assembler/echo-server
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number Zero 2016-02-21 01:00:03 +03:00
parent a7fd2b390c
commit 81e488e287
1 changed files with 60 additions and 24 deletions
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72
main.S
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@ -13,16 +13,22 @@
#define PORT 20335 #define PORT 20335
.data .data
greeting: .ascii "Socket test!\n" greeting:
.ascii "Welcome to the minimalistic echo server!\n"
.ascii "It is written in pure assembly, and it don't use the standard library, only raw system calls.\n"
.ascii "\n"
.ascii "To exit, press Ctrl+C, as usual\n"
.ascii "\n"
.set greeting_len, .-greeting .set greeting_len, .-greeting
bye: .ascii "Sockets tested!\n" message: .ascii "Client connected\n"
.set bye_len, .-bye .set message_len, .-message
errstr: .ascii "Error happened\n" errstr: .ascii "Error happened\n"
.set errstr_len, .-errstr .set errstr_len, .-errstr
s: .quad 0 s: .quad 0
s2: .quad 0
true_val: .quad 1 true_val: .quad 1
.set true_val_len, .-true_val .set true_val_len, .-true_val
@ -39,7 +45,7 @@ myaddr:
.text .text
.global _start .global _start
_start: _start:
movq $STDERR, %rdi movq $STDOUT, %rdi
movq $greeting, %rsi movq $greeting, %rsi
movq $greeting_len, %rdx movq $greeting_len, %rdx
call write_buf call write_buf
@ -78,6 +84,7 @@ _start:
test %rax, %rax test %rax, %rax
jnz error jnz error
loop:
movq $__NR_accept, %rax movq $__NR_accept, %rax
movq s, %rdi movq s, %rdi
movq $0, %rsi movq $0, %rsi
@ -86,34 +93,63 @@ _start:
syscall syscall
cmp $-1, %rax cmp $-1, %rax
jz error jz error
movq %rax, s2
test %rax, %rax movq $STDOUT, %rdi
jz error movq $message, %rsi
movq $message_len, %rdx
movq %rax, %rdi
movq $STDOUT, %rsi
call passthru
movq $STDERR, %rdi
movq $bye, %rsi
movq $bye_len, %rdx
call write_buf call write_buf
movq $__NR_fork, %rax
syscall /* fork! */
cmp $-1, %rax
jz error
test %rax, %rax
jz child
/* we're in the parent if we reach this line */
movq $__NR_close, %rax
movq s2, %rdi
syscall
test %rax, %rax
jnz error
jmp loop
exit: exit:
movq $__NR_close, %rax movq $__NR_close, %rax
movq s, %rdi movq s, %rdi
syscall syscall
test %rax, %rax
jnz error
_exit:
movq $__NR_exit, %rax movq $__NR_exit, %rax
movq $0, %rdi movq $0, %rdi
syscall syscall
movq $0, 0 /* this line is unreachable */
error: error:
movq $__NR_write, %rax movq $__NR_write, %rax
movq $STDERR, %rdi movq $STDOUT, %rdi
movq $errstr, %rsi movq $errstr, %rsi
movq $errstr_len, %rdx movq $errstr_len, %rdx
syscall syscall
jmp _exit
movq $__NR_exit, %rax
movq $0, %rdi
syscall
/* this line is unreachable */
child:
/* we're in the child if we reach this line */
movq s2, %rdi
movq s2, %rsi
call passthru
movq $__NR_close, %rax
movq s2, %rdi
syscall
movq $__NR_exit, %rax
movq $0, %rdi
syscall
/* this line is unreachable */