[lxc-devel] [PATCH] Add get_interfaces to the API - v2
Stéphane Graber
stgraber at ubuntu.com
Mon Sep 16 18:39:34 UTC 2013
On Mon, Sep 16, 2013 at 02:26:47PM -0400, S.Çağlar Onur wrote:
> 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.
>
> Signed-off-by: S.Çağlar Onur <caglar at 10ur.org>
I think I'm fine with this version:
One quick comment though, wouldn't we expect get_interfaces() to return
all the interfaces by default, including loopback, including those
without addresses and those that aren't standard packet based IP
interfaces?
I still think we don't want to list loopback addresses in get_ips(), at
least by default, but I think I'd expect get_interfaces to return me all
the existing interfaces without filtering. Does that make sense?
> ---
> src/lxc/lxccontainer.c | 117 ++++++++++++++++++++++++++++++++++---------------
> src/lxc/lxccontainer.h | 1 +
> src/lxc/utils.c | 22 +++++++++-
> src/lxc/utils.h | 1 +
> 4 files changed, 105 insertions(+), 36 deletions(-)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 79237df..6aa59fc 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 +1208,78 @@ 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;
> + 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) {
> + /* filter out loopback interface */
> + if(tempIfAddr->ifa_addr == NULL || tempIfAddr->ifa_addr->sa_family != AF_PACKET || strcmp("lo", tempIfAddr->ifa_name) == 0)
> + continue;
> +
> + count += 1;
> + temp = realloc(interfaces, count * sizeof(*interfaces));
> + if (!temp) {
> + count -= 1;
> + goto out;
> + }
> + interfaces = temp;
> + interfaces[count - 1] = strdup(tempIfAddr->ifa_name);
> + }
> +
> +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)) {
> @@ -1243,7 +1308,6 @@ char** lxcapi_get_ips(struct lxc_container *c, char* interface, char* family, in
> continue;
> else if (!interface && strcmp("lo", tempIfAddr->ifa_name) == 0)
> continue;
> -
> address = (char *)inet_ntop(tempIfAddr->ifa_addr->sa_family,
> tempAddrPtr,
> addressOutputBuffer,
> @@ -1265,28 +1329,10 @@ 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 +2622,7 @@ 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..f17d975 100644
> --- a/src/lxc/lxccontainer.h
> +++ b/src/lxc/lxccontainer.h
> @@ -90,6 +90,7 @@ 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);
> + char** (*get_interfaces)(struct lxc_container *c);
> 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
> --
> 1.8.1.2
>
>
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--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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