我希望你能够懂,每个操作系统在内核中都有一些最为基本的函数给系统的其他操作调用.在Linux系统中这些函数就被称为系统调用(System Call).他们代表了一个从用户级别到内核级别的转换.
1.2什么是系统调用
我希望你能够懂,每个操作系统在内核中都有一些最为基本的函数给系统的其他操作调用.在Linux系统中这些函数就被称为系统调用(System Call).他们代表了一个从用户级别到内核级别的转换.在用户级别中打开一个文件在内核级别中是通过sys_open这个系统调用实现的.在/usr/include/sys/syscall.h中有一个完整的系统调用列表.下面的列表是我的syscall.h
#ifndef _SYS_SYSCALL_H
#define _SYS_SYSCALL_H
#define SYS_setup 0
/* 只被init使用,用来启动系统的*/
#define SYS_exit 1
#define SYS_fork 2
#define SYS_read 3
#define SYS_write 4
#define SYS_open 5
#define SYS_close 6
#define SYS_waitpid 7
#define SYS_creat 8
#define SYS_link 9
#define SYS_unlink 10
#define SYS_execve 11
#define SYS_chdir 12
#define SYS_time 13
#define SYS_prev_mknod 14
#define SYS_chmod 15
#define SYS_chown 16
#define SYS_break 17
#define SYS_oldstat 18
#define SYS_lseek 19
#define SYS_getpid 20
#define SYS_mount 21
#define SYS_umount 22
#define SYS_setuid 23
#define SYS_getuid 24
#define SYS_stime 25
#define SYS_ptrace 26
#define SYS_alarm 27
#define SYS_oldfstat 28
#define SYS_pause 29
#define SYS_utime 30
#define SYS_stty 31
#define SYS_gtty 32
#define SYS_access 33
#define SYS_nice 34
#define SYS_ftime 35
#define SYS_sync 36
#define SYS_kill 37
#define SYS_rename 38
#define SYS_mkdir 39
#define SYS_rmdir 40
#define SYS_dup 41
#define SYS_pipe 42
#define SYS_times 43
#define SYS_prof 44
#define SYS_brk 45
#define SYS_setgid 46
#define SYS_getgid 47
#define SYS_signal 48
#define SYS_geteuid 49
#define SYS_getegid 50
#define SYS_acct 51
#define SYS_phys 52
#define SYS_lock 53
#define SYS_ioctl 54
#define SYS_fcntl 55
#define SYS_mpx 56
#define SYS_setpgid 57
#define SYS_ulimit 58
#define SYS_oldolduname 59
#define SYS_umask 60
#define SYS_chroot 61
#define SYS_prev_ustat 62
#define SYS_dup2 63
#define SYS_getppid 64
#define SYS_getpgrp 65
#define SYS_setsid 66
#define SYS_sigaction 67
#define SYS_siggetmask 68
#define SYS_sigsetmask 69
#define SYS_setreuid 70
#define SYS_setregid 71
#define SYS_sigsuspend 72
#define SYS_sigpending 73
#define SYS_sethostname 74
#define SYS_setrlimit 75
#define SYS_getrlimit 76
#define SYS_getrusage 77
#define SYS_gettimeofday 78
#define SYS_settimeofday 79
#define SYS_getgroups 80
#define SYS_setgroups 81
#define SYS_select 82
#define SYS_symlink 83
#define SYS_oldlstat 84
#define SYS_readlink 85
#define SYS_uselib 86
#define SYS_swapon 87
#define SYS_reboot 88
#define SYS_readdir 89
#define SYS_mmap 90
#define SYS_munmap 91
#define SYS_truncate 92
#define SYS_ftruncate 93
#define SYS_fchmod 94
#define SYS_fchown 95
#define SYS_getpriority 96
#define SYS_setpriority 97
#define SYS_profil 98
#define SYS_statfs 99
#define SYS_fstatfs 100
#define SYS_ioperm 101
#define SYS_socketcall 102
#define SYS_klog 103
#define SYS_setitimer 104
#define SYS_getitimer 105
#define SYS_prev_stat 106
#define SYS_prev_lstat 107
#define SYS_prev_fstat 108
#define SYS_olduname 109
#define SYS_iopl 110
#define SYS_vhangup 111
#define SYS_idle 112
#define SYS_vm86old 113
#define SYS_wait4 114
#define SYS_swapoff 115
#define SYS_sysinfo 116
#define SYS_ipc 117
#define SYS_fsync 118
#define SYS_sigreturn 119
#define SYS_clone 120
#define SYS_setdomainname 121
#define SYS_uname 122
#define SYS_modify_ldt 123
#define SYS_adjtimex 124
#define SYS_mprotect 125
#define SYS_sigprocmask 126
#define SYS_create_module 127
#define SYS_init_module 128
#define SYS_delete_module 129
#define SYS_get_kernel_syms 130
#define SYS_quotactl 131
#define SYS_getpgid 132
#define SYS_fchdir 133
#define SYS_bdflush 134
#define SYS_sysfs 135
#define SYS_personality 136
#define SYS_afs_syscall 137
#define SYS_setfsuid 138
#define SYS_setfsgid 139
#define SYS__llseek 140
#define SYS_getdents 141
#define SYS__newselect 142
#define SYS_flock 143
#define SYS_syscall_flock SYS_flock
#define SYS_msync 144
#define SYS_readv 145
#define SYS_syscall_readv SYS_readv
#define SYS_writev 146
#define SYS_syscall_writev SYS_writev
#define SYS_getsid 147
#define SYS_fdatasync 148
#define SYS__sysctl 149
#define SYS_mlock 150
#define SYS_munlock 151
#define SYS_mlockall 152
#define SYS_munlockall 153
#define SYS_sched_setparam 154
#define SYS_sched_getparam 155
#define SYS_sched_setscheduler 156
#define SYS_sched_getscheduler 157
#define SYS_sched_yield 158
#define SYS_sched_get_priority_max 159
#define SYS_sched_get_priority_min 160
#define SYS_sched_rr_get_interval 161
#define SYS_nanosleep 162
#define SYS_mremap 163
#define SYS_setresuid 164
#define SYS_getresuid 165
#define SYS_vm86 166
#define SYS_query_module 167
#define SYS_poll 168
#define SYS_syscall_poll SYS_poll
#endif /* */ |
每个系统调用都有一个预定义的数字(见上表),那实际上是用来进行这些调用的.内核通过中断0x80来控制每一个系统调用.这些系统调用的数字以及任何参数都将被放入某些寄存器(eax用来放那些代表系统调用的数字,比如说)
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