Add a "fork" of musl as //fusl.

fusl/src/passwd/nscd_query.c

+#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;
+}