nss-mymachines: add new NSS module for automatically resolving addresses of all local containers

7 files changed, 460 insertions, 1 deletions

diff --git a/Makefile.am b/Makefile.am
index 734e5c148e..f934bb1473 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4497,6 +4497,25 @@ BUSNAMES_TARGET_WANTS += \
 EXTRA_DIST += \
 	units/systemd-machined.service.in
 
+libnss_mymachines_la_SOURCES = \
+	src/nss-mymachines/nss-mymachines.sym \
+	src/nss-mymachines/nss-mymachines.c
+
+libnss_mymachines_la_LDFLAGS = \
+	$(AM_LDFLAGS) \
+	-module \
+	-export-dynamic \
+	-avoid-version \
+	-shared \
+	-shrext .so.2 \
+	-Wl,--version-script=$(top_srcdir)/src/nss-mymachines/nss-mymachines.sym
+
+libnss_mymachines_la_LIBADD = \
+	libsystemd-shared.la \
+	libsystemd-internal.la
+
+lib_LTLIBRARIES += \
+	libnss_mymachines.la
 endif
 
 # ------------------------------------------------------------------------------
diff --git a/src/libsystemd/libsystemd.sym.m4 b/src/libsystemd/libsystemd.sym.m4
index 39e1f51f7c..48572cc0b3 100644
--- a/src/libsystemd/libsystemd.sym.m4
+++ b/src/libsystemd/libsystemd.sym.m4
@@ -148,6 +148,11 @@ global:
         sd_pid_notifyf;
 } LIBSYSTEMD_213;
 
+LIBSYSTEMD_216 {
+global:
+        sd_machine_get_ifindexes;
+} LIBSYSTEMD_214;
+
 m4_ifdef(`ENABLE_KDBUS',
 LIBSYSTEMD_FUTURE {
 global:
@@ -444,5 +449,5 @@ global:
         /* sd-path */
         sd_path_home;
         sd_path_search;
-} LIBSYSTEMD_214;
+} LIBSYSTEMD_216;
 )
diff --git a/src/libsystemd/sd-login/sd-login.c b/src/libsystemd/sd-login/sd-login.c
index d1478ddb78..83d6449241 100644
--- a/src/libsystemd/sd-login/sd-login.c
+++ b/src/libsystemd/sd-login/sd-login.c
@@ -786,6 +786,49 @@ _public_ int sd_machine_get_class(const char *machine, char **class) {
         return 0;
 }
 
+_public_ int sd_machine_get_ifindexes(const char *machine, int **ifindexes) {
+        _cleanup_free_ char *netif = NULL;
+        size_t l, allocated = 0, nr = 0;
+        char *w, *state;
+        int *ni = NULL;
+        const char *p;
+        int r;
+
+        assert_return(machine_name_is_valid(machine), -EINVAL);
+        assert_return(ifindexes, -EINVAL);
+
+        p = strappenda("/run/systemd/machines/", machine);
+        r = parse_env_file(p, NEWLINE, "NETIF", &netif, NULL);
+        if (r < 0)
+                return r;
+        if (!netif) {
+                *ifindexes = NULL;
+                return 0;
+        }
+
+        FOREACH_WORD(w, l, netif, state) {
+                char buf[l+1];
+                int ifi;
+
+                *(char*) (mempcpy(buf, w, l)) = 0;
+
+                if (safe_atoi(buf, &ifi) < 0)
+                        continue;
+                if (ifi <= 0)
+                        continue;
+
+                if (!GREEDY_REALLOC(ni, allocated, nr+1)) {
+                        free(ni);
+                        return -ENOMEM;
+                }
+
+                ni[nr++] = ifi;
+        }
+
+        *ifindexes = ni;
+        return nr;
+}
+
 static inline int MONITOR_TO_FD(sd_login_monitor *m) {
         return (int) (unsigned long) m - 1;
 }
diff --git a/src/nss-mymachines/Makefile b/src/nss-mymachines/Makefile
new file mode 120000
index 0000000000..d0b0e8e008
--- /dev/null
+++ b/src/nss-mymachines/Makefile
@@ -0,0 +1 @@
+../Makefile
\ No newline at end of file
diff --git a/src/nss-mymachines/nss-mymachines.c b/src/nss-mymachines/nss-mymachines.c
new file mode 100644
index 0000000000..2d3e54210c
--- /dev/null
+++ b/src/nss-mymachines/nss-mymachines.c
@@ -0,0 +1,371 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <nss.h>
+#include <netdb.h>
+
+#include "sd-bus.h"
+#include "sd-login.h"
+#include "macro.h"
+#include "util.h"
+#include "nss-util.h"
+#include "bus-util.h"
+#include "in-addr-util.h"
+
+NSS_GETHOSTBYNAME_PROTOTYPES(mymachines);
+
+static int count_addresses(sd_bus_message *m, unsigned af, unsigned *ret) {
+        unsigned c = 0;
+        int r;
+
+        assert(m);
+        assert(ret);
+
+        while ((r = sd_bus_message_enter_container(m, 'r', "yay")) > 0) {
+                unsigned char family;
+
+                r = sd_bus_message_read(m, "y", &family);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, "ay");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_exit_container(m);
+                if (r < 0)
+                        return r;
+
+                if (af != AF_UNSPEC && family != af)
+                        continue;
+
+                c ++;
+        }
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_rewind(m, false);
+        if (r < 0)
+                return r;
+
+        *ret = c;
+        return 0;
+}
+
+enum nss_status _nss_mymachines_gethostbyname4_r(
+                const char *name,
+                struct gaih_addrtuple **pat,
+                char *buffer, size_t buflen,
+                int *errnop, int *h_errnop,
+                int32_t *ttlp) {
+
+        struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL;
+        _cleanup_bus_message_unref_ sd_bus_message* reply = NULL;
+        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_free_ int *ifindexes = NULL;
+        _cleanup_free_ char *class = NULL;
+        size_t l, ms, idx;
+        unsigned i = 0, c = 0;
+        char *r_name;
+        int n_ifindexes, r;
+
+        assert(name);
+        assert(pat);
+        assert(buffer);
+        assert(errnop);
+        assert(h_errnop);
+
+        r = sd_machine_get_class(name, &class);
+        if (r < 0)
+                goto fail;
+        if (!streq(class, "container")) {
+                r = -ENOTTY;
+                goto fail;
+        }
+
+        n_ifindexes = sd_machine_get_ifindexes(name, &ifindexes);
+        if (n_ifindexes < 0) {
+                r = n_ifindexes;
+                goto fail;
+        }
+
+        r = sd_bus_open_system(&bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_call_method(bus,
+                               "org.freedesktop.machine1",
+                               "/org/freedesktop/machine1",
+                               "org.freedesktop.machine1.Manager",
+                               "GetMachineAddresses",
+                               NULL,
+                               &reply,
+                               "s", name);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_enter_container(reply, 'a', "(yay)");
+        if (r < 0)
+                goto fail;
+
+        r = count_addresses(reply, AF_UNSPEC, &c);
+        if (r < 0)
+                goto fail;
+
+        if (c <= 0) {
+                *errnop = ENOENT;
+                *h_errnop = HOST_NOT_FOUND;
+                return NSS_STATUS_NOTFOUND;
+        }
+
+        l = strlen(name);
+        ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c;
+        if (buflen < ms) {
+                *errnop = ENOMEM;
+                *h_errnop = NO_RECOVERY;
+                return NSS_STATUS_TRYAGAIN;
+        }
+
+        /* First, append name */
+        r_name = buffer;
+        memcpy(r_name, name, l+1);
+        idx = ALIGN(l+1);
+
+        /* Second, append addresses */
+        r_tuple_first = (struct gaih_addrtuple*) (buffer + idx);
+        while ((r = sd_bus_message_enter_container(reply, 'r', "yay")) > 0) {
+                unsigned char family;
+                const void *a;
+                size_t sz;
+
+                r = sd_bus_message_read(reply, "y", &family);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_bus_message_read_array(reply, 'y', &a, &sz);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_bus_message_exit_container(reply);
+                if (r < 0)
+                        goto fail;
+
+                if (sz != PROTO_ADDRESS_SIZE(family)) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
+                r_tuple->next = i == c-1 ? NULL : (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple)));
+                r_tuple->name = r_name;
+                r_tuple->family = family;
+                r_tuple->scopeid = n_ifindexes == 1 ? ifindexes[0] : 0;
+                memcpy(r_tuple->addr, a, sz);
+
+                idx += ALIGN(sizeof(struct gaih_addrtuple));
+                i++;
+        }
+
+        assert(i == c);
+
+        r = sd_bus_message_exit_container(reply);
+        if (r < 0)
+                goto fail;
+
+        assert(idx == ms);
+
+        if (*pat)
+                **pat = *r_tuple_first;
+        else
+                *pat = r_tuple_first;
+
+        if (ttlp)
+                *ttlp = 0;
+
+        return NSS_STATUS_SUCCESS;
+
+fail:
+        *errnop = -r;
+        *h_errnop = NO_DATA;
+        return NSS_STATUS_UNAVAIL;
+}
+
+enum nss_status _nss_mymachines_gethostbyname3_r(
+                const char *name,
+                int af,
+                struct hostent *result,
+                char *buffer, size_t buflen,
+                int *errnop, int *h_errnop,
+                int32_t *ttlp,
+                char **canonp) {
+
+        _cleanup_bus_message_unref_ sd_bus_message* reply = NULL;
+        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_free_ char *class = NULL;
+        unsigned c = 0, i = 0;
+        char *r_name, *r_aliases, *r_addr, *r_addr_list;
+        size_t l, idx, ms, alen;
+        int r;
+
+        assert(name);
+        assert(result);
+        assert(buffer);
+        assert(errnop);
+        assert(h_errnop);
+
+        if (af == AF_UNSPEC)
+                af = AF_INET;
+
+        if (af != AF_INET && af != AF_INET6) {
+                r = -EAFNOSUPPORT;
+                goto fail;
+        }
+
+        r = sd_machine_get_class(name, &class);
+        if (r < 0)
+                goto fail;
+        if (!streq(class, "container")) {
+                r = -ENOTTY;
+                goto fail;
+        }
+
+        r = sd_bus_open_system(&bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_call_method(bus,
+                               "org.freedesktop.machine1",
+                               "/org/freedesktop/machine1",
+                               "org.freedesktop.machine1.Manager",
+                               "GetMachineAddresses",
+                               NULL,
+                               &reply,
+                               "s", name);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_enter_container(reply, 'a', "(yay)");
+        if (r < 0)
+                goto fail;
+
+        r = count_addresses(reply, af, &c);
+        if (r < 0)
+                goto fail;
+
+        if (c <= 0) {
+                *errnop = ENOENT;
+                *h_errnop = HOST_NOT_FOUND;
+                return NSS_STATUS_NOTFOUND;
+        }
+
+        alen = PROTO_ADDRESS_SIZE(af);
+        l = strlen(name);
+
+        ms = ALIGN(l+1) +
+                sizeof(char*) +
+                (c > 0 ? c : 1) * ALIGN(alen) +
+                (c > 0 ? c+1 : 2) * sizeof(char*);
+
+        if (buflen < ms) {
+                *errnop = ENOMEM;
+                *h_errnop = NO_RECOVERY;
+                return NSS_STATUS_TRYAGAIN;
+        }
+
+        /* First, append name */
+        r_name = buffer;
+        memcpy(r_name, name, l+1);
+        idx = ALIGN(l+1);
+
+        /* Second, create aliases array */
+        r_aliases = buffer + idx;
+        ((char**) r_aliases)[0] = NULL;
+        idx += sizeof(char*);
+
+        /* Third, append addresses */
+        r_addr = buffer + idx;
+        while ((r = sd_bus_message_enter_container(reply, 'r', "yay")) > 0) {
+                unsigned char family;
+                const void *a;
+                size_t sz;
+
+                r = sd_bus_message_read(reply, "y", &family);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_bus_message_read_array(reply, 'y', &a, &sz);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_bus_message_exit_container(reply);
+                if (r < 0)
+                        goto fail;
+
+                if (family != af)
+                        continue;
+
+                if (sz != alen) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+                memcpy(r_addr + i*ALIGN(alen), a, alen);
+                i++;
+        }
+
+        assert(i == c);
+        idx += c * ALIGN(alen);
+
+        r = sd_bus_message_exit_container(reply);
+        if (r < 0)
+                goto fail;
+
+        /* Third, append address pointer array */
+        r_addr_list = buffer + idx;
+        for (i = 0; i < c; i++)
+                ((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen);
+
+        ((char**) r_addr_list)[i] = NULL;
+        idx += (c+1) * sizeof(char*);
+
+        assert(idx == ms);
+
+        result->h_name = r_name;
+        result->h_aliases = (char**) r_aliases;
+        result->h_addrtype = af;
+        result->h_length = alen;
+        result->h_addr_list = (char**) r_addr_list;
+
+        if (ttlp)
+                *ttlp = 0;
+
+        if (canonp)
+                *canonp = r_name;
+
+        return NSS_STATUS_SUCCESS;
+
+fail:
+        *errnop = -r;
+        *h_errnop = NO_DATA;
+        return NSS_STATUS_UNAVAIL;
+}
+
+NSS_GETHOSTBYNAME_FALLBACKS(mymachines)
diff --git a/src/nss-mymachines/nss-mymachines.sym b/src/nss-mymachines/nss-mymachines.sym
new file mode 100644
index 0000000000..f80b51c1aa
--- /dev/null
+++ b/src/nss-mymachines/nss-mymachines.sym
@@ -0,0 +1,17 @@
+/***
+  This file is part of systemd.
+
+  systemd 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.
+***/
+
+{
+global:
+        _nss_mymachines_gethostbyname_r;
+        _nss_mymachines_gethostbyname2_r;
+        _nss_mymachines_gethostbyname3_r;
+        _nss_mymachines_gethostbyname4_r;
+local: *;
+};
diff --git a/src/systemd/sd-login.h b/src/systemd/sd-login.h
index dad459a7e8..b289ad2a59 100644
--- a/src/systemd/sd-login.h
+++ b/src/systemd/sd-login.h
@@ -181,6 +181,9 @@ int sd_seat_can_graphical(const char *seat);
 /* Return the class of machine */
 int sd_machine_get_class(const char *machine, char **clazz);
 
+/* Return the list if host-side network interface indexes of a machine */
+int sd_machine_get_ifindexes(const char *machine, int **ifindexes);
+
 /* Get all seats, store in *seats. Returns the number of seats. If
  * seats is NULL, this only returns the number of seats. */
 int sd_get_seats(char ***seats);