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| | #include <sys/socket.h>
#include <byteswap.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "nscd.h"
static const struct {
short sun_family;
char sun_path[21];
} addr = {
AF_UNIX,
"/var/run/nscd/socket"
};
static ssize_t full_sendmsg(int fd, struct msghdr *m, int flags)
{
ssize_t n, count = 0;
while (m->msg_iovlen) {
n = sendmsg(fd, m, flags);
if(n < 0) return n;
count += n;
while (n) {
if (n >= m->msg_iov[0].iov_len) {
n -= m->msg_iov[0].iov_len;
m->msg_iov++;
m->msg_iovlen--;
} else {
m->msg_iov[0].iov_len -= n;
n = 0;
}
}
}
return count;
}
FILE *__nscd_query(int32_t req, const char *key, int32_t *buf, size_t len, int *swap)
{
size_t i;
int fd;
int res = 0;
FILE *f = 0;
int32_t req_buf[REQ_LEN] = {
NSCDVERSION,
req,
strlen(key)+1
};
struct msghdr msg = {
.msg_iov = (struct iovec[]){
{&req_buf, sizeof(req_buf)},
{(char*)key, strlen(key)+1}
},
.msg_iovlen = 2
};
if (strlen(key) > INT32_MAX - 1) {
return (FILE*)-1;
}
*swap = 0;
retry:
fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd < 0) return NULL;
if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
/* If there isn't a running nscd we return -1 to indicate that
* that is precisely what happened
*/
if (errno == EACCES || errno == ECONNREFUSED || errno == ENOENT) {
res = -1;
}
goto error;
}
if (full_sendmsg(fd, &msg, MSG_NOSIGNAL) < 0)
goto error;
f = fdopen(fd, "r");
if (fread(buf, 1, len, f) < len) {
/* 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 (!feof(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 {
fclose(f);
res = -1;
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) {
res = -1;
errno = EIO;
goto error;
}
return f;
error:
fclose(f);
return (FILE*)res;
}
|