&req_buf, sizeof(req_buf)},
{(char*)key, strlen(key)+1}
},
.msg_iovlen = 2
};
int errno_save = errno;
*swap = 0;
retry:
memset(buf, 0, len);
buf[0] = NSCDVERSION;
fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd < 0) return NULL;
if(!(f = fdopen(fd, "r"))) {
close(fd);
return 0;
}
if (req_buf[2] > LOGIN_NAME_MAX)
return f;
if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
/* If there isn't a running nscd we simulate a "not found"
* result and the caller is responsible for calling
* fclose on the (unconnected) socket. The value of
* errno must be left unchanged in this case. */
if (errno == EACCES || errno == ECONNREFUSED || errno == ENOENT) {
errno = errno_save;
return f;
}
goto error;
}
if (sendmsg(fd, &msg, MSG_NOSIGNAL) < 0)
goto error;
if (!fread(buf, len, 1, f)) {
/* If the VERSION entry mismatches nscd will disconnect. The
* most likely cause is that the endianness mismatched. So, we
* byteswap and try once more. (if we already swapped, just
* fail out)
*/
if (ferror(f)) goto error;
if (!*swap) {
fclose(f);
for (i = 0; i < sizeof(req_buf)/sizeof(req_buf[0]); i++) {
req_buf[i] = bswap_32(req_buf[i]);
}
*swap = 1;
goto retry;
} else {
errno = EIO;
goto error;
}
}
if (*swap) {
for (i = 0; i < len/sizeof(buf[0]); i++) {
buf[i] = bswap_32(buf[i]);
}
}
/* The first entry in every nscd response is the version number. This
* really shouldn't happen, and is evidence of some form of malformed
* response.
*/
if(buf[0] != NSCDVERSION) {
errno = EIO;
goto error;
}
return f;
error:
fclose(f);
return 0;
}
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