Fix all warnings, cleanup application interface code

Signed-off-by: Mahavir Jain <[email protected]>

Makefile

@@ -4,6 +4,7 @@ CC := gcc
 AS := nasm
 OBJDUMP := objdump
 OBJCOPY := objcopy
+AR := ar
 
 # Tiny OS version
 VERSION := 0.1
@@ -35,7 +36,12 @@ c_srcs := $(foreach dir, $(kernel_src_dir), $(wildcard $(dir)/*.c))
 asm_srcs := $(foreach dir, $(boot_src_dir), $(wildcard $(dir)/*.s))
 c_objs := $(c_srcs:%.c=$(objdir)/%.o)
 asm_objs := $(asm_srcs:%.s=$(objdir)/%.o)
-syscall_obj := $(objdir)/$(boot_src_dir)/syscall.o
+
+app_lib_objs := $(objdir)/$(boot_src_dir)/syscall.o \
+		$(objdir)/stdlib/stdlib.o \
+		$(objdir)/stdlib/printf.o \
+
+app_lib := $(objdir)/lib_helper.a
 
 CFLAGS := -g -O2 -m32 -ffreestanding -Wall -Wextra -DVERSION=\"$(VERSION)\"
 CFLAGS += -Iinclude/kernel \
@@ -44,7 +50,7 @@ CFLAGS += -Iinclude/kernel \
 LDSCRIPT = -T ldscript/linker.ld
 APP_LDSCRIPT = -T app/linker.ld
 LDFLAGS = -nostdlib -Wl,--build-id=none
-APP_CFLAGS := -g -O2 -m32 -static -fno-pic -Wall -Wextra -ffreestanding
+APP_CFLAGS := -g -O2 -m32 -static -fno-pic -Wall -Wextra -ffreestanding -I app/
 APP_LDFLAGS := -nostdlib -Ttext 0x100000 -e main -Wl,--build-id=none
 ASFLAGS = -f elf
 
@@ -57,17 +63,20 @@ endef
 
 all: pre-build $(kernel) $(os_image)
 
-ramfs.obj: $(app_obj_dir)/init $(app_obj_dir)/shell
+ramfs.obj: $(app_lib) $(app_obj_dir)/init $(app_obj_dir)/shell
 	$(V)cd $(app_obj_dir) && find . | cpio -o -H newc > ../ramfs.cpio
 	$(V)cd $(objdir) && $(OBJCOPY) -I binary -O elf32-i386 -B i386 ramfs.cpio $@
 
+$(app_lib): $(app_lib_objs)
+	$(V)$(AR) cru $@ $^
+
 $(app_obj_dir)/init: $(app_src_dir)/init.c
 	@echo "  APP   $<"
-	$(V)$(CC) $(APP_CFLAGS) $(APP_LDFLAGS) $< $(syscall_obj) -o $@
+	$(V)$(CC) $(APP_CFLAGS) $(APP_LDFLAGS) $< $(app_lib) -o $@
 
 $(app_obj_dir)/shell: $(app_src_dir)/shell.c
 	@echo "  APP   $<"
-	$(V)$(CC) $(APP_CFLAGS) $(APP_LDFLAGS) $< $(syscall_obj) -o $@
+	$(V)$(CC) $(APP_CFLAGS) $(APP_LDFLAGS) $< $(app_lib) -o $@
 
 pre-build:
 	@mkdir -p $(objdir)

app/init.c

@@ -1,15 +1,19 @@
+#include <tinyos.h>
+#include <unistd.h>
+
 char a[] = "Hello World Parent!\n";
 char b[] = "Hello World Child!\n";
 
 int main(void)
 {
-	write("User application started\n", 25);
+	char *argv = NULL;
+	printf("User application started\n");
 	int ret = fork();
 	if (ret == 0) {
-		exec("shell");
+		execve("shell", &argv, NULL);
 	} else {
 		for (;;) {
-			write(a, sizeof(a)-1);
+			printf("%s", a);
 			volatile int a = 1 << 23;
 			while (a--)
 				;

app/shell.c

@@ -1,10 +1,11 @@
+#include <tinyos.h>
+
 int a = 0xa5a5;
-char buf[5000];
 int main()
 {
-	if (a = 0xa5a5 && !buf[4500])
-		write("I am shell\n", 11);
+	if (a == 0xa5a5)
+		printf("I am shell\n");
 	else
-		write("I lost you\n", 11);
+		printf("I lost you\n");
 	for(;;);
 }

app/tinyos.h

@@ -0,0 +1,6 @@
+#ifndef __TINYOS_H__
+#define __TINYOS_H__
+
+int printf(const char *fmt, ...);
+
+#endif /* __TINYOS_H__ */

boot/syscall.s

@@ -10,8 +10,8 @@ fork:
 	int 64
 	ret
 
-[GLOBAL exec]
-exec:
+[GLOBAL execve]
+execve:
 	mov eax, 2
 	int 64
 	ret

include/drivers/vga.h

@@ -4,6 +4,6 @@
 void init_vga();
 void vga_write_char(char ch);
 void vga_write_buf(char *buf, int len);
-void printk(const char *fmt, ...);
+int printk(const char *fmt, ...);
 
 #endif /* __VGA_H__ */

kernel/isr.c

@@ -77,10 +77,11 @@ static void syscall_handler(registers_t *r)
 {
 	/* write system call */
 	if (r->eax == 0) {
+		/* First argument is fd, ignore for now */
 		/* buffer to print on VGA */
-		char *buf = (char *) (*(int *)(r->useresp + 4));
+		char *buf = (char *) (*(int *)(r->useresp + 8));
 		/* length of buffer */
-		int len = *(int *) (r->useresp + 8);
+		int len = *(int *) (r->useresp + 12);
 		vga_write_buf(buf, len);
 	/* fork system call */
 	} else if (r->eax == 1) {

kernel/task.c

@@ -68,7 +68,6 @@ static int load_elf(struct task *t, pd_t *pd, void *data)
 	t->irqf->useresp = STACK_ADDR - 16;
 
 	/* Set task entry point */
-	printk("Setting entry point %x\n", elf_hdr->e_entry);
 	t->irqf->eip = elf_hdr->e_entry;
 
 	return 0;

ldscript/linker.ld

@@ -24,11 +24,6 @@ SECTIONS {
 		*(.bss*)             /* all bss sections from all files */
 	}
 
-	.userapp ALIGN (0x1000) :    /* align at 4 KB */
-	{
-		*(.userapp*)
-	}
-
 	. = ALIGN(4);
 	end = .;
 }

stdlib/printf.c

@@ -0,0 +1,61 @@
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+extern int hex_to_str(const int num, char buf[]);
+extern int dec_to_str(const int num, char buf[]);
+
+int printf(const char *fmt, ...)
+{
+	va_list ap;
+	int d, x;
+	char c, *s;
+	const char *p;
+	void *pi;
+	char buf[96];
+	int index = 0;
+	int ret;
+
+	va_start(ap, fmt);
+	for (p = fmt; *p; p++) {
+		if (*p != '%') {
+			buf[index++] = *p;
+			continue;
+		}
+		switch (*++p) {
+		case 's':              /* string */
+			s = va_arg(ap, char *);
+			strncpy(&buf[index], s, strlen(s));
+			index += strlen(s);
+			break;
+		case 'd':              /* int */
+			d = va_arg(ap, int);
+			ret = dec_to_str(d, &buf[index]);
+			index += ret;
+			break;
+		case 'x':		/* hex */
+			x = va_arg(ap, int);
+			ret = hex_to_str(x, &buf[index]);
+			index += ret;
+			break;
+		case 'p':		/* pointer */
+			pi = va_arg(ap, void *);
+			if (pi) {
+				ret = hex_to_str((int) pi, &buf[index]);
+				index += ret;
+			} else {
+				strncpy(&buf[index], "NULL", strlen("NULL"));
+				index += strlen("NULL");
+			}
+			break;
+		case 'c':              /* char */
+			/* need a cast here since va_arg only
+			   takes fully promoted types */
+			c = (char) va_arg(ap, int);
+			buf[index++] = c;
+			break;
+		}
+	}
+	va_end(ap);
+	return write(1, buf, index);
+}

stdlib/printk.c

@@ -1,67 +1,23 @@
 #include <stdarg.h>
 #include <vga.h>
 
+extern int hex_to_str(const int num, char buf[]);
+extern int dec_to_str(const int num, char buf[]);
+
 static void write_str(const char *buf)
 {
 	while (*buf)
 		vga_write_char(*buf++);
 }
 
-static void to_decimal(const int num)
-{
-	int quot, i;
-	char rem;
-	char str[32];
-
-	quot = num;
-	i = 0;
-	do {
-		rem = (quot % 10) + '0';
-		quot /= 10;
-		str[i++] = rem;
-	} while (quot);
-
-	int start, end;
-	char temp;
-	for (end = i - 1, start = 0; start < end; end--, start++) {
-		temp = str[start];
-		str[start] = str[end];
-		str[end] = temp;
-	}
-
-	str[i] = '\0';
-	write_str(str);
-}
-
-static void to_hex(const int num)
-{
-	int index = 32;
-	int val;
-
-	do {
-		index -= 4;
-		val = (num >> index) & 0xf;
-	} while (!val && index);
-
-	write_str("0x");
-	do {
-		if (val > 9)
-			val = 'A' + (val - 10);
-		else
-			val += '0';
-		vga_write_char(val);
-		index -= 4;
-		val = (num >> index) & 0xf;
-	} while (index >= 0);
-}
-
-void printk(const char *fmt, ...)
+int printk(const char *fmt, ...)
 {
 	va_list ap;
 	int d, x;
 	char c, *s;
 	const char *p;
 	void *pi;
+	char tmp_buf[16];
 
 	va_start(ap, fmt);
 	for (p = fmt; *p; p++) {
@@ -76,18 +32,22 @@ void printk(const char *fmt, ...)
 			break;
 		case 'd':              /* int */
 			d = va_arg(ap, int);
-			to_decimal(d);
+			dec_to_str(d, tmp_buf);
+			write_str(tmp_buf);
 			break;
 		case 'x':		/* hex */
 			x = va_arg(ap, int);
-			to_hex(x);
+			hex_to_str(x, tmp_buf);
+			write_str(tmp_buf);
 			break;
 		case 'p':		/* pointer */
 			pi = va_arg(ap, void *);
-			if (pi)
-				to_hex((int) pi);
-			else
+			if (pi) {
+				hex_to_str((int) pi, tmp_buf);
+				write_str(tmp_buf);
+			} else {
 				write_str("NULL");
+			}
 			break;
 		case 'c':              /* char */
 			/* need a cast here since va_arg only
@@ -98,4 +58,5 @@ void printk(const char *fmt, ...)
 		}
 	}
 	va_end(ap);
+	return 0;
 }

stdlib/string.c → stdlib/stdlib.c

@@ -1,6 +1,58 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+int dec_to_str(const int num, char ostr[])
+{
+	int quot, i;
+	char rem;
+
+	quot = num;
+	i = 0;
+	do {
+		rem = (quot % 10) + '0';
+		quot /= 10;
+		ostr[i++] = rem;
+	} while (quot);
+
+	int start, end;
+	char temp;
+	for (end = i - 1, start = 0; start < end; end--, start++) {
+		temp = ostr[start];
+		ostr[start] = ostr[end];
+		ostr[end] = temp;
+	}
+
+	ostr[i] = '\0';
+	return i;
+}
+
+int hex_to_str(const int num, char ostr[])
+{
+	int index = 32;
+	int val;
+	int cnt = 0;
+
+	do {
+		index -= 4;
+		val = (num >> index) & 0xf;
+	} while (!val && index);
+
+	ostr[cnt++] = '0';
+	ostr[cnt++] = 'x';
+	do {
+		if (val > 9)
+			val = 'A' + (val - 10);
+		else
+			val += '0';
+		ostr[cnt++] = val;
+		index -= 4;
+		val = (num >> index) & 0xf;
+	} while (index >= 0);
+
+	ostr[cnt] = '\0';
+	return cnt;
+}
+
 size_t strlen(const char *s)
 {
 	int i;