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qemu-e2k/include/qemu/osdep.h
Eric Blake e9fd416e66 osdep: Document differences in rounding macros 
Make it obvious which macros are safe in which situations.

Useful since QEMU_ALIGN_UP and ROUND_UP both purport to do
the same thing, but differ on whether the alignment must be
a power of 2.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1469129688-22848-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-03 18:44:56 +02:00

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/*
* OS includes and handling of OS dependencies
*
* This header exists to pull in some common system headers that
* most code in QEMU will want, and to fix up some possible issues with
* it (missing defines, Windows weirdness, and so on).
*
* To avoid getting into possible circular include dependencies, this
* file should not include any other QEMU headers, with the exceptions
* of config-host.h, config-target.h, qemu/compiler.h,
* sysemu/os-posix.h, sysemu/os-win32.h, glib-compat.h and
* qemu/typedefs.h, all of which are doing a similar job to this file
* and are under similar constraints.
*
* This header also contains prototypes for functions defined in
* os-*.c and util/oslib-*.c; those would probably be better split
* out into separate header files.
*
* In an ideal world this header would contain only:
* (1) things which everybody needs
* (2) things without which code would work on most platforms but
* fail to compile or misbehave on a minority of host OSes
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QEMU_OSDEP_H
#define QEMU_OSDEP_H
#include "config-host.h"
#ifdef NEED_CPU_H
#include "config-target.h"
#else
#include "exec/poison.h"
#endif
#include "qemu/compiler.h"
/* Older versions of C++ don't get definitions of various macros from
* stdlib.h unless we define these macros before first inclusion of
* that system header.
*/
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS
#endif
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
/* The following block of code temporarily renames the daemon() function so the
* compiler does not see the warning associated with it in stdlib.h on OSX
*/
#ifdef __APPLE__
#define daemon qemu_fake_daemon_function
#include <stdlib.h>
#undef daemon
extern int daemon(int, int);
#endif
#include <stdarg.h>
#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <inttypes.h>
#include <limits.h>
/* Put unistd.h before time.h as that triggers localtime_r/gmtime_r
* function availability on recentish Mingw-w64 platforms. */
#include <unistd.h>
#include <time.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <assert.h>
/* setjmp must be declared before sysemu/os-win32.h
* because it is redefined there. */
#include <setjmp.h>
#include <signal.h>
#ifdef __OpenBSD__
#include <sys/signal.h>
#endif
#ifndef _WIN32
#include <sys/wait.h>
#else
#define WIFEXITED(x) 1
#define WEXITSTATUS(x) (x)
#endif
#ifdef _WIN32
#include "sysemu/os-win32.h"
#endif
#ifdef CONFIG_POSIX
#include "sysemu/os-posix.h"
#endif
#include "glib-compat.h"
#include "qemu/typedefs.h"
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
#ifndef ENOMEDIUM
#define ENOMEDIUM ENODEV
#endif
#if !defined(ENOTSUP)
#define ENOTSUP 4096
#endif
#if !defined(ECANCELED)
#define ECANCELED 4097
#endif
#if !defined(EMEDIUMTYPE)
#define EMEDIUMTYPE 4098
#endif
#ifndef TIME_MAX
#define TIME_MAX LONG_MAX
#endif
/* HOST_LONG_BITS is the size of a native pointer in bits. */
#if UINTPTR_MAX == UINT32_MAX
# define HOST_LONG_BITS 32
#elif UINTPTR_MAX == UINT64_MAX
# define HOST_LONG_BITS 64
#else
# error Unknown pointer size
#endif
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif
#ifndef MAX
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#endif
/* Minimum function that returns zero only iff both values are zero.
* Intended for use with unsigned values only. */
#ifndef MIN_NON_ZERO
#define MIN_NON_ZERO(a, b) ((a) == 0 ? (b) : \
((b) == 0 ? (a) : (MIN(a, b))))
#endif
/* Round number down to multiple */
#define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
/* Round number up to multiple. Safe when m is not a power of 2 (see
* ROUND_UP for a faster version when a power of 2 is guaranteed) */
#define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
/* Check if n is a multiple of m */
#define QEMU_IS_ALIGNED(n, m) (((n) % (m)) == 0)
/* n-byte align pointer down */
#define QEMU_ALIGN_PTR_DOWN(p, n) \
((typeof(p))QEMU_ALIGN_DOWN((uintptr_t)(p), (n)))
/* n-byte align pointer up */
#define QEMU_ALIGN_PTR_UP(p, n) \
((typeof(p))QEMU_ALIGN_UP((uintptr_t)(p), (n)))
/* Check if pointer p is n-bytes aligned */
#define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n))
/* Round number up to multiple. Requires that d be a power of 2 (see
* QEMU_ALIGN_UP for a safer but slower version on arbitrary
* numbers) */
#ifndef ROUND_UP
#define ROUND_UP(n,d) (((n) + (d) - 1) & -(d))
#endif
#ifndef DIV_ROUND_UP
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
#endif
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#endif
int qemu_daemon(int nochdir, int noclose);
void *qemu_try_memalign(size_t alignment, size_t size);
void *qemu_memalign(size_t alignment, size_t size);
void *qemu_anon_ram_alloc(size_t size, uint64_t *align);
void qemu_vfree(void *ptr);
void qemu_anon_ram_free(void *ptr, size_t size);
#define QEMU_MADV_INVALID -1
#if defined(CONFIG_MADVISE)
#define QEMU_MADV_WILLNEED MADV_WILLNEED
#define QEMU_MADV_DONTNEED MADV_DONTNEED
#ifdef MADV_DONTFORK
#define QEMU_MADV_DONTFORK MADV_DONTFORK
#else
#define QEMU_MADV_DONTFORK QEMU_MADV_INVALID
#endif
#ifdef MADV_MERGEABLE
#define QEMU_MADV_MERGEABLE MADV_MERGEABLE
#else
#define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
#endif
#ifdef MADV_UNMERGEABLE
#define QEMU_MADV_UNMERGEABLE MADV_UNMERGEABLE
#else
#define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
#endif
#ifdef MADV_DODUMP
#define QEMU_MADV_DODUMP MADV_DODUMP
#else
#define QEMU_MADV_DODUMP QEMU_MADV_INVALID
#endif
#ifdef MADV_DONTDUMP
#define QEMU_MADV_DONTDUMP MADV_DONTDUMP
#else
#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
#endif
#ifdef MADV_HUGEPAGE
#define QEMU_MADV_HUGEPAGE MADV_HUGEPAGE
#else
#define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
#endif
#ifdef MADV_NOHUGEPAGE
#define QEMU_MADV_NOHUGEPAGE MADV_NOHUGEPAGE
#else
#define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
#endif
#elif defined(CONFIG_POSIX_MADVISE)
#define QEMU_MADV_WILLNEED POSIX_MADV_WILLNEED
#define QEMU_MADV_DONTNEED POSIX_MADV_DONTNEED
#define QEMU_MADV_DONTFORK QEMU_MADV_INVALID
#define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
#define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
#define QEMU_MADV_DODUMP QEMU_MADV_INVALID
#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
#define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
#define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
#else /* no-op */
#define QEMU_MADV_WILLNEED QEMU_MADV_INVALID
#define QEMU_MADV_DONTNEED QEMU_MADV_INVALID
#define QEMU_MADV_DONTFORK QEMU_MADV_INVALID
#define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
#define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
#define QEMU_MADV_DODUMP QEMU_MADV_INVALID
#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
#define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
#define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
#endif
#if defined(__linux__) && \
(defined(__x86_64__) || defined(__arm__) || defined(__aarch64__))
/* Use 2 MiB alignment so transparent hugepages can be used by KVM.
Valgrind does not support alignments larger than 1 MiB,
therefore we need special code which handles running on Valgrind. */
# define QEMU_VMALLOC_ALIGN (512 * 4096)
#elif defined(__linux__) && defined(__s390x__)
/* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
# define QEMU_VMALLOC_ALIGN (256 * 4096)
#else
# define QEMU_VMALLOC_ALIGN getpagesize()
#endif
int qemu_madvise(void *addr, size_t len, int advice);
int qemu_open(const char *name, int flags, ...);
int qemu_close(int fd);
#ifndef _WIN32
int qemu_dup(int fd);
#endif
#if defined(__HAIKU__) && defined(__i386__)
#define FMT_pid "%ld"
#elif defined(WIN64)
#define FMT_pid "%" PRId64
#else
#define FMT_pid "%d"
#endif
int qemu_create_pidfile(const char *filename);
int qemu_get_thread_id(void);
#ifndef CONFIG_IOVEC
struct iovec {
void *iov_base;
size_t iov_len;
};
/*
* Use the same value as Linux for now.
*/
#define IOV_MAX 1024
ssize_t readv(int fd, const struct iovec *iov, int iov_cnt);
ssize_t writev(int fd, const struct iovec *iov, int iov_cnt);
#else
#include <sys/uio.h>
#endif
#ifdef _WIN32
static inline void qemu_timersub(const struct timeval *val1,
const struct timeval *val2,
struct timeval *res)
{
res->tv_sec = val1->tv_sec - val2->tv_sec;
if (val1->tv_usec < val2->tv_usec) {
res->tv_sec--;
res->tv_usec = val1->tv_usec - val2->tv_usec + 1000 * 1000;
} else {
res->tv_usec = val1->tv_usec - val2->tv_usec;
}
}
#else
#define qemu_timersub timersub
#endif
void qemu_set_cloexec(int fd);
/* Starting on QEMU 2.5, qemu_hw_version() returns "2.5+" by default
* instead of QEMU_VERSION, so setting hw_version on MachineClass
* is no longer mandatory.
*
* Do NOT change this string, or it will break compatibility on all
* machine classes that don't set hw_version.
*/
#define QEMU_HW_VERSION "2.5+"
/* QEMU "hardware version" setting. Used to replace code that exposed
* QEMU_VERSION to guests in the past and need to keep compatibility.
* Do not use qemu_hw_version() in new code.
*/
void qemu_set_hw_version(const char *);
const char *qemu_hw_version(void);
void fips_set_state(bool requested);
bool fips_get_state(void);
/* Return a dynamically allocated pathname denoting a file or directory that is
* appropriate for storing local state.
*
* @relative_pathname need not start with a directory separator; one will be
* added automatically.
*
* The caller is responsible for releasing the value returned with g_free()
* after use.
*/
char *qemu_get_local_state_pathname(const char *relative_pathname);
/* Find program directory, and save it for later usage with
* qemu_get_exec_dir().
* Try OS specific API first, if not working, parse from argv0. */
void qemu_init_exec_dir(const char *argv0);
/* Get the saved exec dir.
* Caller needs to release the returned string by g_free() */
char *qemu_get_exec_dir(void);
/**
* qemu_getauxval:
* @type: the auxiliary vector key to lookup
*
* Search the auxiliary vector for @type, returning the value
* or 0 if @type is not present.
*/
unsigned long qemu_getauxval(unsigned long type);
void qemu_set_tty_echo(int fd, bool echo);
void os_mem_prealloc(int fd, char *area, size_t sz, Error **errp);
int qemu_read_password(char *buf, int buf_size);
/**
* qemu_fork:
*
* A version of fork that avoids signal handler race
* conditions that can lead to child process getting
* signals that are otherwise only expected by the
* parent. It also resets all signal handlers to the
* default settings.
*
* Returns 0 to child process, pid number to parent
* or -1 on failure.
*/
pid_t qemu_fork(Error **errp);
#endif
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