finished file-related syscalls chapter

Makefile

@@ -18,8 +18,8 @@ S_SOURCES=$(shell find ./src/ -name "*.s")
 S_OBJECTS=$(patsubst %.s, %.o, $(S_SOURCES))
 
 INIT_SOURCE=./user/init.c
-INIT_OBJECT=./user/init.o
-INIT_LINKED=./user/init.out
+INIT_OBJECT=./user/init.c.o
+INIT_LINKED=./user/init.bin
 INIT_BINARY=./user/init
 
 ULIB_C_SOURCES=$(shell find ./user/lib/ -name "*.c")
@@ -28,8 +28,10 @@ ULIB_C_OBJECTS=$(patsubst %.c, %.o, $(ULIB_C_SOURCES))
 ULIB_S_SOURCES=$(shell find ./user/lib/ -name "*.s")
 ULIB_S_OBJECTS=$(patsubst %.s, %.o, $(ULIB_S_SOURCES))
 
-USER_SOURCES=$(filter-out $(INIT_SOURCE), $(shell find ./user/ -maxdepth 1 -name "*.c"))
-USER_BINARYS=$(patsubst %.c, %.bin, $(USER_SOURCES))
+USER_SOURCES_ALL=$(shell find ./user/ -name "*.c" ! -path "./user/lib/*")
+USER_SOURCES=$(filter-out $(INIT_SOURCE), $(USER_SOURCES_ALL))
+USER_OBJECTS=$(patsubst %.c, %.c.o, $(USER_SOURCES))
+USER_LINKEDS=$(patsubst %.c, %.bin, $(USER_SOURCES))
 
 FILESYS_IMG=vsfs.img
 
@@ -59,7 +61,7 @@ HUX_MSG="[--Hux->]"
 
 
 ALL_DEPS := $(S_OBJECTS) $(C_OBJECTS)
-ALL_DEPS += $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS) $(USER_BINARYS) initproc
+ALL_DEPS += $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS) $(USER_LINKEDS) initproc
 ALL_DEPS += filesys kernel verify update
 all: $(ALL_DEPS)
 
@@ -88,7 +90,7 @@ $(ULIB_C_OBJECTS): %.o: %.c
 	@echo $(HUX_MSG) "Compiling user lib C code '$<'..."
 	$(CC) $(C_FLAGS_USER) -o $@ $<
 
-$(USER_BINARYS): %.bin: %.c $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS)
+$(USER_LINKEDS): %.bin: %.c $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS)
 	@echo
 	@echo $(HUX_MSG) "Compiling & linking user program '$<'..."
 	$(CC) $(C_FLAGS_USER) -o $<.o $<
@@ -110,8 +112,9 @@ initproc: $(INIT_SOURCE) $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS)
 kernel: $(S_OBJECTS) $(C_OBJECTS) initproc
 	@echo
 	@echo $(HUX_MSG) "Linking kernel image..."
-	$(LD) $(LD_FLAGS) -T scripts/kernel.ld -lgcc -o $(TARGET_BIN) -Wl,--oformat,elf32-i386 \
-		$(S_OBJECTS) $(C_OBJECTS) -Wl,-b,binary,$(INIT_BINARY)
+	$(LD) $(LD_FLAGS) -T scripts/kernel.ld -lgcc -o $(TARGET_BIN) \
+		-Wl,--oformat,elf32-i386 $(S_OBJECTS) $(C_OBJECTS)        \
+		-Wl,-b,binary,$(INIT_BINARY)
 	$(OBJCOPY) --only-keep-debug $(TARGET_BIN) $(TARGET_SYM)
 	$(OBJCOPY) --strip-debug $(TARGET_BIN)
 
@@ -123,20 +126,20 @@ kernel: $(S_OBJECTS) $(C_OBJECTS) initproc
 filesys:
 	@echo
 	@echo $(HUX_MSG) "Making the file system image..."
-	python3 scripts/mkfs.py $(FILESYS_IMG) $(USER_BINARYS)
+	python3 scripts/mkfs.py $(FILESYS_IMG) $(USER_LINKEDS)
 
 
 #
 # Verify GRUB multiboot sanity.
 #
 .PHONY: verify
 verify:
-	@if grub-file --is-x86-multiboot $(TARGET_BIN); then	\
-		echo; 												\
-		echo $(HUX_MSG) "VERIFY MULTIBOOT: Confirmed ✓"; 	\
-	else													\
-		echo; 												\
-		echo $(HUX_MSG) "VERIFY MULTIBOOT: FAILED ✗";		\
+	@if grub-file --is-x86-multiboot $(TARGET_BIN); then \
+		echo;                                            \
+		echo $(HUX_MSG) "VERIFY MULTIBOOT: Confirmed ✓"; \
+	else                                                 \
+		echo;                                            \
+		echo $(HUX_MSG) "VERIFY MULTIBOOT: FAILED ✗";    \
 	fi
 
 
@@ -183,5 +186,6 @@ clean:
 	@echo
 	@echo $(HUX_MSG) "Cleaning the build..."
 	rm -f $(S_OBJECTS) $(C_OBJECTS) $(ULIB_S_OBJECTS) $(ULIB_C_OBJECTS) \
-		$(INIT_OBJECT) $(INIT_LINKED) $(INIT_BINARY) $(USER_BINARYS) 	\
-		$(TARGET_BIN) $(TARGET_ISO) $(TARGET_SYM) $(FILESYS_IMG)
+		$(INIT_OBJECT) $(INIT_LINKED) $(INIT_BINARY)                    \
+		$(USER_OBJECTS) $(USER_LINKEDS) $(FILESYS_IMG)                  \
+		$(TARGET_BIN) $(TARGET_ISO) $(TARGET_SYM) 

src/boot/elf.h

@@ -1,6 +1,6 @@
 /**
- * ELF format related structures.
- * See http://www.cs.cmu.edu/afs/cs/academic/class/15213-f00/docs/elf.pdf.
+ * ELF 32-bit format related structures.
+ * See http://www.cs.cmu.edu/afs/cs/academic/class/15213-f00/docs/elf.pdf
  */
 
 
@@ -11,12 +11,53 @@
 #include <stdint.h>
 
 
+/** ELF file header. */
+struct elf_file_header {
+    uint32_t magic;         /** In little-endian on x86. */
+    uint8_t  ident[12];     /** Rest of `e_ident`. */
+    uint16_t type;
+    uint16_t machine;
+    uint32_t version;
+    uint32_t entry;
+    uint32_t phoff;
+    uint32_t shoff;
+    uint32_t flags;
+    uint16_t ehsize;
+    uint16_t phentsize;
+    uint16_t phnum;
+    uint16_t shentsize;
+    uint16_t shnum;
+    uint16_t shstrndx;
+} __attribute__((packed));
+typedef struct elf_file_header elf_file_header_t;
+
 /**
- * For getting the type of a symbol table entry. Function type code == 0x2.
- * See https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-79797.html#chapter6-tbl-21.
+ * ELF magic number 0x7F'E''L''F' in little endian.
+ * See https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html#elfid
  */
-#define ELF_SYM_TYPE(info) ((info) & 0xf)
-#define ELF_SYM_TYPE_FUNC  0x2
+#define ELF_MAGIC 0x464C457F
+
+
+/** ELF program header. */
+struct elf_program_header {
+    uint32_t type;
+    uint32_t offset;
+    uint32_t vaddr;
+    uint32_t paddr;
+    uint32_t filesz;
+    uint32_t memsz;
+    uint32_t flags;
+    uint32_t align;
+} __attribute__((packed));
+typedef struct elf_program_header elf_program_header_t;
+
+/** ELF program header flags. */
+#define ELF_PROG_FLAG_EXEC  0x1
+#define ELF_PROG_FLAG_WRITE 0x2
+#define ELF_PROG_FLAG_READ  0x4
+
+/** ELF program header types. */
+#define ELF_PROG_TYPE_LOAD  0x1
 
 
 /** ELF section header. */
@@ -46,5 +87,12 @@ struct elf_symbol {
 } __attribute__((packed));
 typedef struct elf_symbol elf_symbol_t;
 
+/**
+ * For getting the type of a symbol table entry. Function type code == 0x2.
+ * See https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-79797.html#chapter6-tbl-21
+ */
+#define ELF_SYM_TYPE(info) ((info) & 0xf)
+#define ELF_SYM_TYPE_FUNC  0x2
+
 
 #endif

src/boot/multiboot.h

@@ -1,7 +1,7 @@
 /**
  * Multiboot1 related structures.
- * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html.
- * See https://www.gnu.org/software/grub/manual/multiboot/html_node/Example-OS-code.html.
+ * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html
+ * See https://www.gnu.org/software/grub/manual/multiboot/html_node/Example-OS-code.html
  */
 
 
@@ -18,7 +18,7 @@
 
 /**
  * Multiboot1 header.
- * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Header-layout.
+ * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Header-layout
  */
 struct multiboot_header {
     uint32_t magic;     /* Must be header magic 0x1BADB002. */
@@ -38,7 +38,7 @@ typedef struct multiboot_header multiboot_header_t;
  * header table from an ELF kernel is, the size of each entry, number of
  * entries, and the string table used as the index of names", stated on GRUB
  * multiboot1 specification.
- * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format.
+ * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format
  */
 struct multiboot_elf_section_header_table {
     uint32_t num;
@@ -51,7 +51,7 @@ typedef struct multiboot_elf_section_header_table multiboot_elf_section_header_t
 
 /**
  * Multiboot1 information.
- * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format.
+ * See https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format
  */
 struct multiboot_info {
     uint32_t flags;         /* Multiboot info version number. */

src/common/bitmap.c

@@ -35,6 +35,8 @@ inline void
 bitmap_clear(bitmap_t *bitmap, uint32_t slot_no)
 {
     assert(slot_no < bitmap->slots);
+    if (slot_no == 0)
+        info("clearing 0");
 
     spinlock_acquire(&(bitmap->lock));