164 lines
6.7 KiB
Plaintext
164 lines
6.7 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program dnsquery.s */
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/************************************/
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/* Constantes */
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/************************************/
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.equ STDIN, 0 @ Linux input console
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.equ STDOUT, 1 @ Linux output console
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.equ EXIT, 1 @ Linux syscall END PROGRAM
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.equ FORK, 2 @ Linux syscall
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.equ READ, 3 @ Linux syscall
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.equ WRITE, 4 @ Linux syscall
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.equ OPEN, 5 @ Linux syscall
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.equ CLOSE, 6 @ Linux syscall
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.equ EXECVE, 0xB @ Linux syscall
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.equ PIPE, 0x2A @ Linux syscall
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.equ DUP2, 0x3F @ Linux syscall
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.equ WAIT4, 0x72 @ Linux syscall
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.equ WUNTRACED, 2 @ Wait, return status of stopped child
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.equ TAILLEBUFFER, 500
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/*********************************/
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/* Initialized data */
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/*********************************/
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.data
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szCarriageReturn: .asciz "\n"
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szMessFinOK: .asciz "Fin normale du programme. \n"
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szMessError: .asciz "Error occured !!!"
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szCommand: .asciz "/usr/bin/host" @ command host
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szNameHost: .asciz "www.kame.net" @ string query name
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.align 4
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stArg1: .int szCommand @ address command
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.int szNameHost @ address argument
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.int 0,0 @ zeroes
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/*********************************/
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/* UnInitialized data */
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/*********************************/
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.bss
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.align 4
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iStatusThread: .skip 4
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pipefd: .skip 8
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sBuffer: .skip TAILLEBUFFER
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stRusage: .skip TAILLEBUFFER
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/*********************************/
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/* code section */
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/*********************************/
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.text
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.global main
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main: @ entry of program
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/* création pipe */
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ldr r0,iAdrpipefd @ FDs address
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mov r7, #PIPE @ create pipe
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svc 0 @ call system Linux
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cmp r0,#0 @ error ?
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blt 99f
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/* create child thread */
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mov r0,#0
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mov r7, #FORK @ call system
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svc #0
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cmp r0,#0 @ error ?
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blt 99f
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bne parent @ if <> zero r0 contains father pid
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@ else is the child
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/****************************************/
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/* Child thread */
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/****************************************/
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/* redirection sysout -> pipe */
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ldr r0,iAdrpipefd
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ldr r0,[r0,#4]
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mov r7, #DUP2 @ call system linux
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mov r1, #STDOUT @
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svc #0
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cmp r0,#0 @ error ?
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blt 99f
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/* run command host */
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ldr r0, iAdrszCommand @ r0 = address de "/usr/bin/host"
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ldr r1,iAdrstArg1 @ address argument 1
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mov r2,#0
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mov r7, #EXECVE @ call system linux (execve)
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svc #0 @ if ok -> no return !!!
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b 100f @ never exec this label
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/****************************************/
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/* Father thread */
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/****************************************/
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parent:
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mov r4,r0 @ save child pid
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1: @ loop child signal
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mov r0,r4
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ldr r1,iAdriStatusThread @ return status thread
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mov r2,#WUNTRACED @ flags
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ldr r3,iAdrstRusage @ return structure thread
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mov r7, #WAIT4 @ Call System
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svc #0
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cmp r0,#0 @ error ?
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blt 99f
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@ recup status
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ldr r0,iAdriStatusThread @ analyse status
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ldrb r0,[r0] @ firest byte
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cmp r0,#0 @ normal end thread ?
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bne 1b @ loop
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/* close entry pipe */
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ldr r0,iAdrpipefd
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mov r7,#CLOSE @ call system
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svc #0
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/* read datas pipe */
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ldr r0,iAdrpipefd
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ldr r0,[r0]
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ldr r1,iAdrsBuffer @ buffer address
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mov r2,#TAILLEBUFFER @ buffer size
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mov r7, #READ @ call system
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svc #0
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ldr r0,iAdrsBuffer @ display buffer
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bl affichageMess
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ldr r0,iAdrszMessFinOK @ display message Ok
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bl affichageMess
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mov r0, #0 @ return code
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b 100f
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99:
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ldr r0,iAdrszMessError @ erreur
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bl affichageMess
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mov r0, #1 @ return code
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b 100f
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100: @ standard end of the program
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mov r7, #EXIT @ request to exit program
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svc #0 @ perform the system call
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iAdrszCarriageReturn: .int szCarriageReturn
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iAdrszMessFinOK: .int szMessFinOK
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iAdrszMessError: .int szMessError
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iAdrsBuffer: .int sBuffer
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iAdrpipefd: .int pipefd
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iAdrszCommand: .int szCommand
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iAdrstArg1: .int stArg1
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iAdriStatusThread: .int iStatusThread
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iAdrstRusage: .int stRusage
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/******************************************************************/
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/* display text with size calculation */
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/******************************************************************/
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/* r0 contains the address of the message */
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affichageMess:
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push {r0,r1,r2,r7,lr} @ save registres
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mov r2,#0 @ counter length
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1: @ loop length calculation
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ldrb r1,[r0,r2] @ read octet start position + index
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cmp r1,#0 @ if 0 its over
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addne r2,r2,#1 @ else add 1 in the length
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bne 1b @ and loop
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@ so here r2 contains the length of the message
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mov r1,r0 @ address message in r1
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mov r0,#STDOUT @ code to write to the standard output Linux
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mov r7, #WRITE @ code call system "write"
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svc #0 @ call systeme
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pop {r0,r1,r2,r7,lr} @ restaur des 2 registres */
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bx lr @ return
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