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qemu/linux-user/qemu.h
Alex Bennée 708b6a643c linux-user: introduce preexit_cleanup 
To avoid repeating ourselves move our preexit clean-up code into a
helper function. I figured the continuing effort to split of the
syscalls made it worthwhile creating a new file for it now.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
2018-07-05 15:59:41 +01:00

642 lines
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#ifndef QEMU_H
#define QEMU_H
#include "hostdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#undef DEBUG_REMAP
#ifdef DEBUG_REMAP
#endif /* DEBUG_REMAP */
#include "exec/user/abitypes.h"
#include "exec/user/thunk.h"
#include "syscall_defs.h"
#include "target_syscall.h"
#include "exec/gdbstub.h"
#include "qemu/queue.h"
/* This is the size of the host kernel's sigset_t, needed where we make
* direct system calls that take a sigset_t pointer and a size.
*/
#define SIGSET_T_SIZE (_NSIG / 8)
/* This struct is used to hold certain information about the image.
* Basically, it replicates in user space what would be certain
* task_struct fields in the kernel
*/
struct image_info {
abi_ulong load_bias;
abi_ulong load_addr;
abi_ulong start_code;
abi_ulong end_code;
abi_ulong start_data;
abi_ulong end_data;
abi_ulong start_brk;
abi_ulong brk;
abi_ulong start_mmap;
abi_ulong start_stack;
abi_ulong stack_limit;
abi_ulong entry;
abi_ulong code_offset;
abi_ulong data_offset;
abi_ulong saved_auxv;
abi_ulong auxv_len;
abi_ulong arg_start;
abi_ulong arg_end;
abi_ulong arg_strings;
abi_ulong env_strings;
abi_ulong file_string;
uint32_t elf_flags;
int personality;
/* The fields below are used in FDPIC mode. */
abi_ulong loadmap_addr;
uint16_t nsegs;
void *loadsegs;
abi_ulong pt_dynamic_addr;
abi_ulong interpreter_loadmap_addr;
abi_ulong interpreter_pt_dynamic_addr;
struct image_info *other_info;
};
#ifdef TARGET_I386
/* Information about the current linux thread */
struct vm86_saved_state {
uint32_t eax; /* return code */
uint32_t ebx;
uint32_t ecx;
uint32_t edx;
uint32_t esi;
uint32_t edi;
uint32_t ebp;
uint32_t esp;
uint32_t eflags;
uint32_t eip;
uint16_t cs, ss, ds, es, fs, gs;
};
#endif
#if defined(TARGET_ARM) && defined(TARGET_ABI32)
/* FPU emulator */
#include "nwfpe/fpa11.h"
#endif
#define MAX_SIGQUEUE_SIZE 1024
struct emulated_sigtable {
int pending; /* true if signal is pending */
target_siginfo_t info;
};
/* NOTE: we force a big alignment so that the stack stored after is
aligned too */
typedef struct TaskState {
pid_t ts_tid; /* tid (or pid) of this task */
#ifdef TARGET_ARM
# ifdef TARGET_ABI32
/* FPA state */
FPA11 fpa;
# endif
int swi_errno;
#endif
#if defined(TARGET_I386) && !defined(TARGET_X86_64)
abi_ulong target_v86;
struct vm86_saved_state vm86_saved_regs;
struct target_vm86plus_struct vm86plus;
uint32_t v86flags;
uint32_t v86mask;
#endif
abi_ulong child_tidptr;
#ifdef TARGET_M68K
int sim_syscalls;
abi_ulong tp_value;
#endif
#if defined(TARGET_ARM) || defined(TARGET_M68K)
/* Extra fields for semihosted binaries. */
abi_ulong heap_base;
abi_ulong heap_limit;
#endif
abi_ulong stack_base;
int used; /* non zero if used */
struct image_info *info;
struct linux_binprm *bprm;
struct emulated_sigtable sync_signal;
struct emulated_sigtable sigtab[TARGET_NSIG];
/* This thread's signal mask, as requested by the guest program.
* The actual signal mask of this thread may differ:
* + we don't let SIGSEGV and SIGBUS be blocked while running guest code
* + sometimes we block all signals to avoid races
*/
sigset_t signal_mask;
/* The signal mask imposed by a guest sigsuspend syscall, if we are
* currently in the middle of such a syscall
*/
sigset_t sigsuspend_mask;
/* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
int in_sigsuspend;
/* Nonzero if process_pending_signals() needs to do something (either
* handle a pending signal or unblock signals).
* This flag is written from a signal handler so should be accessed via
* the atomic_read() and atomic_write() functions. (It is not accessed
* from multiple threads.)
*/
int signal_pending;
} __attribute__((aligned(16))) TaskState;
extern char *exec_path;
void init_task_state(TaskState *ts);
void task_settid(TaskState *);
void stop_all_tasks(void);
extern const char *qemu_uname_release;
extern unsigned long mmap_min_addr;
/* ??? See if we can avoid exposing so much of the loader internals. */
/* Read a good amount of data initially, to hopefully get all the
program headers loaded. */
#define BPRM_BUF_SIZE 1024
/*
* This structure is used to hold the arguments that are
* used when loading binaries.
*/
struct linux_binprm {
char buf[BPRM_BUF_SIZE] __attribute__((aligned));
abi_ulong p;
int fd;
int e_uid, e_gid;
int argc, envc;
char **argv;
char **envp;
char * filename; /* Name of binary */
int (*core_dump)(int, const CPUArchState *); /* coredump routine */
};
void do_init_thread(struct target_pt_regs *regs, struct image_info *infop);
abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
abi_ulong stringp, int push_ptr);
int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
struct target_pt_regs * regs, struct image_info *infop,
struct linux_binprm *);
/* Returns true if the image uses the FDPIC ABI. If this is the case,
* we have to provide some information (loadmap, pt_dynamic_info) such
* that the program can be relocated adequately. This is also useful
* when handling signals.
*/
int info_is_fdpic(struct image_info *info);
uint32_t get_elf_eflags(int fd);
int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);
int load_flt_binary(struct linux_binprm *bprm, struct image_info *info);
abi_long memcpy_to_target(abi_ulong dest, const void *src,
unsigned long len);
void target_set_brk(abi_ulong new_brk);
abi_long do_brk(abi_ulong new_brk);
void syscall_init(void);
abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
abi_long arg2, abi_long arg3, abi_long arg4,
abi_long arg5, abi_long arg6, abi_long arg7,
abi_long arg8);
void gemu_log(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
extern __thread CPUState *thread_cpu;
void cpu_loop(CPUArchState *env);
const char *target_strerror(int err);
int get_osversion(void);
void init_qemu_uname_release(void);
void fork_start(void);
void fork_end(int child);
/* Creates the initial guest address space in the host memory space using
* the given host start address hint and size. The guest_start parameter
* specifies the start address of the guest space. guest_base will be the
* difference between the host start address computed by this function and
* guest_start. If fixed is specified, then the mapped address space must
* start at host_start. The real start address of the mapped memory space is
* returned or -1 if there was an error.
*/
unsigned long init_guest_space(unsigned long host_start,
unsigned long host_size,
unsigned long guest_start,
bool fixed);
#include "qemu/log.h"
/* safe_syscall.S */
/**
* safe_syscall:
* @int number: number of system call to make
* ...: arguments to the system call
*
* Call a system call if guest signal not pending.
* This has the same API as the libc syscall() function, except that it
* may return -1 with errno == TARGET_ERESTARTSYS if a signal was pending.
*
* Returns: the system call result, or -1 with an error code in errno
* (Errnos are host errnos; we rely on TARGET_ERESTARTSYS not clashing
* with any of the host errno values.)
*/
/* A guide to using safe_syscall() to handle interactions between guest
* syscalls and guest signals:
*
* Guest syscalls come in two flavours:
*
* (1) Non-interruptible syscalls
*
* These are guest syscalls that never get interrupted by signals and
* so never return EINTR. They can be implemented straightforwardly in
* QEMU: just make sure that if the implementation code has to make any
* blocking calls that those calls are retried if they return EINTR.
* It's also OK to implement these with safe_syscall, though it will be
* a little less efficient if a signal is delivered at the 'wrong' moment.
*
* Some non-interruptible syscalls need to be handled using block_signals()
* to block signals for the duration of the syscall. This mainly applies
* to code which needs to modify the data structures used by the
* host_signal_handler() function and the functions it calls, including
* all syscalls which change the thread's signal mask.
*
* (2) Interruptible syscalls
*
* These are guest syscalls that can be interrupted by signals and
* for which we need to either return EINTR or arrange for the guest
* syscall to be restarted. This category includes both syscalls which
* always restart (and in the kernel return -ERESTARTNOINTR), ones
* which only restart if there is no handler (kernel returns -ERESTARTNOHAND
* or -ERESTART_RESTARTBLOCK), and the most common kind which restart
* if the handler was registered with SA_RESTART (kernel returns
* -ERESTARTSYS). System calls which are only interruptible in some
* situations (like 'open') also need to be handled this way.
*
* Here it is important that the host syscall is made
* via this safe_syscall() function, and *not* via the host libc.
* If the host libc is used then the implementation will appear to work
* most of the time, but there will be a race condition where a
* signal could arrive just before we make the host syscall inside libc,
* and then then guest syscall will not correctly be interrupted.
* Instead the implementation of the guest syscall can use the safe_syscall
* function but otherwise just return the result or errno in the usual
* way; the main loop code will take care of restarting the syscall
* if appropriate.
*
* (If the implementation needs to make multiple host syscalls this is
* OK; any which might really block must be via safe_syscall(); for those
* which are only technically blocking (ie which we know in practice won't
* stay in the host kernel indefinitely) it's OK to use libc if necessary.
* You must be able to cope with backing out correctly if some safe_syscall
* you make in the implementation returns either -TARGET_ERESTARTSYS or
* EINTR though.)
*
* block_signals() cannot be used for interruptible syscalls.
*
*
* How and why the safe_syscall implementation works:
*
* The basic setup is that we make the host syscall via a known
* section of host native assembly. If a signal occurs, our signal
* handler checks the interrupted host PC against the addresse of that
* known section. If the PC is before or at the address of the syscall
* instruction then we change the PC to point at a "return
* -TARGET_ERESTARTSYS" code path instead, and then exit the signal handler
* (causing the safe_syscall() call to immediately return that value).
* Then in the main.c loop if we see this magic return value we adjust
* the guest PC to wind it back to before the system call, and invoke
* the guest signal handler as usual.
*
* This winding-back will happen in two cases:
* (1) signal came in just before we took the host syscall (a race);
* in this case we'll take the guest signal and have another go
* at the syscall afterwards, and this is indistinguishable for the
* guest from the timing having been different such that the guest
* signal really did win the race
* (2) signal came in while the host syscall was blocking, and the
* host kernel decided the syscall should be restarted;
* in this case we want to restart the guest syscall also, and so
* rewinding is the right thing. (Note that "restart" semantics mean
* "first call the signal handler, then reattempt the syscall".)
* The other situation to consider is when a signal came in while the
* host syscall was blocking, and the host kernel decided that the syscall
* should not be restarted; in this case QEMU's host signal handler will
* be invoked with the PC pointing just after the syscall instruction,
* with registers indicating an EINTR return; the special code in the
* handler will not kick in, and we will return EINTR to the guest as
* we should.
*
* Notice that we can leave the host kernel to make the decision for
* us about whether to do a restart of the syscall or not; we do not
* need to check SA_RESTART flags in QEMU or distinguish the various
* kinds of restartability.
*/
#ifdef HAVE_SAFE_SYSCALL
/* The core part of this function is implemented in assembly */
extern long safe_syscall_base(int *pending, long number, ...);
#define safe_syscall(...) \
({ \
long ret_; \
int *psp_ = &((TaskState *)thread_cpu->opaque)->signal_pending; \
ret_ = safe_syscall_base(psp_, __VA_ARGS__); \
if (is_error(ret_)) { \
errno = -ret_; \
ret_ = -1; \
} \
ret_; \
})
#else
/* Fallback for architectures which don't yet provide a safe-syscall assembly
* fragment; note that this is racy!
* This should go away when all host architectures have been updated.
*/
#define safe_syscall syscall
#endif
/* syscall.c */
int host_to_target_waitstatus(int status);
/* strace.c */
void print_syscall(int num,
abi_long arg1, abi_long arg2, abi_long arg3,
abi_long arg4, abi_long arg5, abi_long arg6);
void print_syscall_ret(int num, abi_long arg1);
/**
* print_taken_signal:
* @target_signum: target signal being taken
* @tinfo: target_siginfo_t which will be passed to the guest for the signal
*
* Print strace output indicating that this signal is being taken by the guest,
* in a format similar to:
* --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} ---
*/
void print_taken_signal(int target_signum, const target_siginfo_t *tinfo);
extern int do_strace;
/* signal.c */
void process_pending_signals(CPUArchState *cpu_env);
void signal_init(void);
int queue_signal(CPUArchState *env, int sig, int si_type,
target_siginfo_t *info);
void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info);
void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo);
int target_to_host_signal(int sig);
int host_to_target_signal(int sig);
long do_sigreturn(CPUArchState *env);
long do_rt_sigreturn(CPUArchState *env);
abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);
int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
/**
* block_signals: block all signals while handling this guest syscall
*
* Block all signals, and arrange that the signal mask is returned to
* its correct value for the guest before we resume execution of guest code.
* If this function returns non-zero, then the caller should immediately
* return -TARGET_ERESTARTSYS to the main loop, which will take the pending
* signal and restart execution of the syscall.
* If block_signals() returns zero, then the caller can continue with
* emulation of the system call knowing that no signals can be taken
* (and therefore that no race conditions will result).
* This should only be called once, because if it is called a second time
* it will always return non-zero. (Think of it like a mutex that can't
* be recursively locked.)
* Signals will be unblocked again by process_pending_signals().
*
* Return value: non-zero if there was a pending signal, zero if not.
*/
int block_signals(void); /* Returns non zero if signal pending */
#ifdef TARGET_I386
/* vm86.c */
void save_v86_state(CPUX86State *env);
void handle_vm86_trap(CPUX86State *env, int trapno);
void handle_vm86_fault(CPUX86State *env);
int do_vm86(CPUX86State *env, long subfunction, abi_ulong v86_addr);
#elif defined(TARGET_SPARC64)
void sparc64_set_context(CPUSPARCState *env);
void sparc64_get_context(CPUSPARCState *env);
#endif
/* mmap.c */
int target_mprotect(abi_ulong start, abi_ulong len, int prot);
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
int flags, int fd, abi_ulong offset);
int target_munmap(abi_ulong start, abi_ulong len);
abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
abi_ulong new_size, unsigned long flags,
abi_ulong new_addr);
extern unsigned long last_brk;
extern abi_ulong mmap_next_start;
abi_ulong mmap_find_vma(abi_ulong, abi_ulong);
void mmap_fork_start(void);
void mmap_fork_end(int child);
/* main.c */
extern unsigned long guest_stack_size;
/* user access */
#define VERIFY_READ 0
#define VERIFY_WRITE 1 /* implies read access */
static inline int access_ok(int type, abi_ulong addr, abi_ulong size)
{
return page_check_range((target_ulong)addr, size,
(type == VERIFY_READ) ? PAGE_READ : (PAGE_READ | PAGE_WRITE)) == 0;
}
/* NOTE __get_user and __put_user use host pointers and don't check access.
These are usually used to access struct data members once the struct has
been locked - usually with lock_user_struct. */
/* Tricky points:
- Use __builtin_choose_expr to avoid type promotion from ?:,
- Invalid sizes result in a compile time error stemming from
the fact that abort has no parameters.
- It's easier to use the endian-specific unaligned load/store
functions than host-endian unaligned load/store plus tswapN. */
#define __put_user_e(x, hptr, e) \
(__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort)))) \
((hptr), (x)), (void)0)
#define __get_user_e(x, hptr, e) \
((x) = (typeof(*hptr))( \
__builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p, \
__builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort)))) \
(hptr)), (void)0)
#ifdef TARGET_WORDS_BIGENDIAN
# define __put_user(x, hptr) __put_user_e(x, hptr, be)
# define __get_user(x, hptr) __get_user_e(x, hptr, be)
#else
# define __put_user(x, hptr) __put_user_e(x, hptr, le)
# define __get_user(x, hptr) __get_user_e(x, hptr, le)
#endif
/* put_user()/get_user() take a guest address and check access */
/* These are usually used to access an atomic data type, such as an int,
* that has been passed by address. These internally perform locking
* and unlocking on the data type.
*/
#define put_user(x, gaddr, target_type) \
({ \
abi_ulong __gaddr = (gaddr); \
target_type *__hptr; \
abi_long __ret = 0; \
if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
__put_user((x), __hptr); \
unlock_user(__hptr, __gaddr, sizeof(target_type)); \
} else \
__ret = -TARGET_EFAULT; \
__ret; \
})
#define get_user(x, gaddr, target_type) \
({ \
abi_ulong __gaddr = (gaddr); \
target_type *__hptr; \
abi_long __ret = 0; \
if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
__get_user((x), __hptr); \
unlock_user(__hptr, __gaddr, 0); \
} else { \
/* avoid warning */ \
(x) = 0; \
__ret = -TARGET_EFAULT; \
} \
__ret; \
})
#define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
#define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
#define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
#define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
#define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
#define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
#define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
#define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
#define put_user_u8(x, gaddr) put_user((x), (gaddr), uint8_t)
#define put_user_s8(x, gaddr) put_user((x), (gaddr), int8_t)
#define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
#define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
#define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
#define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
#define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
#define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
#define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
#define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
#define get_user_u8(x, gaddr) get_user((x), (gaddr), uint8_t)
#define get_user_s8(x, gaddr) get_user((x), (gaddr), int8_t)
/* copy_from_user() and copy_to_user() are usually used to copy data
* buffers between the target and host. These internally perform
* locking/unlocking of the memory.
*/
abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len);
abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len);
/* Functions for accessing guest memory. The tget and tput functions
read/write single values, byteswapping as necessary. The lock_user function
gets a pointer to a contiguous area of guest memory, but does not perform
any byteswapping. lock_user may return either a pointer to the guest
memory, or a temporary buffer. */
/* Lock an area of guest memory into the host. If copy is true then the
host area will have the same contents as the guest. */
static inline void *lock_user(int type, abi_ulong guest_addr, long len, int copy)
{
if (!access_ok(type, guest_addr, len))
return NULL;
#ifdef DEBUG_REMAP
{
void *addr;
addr = g_malloc(len);
if (copy)
memcpy(addr, g2h(guest_addr), len);
else
memset(addr, 0, len);
return addr;
}
#else
return g2h(guest_addr);
#endif
}
/* Unlock an area of guest memory. The first LEN bytes must be
flushed back to guest memory. host_ptr = NULL is explicitly
allowed and does nothing. */
static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
long len)
{
#ifdef DEBUG_REMAP
if (!host_ptr)
return;
if (host_ptr == g2h(guest_addr))
return;
if (len > 0)
memcpy(g2h(guest_addr), host_ptr, len);
g_free(host_ptr);
#endif
}
/* Return the length of a string in target memory or -TARGET_EFAULT if
access error. */
abi_long target_strlen(abi_ulong gaddr);
/* Like lock_user but for null terminated strings. */
static inline void *lock_user_string(abi_ulong guest_addr)
{
abi_long len;
len = target_strlen(guest_addr);
if (len < 0)
return NULL;
return lock_user(VERIFY_READ, guest_addr, (long)(len + 1), 1);
}
/* Helper macros for locking/unlocking a target struct. */
#define lock_user_struct(type, host_ptr, guest_addr, copy) \
(host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
#define unlock_user_struct(host_ptr, guest_addr, copy) \
unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
#include <pthread.h>
static inline int is_error(abi_long ret)
{
return (abi_ulong)ret >= (abi_ulong)(-4096);
}
/**
* preexit_cleanup: housekeeping before the guest exits
*
* env: the CPU state
* code: the exit code
*/
void preexit_cleanup(CPUArchState *env, int code);
/* Include target-specific struct and function definitions;
* they may need access to the target-independent structures
* above, so include them last.
*/
#include "target_cpu.h"
#include "target_structs.h"
#endif /* QEMU_H */
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