path: root/tools/libxl/libxl_internal.h

/*
 * Copyright (C) 2009      Citrix Ltd.
 * Author Vincent Hanquez <vincent.hanquez@eu.citrix.com>
 * Author Stefano Stabellini <stefano.stabellini@eu.citrix.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; version 2.1 only. with the special
 * exception on linking described in file LICENSE.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 */

#ifndef LIBXL_INTERNAL_H
#define LIBXL_INTERNAL_H

#include "libxl_osdeps.h" /* must come before any other headers */

#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>

#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <xs.h>
#include <xenctrl.h>

#include "xentoollog.h"

#include <xen/io/xenbus.h>

#include "libxl.h"
#include "_libxl_paths.h"

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)
#define _hidden __attribute__((visibility("hidden")))
#define _protected __attribute__((visibility("protected")))
#else
#define _hidden
#define _protected
#endif

#include "flexarray.h"
#include "libxl_utils.h"

#include "libxl_json.h"

#include "_libxl_types_internal.h"
#include "_libxl_types_internal_json.h"

#define LIBXL_DESTROY_TIMEOUT 10
#define LIBXL_DEVICE_MODEL_START_TIMEOUT 10
#define LIBXL_XENCONSOLE_LIMIT 1048576
#define LIBXL_XENCONSOLE_PROTOCOL "vt100"
#define LIBXL_MAXMEM_CONSTANT 1024
#define LIBXL_PV_EXTRA_MEMORY 1024
#define LIBXL_HVM_EXTRA_MEMORY 2048
#define LIBXL_MIN_DOM0_MEM (128*1024)
#define QEMU_SIGNATURE "DeviceModelRecord0002"
#define STUBDOM_CONSOLE_LOGGING 0
#define STUBDOM_CONSOLE_SAVE 1
#define STUBDOM_CONSOLE_RESTORE 2
#define STUBDOM_CONSOLE_SERIAL 3
#define STUBDOM_SPECIAL_CONSOLES 3
#define TAP_DEVICE_SUFFIX "-emu"

#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

#define LIBXL__LOGGING_ENABLED

#ifdef LIBXL__LOGGING_ENABLED
#define LIBXL__LOG(ctx, loglevel, _f, _a...)   libxl__log(ctx, loglevel, -1, __FILE__, __LINE__, __func__, _f, ##_a)
#define LIBXL__LOG_ERRNO(ctx, loglevel, _f, _a...)   libxl__log(ctx, loglevel, errno, __FILE__, __LINE__, __func__, _f, ##_a)
#define LIBXL__LOG_ERRNOVAL(ctx, loglevel, errnoval, _f, _a...)   libxl__log(ctx, loglevel, errnoval, __FILE__, __LINE__, __func__, _f, ##_a)
#else
#define LIBXL__LOG(ctx, loglevel, _f, _a...)
#define LIBXL__LOG_ERRNO(ctx, loglevel, _f, _a...)
#define LIBXL__LOG_ERRNOVAL(ctx, loglevel, errnoval, _f, _a...)
#endif
  /* all of these macros preserve errno (saving and restoring) */

/* logging */
_hidden void libxl__logv(libxl_ctx *ctx, xentoollog_level msglevel, int errnoval,
             const char *file /* may be 0 */, int line /* ignored if !file */,
             const char *func /* may be 0 */,
             const char *fmt, va_list al)
     __attribute__((format(printf,7,0)));

_hidden void libxl__log(libxl_ctx *ctx, xentoollog_level msglevel, int errnoval,
            const char *file /* may be 0 */, int line /* ignored if !file */,
            const char *func /* may be 0 */,
            const char *fmt, ...)
     __attribute__((format(printf,7,8)));

     /* these functions preserve errno (saving and restoring) */

typedef struct libxl__gc libxl__gc;
typedef struct libxl__egc libxl__egc;
typedef struct libxl__ao libxl__ao;

_hidden void libxl__alloc_failed(libxl_ctx *, const char *func,
                         size_t nmemb, size_t size) __attribute__((noreturn));
  /* func, size and nmemb are used only in the log message.
   * You may pass size==0 if size and nmemb are not meaningful
   * and should not be printed. */

typedef struct libxl__ev_fd libxl__ev_fd;
typedef void libxl__ev_fd_callback(libxl__egc *egc, libxl__ev_fd *ev,
                                   int fd, short events, short revents);
  /* Note that revents may contain POLLERR or POLLHUP regardless of
   * events; otherwise revents contains only bits in events.  Contrary
   * to the documentation for poll(2), POLLERR and POLLHUP can occur
   * even if only POLLIN was set in events.  (POLLNVAL is a fatal
   * error and will cause libxl event machinery to fail an assertion.)
   *
   * It is not permitted to listen for the same or overlapping events
   * on the same fd using multiple different libxl__ev_fd's.
   */
struct libxl__ev_fd {
    /* caller should include this in their own struct */
    /* read-only for caller, who may read only when registered: */
    int fd;
    short events;
    libxl__ev_fd_callback *func;
    /* remainder is private for libxl__ev_fd... */
    LIBXL_LIST_ENTRY(libxl__ev_fd) entry;
    void *for_app_reg;
};


typedef struct libxl__ev_time libxl__ev_time;
typedef void libxl__ev_time_callback(libxl__egc *egc, libxl__ev_time *ev,
                                     const struct timeval *requested_abs);
struct libxl__ev_time {
    /* caller should include this in their own struct */
    /* read-only for caller, who may read only when registered: */
    libxl__ev_time_callback *func;
    /* remainder is private for libxl__ev_time... */
    int infinite; /* not registered in list or with app if infinite */
    LIBXL_TAILQ_ENTRY(libxl__ev_time) entry;
    struct timeval abs;
    void *for_app_reg;
};

typedef struct libxl__ev_xswatch libxl__ev_xswatch;
typedef void libxl__ev_xswatch_callback(libxl__egc *egc, libxl__ev_xswatch*,
                            const char *watch_path, const char *event_path);
struct libxl__ev_xswatch {
    /* caller should include this in their own struct */
    /* read-only for caller, who may read only when registered: */
    char *path;
    libxl__ev_xswatch_callback *callback;
    /* remainder is private for libxl__ev_xswatch... */
    int slotnum; /* registered iff slotnum >= 0 */
    uint32_t counterval;
};

/*
 * An entry in the watch_slots table is either:
 *  1. an entry in the free list, ie NULL or pointer to next free list entry
 *  2. an pointer to a libxl__ev_xswatch
 *
 * But we don't want to use unions or type-punning because the
 * compiler might "prove" that our code is wrong and misoptimise it.
 *
 * The rules say that all struct pointers have identical
 * representation and alignment requirements (C99+TC1+TC2 6.2.5p26) so
 * what we do is simply declare our array as containing only the free
 * list pointers, and explicitly convert from and to our actual
 * xswatch pointers when we store and retrieve them.
 */
typedef struct libxl__ev_watch_slot {
    LIBXL_SLIST_ENTRY(struct libxl__ev_watch_slot) empty;
} libxl__ev_watch_slot;
    
_hidden libxl__ev_xswatch *libxl__watch_slot_contents(libxl__gc *gc,
                                                      int slotnum);


/*
 * evgen structures, which are the state we use for generating
 * events for the caller.
 *
 * In general in each case there's an internal and an external
 * version of the _evdisable_FOO function; the internal one is
 * used during cleanup.
 */
struct libxl__evgen_domain_death {
    uint32_t domid;
    unsigned shutdown_reported:1, death_reported:1;
    LIBXL_TAILQ_ENTRY(libxl_evgen_domain_death) entry;
        /* on list .death_reported ? CTX->death_list : CTX->death_reported */
    libxl_ev_user user;
};
_hidden void
libxl__evdisable_domain_death(libxl__gc*, libxl_evgen_domain_death*);

struct libxl__evgen_disk_eject {
    libxl__ev_xswatch watch;
    uint32_t domid;
    LIBXL_LIST_ENTRY(libxl_evgen_disk_eject) entry;
    libxl_ev_user user;
    char *vdev;
};
_hidden void
libxl__evdisable_disk_eject(libxl__gc*, libxl_evgen_disk_eject*);

typedef struct libxl__poller libxl__poller;
struct libxl__poller {
    /*
     * These are used to allow other threads to wake up a thread which
     * may be stuck in poll, because whatever it was waiting for
     * hadn't happened yet.  Threads which generate events will write
     * a byte to each pipe.  A thread which is waiting will empty its
     * own pipe, and put its poller on the pollers_event list, before
     * releasing the ctx lock and going into poll; when it comes out
     * of poll it will take the poller off the pollers_event list.
     *
     * A thread which is waiting for completion of a synchronous ao
     * will allocate a poller and record it in the ao, so that other
     * threads can wake it up.
     *
     * When a thread is done with a poller it should put it onto
     * pollers_idle, where it can be reused later.
     *
     * The "poller_app" is never idle, but is sometimes on
     * pollers_event.
     */
    LIBXL_LIST_ENTRY(libxl__poller) entry;

    struct pollfd *fd_polls;
    int fd_polls_allocd;

    int fd_rindices_allocd;
    int (*fd_rindices)[3]; /* see libxl_osevent_beforepoll */

    int wakeup_pipe[2]; /* 0 means no fd allocated */
};

struct libxl__ctx {
    xentoollog_logger *lg;
    xc_interface *xch;
    struct xs_handle *xsh;

    const libxl_event_hooks *event_hooks;
    void *event_hooks_user;

    pthread_mutex_t lock; /* protects data structures hanging off the ctx */
      /* Always use libxl__ctx_lock and _unlock (or the convenience
       * macors CTX_LOCK and CTX_UNLOCK) to manipulate this.
       *
       * You may acquire this mutex recursively if it is convenient to
       * do so.  You may not acquire this lock at the same time as any
       * other lock.  If you need to call application code outside
       * libxl (ie, a callback) with this lock held then it is
       * necessaray to impose restrictions on the caller to maintain a
       * proper lock hierarchy, and these restrictions must then be
       * documented in the libxl public interface.
       */

    LIBXL_TAILQ_HEAD(libxl__event_list, libxl_event) occurred;

    int osevent_in_hook;
    const libxl_osevent_hooks *osevent_hooks;
    void *osevent_user;
      /* See the comment for OSEVENT_HOOK_INTERN in libxl_event.c
       * for restrictions on the use of the osevent fields. */

    libxl__poller poller_app; /* libxl_osevent_beforepoll and _afterpoll */
    LIBXL_LIST_HEAD(, libxl__poller) pollers_event, pollers_idle;

    LIBXL_LIST_HEAD(, libxl__ev_fd) efds;
    LIBXL_TAILQ_HEAD(, libxl__ev_time) etimes;

    libxl__ev_watch_slot *watch_slots;
    int watch_nslots;
    LIBXL_SLIST_HEAD(, libxl__ev_watch_slot) watch_freeslots;
    uint32_t watch_counter; /* helps disambiguate slot reuse */
    libxl__ev_fd watch_efd;

    LIBXL_TAILQ_HEAD(libxl__evgen_domain_death_list, libxl_evgen_domain_death)
        death_list /* sorted by domid */,
        death_reported;
    libxl__ev_xswatch death_watch;
    
    LIBXL_LIST_HEAD(, libxl_evgen_disk_eject) disk_eject_evgens;

    /* for callers who reap children willy-nilly; caller must only
     * set this after libxl_init and before any other call - or
     * may leave them untouched */
    int (*waitpid_instead)(pid_t pid, int *status, int flags);
    libxl_version_info version_info;
};

typedef struct {
    uint32_t backend_devid;
    uint32_t backend_domid;
    uint32_t devid;
    uint32_t domid;
    libxl__device_kind backend_kind;
    libxl__device_kind kind;
} libxl__device;

#define XC_PCI_BDF             "0x%x, 0x%x, 0x%x, 0x%x"
#define PCI_DEVFN(slot, func)   ((((slot) & 0x1f) << 3) | ((func) & 0x07))
#define PCI_SLOT(devfn)         (((devfn) >> 3) & 0x1f)
#define PCI_FUNC(devfn)         ((devfn) & 0x07)
#define AUTO_PHP_SLOT          0x100
#define SYSFS_PCI_DEV          "/sys/bus/pci/devices"
#define SYSFS_PCIBACK_DRIVER   "/sys/bus/pci/drivers/pciback"
#define XENSTORE_PID_FILE      "/var/run/xenstored.pid"

#define PROC_PCI_NUM_RESOURCES 7
#define PCI_BAR_IO             0x01

#define PRINTF_ATTRIBUTE(x, y) __attribute__((format(printf, x, y)))

struct libxl__gc {
    /* mini-GC */
    int alloc_maxsize;
    void **alloc_ptrs;
    libxl_ctx *owner;
};

struct libxl__egc {
    /* for event-generating functions only */
    struct libxl__gc gc;
    struct libxl__event_list occurred_for_callback;
    LIBXL_TAILQ_HEAD(, libxl__ao) aos_for_callback;
};

#define LIBXL__AO_MAGIC              0xA0FACE00ul
#define LIBXL__AO_MAGIC_DESTROYED    0xA0DEAD00ul

struct libxl__ao {
    uint32_t magic;
    unsigned constructing:1, in_initiator:1, complete:1, notified:1;
    int rc;
    libxl__gc gc;
    libxl_asyncop_how how;
    libxl__poller *poller;
    uint32_t domid;
    LIBXL_TAILQ_ENTRY(libxl__ao) entry_for_callback;
};

#define LIBXL_INIT_GC(gc,ctx) do{               \
        (gc).alloc_maxsize = 0;                 \
        (gc).alloc_ptrs = 0;                    \
        (gc).owner = (ctx);                     \
    } while(0)

static inline libxl_ctx *libxl__gc_owner(libxl__gc *gc)
{
    return gc->owner;
}

/*
 * Memory allocation tracking/helpers
 *
 * See comment "libxl memory management" in libxl.h for a description
 * of the framework which these calls belong to.
 *
 * These functions deal with memory allocations of type (a) and (d) in
 * that description.
 *
 * All pointers returned by these functions are registered for garbage
 * collection on exit from the outermost libxl callframe.
 *
 * However, where the argument is stated to be "gc_opt", NULL may be
 * passed instead, in which case no garbage collection will occur; the
 * pointer must later be freed with free().  This is for memory
 * allocations of types (b) and (c).
 */
/* register @ptr in @gc for free on exit from outermost libxl callframe. */
_hidden void libxl__ptr_add(libxl__gc *gc_opt, void *ptr);
/* if this is the outermost libxl callframe then free all pointers in @gc */
_hidden void libxl__free_all(libxl__gc *gc);
/* allocate and zero @bytes. (similar to a gc'd malloc(3)+memzero()) */
_hidden void *libxl__zalloc(libxl__gc *gc_opt, int bytes);
/* allocate and zero memory for an array of @nmemb members of @size each.
 * (similar to a gc'd calloc(3)). */
_hidden void *libxl__calloc(libxl__gc *gc_opt, size_t nmemb, size_t size);
/* change the size of the memory block pointed to by @ptr to @new_size bytes.
 * unlike other allocation functions here any additional space between the
 * oldsize and @new_size is not initialised (similar to a gc'd realloc(3)). */
_hidden void *libxl__realloc(libxl__gc *gc_opt, void *ptr, size_t new_size);
/* print @fmt into an allocated string large enoughto contain the result.
 * (similar to gc'd asprintf(3)). */
_hidden char *libxl__sprintf(libxl__gc *gc_opt, const char *fmt, ...) PRINTF_ATTRIBUTE(2, 3);
/* duplicate the string @c (similar to a gc'd strdup(3)). */
_hidden char *libxl__strdup(libxl__gc *gc_opt, const char *c);
/* duplicate at most @n bytes of string @c (similar to a gc'd strndup(3)). */
_hidden char *libxl__strndup(libxl__gc *gc_opt, const char *c, size_t n);
/* strip the last path component from @s and return as a newly allocated
 * string. (similar to a gc'd dirname(3)). */
_hidden char *libxl__dirname(libxl__gc *gc_opt, const char *s);

_hidden char **libxl__xs_kvs_of_flexarray(libxl__gc *gc, flexarray_t *array, int length);

_hidden int libxl__xs_writev(libxl__gc *gc, xs_transaction_t t,
                             const char *dir, char **kvs);
_hidden int libxl__xs_write(libxl__gc *gc, xs_transaction_t t,
               const char *path, const char *fmt, ...) PRINTF_ATTRIBUTE(4, 5);
   /* Each fn returns 0 on success.
    * On error: returns -1, sets errno (no logging) */

_hidden char *libxl__xs_get_dompath(libxl__gc *gc, uint32_t domid);
   /* On error: logs, returns NULL, sets errno. */

_hidden char *libxl__xs_read(libxl__gc *gc, xs_transaction_t t,
                             const char *path);
_hidden char **libxl__xs_directory(libxl__gc *gc, xs_transaction_t t,
                                   const char *path, unsigned int *nb);
   /* On error: returns NULL, sets errno (no logging) */
_hidden bool libxl__xs_mkdir(libxl__gc *gc, xs_transaction_t t,
                             const char *path, struct xs_permissions *perms,
			     unsigned int num_perms);

_hidden char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid);


/*
 * Event generation functions provided by the libxl event core to the
 * rest of libxl.  Implemented in terms of _beforepoll/_afterpoll
 * and/or the fd registration machinery, as provided by the
 * application.
 *
 * Semantics are similar to those of the fd and timeout registration
 * functions provided to libxl_osevent_register_hooks.
 *
 * Non-0 returns from libxl__ev_{modify,deregister} have already been
 * logged by the core and should be returned unmodified to libxl's
 * caller; NB that they may be valid libxl error codes but they may
 * also be positive numbers supplied by the caller.
 *
 * In each case, there is a libxl__ev_FOO structure which can be in
 * one of three states:
 *
 *   Undefined   - Might contain anything.  All-bits-zero is
 *                 an undefined state.
 *
 *   Idle        - Struct contents are defined enough to pass to any
 *                 libxl__ev_FOO function but not registered and
 *                 callback will not be called.  The struct does not
 *                 contain references to any allocated resources so
 *                 can be thrown away.
 *
 *   Active      - Request for events has been registered and events
 *                 may be generated.  _deregister must be called to
 *                 reclaim resources.
 *
 * These functions are provided for each kind of event KIND:
 *
 *   int libxl__ev_KIND_register(libxl__gc *gc, libxl__ev_KIND *GEN,
 *                              libxl__ev_KIND_callback *FUNC,
 *                              DETAILS);
 *      On entry *GEN must be in state Undefined or Idle.
 *      Returns a libxl error code; on error return *GEN is Idle.
 *      On successful return *GEN is Active and FUNC wil be
 *      called by the event machinery in future.  FUNC will
 *      not be called from within the call to _register.
 *      FUNC will be called with the context locked (with CTX_LOCK).
 *
 *  void libxl__ev_KIND_deregister(libxl__gc *gc, libxl__ev_KIND *GEN_upd);
 *      On entry *GEN must be in state Active or Idle.
 *      On return it is Idle.  (Idempotent.)
 *
 *  void libxl__ev_KIND_init(libxl__ev_KIND *GEN);
 *      Provided for initialising an Undefined KIND.
 *      On entry *GEN must be in state Idle or Undefined.
 *      On return it is Idle.  (Idempotent.)
 *
 *  int libxl__ev_KIND_isregistered(const libxl__ev_KIND *GEN);
 *      On entry *GEN must be Idle or Active.
 *      Returns nonzero if it is Active, zero otherwise.
 *      Cannot fail.
 *
 *  int libxl__ev_KIND_modify(libxl__gc*, libxl__ev_KIND *GEN,
 *                            DETAILS);
 *      Only provided for some kinds of generator.
 *      On entry *GEN must be Active and on return, whether successful
 *      or not, it will be Active.
 *      Returns a libxl error code; on error the modification
 *      is not effective.
 *
 * All of these functions are fully threadsafe and may be called by
 * general code in libxl even from within event callback FUNCs.
 * The ctx will be locked on entry to each FUNC and FUNC should not
 * unlock it.
 *
 * Callers of libxl__ev_KIND_register must ensure that the
 * registration is undone, with _deregister, in libxl_ctx_free.
 * This means that normally each kind of libxl__evgen (ie each
 * application-requested event source) needs to be on a list so that
 * it can be automatically deregistered as promised in libxl_event.h.
 */


_hidden int libxl__ev_fd_register(libxl__gc*, libxl__ev_fd *ev_out,
                                  libxl__ev_fd_callback*,
                                  int fd, short events /* as for poll(2) */);
_hidden int libxl__ev_fd_modify(libxl__gc*, libxl__ev_fd *ev,
                                short events);
_hidden void libxl__ev_fd_deregister(libxl__gc*, libxl__ev_fd *ev);
static inline void libxl__ev_fd_init(libxl__ev_fd *efd)
                    { efd->fd = -1; }
static inline int libxl__ev_fd_isregistered(libxl__ev_fd *efd)
                    { return efd->fd >= 0; }

_hidden int libxl__ev_time_register_rel(libxl__gc*, libxl__ev_time *ev_out,
                                        libxl__ev_time_callback*,
                                        int milliseconds /* as for poll(2) */);
_hidden int libxl__ev_time_register_abs(libxl__gc*, libxl__ev_time *ev_out,
                                        libxl__ev_time_callback*,
                                        struct timeval);
_hidden int libxl__ev_time_modify_rel(libxl__gc*, libxl__ev_time *ev,
                                      int milliseconds /* as for poll(2) */);
_hidden int libxl__ev_time_modify_abs(libxl__gc*, libxl__ev_time *ev,
                                      struct timeval);
_hidden void libxl__ev_time_deregister(libxl__gc*, libxl__ev_time *ev);
static inline void libxl__ev_time_init(libxl__ev_time *ev)
                { ev->func = 0; }
static inline int libxl__ev_time_isregistered(libxl__ev_time *ev)
                { return !!ev->func; }


_hidden int libxl__ev_xswatch_register(libxl__gc*, libxl__ev_xswatch *xsw_out,
                                       libxl__ev_xswatch_callback*,
                                       const char *path /* copied */);
_hidden void libxl__ev_xswatch_deregister(libxl__gc *gc, libxl__ev_xswatch*);

static inline void libxl__ev_xswatch_init(libxl__ev_xswatch *xswatch_out)
                { xswatch_out->slotnum = -1; }
static inline int libxl__ev_xswatch_isregistered(const libxl__ev_xswatch *xw)
                { return xw->slotnum >= 0; }


/*
 * Other event-handling support provided by the libxl event core to
 * the rest of libxl.
 */

_hidden void libxl__event_occurred(libxl__egc*, libxl_event *event);
  /* Arranges to notify the application that the event has occurred.
   * event should be suitable for passing to libxl_event_free. */

_hidden libxl_event *libxl__event_new(libxl__egc*, libxl_event_type,
                                      uint32_t domid);
  /* Convenience function.
   * Allocates a new libxl_event, fills in domid and type.
   * If allocation fails, calls _disaster, and returns NULL. */

#define NEW_EVENT(egc, type, domid)                              \
    libxl__event_new((egc), LIBXL_EVENT_TYPE_##type, (domid));
    /* Convenience macro. */

/*
 * In general, call this via the macro LIBXL__EVENT_DISASTER.
 *
 * Event-generating functions may call this if they might have wanted
 * to generate an event (either an internal one ie a
 * libxl__ev_FOO_callback or an application event), but are prevented
 * from doing so due to eg lack of memory.
 *
 * NB that this function may return and the caller isn't supposed to
 * then crash, although it may fail (and henceforth leave things in a
 * state where many or all calls fail).
 */
_hidden void libxl__event_disaster(libxl__egc*, const char *msg, int errnoval,
                                   libxl_event_type type /* may be 0 */,
                                   const char *file, int line,
                                   const char *func);
#define LIBXL__EVENT_DISASTER(egc, msg, errnoval, type) \
    libxl__event_disaster(egc, msg, errnoval, type, __FILE__,__LINE__,__func__)


/* Fills in, or disposes of, the resources held by, a poller whose
 * space the caller has allocated.  ctx must be locked. */
_hidden int libxl__poller_init(libxl_ctx *ctx, libxl__poller *p);
_hidden void libxl__poller_dispose(libxl__poller *p);

/* Obtain a fresh poller from malloc or the idle list, and put it
 * away again afterwards.  _get can fail, returning NULL.
 * ctx must be locked. */
_hidden libxl__poller *libxl__poller_get(libxl_ctx *ctx);
_hidden void libxl__poller_put(libxl_ctx *ctx, libxl__poller *p);

/* Notifies whoever is polling using p that they should wake up.
 * ctx must be locked. */
_hidden void libxl__poller_wakeup(libxl__egc *egc, libxl__poller *p);


_hidden int libxl__atfork_init(libxl_ctx *ctx);


/* from xl_dom */
_hidden libxl_domain_type libxl__domain_type(libxl__gc *gc, uint32_t domid);
_hidden int libxl__domain_shutdown_reason(libxl__gc *gc, uint32_t domid);
_hidden int libxl__sched_set_params(libxl__gc *gc, uint32_t domid, libxl_sched_params *scparams);
#define LIBXL__DOMAIN_IS_TYPE(gc, domid, type) \
    libxl__domain_type((gc), (domid)) == LIBXL_DOMAIN_TYPE_##type
typedef struct {
    uint32_t store_port;
    uint32_t store_domid;
    unsigned long store_mfn;

    uint32_t console_port;
    uint32_t console_domid;
    unsigned long console_mfn;

    unsigned long vm_generationid_addr;

    char *saved_state;
} libxl__domain_build_state;

_hidden int libxl__build_pre(libxl__gc *gc, uint32_t domid,
              libxl_domain_build_info *info, libxl__domain_build_state *state);
_hidden int libxl__build_post(libxl__gc *gc, uint32_t domid,
               libxl_domain_build_info *info, libxl__domain_build_state *state,
               char **vms_ents, char **local_ents);

_hidden int libxl__build_pv(libxl__gc *gc, uint32_t domid,
             libxl_domain_build_info *info, libxl__domain_build_state *state);
_hidden int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
              libxl_domain_build_info *info,
              libxl__domain_build_state *state);

_hidden int libxl__qemu_traditional_cmd(libxl__gc *gc, uint32_t domid,
                                        const char *cmd);
_hidden int libxl__domain_rename(libxl__gc *gc, uint32_t domid,
                                 const char *old_name, const char *new_name,
                                 xs_transaction_t trans);

_hidden int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
                                         libxl_domain_build_info *info,
                                         libxl__domain_build_state *state,
                                         int fd);
_hidden int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
                                         libxl_domain_type type,
                                         int live, int debug);
_hidden const char *libxl__device_model_savefile(libxl__gc *gc, uint32_t domid);
_hidden int libxl__domain_save_device_model(libxl__gc *gc, uint32_t domid, int fd);
_hidden void libxl__userdata_destroyall(libxl__gc *gc, uint32_t domid);

_hidden int libxl__domain_pvcontrol_available(libxl__gc *gc, uint32_t domid);
_hidden char * libxl__domain_pvcontrol_read(libxl__gc *gc,
                                            xs_transaction_t t, uint32_t domid);
_hidden int libxl__domain_pvcontrol_write(libxl__gc *gc, xs_transaction_t t,
                                          uint32_t domid, const char *cmd);

/* from xl_device */
_hidden char *libxl__device_disk_string_of_backend(libxl_disk_backend backend);
_hidden char *libxl__device_disk_string_of_format(libxl_disk_format format);
_hidden int libxl__device_disk_set_backend(libxl__gc*, libxl_device_disk*);

_hidden int libxl__device_physdisk_major_minor(const char *physpath, int *major, int *minor);
_hidden int libxl__device_disk_dev_number(const char *virtpath,
                                          int *pdisk, int *ppartition);

_hidden int libxl__device_console_add(libxl__gc *gc, uint32_t domid,
                                      libxl__device_console *console,
                                      libxl__domain_build_state *state);

_hidden int libxl__device_generic_add(libxl__gc *gc, libxl__device *device,
                             char **bents, char **fents);
_hidden char *libxl__device_backend_path(libxl__gc *gc, libxl__device *device);
_hidden char *libxl__device_frontend_path(libxl__gc *gc, libxl__device *device);
_hidden int libxl__parse_backend_path(libxl__gc *gc, const char *path,
                                      libxl__device *dev);
_hidden int libxl__device_destroy(libxl__gc *gc, libxl__device *dev);
_hidden int libxl__devices_destroy(libxl__gc *gc, uint32_t domid);
_hidden int libxl__wait_for_backend(libxl__gc *gc, char *be_path, char *state);

/*
 * For each aggregate type which can be used as an input we provide:
 *
 * int libxl__<type>_setdefault(gc, <type> *p):
 *
 *     Idempotently sets any members of "p" which is currently set to
 *     a special value indicating that the defaults should be used
 *     (per libxl_<type>_init) to a specific value.
 *
 *     All libxl API functions are expected to have arranged for this
 *     to be called before using any values within these structures.
 */
_hidden int libxl__domain_create_info_setdefault(libxl__gc *gc,
                                        libxl_domain_create_info *c_info);
_hidden int libxl__domain_build_info_setdefault(libxl__gc *gc,
                                        libxl_domain_build_info *b_info);
_hidden int libxl__device_disk_setdefault(libxl__gc *gc,
                                          libxl_device_disk *disk);
_hidden int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic);
_hidden int libxl__device_vfb_setdefault(libxl__gc *gc, libxl_device_vfb *vfb);
_hidden int libxl__device_vkb_setdefault(libxl__gc *gc, libxl_device_vkb *vkb);
_hidden int libxl__device_pci_setdefault(libxl__gc *gc, libxl_device_pci *pci);

_hidden const char *libxl__device_nic_devname(libxl__gc *gc,
                                              uint32_t domid,
                                              uint32_t devid,
                                              libxl_nic_type type);

/* Arranges that dev will be removed from its guest.  When
 * this is done, the ao will be completed.  An error
 * return from libxl__initiate_device_remove means that the ao
 * will _not_ be completed and the caller must do so. */
_hidden int libxl__initiate_device_remove(libxl__egc*, libxl__ao*,
                                          libxl__device *dev);

/*
 * libxl__ev_devstate - waits a given time for a device to
 * reach a given state.  Follows the libxl_ev_* conventions.
 * Will generate only one event, and after that is automatically
 * cancelled.
 */
typedef struct libxl__ev_devstate libxl__ev_devstate;
typedef void libxl__ev_devstate_callback(libxl__egc *egc, libxl__ev_devstate*,
                                         int rc);
  /* rc will be 0, ERROR_TIMEDOUT, ERROR_INVAL (meaning path was removed),
   * or ERROR_FAIL if other stuff went wrong (in which latter case, logged) */

struct libxl__ev_devstate {
    /* read-only for caller, who may read only when waiting: */
    int wanted;
    libxl__ev_devstate_callback *callback;
    /* as for the remainder, read-only public parts may also be
     * read by the caller (notably, watch.path), but only when waiting: */
    libxl__ev_xswatch watch;
    libxl__ev_time timeout;
};

static inline void libxl__ev_devstate_init(libxl__ev_devstate *ds)
{
    libxl__ev_time_init(&ds->timeout);
    libxl__ev_xswatch_init(&ds->watch);
}

static inline void libxl__ev_devstate_cancel(libxl__gc *gc,
                                             libxl__ev_devstate *ds)
{
    libxl__ev_time_deregister(gc,&ds->timeout);
    libxl__ev_xswatch_deregister(gc,&ds->watch);
}

_hidden int libxl__ev_devstate_wait(libxl__gc *gc, libxl__ev_devstate *ds,
                                    libxl__ev_devstate_callback cb,
                                    const char *state_path,
                                    int state, int milliseconds);


/*
 * libxl__try_phy_backend - Check if there's support for the passed
 * type of file using the PHY backend
 * st_mode: mode_t of the file, as returned by stat function
 *
 * Returns 0 on success, and < 0 on error.
 */
_hidden int libxl__try_phy_backend(mode_t st_mode);

/* from libxl_pci */

_hidden int libxl__device_pci_add(libxl__gc *gc, uint32_t domid, libxl_device_pci *pcidev, int starting);
_hidden int libxl__create_pci_backend(libxl__gc *gc, uint32_t domid,
                                      libxl_device_pci *pcidev, int num);
_hidden int libxl__device_pci_destroy_all(libxl__gc *gc, uint32_t domid);

/* xl_exec */

 /* higher-level double-fork and separate detach eg as for device models */

typedef struct {
    /* put this in your own status structure as returned to application */
    /* all fields are private to libxl_spawn_... */
    pid_t intermediate;
    int fd;
    char *what; /* malloc'd in spawn_spawn */
} libxl__spawn_starting;

typedef struct {
    char *dom_path; /* from libxl_malloc, only for libxl_spawner_record_pid */
    const char *pid_path; /* only for libxl_spawner_record_pid */
    int domid;
    libxl__spawn_starting *for_spawn;
} libxl__spawner_starting;

/*
 * libxl__spawn_spawn - Create a new process
 * gc: allocation pool
 * for_spawn: malloc'd pointer to libxl__spawn_starting (optional)
 * what: string describing the spawned process
 * intermediate_hook: helper to record pid, such as libxl_spawner_record_pid
 * hook_data: data to pass to the hook function
 *
 * Logs errors.  A copy of "what" is taken. 
 * Return values:
 *  < 0   error, for_spawn need not be detached
 *   +1   caller is the parent, must call detach on *for_spawn eventually
 *    0   caller is now the inner child, should probably call libxl__exec
 * Caller, may pass 0 for for_spawn, in which case no need to detach.
 */
_hidden int libxl__spawn_spawn(libxl__gc *gc,
                      libxl__spawn_starting *for_spawn,
                      const char *what,
                      void (*intermediate_hook)(void *for_spawn, pid_t innerchild),
                      void *hook_data);

/*
 * libxl_spawner_record_pid - Record given pid in xenstore
 * for_spawn: malloc'd pointer to libxl__spawn_starting (optional)
 * innerchild: pid of the child
 *
 * This function is passed as intermediate_hook to libxl__spawn_spawn.
 */
_hidden void libxl_spawner_record_pid(void *for_spawn, pid_t innerchild);

/*
 * libxl__spawn_confirm_offspring_startup - Wait for child state
 * gc: allocation pool
 * timeout: how many seconds to wait for the child
 * what: string describing the spawned process
 * path: path to the state file in xenstore
 * state: expected string to wait for in path (optional)
 * starting: malloc'd pointer to libxl__spawner_starting
 *
 * Returns 0 on success, and < 0 on error.
 *
 * This function waits the given timeout for the given path to appear
 * in xenstore, and optionally for state in path.
 * The intermediate process created in libxl__spawn_spawn is killed.
 * The memory referenced by starting->for_spawn and starting is free'd.
 */
_hidden int libxl__spawn_confirm_offspring_startup(libxl__gc *gc,
                                       uint32_t timeout, char *what,
                                       char *path, char *state,
                                       libxl__spawner_starting *starting);

/*
 * libxl__wait_for_offspring - Wait for child state
 * gc: allocation pool
 * domid: guest to work with
 * timeout: how many seconds to wait for the state to appear
 * what: string describing the spawned process
 * path: path to the state file in xenstore
 * state: expected string to wait for in path (optional)
 * spawning: malloc'd pointer to libxl__spawn_starting (optional)
 * check_callback: (optional)
 * check_callback_userdata: data to pass to the callback function
 *
 * Returns 0 on success, and < 0 on error.
 *
 * This function waits the given timeout for the given path to appear
 * in xenstore, and optionally for state in path.
 * If path appears and state matches, check_callback is called.
 * If check_callback returns > 0, waiting for path or state continues.
 * Otherwise libxl__wait_for_offspring returns.
 */
_hidden int libxl__wait_for_offspring(libxl__gc *gc,
                                 uint32_t domid,
                                 uint32_t timeout, char *what,
                                 char *path, char *state,
                                 libxl__spawn_starting *spawning,
                                 int (*check_callback)(libxl__gc *gc,
                                                       uint32_t domid,
                                                       const char *state,
                                                       void *userdata),
                                 void *check_callback_userdata);

/*
 * libxl__spawn_detach - Kill intermediate process from spawn_spawn
 * gc: allocation pool
 * for_spawn: malloc'd pointer to libxl__spawn_starting (optional)
 *
 * Returns 0 on success, and < 0 on error.
 *
 * Logs errors.  Idempotent, but only permitted after successful
 * call to libxl__spawn_spawn, and no point calling it again if it fails.
 */
_hidden int libxl__spawn_detach(libxl__gc *gc,
                       libxl__spawn_starting *for_spawn);

/*
 * libxl__spawn_check - Check intermediate child process
 * gc: allocation pool
 * for_spawn: malloc'd pointer to libxl__spawn_starting (optional)
 *
 * Returns 0 on success, and < 0 on error.
 *
 * Logs errors but also returns them.
 * Caller must still call detach.
 */
_hidden int libxl__spawn_check(libxl__gc *gc,
                       libxl__spawn_starting *for_spawn);

 /* low-level stuff, for synchronous subprocesses etc. */

_hidden void libxl__exec(int stdinfd, int stdoutfd, int stderrfd,
               const char *arg0, char **args); // logs errors, never returns

/* from xl_create */
_hidden int libxl__domain_make(libxl__gc *gc,
                               libxl_domain_create_info *info,
                               uint32_t *domid);
_hidden int libxl__domain_build(libxl__gc *gc,
                                libxl_domain_build_info *info,
                                uint32_t domid,
                                libxl__domain_build_state *state);

/* for device model creation */
_hidden const char *libxl__domain_device_model(libxl__gc *gc,
                                        const libxl_domain_build_info *info);
_hidden int libxl__create_device_model(libxl__gc *gc,
                              int domid,
                              libxl_domain_config *guest_config,
                              libxl__domain_build_state *state,
                              libxl__spawner_starting **starting_r);
_hidden int libxl__create_xenpv_qemu(libxl__gc *gc, uint32_t domid,
                              libxl_domain_config *guest_config,
                              libxl__domain_build_state *state,
                              libxl__spawner_starting **starting_r);
_hidden int libxl__need_xenpv_qemu(libxl__gc *gc,
        int nr_consoles, libxl__device_console *consoles,
        int nr_vfbs, libxl_device_vfb *vfbs,
        int nr_disks, libxl_device_disk *disks);
  /* Caller must either: pass starting_r==0, or on successful
   * return pass *starting_r (which will be non-0) to
   * libxl__confirm_device_model_startup or libxl__detach_device_model. */
_hidden int libxl__confirm_device_model_startup(libxl__gc *gc,
                              libxl__domain_build_state *state,
                              libxl__spawner_starting *starting);
_hidden int libxl__detach_device_model(libxl__gc *gc, libxl__spawner_starting *starting);
_hidden int libxl__wait_for_device_model(libxl__gc *gc,
                                uint32_t domid, char *state,
                                libxl__spawn_starting *spawning,
                                int (*check_callback)(libxl__gc *gc,
                                                      uint32_t domid,
                                                      const char *state,
                                                      void *userdata),
                                void *check_callback_userdata);

_hidden int libxl__destroy_device_model(libxl__gc *gc, uint32_t domid);

_hidden const libxl_vnc_info *libxl__dm_vnc(const libxl_domain_config *g_cfg);

_hidden char *libxl__abs_path(libxl__gc *gc, const char *s, const char *path);

#define LIBXL__LOG_DEBUG   XTL_DEBUG
#define LIBXL__LOG_INFO    XTL_INFO
#define LIBXL__LOG_WARNING XTL_WARN
#define LIBXL__LOG_ERROR   XTL_ERROR

_hidden char *libxl__domid_to_name(libxl__gc *gc, uint32_t domid);
_hidden char *libxl__cpupoolid_to_name(libxl__gc *gc, uint32_t poolid);

_hidden int libxl__enum_from_string(const libxl_enum_string_table *t,
                                    const char *s, int *e);

_hidden yajl_gen_status libxl__yajl_gen_asciiz(yajl_gen hand, const char *str);

_hidden yajl_gen_status libxl__string_gen_json(yajl_gen hand, const char *p);

typedef yajl_gen_status (*libxl__gen_json_callback)(yajl_gen hand, void *);
_hidden char *libxl__object_to_json(libxl_ctx *ctx, const char *type,
                                    libxl__gen_json_callback gen, void *p);

  /* holds the CPUID response for a single CPUID leaf
   * input contains the value of the EAX and ECX register,
   * and each policy string contains a filter to apply to
   * the host given values for that particular leaf.
   */
struct libxl__cpuid_policy {
    uint32_t input[2];
    char *policy[4];
};

/*
 * blktap2 support
 */

/* libxl__blktap_enabled:
 *    return true if blktap/blktap2 support is available.
 */
_hidden int libxl__blktap_enabled(libxl__gc *gc);

/* libxl__blktap_devpath:
 *    Argument: path and disk image as specified in config file.
 *      The type specifies whether this is aio, qcow, qcow2, etc.
 *    returns device path xenstore wants to have. returns NULL
 *      if no device corresponds to the disk.
 */
_hidden char *libxl__blktap_devpath(libxl__gc *gc,
                                    const char *disk,
                                    libxl_disk_format format);

/* libxl__device_destroy_tapdisk:
 *   Destroys any tapdisk process associated with the backend represented
 *   by be_path.
 */
_hidden void libxl__device_destroy_tapdisk(libxl__gc *gc, char *be_path);

_hidden char *libxl__uuid2string(libxl__gc *gc, const libxl_uuid uuid);

struct libxl__xen_console_reader {
    char *buffer;
    unsigned int size;
    unsigned int count;
    unsigned int clear;
    unsigned int incremental;
    unsigned int index;
};

_hidden int libxl__error_set(libxl__gc *gc, int code);

_hidden int libxl__file_reference_map(libxl_file_reference *f);
_hidden int libxl__file_reference_unmap(libxl_file_reference *f);

_hidden int libxl__e820_alloc(libxl__gc *gc, uint32_t domid, libxl_domain_config *d_config);

/* parse the string @s as a sequence of 6 colon separated bytes in to @mac */
_hidden int libxl__parse_mac(const char *s, libxl_mac mac);
/* compare mac address @a and @b. 0 if the same, -ve if a<b and +ve if a>b */
_hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b);
/* init a recursive mutex */
_hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t *lock);

_hidden int libxl__gettimeofday(libxl__gc *gc, struct timeval *now_r);

#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)

/* from libxl_qmp */
typedef struct libxl__qmp_handler libxl__qmp_handler;

/* Initialise and connect to the QMP socket.
 *   Return an handler or NULL if there is an error
 */
_hidden libxl__qmp_handler *libxl__qmp_initialize(libxl__gc *gc,
                                                  uint32_t domid);
/* ask to QEMU the serial port information and store it in xenstore. */
_hidden int libxl__qmp_query_serial(libxl__qmp_handler *qmp);
_hidden int libxl__qmp_pci_add(libxl__gc *gc, int d, libxl_device_pci *pcidev);
_hidden int libxl__qmp_pci_del(libxl__gc *gc, int domid,
                               libxl_device_pci *pcidev);
/* Save current QEMU state into fd. */
_hidden int libxl__qmp_save(libxl__gc *gc, int domid, const char *filename);
/* close and free the QMP handler */
_hidden void libxl__qmp_close(libxl__qmp_handler *qmp);
/* remove the socket file, if the file has already been removed,
 * nothing happen */
_hidden void libxl__qmp_cleanup(libxl__gc *gc, uint32_t domid);

/* this helper calls qmp_initialize, query_serial and qmp_close */
_hidden int libxl__qmp_initializations(libxl__gc *gc, uint32_t domid,
                                       const libxl_domain_config *guest_config);

/* from libxl_json */
#include <yajl/yajl_gen.h>

_hidden yajl_gen_status libxl__yajl_gen_asciiz(yajl_gen hand, const char *str);
_hidden yajl_gen_status libxl__yajl_gen_enum(yajl_gen hand, const char *str);

typedef enum {
    JSON_ERROR,
    JSON_NULL,
    JSON_TRUE,
    JSON_FALSE,
    JSON_INTEGER,
    JSON_DOUBLE,
    /* number is store in string, it's too big to be a long long or a double */
    JSON_NUMBER,
    JSON_STRING,
    JSON_MAP,
    JSON_ARRAY,
    JSON_ANY
} libxl__json_node_type;

typedef struct libxl__json_object {
    libxl__json_node_type type;
    union {
        long long i;
        double d;
        char *string;
        /* List of libxl__json_object */
        flexarray_t *array;
        /* List of libxl__json_map_node */
        flexarray_t *map;
    } u;
    struct libxl__json_object *parent;
} libxl__json_object;

typedef struct {
    char *map_key;
    libxl__json_object *obj;
} libxl__json_map_node;

typedef struct libxl__yajl_ctx libxl__yajl_ctx;

static inline bool libxl__json_object_is_string(const libxl__json_object *o)
{
    return o != NULL && o->type == JSON_STRING;
}
static inline bool libxl__json_object_is_integer(const libxl__json_object *o)
{
    return o != NULL && o->type == JSON_INTEGER;
}
static inline bool libxl__json_object_is_map(const libxl__json_object *o)
{
    return o != NULL && o->type == JSON_MAP;
}
static inline bool libxl__json_object_is_array(const libxl__json_object *o)
{
    return o != NULL && o->type == JSON_ARRAY;
}

static inline
const char *libxl__json_object_get_string(const libxl__json_object *o)
{
    if (libxl__json_object_is_string(o))
        return o->u.string;
    else
        return NULL;
}
static inline
flexarray_t *libxl__json_object_get_map(const libxl__json_object *o)
{
    if (libxl__json_object_is_map(o))
        return o->u.map;
    else
        return NULL;
}
static inline
flexarray_t *libxl__json_object_get_array(const libxl__json_object *o)
{
    if (libxl__json_object_is_array(o))
        return o->u.array;
    else
        return NULL;
}
static inline long long libxl__json_object_get_integer(const libxl__json_object *o)
{
    if (libxl__json_object_is_integer(o))
        return o->u.i;
    else
        return -1;
}

_hidden libxl__json_object *libxl__json_array_get(const libxl__json_object *o,
                                                  int i);
_hidden
libxl__json_map_node *libxl__json_map_node_get(const libxl__json_object *o,
                                               int i);
_hidden const libxl__json_object *libxl__json_map_get(const char *key,
                                          const libxl__json_object *o,
                                          libxl__json_node_type expected_type);
_hidden void libxl__json_object_free(libxl__gc *gc, libxl__json_object *obj);

_hidden libxl__json_object *libxl__json_parse(libxl__gc *gc, const char *s);

  /* Based on /local/domain/$domid/dm-version xenstore key
   * default is qemu xen traditional */
_hidden libxl_device_model_version
libxl__device_model_version_running(libxl__gc *gc, uint32_t domid);


/*
 * Calling context and GC for event-generating functions:
 *
 * These are for use by parts of libxl which directly or indirectly
 * call libxl__event_occurred.  These contain a gc but also a list of
 * deferred events.
 *
 * You should never need to initialise an egc unless you are part of
 * the event machinery itself.  Otherwise you will always be given an
 * egc if you need one.  Even functions which generate specific kinds
 * of events don't need to - rather, they will be passed an egc into
 * their own callback function and should just use the one they're
 * given.
 *
 * Functions using LIBXL__INIT_EGC may *not* generally be called from
 * within libxl, because libxl__egc_cleanup may call back into the
 * application.  This should be documented near the function
 * prototype(s) for callers of LIBXL__INIT_EGC and EGC_INIT.  You
 * should in any case not find it necessary to call egc-creators from
 * within libxl.
 *
 * For the same reason libxl__egc_cleanup (or EGC_FREE) must be called
 * with the ctx *unlocked*.  So the right pattern has the EGC_...
 * macro calls on the outside of the CTX_... ones.
 */

/* useful for all functions which take an egc: */

#define EGC_GC                                  \
    libxl__gc *const gc = &egc->gc

/* egc initialisation and destruction: */

#define LIBXL_INIT_EGC(egc,ctx) do{                     \
        LIBXL_INIT_GC((egc).gc,ctx);                    \
        LIBXL_TAILQ_INIT(&(egc).occurred_for_callback); \
        LIBXL_TAILQ_INIT(&(egc).aos_for_callback);      \
    } while(0)

_hidden void libxl__egc_cleanup(libxl__egc *egc);
  /* Frees memory allocated within this egc's gc, and and report all
   * occurred events via callback, if applicable.  May reenter the
   * application; see restrictions above.  The ctx must be UNLOCKED. */

/* convenience macros: */

#define EGC_INIT(ctx)                       \
    libxl__egc egc[1]; LIBXL_INIT_EGC(egc[0],ctx);      \
    EGC_GC

#define EGC_FREE           libxl__egc_cleanup(egc)


/*
 * Machinery for asynchronous operations ("ao")
 *
 * All "slow" functions (includes anything that might block on a
 * guest or an external script) need to use the asynchronous
 * operation ("ao") machinery.  The function should take a parameter
 * const libxl_asyncop_how *ao_how and must start with a call to
 * AO_INITIATOR_ENTRY.  These functions MAY NOT be called from
 * inside libxl, because they can cause reentrancy callbacks.
 *
 * For the same reason functions taking an ao_how may make themselves
 * an egc with EGC_INIT (and they will generally want to, to be able
 * to immediately complete an ao during its setup).
 *
 * Lifecycle of an ao:
 *
 * - Created by libxl__ao_create (or the AO_CREATE convenience macro).
 *
 * - After creation, can be used by code which implements
 *   the operation as follows:
 *      - the ao's gc, for allocating memory for the lifetime
 *        of the operation (possibly with the help of the AO_GC
 *        macro to introduce the gc into scope)
 *      - the ao itself may be passed about to sub-functions
 *        so that they can stash it away etc.
 *      - in particular, the ao pointer must be stashed in some
 *        per-operation structure which is also passed as a user
 *        pointer to the internal event generation request routines
 *        libxl__evgen_FOO, so that at some point a CALLBACK will be
 *        made when the operation is complete.
 *
 * - If initiation is successful, the initiating function needs
 *   to run libxl__ao_inprogress right before unlocking and
 *   returning, and return whatever it returns (AO_INPROGRESS macro).
 *
 * - If the initiation is unsuccessful, the initiating function must
 *   call libxl__ao_abort before unlocking and returning whatever
 *   error code is appropriate (AO_ABORT macro).
 *
 * - Later, some callback function, whose callback has been requested
 *   directly or indirectly, should call libxl__ao_complete (with the
 *   ctx locked, as it will generally already be in any event callback
 *   function).  This must happen exactly once for each ao (and not if
 *   the ao has been destroyed, obviously).
 *
 * - Note that during callback functions, two gcs are available:
 *    - The one in egc, whose lifetime is only this callback
 *    - The one in ao, whose lifetime is the asynchronous operation
 *   Usually callback function should use CONTAINER_OF to obtain its
 *   own state structure, containing a pointer to the ao.  It should
 *   then obtain the ao and use the ao's gc; this is most easily done
 *   using the convenience macro STATE_AO_GC.
 */

#define AO_CREATE(ctx, domid, ao_how)                           \
    libxl__ctx_lock(ctx);                                       \
    libxl__ao *ao = libxl__ao_create(ctx, domid, ao_how);       \
    if (!ao) { libxl__ctx_unlock(ctx); return ERROR_NOMEM; }    \
    libxl__egc egc[1]; LIBXL_INIT_EGC(egc[0],ctx);              \
    AO_GC;

#define AO_INPROGRESS ({                                        \
        libxl_ctx *ao__ctx = libxl__gc_owner(&ao->gc);          \
        int ao__rc = libxl__ao_inprogress(ao);                  \
        libxl__ctx_unlock(ao__ctx); /* gc is now invalid */     \
        EGC_FREE;                                               \
        (ao__rc);                                               \
   })

#define AO_ABORT(rc) ({                                         \
        libxl_ctx *ao__ctx = libxl__gc_owner(&ao->gc);          \
        assert(rc);                                             \
        libxl__ao_abort(ao);                                    \
        libxl__ctx_unlock(ao__ctx); /* gc is now invalid */     \
        EGC_FREE;                                               \
        (rc);                                                   \
    })

#define AO_GC                                   \
    libxl__gc *const gc = &ao->gc

#define STATE_AO_GC(op_ao)                      \
    libxl__ao *const ao = (op_ao);              \
    AO_GC


/* All of these MUST be called with the ctx locked.
 * libxl__ao_inprogress MUST be called with the ctx locked exactly once. */
_hidden libxl__ao *libxl__ao_create(libxl_ctx*, uint32_t domid,
                                    const libxl_asyncop_how*);
_hidden int libxl__ao_inprogress(libxl__ao *ao); /* temporarily unlocks */
_hidden void libxl__ao_abort(libxl__ao *ao);
_hidden void libxl__ao_complete(libxl__egc *egc, libxl__ao *ao, int rc);

/* For use by ao machinery ONLY */
_hidden void libxl__ao__destroy(libxl_ctx*, libxl__ao *ao);


/*
 * File descriptors and CLOEXEC
 */

/*
 * For libxl functions which create file descriptors, at least one
 * of the following must be true:
 *  (a) libxl does not care if copies of this open-file are inherited
 *      by random children and might remain open indefinitely
 *  (b) libxl must take extra care for the fd (the actual descriptor,
 *      not the open-file) as below.  We call this a "carefd".
 *
 * The rules for opening a carefd are:
 *  (i)   Before bringing any carefds into existence,
 *        libxl code must call libxl__carefd_begin.
 *  (ii)  Then for each carefd brought into existence,
 *        libxl code must call libxl__carefd_record
 *        and remember the libxl__carefd_record*.
 *  (iii) Then it must call libxl__carefd_unlock.
 *  (iv)  When in a child process the fd is to be passed across
 *        exec by libxl, the libxl code must unset FD_CLOEXEC
 *        on the fd eg by using libxl_fd_set_cloexec.
 *  (v)   Later, when the fd is to be closed in the same process,
 *        libxl code must not call close.  Instead, it must call
 *        libxl__carefd_close.
 * Steps (ii) and (iii) can be combined by calling the convenience
 * function libxl__carefd_opened.
 */
/* libxl__carefd_begin and _unlock (or _opened) must be called always
 * in pairs.  They may be called with the CTX lock held.  In between
 * _begin and _unlock, the following are prohibited:
 *   - anything which might block
 *   - any callbacks to the application
 *   - nested calls to libxl__carefd_begin
 *   - fork (libxl__fork)
 * In general nothing should be done before _unlock that could be done
 * afterwards.
 */
typedef struct libxl__carefd libxl__carefd;

_hidden void libxl__carefd_begin(void);
_hidden void libxl__carefd_unlock(void);

/* fd may be -1, in which case this returns a dummy libxl__fd_record
 * on which it _carefd_close is a no-op.  Cannot fail. */
_hidden libxl__carefd *libxl__carefd_record(libxl_ctx *ctx, int fd);

/* Combines _record and _unlock in a single call.  If fd==-1,
 * still does the unlock, but returns 0.  Cannot fail. */
_hidden libxl__carefd *libxl__carefd_opened(libxl_ctx *ctx, int fd);

/* Works just like close(2).  You may pass NULL, in which case it's
 * a successful no-op. */
_hidden int libxl__carefd_close(libxl__carefd*);

/* You may pass NULL in which case the answer is -1. */
_hidden int libxl__carefd_fd(const libxl__carefd*);

/* common paths */
_hidden const char *libxl__libexec_path(void);
_hidden const char *libxl__private_bindir_path(void);
_hidden const char *libxl__xenfirmwaredir_path(void);
_hidden const char *libxl__xen_config_dir_path(void);
_hidden const char *libxl__xen_script_dir_path(void);
_hidden const char *libxl__lock_dir_path(void);
_hidden const char *libxl__run_dir_path(void);

/*
 * Convenience macros.
 */

/*
 * CONTAINER_OF work like this.  Given:
 *    typedef struct {
 *      ...
 *      member_type member_name;
 *      ...
 *    } outer_type;
 *    outer_type outer, *outer_var;
 *    member_type *inner_ptr = &outer->member_name;
 *
 * Then, effectively:
 *    outer_type *CONTAINER_OF(member_type *inner_ptr,
 *                             *outer_var, // or type name for outer_type
 *                             member_name);
 *
 * So that:
 *    CONTAINER_OF(inner_ptr, *outer_var, member_name) == &outer
 *    CONTAINER_OF(inner_ptr, outer_type, member_name) == &outer
 */
#define CONTAINER_OF(inner_ptr, outer, member_name)                     \
    ({                                                                  \
        typeof(outer) *container_of_;                                   \
        container_of_ = (void*)((char*)(inner_ptr) -                    \
                                offsetof(typeof(outer), member_name));  \
        (void)(&container_of_->member_name ==                           \
               (typeof(inner_ptr))0) /* type check */;                  \
        container_of_;                                                  \
    })


/*
 * All of these assume (or define)
 *    libxl__gc *gc;
 * as a local variable.
 */

#define GC_INIT(ctx)  libxl__gc gc[1]; LIBXL_INIT_GC(gc[0],ctx)
#define GC_FREE       libxl__free_all(gc)
#define CTX           libxl__gc_owner(gc)

/* Allocation macros all of which use the gc. */

#define ARRAY_SIZE_OK(ptr, nmemb) ((nmemb) < INT_MAX / (sizeof(*(ptr)) * 2))

/*
 * Expression statement  <type> *GCNEW(<type> *var);
 * Uses                  libxl__gc *gc;
 *
 * Allocates a new object of type <type> from the gc and zeroes it
 * with memset.  Sets var to point to the new object or zero (setting
 * errno).  Returns the new value of var.
 */
#define GCNEW(var)                                      \
    (((var) = libxl__zalloc((gc),sizeof(*(var)))))

/*
 * Expression statement  <type> *GCNEW_ARRAY(<type> *var, ssize_t nmemb);
 * Uses                  libxl__gc *gc;
 *
 * Like GCNEW but allocates an array of nmemb elements, as if from
 * calloc.  Does check for integer overflow due to large nmemb.  If
 * nmemb is 0 may succeed by returning 0.
 */
#define GCNEW_ARRAY(var, nmemb)                                 \
    ((var) = libxl__calloc((gc), (nmemb), sizeof(*(var))))
    
/*
 * Expression statement  <type> *GCREALLOC_ARRAY(<type> *var, size_t nmemb);
 * Uses                  libxl__gc *gc;
 *
 * Reallocates the array var to be of size nmemb elements.  Updates
 * var and returns the new value of var.  Does check for integer
 * overflow due to large nmemb.
 *
 * Do not pass nmemb==0.  old may be 0 on entry.
 */
#define GCREALLOC_ARRAY(var, nmemb)                                     \
    (assert(nmemb > 0),                                                 \
     assert(ARRAY_SIZE_OK((var), (nmemb))),                             \
     (var) = libxl__realloc((gc), (var), (nmemb)*sizeof(*(var)))))


/*
 * Expression            char *GCSPRINTF(const char *fmt, ...);
 * Uses                  libxl__gc *gc;
 *
 * Trivial convenience wrapper for libxl__sprintf.
 */
#define GCSPRINTF(fmt, ...) (libxl__sprintf((gc), (fmt), __VA_ARGS__))


/*
 * Expression statements
 *    void LOG(<xtl_level_suffix>, const char *fmt, ...);
 *    void LOGE(<xtl_level_suffix>, const char *fmt, ...);
 *    void LOGEV(<xtl_level_suffix>, int errnoval, const char *fmt, ...);
 * Use
 *    libxl__gc *gc;
 *
 * Trivial convenience wrappers for LIBXL__LOG, LIBXL__LOG_ERRNO and
 * LIBXL__LOG_ERRNOVAL, respectively (and thus for libxl__log).
 *
 * XTL_<xtl_level_suffix> should exist and be an xentoollog.h log level
 * So <xtl_level_suffix> should be one of
 *   DEBUG VERBOSE DETAIL PROGRESS INFO NOTICE WARN ERROR ERROR CRITICAL
 * Of these, most of libxl uses
 *   DEBUG INFO WARN ERROR
 */
#define LOG(l,f, ...)     LIBXL__LOG(CTX,XTL_##l,(f),##__VA_ARGS__)
#define LOGE(l,f, ...)    LIBXL__LOG_ERRNO(CTX,XTL_##l,(f),##__VA_ARGS__)
#define LOGEV(l,e,f, ...) LIBXL__LOG_ERRNOVAL(CTX,XTL_##l,(e),(f),##__VA_ARGS__)


/* Locking functions.  See comment for "lock" member of libxl__ctx. */

static inline void libxl__ctx_lock(libxl_ctx *ctx) {
    int r = pthread_mutex_lock(&ctx->lock);
    assert(!r);
}

static inline void libxl__ctx_unlock(libxl_ctx *ctx) {
    int r = pthread_mutex_unlock(&ctx->lock);
    assert(!r);
}

#define CTX_LOCK (libxl__ctx_lock(CTX))
#define CTX_UNLOCK (libxl__ctx_unlock(CTX))


/*
 * Inserts "elm_new" into the sorted list "head".
 *
 * "elm_search" must be a loop search variable of the same type as
 * "elm_new".  "new_after_search_p" must be an expression which is
 * true iff the element "elm_new" sorts after the element
 * "elm_search".
 *
 * "search_body" can be empty, or some declaration(s) and statement(s)
 * needed for "new_after_search_p".
 */
#define LIBXL_TAILQ_INSERT_SORTED(head, entry, elm_new, elm_search,     \
                                  search_body, new_after_search_p)      \
    do {                                                                \
        for ((elm_search) = LIBXL_TAILQ_FIRST((head));                  \
             (elm_search);                                              \
             (elm_search) = LIBXL_TAILQ_NEXT((elm_search), entry)) {    \
            search_body;                                                \
            if (!(new_after_search_p))                                  \
                break;                                                  \
        }                                                               \
        /* now elm_search is either the element before which we want    \
         * to place elm_new, or NULL meaning we want to put elm_new at  \
         * the end */                                                   \
        if ((elm_search))                                               \
            LIBXL_TAILQ_INSERT_BEFORE((elm_search), (elm_new), entry);  \
        else                                                            \
            LIBXL_TAILQ_INSERT_TAIL((head), (elm_new), entry);          \
    } while(0)


/*
 * int CTYPE(ISFOO, char c);
 * int CTYPE(toupper, char c);
 * int CTYPE(tolower, char c);
 *
 * This is necessary because passing a simple char to a ctype.h
 * is forbidden.  ctype.h macros take ints derived from _unsigned_ chars.
 *
 * If you have a char which might be EOF then you should already have
 * it in an int representing an unsigned char, and you can use the
 * <ctype.h> macros directly.  This generally happens only with values
 * from fgetc et al.
 *
 * For any value known to be a character (eg, anything that came from
 * a char[]), use CTYPE.
 */
#define CTYPE(isfoo,c) (isfoo((unsigned char)(c)))


#endif

/*
 * Local variables:
 * mode: C
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 */