[lxc-devel] [PATCH] Add get_interfaces to the API - v3
S.Çağlar Onur
caglar at 10ur.org
Mon Sep 16 21:01:11 UTC 2013
get_ips accepts an interface name as a parameter but there was no
way to get the interfaces names from the container. This patch
introduces a new get_interfaces call to the API so that users
can obtain the name of the interfaces.
Support for python bindings also introduced as a part of this version.
Signed-off-by: S.Çağlar Onur <caglar at 10ur.org>
---
src/lxc/lxccontainer.c | 129 ++++++++++++++++++++++++++----------
src/lxc/lxccontainer.h | 3 +
src/lxc/utils.c | 22 +++++-
src/lxc/utils.h | 1 +
src/python-lxc/examples/api_test.py | 5 ++
src/python-lxc/lxc.c | 60 +++++++++++++++--
src/python-lxc/lxc/__init__.py | 8 +++
7 files changed, 189 insertions(+), 39 deletions(-)
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 79237df..8621cd8 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -1179,23 +1179,26 @@ static bool lxcapi_clear_config_item(struct lxc_container *c, const char *key)
return ret == 0;
}
-char** lxcapi_get_ips(struct lxc_container *c, char* interface, char* family, int scope)
-{
- int count = 0;
- struct ifaddrs *interfaceArray = NULL, *tempIfAddr = NULL;
- char addressOutputBuffer[INET6_ADDRSTRLEN];
- void *tempAddrPtr = NULL;
- char **addresses = NULL, **temp;
- char *address = NULL;
+static inline void exit_from_ns(struct lxc_container *c, int *old_netns, int *new_netns) {
+ /* Switch back to original netns */
+ if (*old_netns >= 0 && setns(*old_netns, CLONE_NEWNET))
+ SYSERROR("failed to setns");
+ if (*new_netns >= 0)
+ close(*new_netns);
+ if (*old_netns >= 0)
+ close(*old_netns);
+}
+
+static inline bool enter_to_ns(struct lxc_container *c, int *old_netns, int *new_netns) {
+ int ret = 0;
char new_netns_path[MAXPATHLEN];
- int old_netns = -1, new_netns = -1, ret = 0;
if (!c->is_running(c))
goto out;
/* Save reference to old netns */
- old_netns = open("/proc/self/ns/net", O_RDONLY);
- if (old_netns < 0) {
+ *old_netns = open("/proc/self/ns/net", O_RDONLY);
+ if (*old_netns < 0) {
SYSERROR("failed to open /proc/self/ns/net");
goto out;
}
@@ -1205,16 +1208,91 @@ char** lxcapi_get_ips(struct lxc_container *c, char* interface, char* family, in
if (ret < 0 || ret >= MAXPATHLEN)
goto out;
- new_netns = open(new_netns_path, O_RDONLY);
- if (new_netns < 0) {
+ *new_netns = open(new_netns_path, O_RDONLY);
+ if (*new_netns < 0) {
SYSERROR("failed to open %s", new_netns_path);
goto out;
}
- if (setns(new_netns, CLONE_NEWNET)) {
+ if (setns(*new_netns, CLONE_NEWNET)) {
SYSERROR("failed to setns");
goto out;
}
+ return true;
+out:
+ exit_from_ns(c, old_netns, new_netns);
+ return false;
+}
+
+static char** lxcapi_get_interfaces(struct lxc_container *c)
+{
+ int count = 0, i;
+ bool found = false;
+ struct ifaddrs *interfaceArray = NULL, *tempIfAddr = NULL;
+ char **interfaces = NULL, **temp;
+ int old_netns = -1, new_netns = -1;
+
+ if (!enter_to_ns(c, &old_netns, &new_netns))
+ goto out;
+
+ /* Grab the list of interfaces */
+ if (getifaddrs(&interfaceArray)) {
+ SYSERROR("failed to get interfaces list");
+ goto out;
+ }
+
+ /* Iterate through the interfaces */
+ for (tempIfAddr = interfaceArray; tempIfAddr != NULL; tempIfAddr = tempIfAddr->ifa_next) {
+ /*
+ * WARNING: Following "for" loop does a linear search over the interfaces array
+ * For the containers with lots of interfaces this may be problematic.
+ * I'm not expecting this to be the common usage but if it turns out to be
+ * than using binary search or a hash table could be more elegant solution.
+ */
+ for (i = 0; i < count; i++) {
+ if (strcmp(interfaces[i], tempIfAddr->ifa_name) == 0) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ count += 1;
+ temp = realloc(interfaces, count * sizeof(*interfaces));
+ if (!temp) {
+ count -= 1;
+ goto out;
+ }
+ interfaces = temp;
+ interfaces[count - 1] = strdup(tempIfAddr->ifa_name);
+ }
+ found = false;
+ }
+
+out:
+ if (interfaceArray)
+ freeifaddrs(interfaceArray);
+
+ exit_from_ns(c, &old_netns, &new_netns);
+
+ /* Append NULL to the array */
+ interfaces = (char **)lxc_append_null_to_array((void **)interfaces, count);
+
+ return interfaces;
+}
+
+static char** lxcapi_get_ips(struct lxc_container *c, char* interface, char* family, int scope)
+{
+ int count = 0;
+ struct ifaddrs *interfaceArray = NULL, *tempIfAddr = NULL;
+ char addressOutputBuffer[INET6_ADDRSTRLEN];
+ void *tempAddrPtr = NULL;
+ char **addresses = NULL, **temp;
+ char *address = NULL;
+ int old_netns = -1, new_netns = -1;
+
+ if (!enter_to_ns(c, &old_netns, &new_netns))
+ goto out;
/* Grab the list of interfaces */
if (getifaddrs(&interfaceArray)) {
@@ -1265,28 +1343,10 @@ out:
if(interfaceArray)
freeifaddrs(interfaceArray);
- /* Switch back to original netns */
- if (old_netns >= 0 && setns(old_netns, CLONE_NEWNET))
- SYSERROR("failed to setns");
- if (new_netns >= 0)
- close(new_netns);
- if (old_netns >= 0)
- close(old_netns);
+ exit_from_ns(c, &old_netns, &new_netns);
/* Append NULL to the array */
- if (count) {
- count++;
- temp = realloc(addresses, count * sizeof(*addresses));
- if (!temp) {
- int i;
- for (i = 0; i < count-1; i++)
- free(addresses[i]);
- free(addresses);
- return NULL;
- }
- addresses = temp;
- addresses[count - 1] = NULL;
- }
+ addresses = (char **)lxc_append_null_to_array((void **)addresses, count);
return addresses;
}
@@ -2576,6 +2636,7 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
c->get_config_path = lxcapi_get_config_path;
c->set_config_path = lxcapi_set_config_path;
c->clone = lxcapi_clone;
+ c->get_interfaces = lxcapi_get_interfaces;
c->get_ips = lxcapi_get_ips;
c->attach = lxcapi_attach;
c->attach_run_wait = lxcapi_attach_run_wait;
diff --git a/src/lxc/lxccontainer.h b/src/lxc/lxccontainer.h
index f9ae43b..89b55bd 100644
--- a/src/lxc/lxccontainer.h
+++ b/src/lxc/lxccontainer.h
@@ -90,6 +90,9 @@ struct lxc_container {
* the length which was our would be printed. */
int (*get_config_item)(struct lxc_container *c, const char *key, char *retv, int inlen);
int (*get_keys)(struct lxc_container *c, const char *key, char *retv, int inlen);
+ // Return interface names. The result is strdup()d, so free the result.
+ char** (*get_interfaces)(struct lxc_container *c);
+ // Return IP addresses. The result is strdup()d, so free the result.
char** (*get_ips)(struct lxc_container *c, char* interface, char* family, int scope);
/*
* get_cgroup_item returns the number of bytes read, or an error (<0).
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 78b234d..924cc19 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -852,7 +852,7 @@ int lxc_write_to_file(const char *filename, const void* buf, size_t count, bool
return -1;
ret = lxc_write_nointr(fd, buf, count);
if (ret < 0)
- goto out_error;
+ goto out_error;
if ((size_t)ret != count)
goto out_error;
if (add_newline) {
@@ -899,3 +899,23 @@ int lxc_read_from_file(const char *filename, void* buf, size_t count)
errno = saved_errno;
return ret;
}
+
+void **lxc_append_null_to_array(void **array, size_t count)
+{
+ void **temp;
+
+ /* Append NULL to the array */
+ if (count) {
+ temp = realloc(array, (count + 1) * sizeof(*array));
+ if (!temp) {
+ int i;
+ for (i = 0; i < count; i++)
+ free(array[i]);
+ free(array);
+ return NULL;
+ }
+ array = temp;
+ array[count] = NULL;
+ }
+ return array;
+}
diff --git a/src/lxc/utils.h b/src/lxc/utils.h
index ba7cfb3..55f98fa 100644
--- a/src/lxc/utils.h
+++ b/src/lxc/utils.h
@@ -236,4 +236,5 @@ extern void lxc_free_array(void **array, lxc_free_fn element_free_fn);
extern size_t lxc_array_len(void **array);
extern void **lxc_dup_array(void **array, lxc_dup_fn element_dup_fn, lxc_free_fn element_free_fn);
+extern void **lxc_append_null_to_array(void **array, size_t count);
#endif
diff --git a/src/python-lxc/examples/api_test.py b/src/python-lxc/examples/api_test.py
index e078d2b..4754332 100644
--- a/src/python-lxc/examples/api_test.py
+++ b/src/python-lxc/examples/api_test.py
@@ -89,6 +89,11 @@ assert(container.init_pid > 1)
assert(container.running)
assert(container.state == "RUNNING")
+
+## Checking IP address
+print("Getting the interface names")
+assert(container.get_interfaces() == ('lo', 'eth0'))
+
## Checking IP address
print("Getting the IP addresses")
diff --git a/src/python-lxc/lxc.c b/src/python-lxc/lxc.c
index bd053a7..b6e0804 100644
--- a/src/python-lxc/lxc.c
+++ b/src/python-lxc/lxc.c
@@ -411,6 +411,52 @@ Container_get_keys(Container *self, PyObject *args, PyObject *kwds)
}
static PyObject *
+Container_get_interfaces(Container *self)
+{
+ int i = 0;
+ char** interfaces = NULL;
+
+ PyObject* ret;
+
+ /* Get the interfaces */
+ interfaces = self->container->get_interfaces(self->container);
+ if (!interfaces)
+ return PyTuple_New(0);
+
+ /* Count the entries */
+ while (interfaces[i])
+ i++;
+
+ /* Create the new tuple */
+ ret = PyTuple_New(i);
+ if (!ret)
+ return NULL;
+
+ /* Add the entries to the tuple and free the memory */
+ i = 0;
+ while (interfaces[i]) {
+ PyObject *unicode = PyUnicode_FromString(interfaces[i]);
+ if (!unicode) {
+ Py_DECREF(ret);
+ ret = NULL;
+ break;
+ }
+ PyTuple_SET_ITEM(ret, i, unicode);
+ i++;
+ }
+
+ /* Free the list of IPs */
+ i = 0;
+ while (interfaces[i]) {
+ free(interfaces[i]);
+ i++;
+ }
+ free(interfaces);
+
+ return ret;
+}
+
+static PyObject *
Container_get_ips(Container *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"interface", "family", "scope", NULL};
@@ -898,15 +944,15 @@ LXC_arch_to_personality(PyObject *self, PyObject *arg)
PyErr_SetString(PyExc_ValueError, "Expected a string");
return NULL;
}
-
+
pystr = PyUnicode_AsUTF8String(arg);
if (!pystr)
return NULL;
-
+
str = PyBytes_AsString(pystr);
if (!str)
goto out;
-
+
rv = lxc_config_parse_arch(str);
if (rv == -1)
PyErr_SetString(PyExc_KeyError, "Failed to lookup architecture.");
@@ -1025,6 +1071,12 @@ static PyMethodDef Container_methods[] = {
"\n"
"Get a list of valid sub-keys for a key."
},
+ {"get_interfaces", (PyCFunction)Container_get_interfaces,
+ METH_NOARGS,
+ "get_interface() -> tuple\n"
+ "\n"
+ "Get a tuple of interfaces for the container."
+ },
{"get_ips", (PyCFunction)Container_get_ips,
METH_VARARGS|METH_KEYWORDS,
"get_ips(interface, family, scope) -> tuple\n"
@@ -1205,7 +1257,7 @@ PyInit__lxc(void)
/* add constants */
d = PyModule_GetDict(m);
-
+
#define PYLXC_EXPORT_CONST(c) PyDict_SetItemString(d, #c, PyLong_FromLong(c))
/* environment variable handling */
diff --git a/src/python-lxc/lxc/__init__.py b/src/python-lxc/lxc/__init__.py
index 3fb76dc..6a29903 100644
--- a/src/python-lxc/lxc/__init__.py
+++ b/src/python-lxc/lxc/__init__.py
@@ -333,6 +333,14 @@ class Container(_lxc.Container):
else:
return value
+ def get_interfaces(self):
+ """
+ Get a tuple of interfaces for the container.
+ """
+
+ return _lxc.Container.get_interfaces(self)
+
+
def get_ips(self, interface=None, family=None, scope=None, timeout=0):
"""
Get a tuple of IPs for the container.
--
1.8.1.2
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