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qemu-e2k/include/qemu/osdep.h
Eric Blake f9919116b8 osdep: Make MIN/MAX evaluate arguments only once 
I'm not aware of any immediate bugs in qemu where a second runtime
evaluation of the arguments to MIN() or MAX() causes a problem, but
proactively preventing such abuse is easier than falling prey to an
unintended case down the road.  At any rate, here's the conversation
that sparked the current patch:
https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg05718.html

Update the MIN/MAX macros to only evaluate their argument once at
runtime; this uses typeof(1 ? (a) : (b)) to ensure that we are
promoting the temporaries to the same type as the final comparison (we
have to trigger type promotion, as typeof(bitfield) won't compile; and
we can't use typeof((a) + (b)) or even typeof((a) + 0), as some of our
uses of MAX are on void* pointers where such addition is undefined).

However, we are unable to work around gcc refusing to compile ({}) in
a constant context (such as the array length of a static variable),
even when only used in the dead branch of a __builtin_choose_expr(),
so we have to provide a second macro pair MIN_CONST and MAX_CONST for
use when both arguments are known to be compile-time constants and
where the result must also be usable as a constant; this second form
evaluates arguments multiple times but that doesn't matter for
constants.  By using a void expression as the expansion if a
non-constant is presented to this second form, we can enlist the
compiler to ensure the double evaluation is not attempted on
non-constants.

Alas, as both macros now rely on compiler intrinsics, they are no
longer usable in preprocessor #if conditions; those will just have to
be open-coded or the logic rewritten into #define or runtime 'if'
conditions (but where the compiler dead-code-elimination will probably
still apply).

I tested that both gcc 10.1.1 and clang 10.0.0 produce errors for all
forms of macro mis-use.  As the errors can sometimes be cryptic, I'm
demonstrating the gcc output:

Use of MIN when MIN_CONST is needed:

In file included from /home/eblake/qemu/qemu-img.c:25:
/home/eblake/qemu/include/qemu/osdep.h:249:5: error: braced-group within expression allowed only inside a function
  249 |     ({                                                  \
      |     ^
/home/eblake/qemu/qemu-img.c:92:12: note: in expansion of macro ‘MIN’
   92 | char array[MIN(1, 2)] = "";
      |            ^~~

Use of MIN_CONST when MIN is needed:

/home/eblake/qemu/qemu-img.c: In function ‘is_allocated_sectors’:
/home/eblake/qemu/qemu-img.c:1225:15: error: void value not ignored as it ought to be
 1225 |             i = MIN_CONST(i, n);
      |               ^

Use of MIN in the preprocessor:

In file included from /home/eblake/qemu/accel/tcg/translate-all.c:20:
/home/eblake/qemu/accel/tcg/translate-all.c: In function ‘page_check_range’:
/home/eblake/qemu/include/qemu/osdep.h:249:6: error: token "{" is not valid in preprocessor expressions
  249 |     ({                                                  \
      |      ^

Fix the resulting callsites that used #if or computed a compile-time
constant min or max to use the new macros.  cpu-defs.h is interesting,
as CPU_TLB_DYN_MAX_BITS is sometimes used as a constant and sometimes
dynamic.

It may be worth improving glib's MIN/MAX definitions to be saner, but
that is a task for another day.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200625162602.700741-1-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-26 09:39:39 -04:00

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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
#ifdef _WIN32
/* as defined in sdkddkver.h */
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0600 /* Vista */
#endif
/* reduces the number of implicitly included headers */
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#endif
/* enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later) */
#ifdef __MINGW32__
#define __USE_MINGW_ANSI_STDIO 1
#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 <getopt.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"
/*
* For mingw, as of v6.0.0, the function implementing the assert macro is
* not marked as noreturn, so the compiler cannot delete code following an
* assert(false) as unused. We rely on this within the code base to delete
* code that is unreachable when features are disabled.
* All supported versions of Glib's g_assert() satisfy this requirement.
*/
#ifdef __MINGW32__
#undef assert
#define assert(x) g_assert(x)
#endif
/*
* According to waitpid man page:
* WCOREDUMP
* This macro is not specified in POSIX.1-2001 and is not
* available on some UNIX implementations (e.g., AIX, SunOS).
* Therefore, enclose its use inside #ifdef WCOREDUMP ... #endif.
*/
#ifndef WCOREDUMP
#define WCOREDUMP(status) 0
#endif
/*
* We have a lot of unaudited code that may fail in strange ways, or
* even be a security risk during migration, if you disable assertions
* at compile-time. You may comment out these safety checks if you
* absolutely want to disable assertion overhead, but it is not
* supported upstream so the risk is all yours. Meanwhile, please
* submit patches to remove any side-effects inside an assertion, or
* fixing error handling that should use Error instead of assert.
*/
#ifdef NDEBUG
#error building with NDEBUG is not supported
#endif
#ifdef G_DISABLE_ASSERT
#error building with G_DISABLE_ASSERT is not supported
#endif
#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
#if !defined(ESHUTDOWN)
#define ESHUTDOWN 4099
#endif
/* time_t may be either 32 or 64 bits depending on the host OS, and
* can be either signed or unsigned, so we can't just hardcode a
* specific maximum value. This is not a C preprocessor constant,
* so you can't use TIME_MAX in an #ifdef, but for our purposes
* this isn't a problem.
*/
/* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from
* Gnulib, and are under the LGPL v2.1 or (at your option) any
* later version.
*/
/* True if the real type T is signed. */
#define TYPE_SIGNED(t) (!((t)0 < (t)-1))
/* The width in bits of the integer type or expression T.
* Padding bits are not supported.
*/
#define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT)
/* The maximum and minimum values for the integer type T. */
#define TYPE_MAXIMUM(t) \
((t) (!TYPE_SIGNED(t) \
? (t)-1 \
: ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1)))
#ifndef TIME_MAX
#define TIME_MAX TYPE_MAXIMUM(time_t)
#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
/* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
* the wrong type. Our replacement isn't usable in preprocessor
* expressions, but it is sufficient for our needs. */
#if defined(HAVE_BROKEN_SIZE_MAX) && HAVE_BROKEN_SIZE_MAX
#undef SIZE_MAX
#define SIZE_MAX ((size_t)-1)
#endif
/*
* Two variations of MIN/MAX macros. The first is for runtime use, and
* evaluates arguments only once (so it is safe even with side
* effects), but will not work in constant contexts (such as array
* size declarations) because of the '{}'. The second is for constant
* expression use, where evaluating arguments twice is safe because
* the result is going to be constant anyway, but will not work in a
* runtime context because of a void expression where a value is
* expected. Thus, both gcc and clang will fail to compile if you use
* the wrong macro (even if the error may seem a bit cryptic).
*
* Note that neither form is usable as an #if condition; if you truly
* need to write conditional code that depends on a minimum or maximum
* determined by the pre-processor instead of the compiler, you'll
* have to open-code it.
*/
#undef MIN
#define MIN(a, b) \
({ \
typeof(1 ? (a) : (b)) _a = (a), _b = (b); \
_a < _b ? _a : _b; \
})
#define MIN_CONST(a, b) \
__builtin_choose_expr( \
__builtin_constant_p(a) && __builtin_constant_p(b), \
(a) < (b) ? (a) : (b), \
((void)0))
#undef MAX
#define MAX(a, b) \
({ \
typeof(1 ? (a) : (b)) _a = (a), _b = (b); \
_a > _b ? _a : _b; \
})
#define MAX_CONST(a, b) \
__builtin_choose_expr( \
__builtin_constant_p(a) && __builtin_constant_p(b), \
(a) > (b) ? (a) : (b), \
((void)0))
/*
* Minimum function that returns zero only if both values are zero.
* Intended for use with unsigned values only.
*/
#ifndef MIN_NON_ZERO
#define MIN_NON_ZERO(a, b) \
({ \
typeof(1 ? (a) : (b)) _a = (a), _b = (b); \
_a == 0 ? _b : (_b == 0 || _b > _a) ? _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); works even if d is a smaller type than n. */
#ifndef ROUND_UP
#define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
#endif
#ifndef DIV_ROUND_UP
#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
#endif
/*
* &(x)[0] is always a pointer - if it's same type as x then the argument is a
* pointer, not an array.
*/
#define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \
typeof(&(x)[0])))
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \
QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x)))
#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, bool shared);
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
#ifdef MADV_REMOVE
#define QEMU_MADV_REMOVE MADV_REMOVE
#else
#define QEMU_MADV_REMOVE 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
#define QEMU_MADV_REMOVE 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
#define QEMU_MADV_REMOVE QEMU_MADV_INVALID
#endif
#ifdef _WIN32
#define HAVE_CHARDEV_SERIAL 1
#elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
|| defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
|| defined(__GLIBC__) || defined(__APPLE__)
#define HAVE_CHARDEV_SERIAL 1
#endif
#if defined(__linux__) || defined(__FreeBSD__) || \
defined(__FreeBSD_kernel__) || defined(__DragonFly__)
#define HAVE_CHARDEV_PARPORT 1
#endif
#if defined(CONFIG_LINUX)
#ifndef BUS_MCEERR_AR
#define BUS_MCEERR_AR 4
#endif
#ifndef BUS_MCEERR_AO
#define BUS_MCEERR_AO 5
#endif
#endif
#if defined(__linux__) && \
(defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) \
|| defined(__powerpc64__))
/* 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)
#elif defined(__linux__) && defined(__sparc__)
#include <sys/shm.h>
# define QEMU_VMALLOC_ALIGN MAX(qemu_real_host_page_size, SHMLBA)
#else
# define QEMU_VMALLOC_ALIGN qemu_real_host_page_size
#endif
#ifdef CONFIG_POSIX
struct qemu_signalfd_siginfo {
uint32_t ssi_signo; /* Signal number */
int32_t ssi_errno; /* Error number (unused) */
int32_t ssi_code; /* Signal code */
uint32_t ssi_pid; /* PID of sender */
uint32_t ssi_uid; /* Real UID of sender */
int32_t ssi_fd; /* File descriptor (SIGIO) */
uint32_t ssi_tid; /* Kernel timer ID (POSIX timers) */
uint32_t ssi_band; /* Band event (SIGIO) */
uint32_t ssi_overrun; /* POSIX timer overrun count */
uint32_t ssi_trapno; /* Trap number that caused signal */
int32_t ssi_status; /* Exit status or signal (SIGCHLD) */
int32_t ssi_int; /* Integer sent by sigqueue(2) */
uint64_t ssi_ptr; /* Pointer sent by sigqueue(2) */
uint64_t ssi_utime; /* User CPU time consumed (SIGCHLD) */
uint64_t ssi_stime; /* System CPU time consumed (SIGCHLD) */
uint64_t ssi_addr; /* Address that generated signal
(for hardware-generated signals) */
uint8_t pad[48]; /* Pad size to 128 bytes (allow for
additional fields in the future) */
};
int qemu_signalfd(const sigset_t *mask);
void sigaction_invoke(struct sigaction *action,
struct qemu_signalfd_siginfo *info);
#endif
int qemu_madvise(void *addr, size_t len, int advice);
int qemu_mprotect_rwx(void *addr, size_t size);
int qemu_mprotect_none(void *addr, size_t size);
int qemu_open(const char *name, int flags, ...);
int qemu_close(int fd);
int qemu_unlink(const char *name);
#ifndef _WIN32
int qemu_dup(int fd);
#endif
int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
int qemu_unlock_fd(int fd, int64_t start, int64_t len);
int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
bool qemu_has_ofd_lock(void);
#if defined(__HAIKU__) && defined(__i386__)
#define FMT_pid "%ld"
#elif defined(WIN64)
#define FMT_pid "%" PRId64
#else
#define FMT_pid "%d"
#endif
bool qemu_write_pidfile(const char *pidfile, Error **errp);
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, int smp_cpus,
Error **errp);
/**
* qemu_get_pid_name:
* @pid: pid of a process
*
* For given @pid fetch its name. Caller is responsible for
* freeing the string when no longer needed.
* Returns allocated string on success, NULL on failure.
*/
char *qemu_get_pid_name(pid_t pid);
/**
* 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);
/* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
* when intptr_t is 32-bit and we are aligning a long long.
*/
extern uintptr_t qemu_real_host_page_size;
extern intptr_t qemu_real_host_page_mask;
extern int qemu_icache_linesize;
extern int qemu_icache_linesize_log;
extern int qemu_dcache_linesize;
extern int qemu_dcache_linesize_log;
/*
* After using getopt or getopt_long, if you need to parse another set
* of options, then you must reset optind. Unfortunately the way to
* do this varies between implementations of getopt.
*/
static inline void qemu_reset_optind(void)
{
#ifdef HAVE_OPTRESET
optind = 1;
optreset = 1;
#else
optind = 0;
#endif
}
#endif
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