raw_syscalls: add lxc_raw_clone{_cb}()

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

diff --git a/src/lxc/namespace.h b/src/lxc/namespace.h
index 4916950c15d2a0e935cafd610f140ae2fcd7ed75..be2bf8b7133281abd58cb6dd486152ec96b11c2a 100644 (file)
--- a/src/lxc/namespace.h
+++ b/src/lxc/namespace.h
@@ -23,10 +23,41 @@
 #ifndef __LXC_NAMESPACE_H
 #define __LXC_NAMESPACE_H
 
-#include <sys/syscall.h>
 #include <sched.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#ifndef CLONE_PARENT_SETTID
+#define CLONE_PARENT_SETTID 0x00100000
+#endif
+
+#ifndef CLONE_CHILD_CLEARTID
+#define CLONE_CHILD_CLEARTID 0x00200000
+#endif
+
+#ifndef CLONE_CHILD_SETTID
+#define CLONE_CHILD_SETTID 0x01000000
+#endif
+
+#ifndef CLONE_VFORK
+#define CLONE_VFORK 0x00004000
+#endif
+
+#ifndef CLONE_THREAD
+#define CLONE_THREAD 0x00010000
+#endif
 
-#include "config.h"
+#ifndef CLONE_SETTLS
+#define CLONE_SETTLS 0x00080000
+#endif
+
+#ifndef CLONE_VM
+#define CLONE_VM 0x00000100
+#endif
+
+#ifndef CLONE_FILES
+#define CLONE_FILES 0x00000400
+#endif
 
 #ifndef CLONE_FS
 #  define CLONE_FS                0x00000200
@@ -68,6 +99,7 @@ extern const struct ns_info {
        const char *proc_name;
        int clone_flag;
        const char *flag_name;
+       const char *env_name;
 } ns_info[LXC_NS_MAX];
 
 #if defined(__ia64__)
@@ -79,9 +111,42 @@ int clone(int (*fn)(void *), void *child_stack,
        /* pid_t *ptid, struct user_desc *tls, pid_t *ctid */ );
 #endif
 
+/**
+ * lxc_clone() - create a new process
+ *
+ * - allocate stack:
+ *   This function allocates a new stack the size of page and passes it to the
+ *   kernel.
+ *
+ * - support all CLONE_*flags:
+ *   This function supports all CLONE_* flags. If in doubt or not sufficiently
+ *   familiar with process creation in the kernel and interactions with libcs
+ *   this function should be used.
+ *
+ * - pthread_atfork() handlers depending on libc:
+ *   Whether this function runs pthread_atfork() handlers depends on the
+ *   corresponding libc wrapper. glibc currently does not run pthread_atfork()
+ *   handlers but does not guarantee that they are not. Other libcs might or
+ *   might not run pthread_atfork() handlers. If you require guarantees please
+ *   refer to the lxc_raw_clone*() functions in raw_syscalls.{c,h}.
+ *
+ * - should call lxc_raw_getpid():
+ *   The child should use lxc_raw_getpid() to retrieve its pid.
+ */
 extern pid_t lxc_clone(int (*fn)(void *), void *arg, int flags);
 
-extern int lxc_namespace_2_cloneflag(char *namespace);
+extern int lxc_namespace_2_cloneflag(const char *namespace);
+extern int lxc_namespace_2_ns_idx(const char *namespace);
+extern int lxc_namespace_2_std_identifiers(char *namespaces);
 extern int lxc_fill_namespace_flags(char *flaglist, int *flags);
 
+/**
+ * Because of older glibc's pid cache (up to 2.25) whenever clone() is called
+ * the child must must retrieve it's own pid via lxc_raw_getpid().
+ */
+static inline pid_t lxc_raw_getpid(void)
+{
+       return (pid_t) syscall(SYS_getpid);
+}
+
 #endif