initial commit

git-svn-id: svn+ssh://rootserver/home/lennart/svn/private/projects/nss-myhostname@83 bf9bc1cc-28ce-0310-abfb-9041aa761afb

Makefile

@@ -0,0 +1,13 @@
+CFLAGS=-Wall -pipe -W -O2 -Wextra -Wno-unused-parameter
+
+libnss_myhostname.so.2: nss-myhostname.o
+	$(CC) -shared -o $@ -Wl,-soname,$@ $^
+	strip $@
+
+install:
+	install -D -g root -m 644 -o root -s -v libnss_myhostname.so.2 /usr/lib/libnss_myhostname.so.2
+
+clean:
+	rm -f *.o *~ libnss_myhostname.so.2
+
+.PHONY: clean	

nss-myhostname.c

@@ -0,0 +1,164 @@
+/*
+ * This file is part of nss-myhostname.
+ *
+ * nss-myhostname is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * nss-myhostname is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with nss-myhostname; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <limits.h>
+#include <nss.h>
+#include <sys/types.h>
+#include <netdb.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <assert.h>
+#include <unistd.h>
+
+#define LOCALADDRESS (htonl(0x7F0002))
+
+static enum nss_status fill_in_hostent(
+    const char *hn,
+    struct hostent *result,
+    char *buffer,
+    size_t buflen,
+    int *errnop,
+    int *h_errnop) {
+
+    size_t l, idx; 
+    char *r_addr, *r_name, *r_aliases, *r_addr_list;
+
+    l = strlen(hn);
+    if (buflen < l+1+sizeof(char*)+4+sizeof(char*)*2) {
+        *errnop = ENOMEM;
+        *h_errnop = NO_RECOVERY;
+        return NSS_STATUS_TRYAGAIN;
+    }
+    
+    r_name = buffer;
+    strcpy(buffer, hn);
+
+    idx = l+1;
+
+    *(char**) (buffer + idx) = NULL;
+    r_aliases = buffer + idx;
+    idx += sizeof(char*);
+    
+    r_addr = buffer + idx;
+    *(uint32_t*) &buffer[idx] = LOCALADDRESS;
+    idx += 4;
+
+    r_addr_list = buffer + idx;
+    * (char**) (buffer + idx) = r_addr;
+    * (((char**) (buffer + idx)) +1)  = NULL;
+    
+    result->h_name = r_name;
+    result->h_aliases = (char**) r_aliases;
+    result->h_addrtype = AF_INET;
+    result->h_length = 4;
+    result->h_addr_list = (char**) r_addr_list;
+
+    return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status _nss_hostname_gethostbyname2_r(
+    const char *name,
+    int af,
+    struct hostent * result,
+    char *buffer,
+    size_t buflen,
+    int *errnop,
+    int *h_errnop) {
+
+    char hn[HOST_NAME_MAX+1];
+
+    assert(errnop);
+    assert(h_errnop);
+
+    if (af == AF_UNSPEC)
+        af = AF_INET;
+
+    if (af != AF_INET) {
+        *errnop = ENOENT;
+        *h_errnop = HOST_NOT_FOUND;
+        return NSS_STATUS_NOTFOUND;
+    }
+
+    if (gethostname(hn, sizeof(hn)-1) < 0) {
+        *errnop = errno;
+        *h_errnop = NO_RECOVERY;
+        return NSS_STATUS_TRYAGAIN;
+    }
+
+    hn[sizeof(hn)-1] = 0;
+
+    if (strcasecmp(name, hn) != 0) {
+        *errnop = ENOENT;
+        *h_errnop = HOST_NOT_FOUND;
+        return NSS_STATUS_NOTFOUND;
+    }
+
+    return fill_in_hostent(hn, result, buffer, buflen, errnop, h_errnop);
+}
+
+enum nss_status _nss_hostname_gethostbyname_r (
+    const char *name,
+    struct hostent *result,
+    char *buffer,
+    size_t buflen,
+    int *errnop,
+    int *h_errnop) {
+
+    return _nss_hostname_gethostbyname2_r(
+        name,
+        AF_UNSPEC,
+        result,
+        buffer,
+        buflen,
+        errnop,
+        h_errnop);
+}
+
+enum nss_status _nss_hostname_gethostbyaddr_r(
+    const void* addr,
+    int len,
+    int af,
+    struct hostent *result,
+    char *buffer,
+    size_t buflen,
+    int *errnop,
+    int *h_errnop) {
+
+    char hn[HOST_NAME_MAX+1];
+
+    assert(errnop);
+    assert(h_errnop);
+
+    if (af != AF_INET || len != 4 || (*(uint32_t*) addr) != LOCALADDRESS) {
+        *errnop = ENOENT;
+        *h_errnop = HOST_NOT_FOUND;
+        return NSS_STATUS_NOTFOUND;
+    }
+
+    if (gethostname(hn, sizeof(hn)-1) < 0) {
+        *errnop = errno;
+        *h_errnop = NO_RECOVERY;
+        return NSS_STATUS_TRYAGAIN;
+    }
+
+    hn[sizeof(hn)-1] = 0;
+
+    return fill_in_hostent(hn, result, buffer, buflen, errnop, h_errnop);
+}