146 lines
3 KiB
NASM
146 lines
3 KiB
NASM
; Arquivo: pipe_ls_cat.asm
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; Montar com: nasm -felf64 pipe_ls_cat.asm && ld -o pipe_ls_cat pipe_ls_cat.o
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%define SYS_READ 0
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%define SYS_WRITE 1
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%define SYS_CLOSE 3
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%define SYS_PIPE 22
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%define SYS_DUP2 33
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%define SYS_FORK 57
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%define SYS_EXECVE 59
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%define SYS_EXIT 60
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%define SYS_WAITPID 61
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%define STDIN_FD 0
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%define STDOUT_FD 1
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%define STDERR_FD 2
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%define EXIT_SUCCESS 0
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%define EXIT_FAILURE 1
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section .rodata
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cmd_ls db "/bin/ls", 0
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arg0_ls dq cmd_ls
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arg1_ls db "-l", 0
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arg2_ls db "/proc/self/fd", 0
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argv_ls dq arg0_ls, arg1_ls, arg2_ls, 0
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cmd_cat db "/bin/cat", 0
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arg0_cat dq cmd_cat
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argv_cat dq arg0_cat, 0
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envp_null dq 0
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section .bss
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pipefds resq 2 ; 2 x 8 bytes (r/w)
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section .text
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global _start
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_start:
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; Cria pipe
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mov rax, SYS_PIPE
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mov rdi, pipefds
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syscall
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mov r12, [pipefds] ; leitura (pipefds[0])
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mov r13, [pipefds + 8] ; escrita (pipefds[1])
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; Fork para ls
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mov rax, SYS_FORK
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syscall
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test rax, rax
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jz .ls_child
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; Fork para cat
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mov rax, SYS_FORK
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syscall
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test rax, rax
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jz .cat_child
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; Pai: fecha descritores do pipe
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mov rax, SYS_CLOSE
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mov rdi, r12
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syscall
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mov rax, SYS_CLOSE
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mov rdi, r13
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syscall
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; Espera dois filhos
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xor rdi, rdi
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xor rsi, rsi
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xor rdx, rdx
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mov rax, SYS_WAITPID
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syscall
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xor rdi, rdi
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xor rsi, rsi
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xor rdx, rdx
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mov rax, SYS_WAITPID
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syscall
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; Finaliza
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mov rax, SYS_EXIT
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xor rdi, rdi
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syscall
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; -----------------------------------------
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; Processo filho: ls -l /proc/self/fd
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; -----------------------------------------
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.ls_child:
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; Redireciona stdout → pipe[1]
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mov rax, SYS_DUP2
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mov rdi, r13 ; escrita
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mov rsi, STDOUT_FD
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syscall
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; Fecha descritores
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mov rax, SYS_CLOSE
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mov rdi, r12
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syscall
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mov rax, SYS_CLOSE
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mov rdi, r13
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syscall
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; execve("/bin/ls", ["ls", "-l", "/proc/self/fd"], NULL)
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mov rax, SYS_EXECVE
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mov rdi, cmd_ls
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mov rsi, argv_ls
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mov rdx, envp_null
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syscall
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; Se execve falhar
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mov rax, SYS_EXIT
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mov rdi, EXIT_FAILURE
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syscall
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; -----------------------------------------
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; Processo filho: cat
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; -----------------------------------------
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.cat_child:
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; Redireciona stdin ← pipe[0]
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mov rax, SYS_DUP2
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mov rdi, r12 ; leitura
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mov rsi, STDIN_FD
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syscall
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; Fecha descritores
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mov rax, SYS_CLOSE
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mov rdi, r12
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syscall
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mov rax, SYS_CLOSE
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mov rdi, r13
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syscall
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; execve("/bin/cat", ["cat"], NULL)
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mov rax, SYS_EXECVE
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mov rdi, cmd_cat
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mov rsi, argv_cat
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mov rdx, envp_null
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syscall
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; Se execve falhar
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mov rax, SYS_EXIT
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mov rdi, EXIT_FAILURE
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syscall
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