Add basic `ls`

build.sh

@@ -13,7 +13,9 @@ dd if=/dev/zero of=build/os.img bs="${sector_size}" count="$((partition_offset +
 dd if=build/mbr.bin of=build/os.img bs="${sector_size}" count=1 conv=notrunc
 dd if=build/bootloader.bin of=build/os.img bs="${sector_size}" seek=1 count="$((partition_offset - 1))" conv=notrunc
 mkfs.fat -F 16 --offset "${partition_offset}" build/os.img
-mcopy -i build/os.img@@"$((partition_offset * sector_size))" src ::src
+mcopy -i build/os.img@@"$((partition_offset * sector_size))" -s src ::src
 mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/kernel.bin ::kernel.bin
-mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/terminal ::terminal
-mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/echo ::echo
+mmd -i build/os.img@@"$((partition_offset * sector_size))" ::bin
+mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/terminal ::bin/terminal
+mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/echo ::bin/echo
+mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/ls ::bin/ls

meson.build

@@ -146,7 +146,6 @@ custom_target(
   build_by_default: true,
 )
 
-
 echo_start = custom_target(
   'echo_start',
   input:  'src/user/start.asm',
@@ -185,3 +184,42 @@ custom_target(
   command: ['objcopy', '-O', 'binary', '@INPUT@', '@OUTPUT@'],
   build_by_default: true,
 )
+
+ls_start = custom_target(
+  'ls_start',
+  input:  'src/user/start.asm',
+  output: 'ls_start.o',
+  command: [nasm, '-f', 'elf64', '-o', '@OUTPUT@', '@INPUT@'],
+)
+
+ls_syscall = custom_target(
+  'ls_syscall',
+  input:  'src/user/syscall.asm',
+  output: 'ls_syscall.o',
+  command: [nasm, '-f', 'elf64', '-o', '@OUTPUT@', '@INPUT@'],
+)
+
+ls_elf = executable(
+  'ls.elf',
+  sources: [ls_start, ls_syscall, lib_sources, 'src/user/app/ls/ls.c'],
+  c_args: [
+    '-ffreestanding',
+    '-nostdlib',
+    '-fno-stack-protector',
+    '-mcmodel=large',
+    '-DVERSION="' + meson.project_version() + '"',
+  ],
+  link_args: [
+    '-T', meson.project_source_root() / 'src/user/linker.ld',
+    '-nostdlib',
+  ],
+  link_depends: 'src/user/linker.ld',
+)
+
+custom_target(
+  'ls',
+  input:  ls_elf,
+  output: 'ls',
+  command: ['objcopy', '-O', 'binary', '@INPUT@', '@OUTPUT@'],
+  build_by_default: true,
+)

src/kernel/kernel.c

@@ -56,7 +56,7 @@ void kernel_main() {
   kernel->stdin = keyboard_init();
   kernel->stdout = vga_init();
 
-  fs_node_t *bin = fs_open_by(kernel->root, "terminal");
+  fs_node_t *bin = path_open_file(kernel->root, kernel->cwd, "bin/terminal");
 
   ASSERT(bin, "kernel: terminal not found");
 

src/kernel/syscall.asm

@@ -28,6 +28,7 @@ syscall_entry:
     push r14
     push r15
 
+    mov r8, r10     ; arg4
     mov rcx, rdx    ; arg3
     mov rdx, rsi    ; arg2
     mov rsi, rdi    ; arg1

src/kernel/syscall.c

@@ -145,11 +145,36 @@ static uint64_t spawn(const char *path, uint64_t argc, const char **argv) {
   return 0;
 }
 
+static uint64_t readdir(const char *path, uint64_t index, uint64_t max, char *to) {
+  fs_node_t *dir = path_open_directory(current_process->root, current_process->cwd, path);
+  if (!dir) {
+    return (uint64_t)-1;
+  }
+  fs_node_t *item = fs_open_at(dir, index);
+  if (!item) {
+    if (dir != current_process->root) {
+      fs_close(dir);
+    }
+    return 0;
+  }
+  uint64_t length = string_length(item->name);
+  uint64_t size = length > max - 1 ? max - 1 : length;
+  memory_copy(item->name, size, to);
+  to[size] = '\0';
+
+  fs_close(item);
+  if (dir != current_process->root) {
+    fs_close(dir);
+  }
+
+  return size;
+}
+
 static void exit() {
   process_switch_to(&current_process->kernel_rsp, current_process->parent->kernel_rsp, VIRT_TO_PHYS(current_process->parent->pml4));
 }
 
-uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3) {
+uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4) {
   switch (func) {
   case SYSCALL_READ:
     return read(arg1, arg2, (char *)arg3);
@@ -161,6 +186,8 @@ uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t
     return chdir((const char *)arg1);
   case SYSCALL_SPAWN:
     return spawn((const char *)arg1, arg2, (const char **)arg3);
+  case SYSCALL_READDIR:
+    return readdir((const char *)arg1, arg2, arg3, (char *)arg4);
   case SYSCALL_EXIT:
     exit();
     return 0;

src/kernel/syscall.h

@@ -7,8 +7,9 @@
 #define SYSCALL_GETCWD 2
 #define SYSCALL_CHDIR 3
 #define SYSCALL_SPAWN 4
+#define SYSCALL_READDIR 5
 #define SYSCALL_EXIT 60
 
 void syscall_init();
 
-uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3);
+uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4);

src/user/app/echo/echo.c

@@ -1,7 +1,7 @@
 #include "src/lib/string.h"
 #include "src/user/syscall.h"
 
-int main(uint64_t argc, const char **argv) {
+uint64_t main(uint64_t argc, const char **argv) {
   for (uint64_t i = 1; i < argc; i++) {
     if (i > 1) {
       write(1, " ", 1);

src/user/app/ls/ls.c

@@ -0,0 +1,43 @@
+#include "src/lib/string.h"
+#include "src/user/syscall.h"
+
+#define WRITE_S(s) write(1, s, sizeof(s) - 1);
+#define WRITE_D(s) write(1, s, string_length(s));
+
+uint64_t ls(const char *path) {
+  uint64_t i = 0;
+  while (1) {
+    char out[100];
+    uint64_t s = readdir(path, i, 100, out);
+    if (!s) {
+      return 0;
+    }
+    if (s == (uint64_t)-1) {
+      WRITE_S("ls: path does not exist\n");
+      return (uint64_t)-1;
+    }
+    WRITE_D(out);
+    WRITE_S("\n");
+    i++;
+  }
+}
+
+uint64_t main(uint64_t argc, const char **argv) {
+  if (argc == 1) {
+    return ls(".");
+  }
+
+  uint64_t code = 0;
+  for (uint64_t i = 1; i < argc; i++) {
+    if (argc > 2) {
+      WRITE_S("\n");
+      WRITE_D(argv[i]);
+      WRITE_S(":\n");
+    }
+    if (ls(argv[i]) == (uint64_t)-1) {
+      code = (uint64_t)-1;
+    }
+  }
+
+  return code;
+}

src/user/app/terminal/terminal.c

@@ -6,6 +6,8 @@
 static void help(uint8_t argc, char **argv);
 static void cd(uint8_t argc, char **argv);
 
+#define PATH "/bin/"
+
 #define WRITE_S(s) write(1, s, sizeof(s) - 1);
 #define WRITE_D(s) write(1, s, string_length(s));
 
@@ -117,9 +119,14 @@ static void on_enter_pressed() {
     }
   }
   if (i == sizeof(builtins) / sizeof(app_entry_t)) {
-    if (spawn(argv[0], argc, (const char **)argv) == (uint64_t)-1){
+    uint64_t size = sizeof(PATH) + string_length(argv[0]) + 1;
+    char *path = memory_allocate(size);
+    memory_copy(PATH, sizeof(PATH), path);
+    memory_copy(argv[0], size - sizeof(PATH), path + sizeof(PATH) - 1);
+    if (spawn(path, argc, (const char **)argv) == (uint64_t)-1) {
       WRITE_S("terminal: program not found\n");
     }
+    memory_free(path);
   }
   prompt_length = prompt_offset = 0;
   print_prompt();
@@ -258,7 +265,7 @@ static void on_char_received(char c) {
   }
 }
 
-int main() {
+uint64_t main() {
   memory_set('\b', PROMPT_LENGTH, (char *)bs);
   memory_set(' ', PROMPT_LENGTH, (char *)ws);
 

src/user/syscall.asm

@@ -30,6 +30,13 @@ spawn:
     syscall
     ret
 
+global readdir
+readdir:
+    mov r10, rcx
+    mov rax, 5
+    syscall
+    ret
+
 global exit
 exit:
     mov rax, 60

src/user/syscall.h

@@ -12,4 +12,6 @@ uint64_t chdir(const char *path);
 
 uint64_t spawn(const char *path, uint64_t argc, const char **argv);
 
+uint64_t readdir(const char *path, uint64_t index, uint64_t max, char *to);
+
 void exit();