lxc_clone: pass non-stack allocated stack to clone

[mirror_lxc.git] / src / lxc / namespace.c

diff --git a/src/lxc/namespace.c b/src/lxc/namespace.c
index d716676ed9391b790cee5f63b326622ce9ac2d9b..bc14fb52c91aaba4c03c6fb4396fca301fcf2a17 100644 (file)
--- a/src/lxc/namespace.c
+++ b/src/lxc/namespace.c
@@ -21,20 +21,26 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include <alloca.h>
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
 #include <errno.h>
 #include <fcntl.h>
+#include <sched.h>
 #include <signal.h>
-#include <unistd.h>
 #include <sys/param.h>
 #include <sys/stat.h>
+#include <sys/syscall.h>
 #include <sys/types.h>
+#include <unistd.h>
 
+#include "config.h"
 #include "log.h"
+#include "memory_utils.h"
 #include "namespace.h"
 #include "utils.h"
 
-lxc_log_define(lxc_namespace, lxc);
+lxc_log_define(namespace, lxc);
 
 struct clone_arg {
        int (*fn)(void *);
@@ -47,25 +53,29 @@ static int do_clone(void *arg)
        return clone_arg->fn(clone_arg->arg);
 }
 
-pid_t lxc_clone(int (*fn)(void *), void *arg, int flags)
+#define __LXC_STACK_SIZE 4096
+pid_t lxc_clone(int (*fn)(void *), void *arg, int flags, int *pidfd)
 {
+       pid_t ret;
        struct clone_arg clone_arg = {
-               .fn = fn,
-               .arg = arg,
+           .fn = fn,
+           .arg = arg,
        };
+       void *stack;
 
-       size_t stack_size = lxc_getpagesize();
-       void *stack = alloca(stack_size);
-       pid_t ret;
+       stack = malloc(__LXC_STACK_SIZE);
+       if (!stack) {
+               SYSERROR("Failed to allocate clone stack");
+               return -ENOMEM;
+       }
 
 #ifdef __ia64__
-       ret = __clone2(do_clone, stack,
-                      stack_size, flags | SIGCHLD, &clone_arg);
+       ret = __clone2(fn, stack, __LXC_STACK_SIZE, flags | SIGCHLD, &clone_arg, pidfd);
 #else
-       ret = clone(do_clone, stack  + stack_size, flags | SIGCHLD, &clone_arg);
+       ret = clone(fn, stack + __LXC_STACK_SIZE, flags | SIGCHLD, &clone_arg, pidfd);
 #endif
        if (ret < 0)
-               ERROR("Failed to clone (%#x): %s.", flags, strerror(errno));
+               SYSERROR("Failed to clone (%#x)", flags);
 
        return ret;
 }
@@ -99,6 +109,7 @@ const struct ns_info ns_info[LXC_NS_MAX] = {
 int lxc_namespace_2_cloneflag(const char *namespace)
 {
        int i;
+
        for (i = 0; i < LXC_NS_MAX; i++)
                if (!strcasecmp(ns_info[i].proc_name, namespace))
                        return ns_info[i].clone_flag;
@@ -110,6 +121,7 @@ int lxc_namespace_2_cloneflag(const char *namespace)
 int lxc_namespace_2_ns_idx(const char *namespace)
 {
        int i;
+
        for (i = 0; i < LXC_NS_MAX; i++)
                if (!strcmp(ns_info[i].proc_name, namespace))
                        return i;
@@ -118,9 +130,43 @@ int lxc_namespace_2_ns_idx(const char *namespace)
        return -EINVAL;
 }
 
+extern int lxc_namespace_2_std_identifiers(char *namespaces)
+{
+       char **it;
+       char *del;
+
+       /* The identifiers for namespaces used with lxc-attach and lxc-unshare
+        * as given on the manpage do not align with the standard identifiers.
+        * This affects network, mount, and uts namespaces. The standard identifiers
+        * are: "mnt", "uts", and "net" whereas lxc-attach and lxc-unshare uses
+        * "MOUNT", "UTSNAME", and "NETWORK". So let's use some cheap memmove()s
+        * to replace them by their standard identifiers.
+        * Let's illustrate this with an example:
+        * Assume the string:
+        *
+        *      "IPC|MOUNT|PID"
+        *
+        * then we memmove()
+        *
+        *      dest: del + 1 == OUNT|PID
+        *      src:  del + 3 == NT|PID
+        */
+       if (!namespaces)
+               return -1;
+
+       while ((del = strstr(namespaces, "MOUNT")))
+               memmove(del + 1, del + 3, strlen(del) - 2);
+
+       for (it = (char *[]){"NETWORK", "UTSNAME", NULL}; it && *it; it++)
+               while ((del = strstr(namespaces, *it)))
+                       memmove(del + 3, del + 7, strlen(del) - 6);
+
+       return 0;
+}
+
 int lxc_fill_namespace_flags(char *flaglist, int *flags)
 {
-       char *token, *saveptr = NULL;
+       char *token;
        int aflag;
 
        if (!flaglist) {
@@ -128,16 +174,13 @@ int lxc_fill_namespace_flags(char *flaglist, int *flags)
                return -1;
        }
 
-       token = strtok_r(flaglist, "|", &saveptr);
-       while (token) {
-
+       lxc_iterate_parts(token, flaglist, "|") {
                aflag = lxc_namespace_2_cloneflag(token);
                if (aflag < 0)
                        return -1;
 
                *flags |= aflag;
-
-               token = strtok_r(NULL, "|", &saveptr);
        }
+
        return 0;
 }