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handle hashed command socket names (v2)
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With the new hashed command socket names (e858984), it's possible to
have something like below;

[caglar@qop:~/go/src/github.com/lxc/go-lxc(master)] cat /proc/net/unix | grep lxc
0000000000000000: 00000002 00000000 00010000 0001 01 53465 @lxc/d086e835c86f4b8d/command
[...]

list_active_containers reads /proc/net/unix to find all running
containers but this new format no longer includes the container name or
its lxcpath.

This patch introduces two new commands (LXC_CMD_GET_NAME and
LXC_CMD_GET_LXCPATH) and starts to use those in list_active_containers
call.

changes since v1:
 - added sanity check proposed by Serge

Signed-off-by: S.Çağlar Onur <caglar@10ur.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
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@caglar10ur @stgraber
caglar10ur authored and stgraber committed Sep 20, 2014
1 parent f3116a8 commit b656b42
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Showing 3 changed files with 124 additions and 18 deletions.
118 changes: 102 additions & 16 deletions src/lxc/commands.c
View file
Expand Up @@ -75,23 +75,31 @@
lxc_log_define(lxc_commands, lxc);

static int fill_sock_name(char *path, int len, const char *name,
const char *lxcpath)
const char *lxcpath, const char *hashed_sock_name)
{
char *tmppath;
size_t tmplen;
uint64_t hash;
int ret;

if (hashed_sock_name != NULL) {
ret = snprintf(path, len, "lxc/%s/command", hashed_sock_name);
if (ret < 0 || ret >= len) {
ERROR("Error writing to command sock path");
return -1;
}
return 0;
}

if (!lxcpath) {
lxcpath = lxc_global_config_value("lxc.lxcpath");
if (!lxcpath) {
ERROR("Out of memory getting lxcpath");
return -1;
}
}

ret = snprintf(path, len, "%s/%s/command", lxcpath, name);

ret = snprintf(path, len, "%s/%s/command", lxcpath, name);
if (ret < 0) {
ERROR("Error writing to command sock path");
return -1;
Expand All @@ -108,7 +116,7 @@ static int fill_sock_name(char *path, int len, const char *name,
return -1;
}
hash = fnv_64a_buf(tmppath, ret, FNV1A_64_INIT);
ret = snprintf(path, len, "lxc/%016" PRIx64 "/cmd_sock", hash);
ret = snprintf(path, len, "lxc/%016" PRIx64 "/command", hash);
if (ret < 0 || ret >= len) {
ERROR("Command socket name too long");
return -1;
Expand All @@ -127,6 +135,8 @@ static const char *lxc_cmd_str(lxc_cmd_t cmd)
[LXC_CMD_GET_CLONE_FLAGS] = "get_clone_flags",
[LXC_CMD_GET_CGROUP] = "get_cgroup",
[LXC_CMD_GET_CONFIG_ITEM] = "get_config_item",
[LXC_CMD_GET_NAME] = "get_name",
[LXC_CMD_GET_LXCPATH] = "get_lxcpath",
};

if (cmd >= LXC_CMD_MAX)
Expand Down Expand Up @@ -259,7 +269,7 @@ static int lxc_cmd_rsp_send(int fd, struct lxc_cmd_rsp *rsp)
* returned in the cmd response structure.
*/
static int lxc_cmd(const char *name, struct lxc_cmd_rr *cmd, int *stopped,
const char *lxcpath)
const char *lxcpath, const char *hashed_sock_name)
{
int sock, ret = -1;
char path[sizeof(((struct sockaddr_un *)0)->sun_path)] = { 0 };
Expand All @@ -270,7 +280,7 @@ static int lxc_cmd(const char *name, struct lxc_cmd_rr *cmd, int *stopped,
*stopped = 0;

len = sizeof(path)-1;
if (fill_sock_name(offset, len, name, lxcpath))
if (fill_sock_name(offset, len, name, lxcpath, hashed_sock_name))
return -1;

sock = lxc_abstract_unix_connect(path);
Expand Down Expand Up @@ -329,7 +339,7 @@ int lxc_try_cmd(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_GET_INIT_PID },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);

if (stopped)
return 0;
Expand Down Expand Up @@ -369,7 +379,7 @@ pid_t lxc_cmd_get_init_pid(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_GET_INIT_PID },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return ret;

Expand Down Expand Up @@ -399,7 +409,7 @@ int lxc_cmd_get_clone_flags(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_GET_CLONE_FLAGS },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return ret;

Expand Down Expand Up @@ -438,7 +448,7 @@ char *lxc_cmd_get_cgroup_path(const char *name, const char *lxcpath,
},
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return NULL;

Expand Down Expand Up @@ -497,7 +507,7 @@ char *lxc_cmd_get_config_item(const char *name, const char *item,
},
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return NULL;

Expand Down Expand Up @@ -548,7 +558,7 @@ lxc_state_t lxc_cmd_get_state(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_GET_STATE }
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0 && stopped)
return STOPPED;

Expand Down Expand Up @@ -589,7 +599,7 @@ int lxc_cmd_stop(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_STOP },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0) {
if (stopped) {
INFO("'%s' is already stopped", name);
Expand Down Expand Up @@ -650,7 +660,7 @@ int lxc_cmd_console_winch(const char *name, const char *lxcpath)
.req = { .cmd = LXC_CMD_CONSOLE_WINCH },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return ret;

Expand Down Expand Up @@ -685,7 +695,7 @@ int lxc_cmd_console(const char *name, int *ttynum, int *fd, const char *lxcpath)
.req = { .cmd = LXC_CMD_CONSOLE, .data = INT_TO_PTR(*ttynum) },
};

ret = lxc_cmd(name, &cmd, &stopped, lxcpath);
ret = lxc_cmd(name, &cmd, &stopped, lxcpath, NULL);
if (ret < 0)
return ret;

Expand Down Expand Up @@ -744,7 +754,81 @@ static int lxc_cmd_console_callback(int fd, struct lxc_cmd_req *req,
return 1;
}

/*
* lxc_cmd_get_name: Returns the name of the container
*
* @hashed_sock_name: hashed socket name
*
* Returns the name on success, NULL on failure.
*/
char *lxc_cmd_get_name(const char *hashed_sock_name)
{
int ret, stopped;
struct lxc_cmd_rr cmd = {
.req = { .cmd = LXC_CMD_GET_NAME},
};

ret = lxc_cmd(NULL, &cmd, &stopped, NULL, hashed_sock_name);
if (ret < 0) {
return NULL;
}

if (cmd.rsp.ret == 0)
return cmd.rsp.data;
return NULL;
}

static int lxc_cmd_get_name_callback(int fd, struct lxc_cmd_req *req,
struct lxc_handler *handler)
{
struct lxc_cmd_rsp rsp;

memset(&rsp, 0, sizeof(rsp));

rsp.data = handler->name;
rsp.datalen = strlen(handler->name) + 1;
rsp.ret = 0;

return lxc_cmd_rsp_send(fd, &rsp);
}

/*
* lxc_cmd_get_lxcpath: Returns the lxcpath of the container
*
* @hashed_sock_name: hashed socket name
*
* Returns the lxcpath on success, NULL on failure.
*/
char *lxc_cmd_get_lxcpath(const char *hashed_sock_name)
{
int ret, stopped;
struct lxc_cmd_rr cmd = {
.req = { .cmd = LXC_CMD_GET_LXCPATH},
};

ret = lxc_cmd(NULL, &cmd, &stopped, NULL, hashed_sock_name);
if (ret < 0) {
return NULL;
}

if (cmd.rsp.ret == 0)
return cmd.rsp.data;
return NULL;
}

static int lxc_cmd_get_lxcpath_callback(int fd, struct lxc_cmd_req *req,
struct lxc_handler *handler)
{
struct lxc_cmd_rsp rsp;

memset(&rsp, 0, sizeof(rsp));

rsp.data = (char *)handler->lxcpath;
rsp.datalen = strlen(handler->lxcpath) + 1;
rsp.ret = 0;

return lxc_cmd_rsp_send(fd, &rsp);
}

static int lxc_cmd_process(int fd, struct lxc_cmd_req *req,
struct lxc_handler *handler)
Expand All @@ -760,6 +844,8 @@ static int lxc_cmd_process(int fd, struct lxc_cmd_req *req,
[LXC_CMD_GET_CLONE_FLAGS] = lxc_cmd_get_clone_flags_callback,
[LXC_CMD_GET_CGROUP] = lxc_cmd_get_cgroup_callback,
[LXC_CMD_GET_CONFIG_ITEM] = lxc_cmd_get_config_item_callback,
[LXC_CMD_GET_NAME] = lxc_cmd_get_name_callback,
[LXC_CMD_GET_LXCPATH] = lxc_cmd_get_lxcpath_callback,
};

if (req->cmd >= LXC_CMD_MAX) {
Expand Down Expand Up @@ -887,7 +973,7 @@ int lxc_cmd_init(const char *name, struct lxc_handler *handler,
int len;

len = sizeof(path)-1;
if (fill_sock_name(offset, len, name, lxcpath))
if (fill_sock_name(offset, len, name, lxcpath, NULL))
return -1;

fd = lxc_abstract_unix_open(path, SOCK_STREAM, 0);
Expand Down
4 changes: 4 additions & 0 deletions src/lxc/commands.h
View file
Expand Up @@ -41,6 +41,8 @@ typedef enum {
LXC_CMD_GET_CLONE_FLAGS,
LXC_CMD_GET_CGROUP,
LXC_CMD_GET_CONFIG_ITEM,
LXC_CMD_GET_NAME,
LXC_CMD_GET_LXCPATH,
LXC_CMD_MAX,
} lxc_cmd_t;

Expand Down Expand Up @@ -77,6 +79,8 @@ extern char *lxc_cmd_get_cgroup_path(const char *name, const char *lxcpath,
const char *subsystem);
extern int lxc_cmd_get_clone_flags(const char *name, const char *lxcpath);
extern char *lxc_cmd_get_config_item(const char *name, const char *item, const char *lxcpath);
extern char *lxc_cmd_get_name(const char *hashed_sock);
extern char *lxc_cmd_get_lxcpath(const char *hashed_sock);
extern pid_t lxc_cmd_get_init_pid(const char *name, const char *lxcpath);
extern lxc_state_t lxc_cmd_get_state(const char *name, const char *lxcpath);
extern int lxc_cmd_stop(const char *name, const char *lxcpath);
Expand Down
20 changes: 18 additions & 2 deletions src/lxc/lxccontainer.c
View file
Expand Up @@ -3571,6 +3571,7 @@ int list_active_containers(const char *lxcpath, char ***nret,
char **ct_name = NULL;
size_t len = 0;
struct lxc_container *c;
bool is_hashed;

if (!lxcpath)
lxcpath = lxc_global_config_value("lxc.lxcpath");
Expand All @@ -3586,16 +3587,25 @@ int list_active_containers(const char *lxcpath, char ***nret,
return -1;

while (getline(&line, &len, f) != -1) {

char *p = strrchr(line, ' '), *p2;
if (!p)
continue;
p++;
if (*p != 0x40)
continue;
p++;
if (strncmp(p, lxcpath, lxcpath_len) != 0)

is_hashed = false;
if (strncmp(p, lxcpath, lxcpath_len) == 0) {
p += lxcpath_len;
} else if (strncmp(p, "lxc/", 4) == 0) {
p += 4;
is_hashed = true;
} else {
continue;
p += lxcpath_len;
}

while (*p == '/')
p++;

Expand All @@ -3605,6 +3615,12 @@ int list_active_containers(const char *lxcpath, char ***nret,
continue;
*p2 = '\0';

if (is_hashed) {
if (strncmp(lxcpath, lxc_cmd_get_lxcpath(p), lxcpath_len) != 0)
continue;
p = lxc_cmd_get_name(p);
}

if (array_contains(&ct_name, p, ct_name_cnt))
continue;

Expand Down

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