9cef025687
- Created env.c/h: key=value store with ENV_MAX_VARS=32 entries per process. Supports get, set, unset, and copy operations. - Added env_block_t and cwd[128] fields to process_t struct. - process_create() initializes CWD=/ by default. - Fork inherits environment via memcpy of the entire process_t. - Added SYS_GETENV (8) and SYS_SETENV (9) system calls. - Created env-test user app that verifies: CWD default, set/get, and inheritance across fork. - Updated kernel.c to launch 'sh' as init process (for next task). - Updated README.md to check off environment variables task. Tested: env-test reads CWD=/, sets TEST=hello, reads it back, forks child which inherits TEST=hello. All verified via QEMU.
124 lines
2.4 KiB
ArmAsm
124 lines
2.4 KiB
ArmAsm
#
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# env-test: Tests environment variable syscalls.
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#
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# 1. Gets CWD (should be "/")
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# 2. Sets TEST=hello
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# 3. Gets TEST (should be "hello")
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# 4. Forks - child gets TEST, verifies it was copied
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# 5. Both print results and exit
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#
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.section .text
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.global _start
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.equ SYS_EXIT, 0
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.equ SYS_WRITE, 1
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.equ SYS_FORK, 3
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.equ SYS_WAITPID, 6
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.equ SYS_GETENV, 8
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.equ SYS_SETENV, 9
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# Helper: write a string (addr in %ecx, len in %edx) to stdout
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.macro WRITE_STR addr, len
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movl $SYS_WRITE, %eax
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movl $1, %ebx
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movl \addr, %ecx
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movl \len, %edx
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int $0x80
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.endm
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_start:
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# 1. Get CWD env var
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movl $SYS_GETENV, %eax
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movl $key_cwd, %ebx
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movl $buf, %ecx
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movl $128, %edx
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int $0x80
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# Print "CWD="
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WRITE_STR $label_cwd, $4
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# Print the value (length returned in eax)
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movl %eax, %edx # length
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movl $SYS_WRITE, %eax
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movl $1, %ebx
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movl $buf, %ecx
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int $0x80
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WRITE_STR $newline, $1
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# 2. Set TEST=hello
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movl $SYS_SETENV, %eax
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movl $key_test, %ebx
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movl $val_hello, %ecx
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int $0x80
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# 3. Get TEST
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movl $SYS_GETENV, %eax
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movl $key_test, %ebx
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movl $buf, %ecx
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movl $128, %edx
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int $0x80
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# Print "TEST="
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WRITE_STR $label_test, $5
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movl %eax, %edx
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movl $SYS_WRITE, %eax
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movl $1, %ebx
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movl $buf, %ecx
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int $0x80
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WRITE_STR $newline, $1
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# 4. Fork
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movl $SYS_FORK, %eax
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int $0x80
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testl %eax, %eax
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jz .child
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.parent:
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pushl %eax # save child PID
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WRITE_STR $msg_parent, $15
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# Wait for child
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popl %ebx
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movl $SYS_WAITPID, %eax
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int $0x80
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# Exit
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movl $SYS_EXIT, %eax
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movl $0, %ebx
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int $0x80
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.child:
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# Child: get TEST to verify it was inherited
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movl $SYS_GETENV, %eax
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movl $key_test, %ebx
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movl $buf, %ecx
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movl $128, %edx
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int $0x80
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# Print "Child TEST="
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WRITE_STR $label_child_test, $11
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movl %eax, %edx
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movl $SYS_WRITE, %eax
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movl $1, %ebx
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movl $buf, %ecx
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int $0x80
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WRITE_STR $newline, $1
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# Exit
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movl $SYS_EXIT, %eax
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movl $0, %ebx
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int $0x80
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.section .rodata
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key_cwd: .asciz "CWD"
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key_test: .asciz "TEST"
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val_hello: .asciz "hello"
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label_cwd: .ascii "CWD="
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label_test: .ascii "TEST="
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label_child_test: .ascii "Child TEST="
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msg_parent: .ascii "Parent done!\n\0\0"
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newline: .ascii "\n"
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.section .bss
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buf: .space 128
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