; dirtest.asm — KHY OS directory-enumeration test (Phase 21). Proves a Ring 3 ; program can DISCOVER what a directory contains via getdents, not just stat a ; path it already knows. Until now `ls` only worked because the shell is a kernel ; task calling vfs_list_dir directly; a userland program had no way to list a ; directory. getdents is the primitive a userland `ls` is built on. ; ; All work happens under /tmp (created by ramfs_init, so no -hda is needed). The ; caller is root (uid 0). ; ; Sequence (all from Ring 3 via int 0x80): ; 1. chdir /tmp ; mkdir denttest ; chdir denttest (a fresh, isolated dir) ; 2. create f1.txt and write 10 bytes ; mkdir sub ; symlink f1.txt -> lnk ; 3. getdents "." -> exactly 3 entries; scan by name (order-independent) and ; assert: f1.txt is FILE(1) size 10, sub is DIR(2), lnk is SYMLINK(3). ; All three names must be present and no unexpected name may appear. ; 4. getdents "sub" (empty dir) -> 0 entries ; 5. getdents "f1.txt" (a file, not a dir) -> -1 ; 6. cleanup: unlink lnk, unlink f1.txt, rmdir sub, chdir .., rmdir denttest ; Any deviation jumps to .fail (exit 1). Success prints OK and exits 0. ; ; struct khy_dirent layout (src/syscall.h, 64 bytes): d_size@0 (qword), ; d_type@8 (byte), pad@9..15, d_name@16 (48-byte NUL-terminated name). ; ; Syscall ABI (src/syscall.c): rax = number, rdi/rsi/rdx = args, ret in rax. ; The int 0x80 stub preserves every GP register except rax. bits 64 %define SYS_WRITE 1 %define SYS_EXIT 2 %define SYS_OPEN 5 %define SYS_CLOSE 7 %define SYS_WRITE_FILE 18 %define SYS_MKDIR 38 %define SYS_RMDIR 39 %define SYS_UNLINK 40 %define SYS_CHDIR 36 %define SYS_SYMLINK 41 %define SYS_GETDENTS 48 %define O_CREAT 1 ; struct khy_dirent field offsets and stride %define DE_SIZE 0 %define DE_TYPE 8 %define DE_NAME 16 %define DE_STRIDE 64 %define T_FILE 1 %define T_DIR 2 %define T_SYMLINK 3 %macro WRITE 2 lea rdi, [rel %1] mov rsi, %2 mov rax, SYS_WRITE int 0x80 %endmacro section .text global _start _start: sub rsp, 512 ; room for 8 khy_dirent (8 * 64) mov r15, rsp ; r15 -> dirent buffer (callee-saved) ; 1. chdir /tmp ; mkdir denttest ; chdir denttest lea rdi, [rel tmpdir] mov rax, SYS_CHDIR int 0x80 test rax, rax jnz .fail lea rdi, [rel ddir] mov rax, SYS_MKDIR int 0x80 test rax, rax jnz .fail lea rdi, [rel ddir] mov rax, SYS_CHDIR int 0x80 test rax, rax jnz .fail ; 2. create f1.txt (10 bytes), mkdir sub, symlink f1.txt -> lnk lea rdi, [rel n_f1] mov rsi, O_CREAT mov rax, SYS_OPEN int 0x80 test rax, rax js .fail mov rbx, rax ; fd mov rdi, rbx lea rsi, [rel content] mov rdx, content_len ; 10 mov rax, SYS_WRITE_FILE int 0x80 cmp rax, content_len jne .fail mov rdi, rbx mov rax, SYS_CLOSE int 0x80 lea rdi, [rel n_sub] mov rax, SYS_MKDIR int 0x80 test rax, rax jnz .fail lea rdi, [rel n_f1] ; symlink target (verbatim) lea rsi, [rel n_lnk] ; link path mov rax, SYS_SYMLINK int 0x80 test rax, rax jnz .fail ; 3. getdents "." -> 3 entries lea rdi, [rel dot] mov rsi, r15 mov rdx, 8 ; max_entries mov rax, SYS_GETDENTS int 0x80 cmp rax, 3 jne .fail mov r13, rax ; count xor rbx, rbx ; i xor r12, r12 ; found bitmask .scan: cmp rbx, r13 jge .scan_done mov rax, rbx shl rax, 6 ; * DE_STRIDE (64) lea r14, [r15 + rax] ; entry ptr ; compare name (r14+DE_NAME) against the three expected names lea rsi, [r14 + DE_NAME] lea rdi, [rel n_f1] call streq je .is_f1 lea rsi, [r14 + DE_NAME] lea rdi, [rel n_sub] call streq je .is_sub lea rsi, [r14 + DE_NAME] lea rdi, [rel n_lnk] call streq je .is_lnk jmp .fail ; unexpected entry name .is_f1: cmp byte [r14 + DE_TYPE], T_FILE jne .fail cmp qword [r14 + DE_SIZE], 10 jne .fail or r12, 1 jmp .scan_next .is_sub: cmp byte [r14 + DE_TYPE], T_DIR jne .fail or r12, 2 jmp .scan_next .is_lnk: cmp byte [r14 + DE_TYPE], T_SYMLINK jne .fail or r12, 4 jmp .scan_next .scan_next: inc rbx jmp .scan .scan_done: cmp r12, 7 ; all three names seen exactly once jne .fail ; 4. getdents "sub" (empty) -> 0 lea rdi, [rel n_sub] mov rsi, r15 mov rdx, 8 mov rax, SYS_GETDENTS int 0x80 test rax, rax jnz .fail ; 5. getdents "f1.txt" (not a directory) -> -1 (negative) lea rdi, [rel n_f1] mov rsi, r15 mov rdx, 8 mov rax, SYS_GETDENTS int 0x80 test rax, rax jns .fail ; must be negative (error) ; 6. cleanup lea rdi, [rel n_lnk] mov rax, SYS_UNLINK int 0x80 lea rdi, [rel n_f1] mov rax, SYS_UNLINK int 0x80 lea rdi, [rel n_sub] mov rax, SYS_RMDIR int 0x80 lea rdi, [rel dotdot] mov rax, SYS_CHDIR int 0x80 lea rdi, [rel ddir] mov rax, SYS_RMDIR int 0x80 WRITE ok_line, ok_line_len add rsp, 512 xor rdi, rdi mov rax, SYS_EXIT int 0x80 .fail: WRITE bad_line, bad_line_len mov rdi, 1 mov rax, SYS_EXIT int 0x80 ; streq(rsi, rdi) — compare two NUL-terminated strings. Sets ZF iff equal. ; Clobbers rax, rcx; preserves rsi/rdi (caller reloads them anyway). streq: push rsi push rdi .se_loop: mov al, [rsi] mov cl, [rdi] cmp al, cl jne .se_ne test al, al je .se_eq inc rsi inc rdi jmp .se_loop .se_eq: pop rdi pop rsi xor eax, eax ; ZF = 1 (equal) ret .se_ne: pop rdi pop rsi or eax, 1 ; ZF = 0 (not equal) ret section .rodata tmpdir: db "/tmp", 0 ddir: db "denttest", 0 dot: db ".", 0 dotdot: db "..", 0 n_f1: db "f1.txt", 0 n_sub: db "sub", 0 n_lnk: db "lnk", 0 content: db "dirent-pro" content_len equ $ - content ok_line: db "[user] dirtest: getdents enumerates directory -> OK", 0x0A ok_line_len equ $ - ok_line bad_line: db "[user] dirtest: DIRENT FAIL", 0x0A bad_line_len equ $ - bad_line