tools/emul/shell: add filesystem support

With the help of the newly-introduced cfspack tool, we can mount a
filesystem in our emulated shell and play around. Read-only for now.
Unpacking incoming.

tools/cfspack/.gitignore

@@ -0,0 +1,2 @@
+/cfspack
+/cfsunpack

tools/cfspack/Makefile

@@ -0,0 +1,4 @@
+TARGETS = cfspack
+
+cfspack: cfspack.c
+	$(CC) -o $@ $^

tools/cfspack/README.md

@@ -0,0 +1,23 @@
+# cfspack
+
+A tool/library to pack a directory into a CFS blob and unpack a CFS blob into
+a directory.
+
+## Usage
+
+To pack a directory into a CFS blob, run:
+
+    cfspack /path/to/directory
+
+The blob is spit to stdout. If there are subdirectories, they will be prefixes
+to the filenames under it.
+
+The program errors out if a file name is too long (> 26 bytes) or too big
+(> 0x10000 - 0x20 bytes).
+
+To unpack a blob to a directory:
+
+    cfsunpack /path/to/dest < blob
+
+If destination exists, files are created alongside existing ones. If a file to
+unpack already exists, it is overwritten.

tools/cfspack/cfspack.c

@@ -0,0 +1,117 @@
+#include <stdio.h>
+#include <dirent.h>
+#include <string.h>
+
+#define BLKSIZE 0x100
+#define HEADERSIZE 0x20
+#define MAX_FN_LEN 25   // 26 - null char
+#define MAX_FILE_SIZE (BLKSIZE * 0x100) - HEADERSIZE
+
+int spitblock(char *fullpath, char *fn)
+{
+    FILE *fp = fopen(fullpath, "r");
+    fseek(fp, 0, SEEK_END);
+    long fsize = ftell(fp);
+    if (fsize > MAX_FILE_SIZE) {
+        fclose(fp);
+        fprintf(stderr, "File too big: %s %ld\n", fullpath, fsize);
+        return 1;
+    }
+    /* Compute block count.
+     * We always have at least one, which contains 0x100 bytes - 0x20, which is
+     * metadata. The rest of the blocks have a steady 0x100.
+     */
+    unsigned char blockcount = 1;
+    int fsize2 = fsize - (BLKSIZE - HEADERSIZE);
+    if (fsize2 > 0) {
+        blockcount += (fsize2 / BLKSIZE);
+    }
+    if (blockcount * BLKSIZE < fsize) {
+        blockcount++;
+    }
+    putchar('C');
+    putchar('F');
+    putchar('S');
+    putchar(blockcount);
+    // file size is little endian
+    putchar(fsize & 0xff);
+    putchar((fsize >> 8) & 0xff);
+    int fnlen = strlen(fn);
+    for (int i=0; i<MAX_FN_LEN; i++) {
+        if (i < fnlen) {
+            putchar(fn[i]);
+        } else {
+            putchar(0);
+        }
+    }
+    // And the last FN char which is always null
+    putchar(0);
+    char buf[MAX_FILE_SIZE] = {0};
+    rewind(fp);
+    fread(buf, fsize, 1, fp);
+    fclose(fp);
+    fwrite(buf, (blockcount * BLKSIZE) - HEADERSIZE, 1, stdout);
+    fflush(stdout);
+    return 0;
+}
+
+int spitdir(char *path, char *prefix)
+{
+    DIR *dp;
+    struct dirent *ep;
+
+    int prefixlen = strlen(prefix);
+    dp = opendir(path);
+    if (dp == NULL) {
+        fprintf(stderr, "Couldn't open directory.\n");
+        return 1;
+    }
+    while (ep = readdir(dp)) {
+        if ((strcmp(ep->d_name, ".") == 0) || strcmp(ep->d_name, "..") == 0) {
+            continue;
+        }
+        if (ep->d_type != DT_DIR && ep->d_type != DT_REG) {
+            fprintf(stderr, "Only regular file or directories are supported\n");
+            return 1;
+        }
+        int slen = strlen(ep->d_name);
+        if (prefixlen + slen> MAX_FN_LEN) {
+            fprintf(stderr, "Filename too long: %s/%s\n", prefix, ep->d_name);
+            return 1;
+        }
+        char fullpath[0x1000];
+        strcpy(fullpath, path);
+        strcat(fullpath, "/");
+        strcat(fullpath, ep->d_name);
+        char newprefix[MAX_FN_LEN];
+        strcpy(newprefix, prefix);
+        if (prefixlen > 0) {
+            strcat(newprefix, "/");
+        }
+        strcat(newprefix, ep->d_name);
+        if (ep->d_type == DT_DIR) {
+            int r = spitdir(fullpath, newprefix);
+            if (r != 0) {
+                return r;
+            }
+        } else {
+            int r = spitblock(fullpath, newprefix);
+            if (r != 0) {
+                return r;
+            }
+        }
+    }
+    closedir(dp);
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: cfspack /path/to/dir\n");
+        return 1;
+    }
+    char *srcpath = argv[1];
+    return spitdir(srcpath, "");
+}
+

tools/emul/.gitignore

@@ -2,3 +2,5 @@
 /zasm
 /*-kernel.h
 /*-user.h
+/cfsin
+/cfsout

tools/emul/Makefile

@@ -13,7 +13,7 @@ $(KERNEL_HEADERS):
 zasm-user.h: zasm_user.asm
 	scas -o - -I ../../apps/zasm $< | ./bin2c.sh USERSPACE | tee $@ > /dev/null
 
-shell: shell.c libz80/libz80.o shell-kernel.h
+shell: shell.c libz80/libz80.o shell-kernel.h ../cfspack/cfspack
 zasm: zasm.c libz80/libz80.o zasm-kernel.h zasm-user.h
 $(TARGETS):
 	cc $< libz80/libz80.o -o $@
@@ -22,6 +22,9 @@ libz80/libz80.o: libz80/z80.c
 	make -C libz80/codegen opcodes
 	gcc -Wall -ansi -g -c -o libz80/libz80.o libz80/z80.c
 
+../cfspack/cfspack:
+	make -C ../cfspack
+
 .PHONY: clean
 clean:
 	rm -f $(TARGETS) $(KERNEL_HEADERS) $(USER_HEADERS)

tools/emul/shell.c

@@ -4,7 +4,11 @@
 #include "libz80/z80.h"
 #include "shell-kernel.h"
 
-/* Collapse OS vanilla shell
+/* Collapse OS shell with filesystem
+ *
+ * On startup, if "cfsin" directory exists, it packs it as a afke block device
+ * and loads it in. Upon halting, unpcks the contents of that block device in
+ * "cfsout" directory.
  *
  * Memory layout:
  *
@@ -15,14 +19,23 @@
  * I/O Ports:
  *
  * 0 - stdin / stdout
+ * 1 - Filesystem blockdev data read/write. Reading and writing to it advances
+ *     the pointer.
+ * 2 - Filesystem blockdev seek / tell. Low byte
+ * 3 - Filesystem blockdev seek / tell. High byte
  */
 
 // in sync with shell.asm
 #define STDIO_PORT 0x00
-#define STDIN_ST_PORT 0x01
+#define FS_DATA_PORT 0x01
+#define FS_SEEKL_PORT 0x02
+#define FS_SEEKH_PORT 0x03
 
 static Z80Context cpu;
-static uint8_t mem[0xffff];
+static uint8_t mem[0xffff] = {0};
+static uint8_t fsdev[0xffff] = {0};
+static uint16_t fsdev_size = 0;
+static uint16_t fsdev_ptr = 0;
 static int running;
 
 static uint8_t io_read(int unused, uint16_t addr)
@@ -34,6 +47,16 @@ static uint8_t io_read(int unused, uint16_t addr)
             running = 0;
         }
         return c;
+    } else if (addr == FS_DATA_PORT) {
+        if (fsdev_ptr < fsdev_size) {
+            return fsdev[fsdev_ptr++];
+        } else {
+            return 0;
+        }
+    } else if (addr == FS_SEEKL_PORT) {
+        return fsdev_ptr && 0xff;
+    } else if (addr == FS_SEEKH_PORT) {
+        return fsdev_ptr >> 8;
     } else {
         fprintf(stderr, "Out of bounds I/O read: %d\n", addr);
         return 0;
@@ -49,6 +72,14 @@ static void io_write(int unused, uint16_t addr, uint8_t val)
         } else {
             putchar(val);
         }
+    } else if (addr == FS_DATA_PORT) {
+        if (fsdev_ptr < fsdev_size) {
+            fsdev[fsdev_ptr++] = val;
+        }
+    } else if (addr == FS_SEEKL_PORT) {
+        fsdev_ptr = (fsdev_ptr & 0xff00) | val;
+    } else if (addr == FS_SEEKH_PORT) {
+        fsdev_ptr = (fsdev_ptr & 0x00ff) | (val << 8);
     } else {
         fprintf(stderr, "Out of bounds I/O write: %d / %d\n", addr, val);
     }
@@ -66,6 +97,23 @@ static void mem_write(int unused, uint16_t addr, uint8_t val)
 
 int main()
 {
+    // Setup fs blockdev
+    FILE *fp = popen("../cfspack/cfspack cfsin", "r");
+    if (fp != NULL) {
+        printf("Initializing filesystem\n");
+        int i = 0;
+        int c = fgetc(fp);
+        while (c != EOF) {
+            fsdev[i] = c & 0xff;
+            i++;
+            c = fgetc(fp);
+        }
+        fsdev_size = i;
+        pclose(fp);
+    } else {
+        printf("Can't initialize filesystem. Leaving blank.\n");
+    }
+
     // Turn echo off: the shell takes care of its own echoing.
     struct termios termInfo;
     if (tcgetattr(0, &termInfo) == -1) {

tools/emul/shell_.asm

@@ -2,16 +2,11 @@
 RAMSTART	.equ	0x4000
 RAMEND		.equ	0x5000
 STDIO_PORT	.equ	0x00
+FS_DATA_PORT	.equ	0x01
+FS_SEEKL_PORT	.equ	0x02
+FS_SEEKH_PORT	.equ	0x03
 
-jr	init
+jp	init
-
-init:
-	di
-	; setup stack
-	ld	hl, RAMEND
-	ld	sp, hl
-	call	shellInit
-	jp	shellLoop
 
 #include "core.asm"
 .define STDIO_GETC	call emulGetC
@@ -20,19 +15,40 @@ STDIO_RAMSTART	.equ	RAMEND
 #include "stdio.asm"
 
 BLOCKDEV_RAMSTART	.equ	STDIO_RAMEND
-BLOCKDEV_COUNT		.equ	1
+BLOCKDEV_COUNT		.equ	2
 #include "blockdev.asm"
 ; List of devices
 .dw	emulGetC, emulPutC, 0, 0
+.dw	fsdevGetC, fsdevPutC, fsdevSeek, fsdevTell
 
 #include "blockdev_cmds.asm"
 
-SHELL_RAMSTART	.equ	BLOCKDEV_RAMEND
+.equ	FS_RAMSTART	BLOCKDEV_RAMEND
+.equ	FS_HANDLE_COUNT	2
+#include "fs.asm"
+
+SHELL_RAMSTART	.equ	FS_RAMEND
 .define SHELL_IO_GETC	call blkGetCW
 .define SHELL_IO_PUTC	call blkPutC
-SHELL_EXTRA_CMD_COUNT .equ 2
+SHELL_EXTRA_CMD_COUNT .equ 6
 #include "shell.asm"
-.dw	blkBselCmd, blkSeekCmd
+.dw	blkBselCmd, blkSeekCmd, fsOnCmd, flsCmd, fnewCmd, fdelCmd
+
+init:
+	di
+	; setup stack
+	ld	hl, RAMEND
+	ld	sp, hl
+	call	fsInit
+	ld	a, 1	; select fsdev
+	ld	de, BLOCKDEV_GETC
+	call	blkSel
+	call	fsOn
+	xor	a	; select ACIA
+	ld	de, BLOCKDEV_GETC
+	call	blkSel
+	call	shellInit
+	jp	shellLoop
 
 emulGetC:
 	; Blocks until a char is returned
@@ -44,3 +60,24 @@ emulPutC:
 	out	(STDIO_PORT), a
 	ret
 
+fsdevGetC:
+	in	a, (FS_DATA_PORT)
+	ret
+
+fsdevPutC:
+	out	(FS_DATA_PORT), a
+	ret
+
+fsdevSeek:
+	ld	a, l
+	out	(FS_SEEKL_PORT), a
+	ld	a, h
+	out	(FS_SEEKH_PORT), a
+	ret
+
+fsdevTell:
+	in	a, (FS_SEEKL_PORT)
+	ld	l, a
+	in	a, (FS_SEEKH_PORT)
+	ld	h, a
+	ret