Lab 3

user/Makefrag

@@ -0,0 +1,16 @@
+OBJDIRS += user
+
+
+USERLIBS += jos
+
+$(OBJDIR)/user/%.o: user/%.c $(OBJDIR)/.vars.USER_CFLAGS
+	@echo + cc[USER] $<
+	@mkdir -p $(@D)
+	$(V)$(CC) -nostdinc $(USER_CFLAGS) -c -o $@ $<
+
+$(OBJDIR)/user/%: $(OBJDIR)/user/%.o $(OBJDIR)/lib/entry.o $(USERLIBS:%=$(OBJDIR)/lib/lib%.a) user/user.ld
+	@echo + ld $@
+	$(V)$(LD) -o $@ $(ULDFLAGS) $(LDFLAGS) -nostdlib $(OBJDIR)/lib/entry.o $@.o -L$(OBJDIR)/lib $(USERLIBS:%=-l%) $(GCC_LIB)
+	$(V)$(OBJDUMP) -S $@ > $@.asm
+	$(V)$(NM) -n $@ > $@.sym
+

user/badsegment.c

@@ -0,0 +1,11 @@
+// program to cause a general protection exception
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	// Try to load the kernel's TSS selector into the DS register.
+	asm volatile("movw $0x28,%ax; movw %ax,%ds");
+}
+

user/breakpoint.c

@@ -0,0 +1,10 @@
+// program to cause a breakpoint trap
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	asm volatile("int $3");
+}
+

user/buggyhello.c

@@ -0,0 +1,11 @@
+// buggy hello world -- unmapped pointer passed to kernel
+// kernel should destroy user environment in response
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	sys_cputs((char*)1, 1);
+}
+

user/buggyhello2.c

@@ -0,0 +1,13 @@
+// buggy hello world 2 -- pointed-to region extends into unmapped memory
+// kernel should destroy user environment in response
+
+#include <inc/lib.h>
+
+const char *hello = "hello, world\n";
+
+void
+umain(int argc, char **argv)
+{
+	sys_cputs(hello, 1024*1024);
+}
+

user/divzero.c

@@ -0,0 +1,13 @@
+// buggy program - causes a divide by zero exception
+
+#include <inc/lib.h>
+
+int zero;
+
+void
+umain(int argc, char **argv)
+{
+	zero = 0;
+	cprintf("1/0 is %08x!\n", 1/zero);
+}
+

user/evilhello.c

@@ -0,0 +1,12 @@
+// evil hello world -- kernel pointer passed to kernel
+// kernel should destroy user environment in response
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	// try to print the kernel entry point as a string!  mua ha ha!
+	sys_cputs((char*)0xf010000c, 100);
+}
+

user/faultread.c

@@ -0,0 +1,10 @@
+// buggy program - faults with a read from location zero
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	cprintf("I read %08x from location 0!\n", *(unsigned*)0);
+}
+

user/faultreadkernel.c

@@ -0,0 +1,10 @@
+// buggy program - faults with a read from kernel space
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	cprintf("I read %08x from location 0xf0100000!\n", *(unsigned*)0xf0100000);
+}
+

user/faultwrite.c

@@ -0,0 +1,10 @@
+// buggy program - faults with a write to location zero
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	*(unsigned*)0 = 0;
+}
+

user/faultwritekernel.c

@@ -0,0 +1,10 @@
+// buggy program - faults with a write to a kernel location
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	*(unsigned*)0xf0100000 = 0;
+}
+

user/hello.c

@@ -0,0 +1,9 @@
+// hello, world
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	cprintf("hello, world\n");
+	cprintf("i am environment %08x\n", thisenv->env_id);
+}

user/softint.c

@@ -0,0 +1,10 @@
+// buggy program - causes an illegal software interrupt
+
+#include <inc/lib.h>
+
+void
+umain(int argc, char **argv)
+{
+	asm volatile("int $14");	// page fault
+}
+

user/testbss.c

@@ -0,0 +1,27 @@
+// test reads and writes to a large bss
+
+#include <inc/lib.h>
+
+#define ARRAYSIZE (1024*1024)
+
+uint32_t bigarray[ARRAYSIZE];
+
+void
+umain(int argc, char **argv)
+{
+	int i;
+
+	cprintf("Making sure bss works right...\n");
+	for (i = 0; i < ARRAYSIZE; i++)
+		if (bigarray[i] != 0)
+			panic("bigarray[%d] isn't cleared!\n", i);
+	for (i = 0; i < ARRAYSIZE; i++)
+		bigarray[i] = i;
+	for (i = 0; i < ARRAYSIZE; i++)
+		if (bigarray[i] != i)
+			panic("bigarray[%d] didn't hold its value!\n", i);
+
+	cprintf("Yes, good.  Now doing a wild write off the end...\n");
+	bigarray[ARRAYSIZE+1024] = 0;
+	panic("SHOULD HAVE TRAPPED!!!");
+}

user/user.ld

@@ -0,0 +1,72 @@
+/* Simple linker script for JOS user-level programs.
+   See the GNU ld 'info' manual ("info ld") to learn the syntax. */
+
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_ARCH(i386)
+ENTRY(_start)
+
+SECTIONS
+{
+	/* Load programs at this address: "." means the current address */
+	. = 0x800020;
+
+	.text : {
+		*(.text .stub .text.* .gnu.linkonce.t.*)
+	}
+
+	PROVIDE(etext = .);	/* Define the 'etext' symbol to this value */
+
+	.rodata : {
+		*(.rodata .rodata.* .gnu.linkonce.r.*)
+	}
+
+	/* Adjust the address for the data segment to the next page */
+	. = ALIGN(0x1000);
+
+	.data : {
+		*(.data)
+	}
+
+	PROVIDE(edata = .);
+
+	.bss : {
+		*(.bss)
+	}
+
+	PROVIDE(end = .);
+
+
+	/* Place debugging symbols so that they can be found by
+	 * the kernel debugger.
+	 * Specifically, the four words at 0x200000 mark the beginning of
+	 * the stabs, the end of the stabs, the beginning of the stabs
+	 * string table, and the end of the stabs string table, respectively.
+	 */
+
+	.stab_info 0x200000 : {
+		LONG(__STAB_BEGIN__);
+		LONG(__STAB_END__);
+		LONG(__STABSTR_BEGIN__);
+		LONG(__STABSTR_END__);
+	}
+
+	.stab : {
+		__STAB_BEGIN__ = DEFINED(__STAB_BEGIN__) ? __STAB_BEGIN__ : .;
+		*(.stab);
+		__STAB_END__ = DEFINED(__STAB_END__) ? __STAB_END__ : .;
+		BYTE(0)		/* Force the linker to allocate space
+				   for this section */
+	}
+
+	.stabstr : {
+		__STABSTR_BEGIN__ = DEFINED(__STABSTR_BEGIN__) ? __STABSTR_BEGIN__ : .;
+		*(.stabstr);
+		__STABSTR_END__ = DEFINED(__STABSTR_END__) ? __STABSTR_END__ : .;
+		BYTE(0)		/* Force the linker to allocate space
+				   for this section */
+	}
+
+	/DISCARD/ : {
+		*(.eh_frame .note.GNU-stack .comment)
+	}
+}