syscall.c

qemu虚拟机代码

        ret = fcntl(fd, cmd, arg);
        break;
    }
    return ret;
}

#ifdef USE_UID16

static inline int high2lowuid(int uid)
{
    if (uid > 65535)
        return 65534;
    else
        return uid;
}

static inline int high2lowgid(int gid)
{
    if (gid > 65535)
        return 65534;
    else
        return gid;
}

static inline int low2highuid(int uid)
{
    if ((int16_t)uid == -1)
        return -1;
    else
        return uid;
}

static inline int low2highgid(int gid)
{
    if ((int16_t)gid == -1)
        return -1;
    else
        return gid;
}

#endif /* USE_UID16 */

void syscall_init(void)
{
    IOCTLEntry *ie;
    const argtype *arg_type;
    int size;

#define STRUCT(name, list...) thunk_register_struct(STRUCT_ ## name, #name, struct_ ## name ## _def); 
#define STRUCT_SPECIAL(name) thunk_register_struct_direct(STRUCT_ ## name, #name, &struct_ ## name ## _def); 
#include "syscall_types.h"
#undef STRUCT
#undef STRUCT_SPECIAL

    /* we patch the ioctl size if necessary. We rely on the fact that
       no ioctl has all the bits at '1' in the size field */
    ie = ioctl_entries;
    while (ie->target_cmd != 0) {
        if (((ie->target_cmd >> TARGET_IOC_SIZESHIFT) & TARGET_IOC_SIZEMASK) ==
            TARGET_IOC_SIZEMASK) {
            arg_type = ie->arg_type;
            if (arg_type[0] != TYPE_PTR) {
                fprintf(stderr, "cannot patch size for ioctl 0x%x\n", 
                        ie->target_cmd);
                exit(1);
            }
            arg_type++;
            size = thunk_type_size(arg_type, 0);
            ie->target_cmd = (ie->target_cmd & 
                              ~(TARGET_IOC_SIZEMASK << TARGET_IOC_SIZESHIFT)) |
                (size << TARGET_IOC_SIZESHIFT);
        }
        /* automatic consistency check if same arch */
#if defined(__i386__) && defined(TARGET_I386)
        if (ie->target_cmd != ie->host_cmd) {
            fprintf(stderr, "ERROR: ioctl: target=0x%x host=0x%x\n", 
                    ie->target_cmd, ie->host_cmd);
        }
#endif
        ie++;
    }
}

static inline uint64_t target_offset64(uint32_t word0, uint32_t word1)
{
#ifdef TARGET_WORDS_BIG_ENDIAN
    return ((uint64_t)word0 << 32) | word1;
#else
    return ((uint64_t)word1 << 32) | word0;
#endif
}

#ifdef TARGET_NR_truncate64
static inline long target_truncate64(void *cpu_env, const char *arg1,
                                     long arg2, long arg3, long arg4)
{
#ifdef TARGET_ARM
    if (((CPUARMState *)cpu_env)->eabi)
      {
        arg2 = arg3;
        arg3 = arg4;
      }
#endif
    return get_errno(truncate64(arg1, target_offset64(arg2, arg3)));
}
#endif

#ifdef TARGET_NR_ftruncate64
static inline long target_ftruncate64(void *cpu_env, long arg1, long arg2,
                                      long arg3, long arg4)
{
#ifdef TARGET_ARM
    if (((CPUARMState *)cpu_env)->eabi)
      {
        arg2 = arg3;
        arg3 = arg4;
      }
#endif
    return get_errno(ftruncate64(arg1, target_offset64(arg2, arg3)));
}
#endif

static inline void target_to_host_timespec(struct timespec *host_ts,
                                           target_ulong target_addr)
{
    struct target_timespec *target_ts;

    lock_user_struct(target_ts, target_addr, 1);
    host_ts->tv_sec = tswapl(target_ts->tv_sec);
    host_ts->tv_nsec = tswapl(target_ts->tv_nsec);
    unlock_user_struct(target_ts, target_addr, 0);
}

static inline void host_to_target_timespec(target_ulong target_addr,
                                           struct timespec *host_ts)
{
    struct target_timespec *target_ts;

    lock_user_struct(target_ts, target_addr, 0);
    target_ts->tv_sec = tswapl(host_ts->tv_sec);
    target_ts->tv_nsec = tswapl(host_ts->tv_nsec);
    unlock_user_struct(target_ts, target_addr, 1);
}

long do_syscall(void *cpu_env, int num, long arg1, long arg2, long arg3, 
                long arg4, long arg5, long arg6)
{
    long ret;
    struct stat st;
    struct statfs stfs;
    void *p;
    
#ifdef DEBUG
    gemu_log("syscall %d", num);
#endif
    switch(num) {
    case TARGET_NR_exit:
#ifdef HAVE_GPROF
        _mcleanup();
#endif
        gdb_exit(cpu_env, arg1);
        /* XXX: should free thread stack and CPU env */
        _exit(arg1);
        ret = 0; /* avoid warning */
        break;
    case TARGET_NR_read:
        page_unprotect_range(arg2, arg3);
        p = lock_user(arg2, arg3, 0);
        ret = get_errno(read(arg1, p, arg3));
        unlock_user(p, arg2, ret);
        break;
    case TARGET_NR_write:
        p = lock_user(arg2, arg3, 1);
        ret = get_errno(write(arg1, p, arg3));
        unlock_user(p, arg2, 0);
        break;
    case TARGET_NR_open:
        p = lock_user_string(arg1);
        ret = get_errno(open(path(p),
                             target_to_host_bitmask(arg2, fcntl_flags_tbl),
                             arg3));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_close:
        ret = get_errno(close(arg1));
        break;
    case TARGET_NR_brk:
        ret = do_brk(arg1);
        break;
    case TARGET_NR_fork:
        ret = get_errno(do_fork(cpu_env, SIGCHLD, 0));
        break;
    case TARGET_NR_waitpid:
        {
            int status;
            ret = get_errno(waitpid(arg1, &status, arg3));
            if (!is_error(ret) && arg2)
                tput32(arg2, status);
        }
        break;
    case TARGET_NR_creat:
        p = lock_user_string(arg1);
        ret = get_errno(creat(p, arg2));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_link:
        {
            void * p2;
            p = lock_user_string(arg1);
            p2 = lock_user_string(arg2);
            ret = get_errno(link(p, p2));
            unlock_user(p2, arg2, 0);
            unlock_user(p, arg1, 0);
        }
        break;
    case TARGET_NR_unlink:
        p = lock_user_string(arg1);
        ret = get_errno(unlink(p));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_execve:
        {
            char **argp, **envp;
            int argc, envc;
            target_ulong gp;
            target_ulong guest_argp;
            target_ulong guest_envp;
            target_ulong addr;
            char **q;

            argc = 0;
            guest_argp = arg2;
            for (gp = guest_argp; tgetl(gp); gp++)
                argc++;
            envc = 0;
            guest_envp = arg3;
            for (gp = guest_envp; tgetl(gp); gp++)
                envc++;

            argp = alloca((argc + 1) * sizeof(void *));
            envp = alloca((envc + 1) * sizeof(void *));

            for (gp = guest_argp, q = argp; ;
                  gp += sizeof(target_ulong), q++) {
                addr = tgetl(gp);
                if (!addr)
                    break;
                *q = lock_user_string(addr);
            }
            *q = NULL;

            for (gp = guest_envp, q = envp; ;
                  gp += sizeof(target_ulong), q++) {
                addr = tgetl(gp);
                if (!addr)
                    break;
                *q = lock_user_string(addr);
            }
            *q = NULL;

            p = lock_user_string(arg1);
            ret = get_errno(execve(p, argp, envp));
            unlock_user(p, arg1, 0);

            for (gp = guest_argp, q = argp; *q;
                  gp += sizeof(target_ulong), q++) {
                addr = tgetl(gp);
                unlock_user(*q, addr, 0);
            }
            for (gp = guest_envp, q = envp; *q;
                  gp += sizeof(target_ulong), q++) {
                addr = tgetl(gp);
                unlock_user(*q, addr, 0);
            }
        }
        break;
    case TARGET_NR_chdir:
        p = lock_user_string(arg1);
        ret = get_errno(chdir(p));
        unlock_user(p, arg1, 0);
        break;
#ifdef TARGET_NR_time
    case TARGET_NR_time:
        {
            time_t host_time;
            ret = get_errno(time(&host_time));
            if (!is_error(ret) && arg1)
                tputl(arg1, host_time);
        }
        break;
#endif
    case TARGET_NR_mknod:
        p = lock_user_string(arg1);
        ret = get_errno(mknod(p, arg2, arg3));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_chmod:
        p = lock_user_string(arg1);
        ret = get_errno(chmod(p, arg2));
        unlock_user(p, arg1, 0);
        break;
#ifdef TARGET_NR_break
    case TARGET_NR_break:
        goto unimplemented;
#endif
#ifdef TARGET_NR_oldstat
    case TARGET_NR_oldstat:
        goto unimplemented;
#endif
    case TARGET_NR_lseek:
        ret = get_errno(lseek(arg1, arg2, arg3));
        break;
    case TARGET_NR_getpid:
        ret = get_errno(getpid());
        break;
    case TARGET_NR_mount:
        /* need to look at the data field */
        goto unimplemented;
    case TARGET_NR_umount:
        p = lock_user_string(arg1);
        ret = get_errno(umount(p));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_stime:
        {
            time_t host_time;
            host_time = tgetl(arg1);
            ret = get_errno(stime(&host_time));
        }
        break;
    case TARGET_NR_ptrace:
        goto unimplemented;
    case TARGET_NR_alarm:
        ret = alarm(arg1);
        break;
#ifdef TARGET_NR_oldfstat
    case TARGET_NR_oldfstat:
        goto unimplemented;
#endif
    case TARGET_NR_pause:
        ret = get_errno(pause());
        break;
    case TARGET_NR_utime:
        {
            struct utimbuf tbuf, *host_tbuf;
            struct target_utimbuf *target_tbuf;
            if (arg2) {
                lock_user_struct(target_tbuf, arg2, 1);
                tbuf.actime = tswapl(target_tbuf->actime);
                tbuf.modtime = tswapl(target_tbuf->modtime);
                unlock_user_struct(target_tbuf, arg2, 0);
                host_tbuf = &tbuf;
            } else {
                host_tbuf = NULL;
            }
            p = lock_user_string(arg1);
            ret = get_errno(utime(p, host_tbuf));
            unlock_user(p, arg1, 0);
        }
        break;
    case TARGET_NR_utimes:
        {
            struct timeval *tvp, tv[2];
            if (arg2) {
                target_to_host_timeval(&tv[0], arg2);
                target_to_host_timeval(&tv[1],
                    arg2 + sizeof (struct target_timeval));
                tvp = tv;
            } else {
                tvp = NULL;
            }
            p = lock_user_string(arg1);
            ret = get_errno(utimes(p, tvp));
            unlock_user(p, arg1, 0);
        }
        break;
#ifdef TARGET_NR_stty
    case TARGET_NR_stty:
        goto unimplemented;
#endif
#ifdef TARGET_NR_gtty
    case TARGET_NR_gtty:
        goto unimplemented;
#endif
    case TARGET_NR_access:
        p = lock_user_string(arg1);
        ret = get_errno(access(p, arg2));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_nice:
        ret = get_errno(nice(arg1));
        break;
#ifdef TARGET_NR_ftime
    case TARGET_NR_ftime:
        goto unimplemented;
#endif
    case TARGET_NR_sync:
        sync();
        ret = 0;
        break;
    case TARGET_NR_kill:
        ret = get_errno(kill(arg1, arg2));
        break;
    case TARGET_NR_rename:
        {
            void *p2;
            p = lock_user_string(arg1);
            p2 = lock_user_string(arg2);
            ret = get_errno(rename(p, p2));
            unlock_user(p2, arg2, 0);
            unlock_user(p, arg1, 0);
        }
        break;
    case TARGET_NR_mkdir:
        p = lock_user_string(arg1);
        ret = get_errno(mkdir(p, arg2));
        unlock_user(p, arg1, 0);
        break;
    case TARGET_NR_rmdir:
        p = lock_user_string(arg1);