dirinfo command

doc/ints.txt

@@ -25,7 +25,7 @@ invalid system call numbers change eax to -1, and have no other effect.
 table 1:
 
  function      | eax | eax out       | ebx           | ecx         | edx         | esi    | edi
----------------|-----|---------------|---------------|-------------|-----------|--------|-----
+---------------|-----|---------------|---------------|-------------|-------------|--------|-----
  open file     | 0x0 | handle        | drive number  | path        |             |        |
  close file    | 0x1 |               | handle        |             |             |        |
  file read     | 0x2 | read          | handle        | file offset | count       | buffer |
@@ -36,8 +36,7 @@ table 1:
  allocate ram  | 0x7 | start pointer | pages         |             |             |        |
  memory info   | 0x8 | see table 2   | see table 2   |             |             |        |
  wait for task | 0x9 |               | handle        |             |             |        |
-
+ enumerate dir | 0xa | count         | drive number  | path        | see table 3 | max    |
-
 
 
 table 2:
@@ -51,3 +50,17 @@ eax -1 indicates unrecognized ebx
  0x2 | total userspace size
  0x3 | total userspace left
  0x4 | this process memory left
+
+
+table 3:
+edx of "enumerate dir" is a pointer to a buffer where an array of "directory info"s can be put.
+esi is the maximum number of "directory info"s to be placed in the buffer.
+the "directory info" structure is defined as follows:
+  struct {
+    bool is_dir;
+    char name[100];
+    uint32_t size;
+  }
+"is_dir" here indicates whether or not the entry is another directory.
+"name" is a null-terminated string, up to 99 characters, indicating the name of the entry.
+"size" is the size of the file this entry refers to, in bytes.

makefile

@@ -29,7 +29,8 @@ out/fs/bin/%: obj/%.elf
 	objcopy -S $< $@
 
 out/fs: out/fs/bin/init    out/fs/bin/meminfo  out/fs/bin/highway \
-        out/fs/bin/hello out/fs/bin/dumptext out/fs/bin/dumphex
+        out/fs/bin/hello   out/fs/bin/dumptext out/fs/bin/dumphex \
+        out/fs/bin/dirinfo
 	mkdir -p out/fs
 	cp -r fs-skel/* out/fs/
 
@@ -86,3 +87,6 @@ obj/dumptext.elf: obj/dumptext/dumptext.o obj/knob.so
 
 obj/dumphex.elf: obj/dumphex/dumphex.o obj/knob.so
 	ld -T src/user/elf.ld obj/dumphex/* obj/knob.so -o obj/dumphex.elf
+
+obj/dirinfo.elf: obj/dirinfo/dirinfo.o obj/knob.so
+	ld -T src/user/elf.ld obj/dirinfo/* obj/knob.so -o obj/dirinfo.elf

src/kernel/idt.c

@@ -96,6 +96,10 @@ static void sc_wait_for_task(uint32_t handle) {
   active_task->wait_arg = handle;
 }
 
+static uint32_t sc_enumerate_dir(uint32_t drive_number, const char *path, struct directory_content_info *buffer, uint32_t max_entries) {
+  return drives[drive_number].enumerate_dir(drives + drive_number, path, buffer, max_entries);
+}
+
 void const *syscall_table[] = {
   &sc_open_file,
   &sc_close_file,
@@ -106,7 +110,8 @@ void const *syscall_table[] = {
   &get_key_code,
   &sc_allocate_ram,
   &sc_memory_info,
-  &sc_wait_for_task
+  &sc_wait_for_task,
+  &sc_enumerate_dir
 };
 
 //these aren't really void ()'s, but gcc complains if we take an address of a void, so we give it a type

src/kernel/isrs.asm

@@ -23,7 +23,7 @@ extern on_kbd_isr
 extern make_sure_tasks
 extern exception_halt
 
-n_syscalls equ 0xa
+n_syscalls equ 0xb
 
 ;section .bss
 ;_debug_is_start_task resb 1

src/user/dirinfo/dirinfo.c

@@ -0,0 +1,49 @@
+#include <pland/syscall.h>
+#include <knob/format.h>
+#include <knob/file.h>
+#include <knob/user.h>
+
+#define MAX_DIR_ENTRIES 20
+
+void main(const char *arg) {
+  uint8_t dn;
+  const char *path = remove_prefix(arg, &dn);
+
+  tell_user_sz("Directory info for ");
+  tell_user_sz(*arg ? arg : "drive root");
+  tell_user_sz("\n");
+
+  _dir_info_entry infos[MAX_DIR_ENTRIES];
+  uint8_t count = _enumerate_dir(dn, path, infos, MAX_DIR_ENTRIES);
+  tell_user_sz(
+    count == MAX_DIR_ENTRIES
+    ? "Truncated to 20 entries.\n\n"
+    : "\n"
+  );
+
+  uint32_t total_size = 0;
+
+  if (!count)
+    tell_user_sz("(none)\n");
+
+  for (uint8_t i = 0; i < count; ++i) {
+    tell_user_sz(infos[i].name);
+    tell_user_sz(": ");
+    if (infos[i].is_dir)
+      tell_user_sz("dir");
+    else {
+      char nbuf[11];
+      itosz(infos[i].size, nbuf);
+      tell_user_sz(nbuf);
+      tell_user_sz(" bytes");
+      total_size += infos[i].size;
+    }
+    tell_user_sz("\n");
+  }
+
+  tell_user_sz("\nTotal size without subdirectories: ");
+  char nbuf[11];
+  itosz(total_size, nbuf);
+  tell_user_sz(nbuf);
+  tell_user_sz(" bytes\n");
+}

src/user/include/pland/syscall.h

@@ -45,9 +45,16 @@ enum _scn {
   _SCN_GET_KEY,
   _SCN_ALLOCATE_RAM,
   _SCN_MEMORY_INFO,
-  _SCN_WAIT_FOR_TASK
+  _SCN_WAIT_FOR_TASK,
+  _SCN_ENUMERATE_DIR
 };
 
+typedef struct {
+  bool is_dir;
+  char name[100];
+  uint32_t size;
+} _dir_info_entry;
+
 static inline uint32_t _sc0(enum _scn eax) {
   volatile uint32_t out;
   asm (
@@ -166,4 +173,8 @@ static inline void _wait_for_task(_process_handle_t handle) {
   _sc1(_SCN_WAIT_FOR_TASK, handle);
 }
 
+static inline uint32_t _enumerate_dir(_drive_number_t drive_number, const char *path, _dir_info_entry *buffer, uint32_t max_count) {
+  return _sc4(_SCN_ENUMERATE_DIR, drive_number, (uint32_t)path, (uint32_t)buffer, max_count);
+}
+
 #endif

src/user/knob/entry.asm

@@ -19,5 +19,5 @@ _entry:
   jmp main
 
 section .stack nobits alloc noexec write align=16
-resb 1024
+resb 4096
 stack: