feat(tools): fas2sym: .sym file are now usable with gdb

bin/fas2sym/elf.c

@@ -1,10 +1,12 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <elf.h>
 #include "fas2sym.h"
 
 enum sections {
 	SEC_NULL   = 0,
+	SEC_TEXT,
 	SEC_SHSTRTAB,
 	SEC_STRTAB,
 	SEC_SYMTAB,
@@ -17,20 +19,25 @@ static Elf32_Ehdr elf_ehdr = {
 		ELFCLASS32, ELFDATA2LSB, EV_CURRENT,
 		0, 0, 0, 0, 0, 0, 0, 0, 0
 	},
-	ET_REL, EM_386, EV_CURRENT, 0, 0, 0, 0,
+	ET_DYN, EM_386, EV_CURRENT, 0, 0, 0, 0,
     sizeof(Elf32_Ehdr), sizeof(Elf32_Phdr), 0,
 	sizeof(Elf32_Shdr), SEC_END, SEC_SHSTRTAB
 };
 
 static Elf32_Shdr elf_shdrs[SEC_END] = {
 	{ 0, SHT_NULL, 0, 0, 0, 0, SHN_UNDEF, 0, 0, 0 },
+	/* .text */
+	{
+		1, SHT_NOBITS, SHF_ALLOC | SHF_EXECINSTR,
+		0, 0, 0, SHN_UNDEF, 0, 1, 0
+	},
 	/* .shstrtab */
-	{ 1, SHT_STRTAB, 0, 0, 0, 0, SHN_UNDEF, 0, 1, 0 },
+	{ 7, SHT_STRTAB, 0, 0, 0, 0, SHN_UNDEF, 0, 1, 0 },
 	/* .strtab */
-	{ 11, SHT_STRTAB, 0, 0, 0, 0, SHN_UNDEF, 0, 1, 0 },
+	{ 17, SHT_STRTAB, 0, 0, 0, 0, SHN_UNDEF, 0, 1, 0 },
 	/* .symtab */
 	{
-		19, SHT_SYMTAB, 0, 0, 0, 0,
+		25, SHT_SYMTAB, 0, 0, 0, 0,
 		SEC_STRTAB, 0, 4, sizeof(Elf32_Sym)
 	}
 };
@@ -42,7 +49,7 @@ static struct buffer elf_symtab = { 0, 0, NULL };
 static int
 elf_shstrtab_init(void)
 {
-	const uint8_t initial[] = "\0.shstrtab\0.strtab\0.symtab\0";
+	const uint8_t initial[] = "\0.text\0.shstrtab\0.strtab\0.symtab\0";
 
 	return (buffer_put(&elf_shstrtab, initial, sizeof(initial), NULL));
 }
@@ -100,6 +107,8 @@ elf_add_symbol(uint32_t name_off, uint32_t value, uint32_t size,
 	msg_verbose(2, "add symbol: %s",
 				(char *)(elf_strtab.data + name_off));
 
+	elf_shdrs[SEC_SYMTAB].sh_info += 1;
+
 	return (buffer_put(&elf_symtab, (uint8_t *)&sym,
 					   sizeof(Elf32_Sym), NULL));
 }
@@ -146,6 +155,55 @@ elf_compute_section_offsets(void)
 	elf_shdrs[SEC_SYMTAB].sh_size = elf_symtab.cnt;
 }
 
+static void
+elf_resolve_symbols(void)
+{
+	Elf32_Sym *syms;
+	char *strtab;
+	size_t idx;
+	size_t symcnt;
+	uint32_t begin = 0;
+	uint32_t end = 0;
+
+	if (text_begin == NULL || text_end == NULL)
+	{
+		return;
+	}
+
+	syms = (Elf32_Sym *)elf_symtab.data;
+	strtab = (char *)elf_strtab.data;
+	symcnt = (elf_symtab.cnt / sizeof(Elf32_Sym));
+
+	for (idx = 0; idx < symcnt; idx++)
+	{
+		if (strcmp(strtab + syms[idx].st_name, text_begin) == 0)
+		{
+			begin = syms[idx].st_value;
+			msg_verbose(1, "Sym %s: %X\n", text_begin, begin);
+		}
+		else if (strcmp(strtab + syms[idx].st_name, text_end) == 0)
+		{
+			end = syms[idx].st_value;
+		}
+
+		if (begin != 0 && end != 0)
+		{
+			break;
+		}
+	}
+
+	elf_shdrs[SEC_TEXT].sh_addr = begin;
+	elf_shdrs[SEC_TEXT].sh_size = end - begin;
+
+	for (idx = 0; idx < symcnt; idx++)
+	{
+		if (syms[idx].st_value >= begin && syms[idx].st_value <= end)
+		{
+			syms[idx].st_shndx = SEC_TEXT;
+		}
+	}
+}
+
 int
 elf_write(const char *file)
 {
@@ -167,6 +225,8 @@ elf_write(const char *file)
 	elf_ehdr.e_shoff += elf_shstrtab.cnt +  elf_strtab.cnt;
 	elf_ehdr.e_shoff += elf_symtab.cnt;
 
+	elf_resolve_symbols();
+
 	if (fwrite(&elf_ehdr, sizeof(Elf32_Ehdr), 1, fp) != 1)
 	{
 		msg_errx("%s: An error occurred while writting elf header", file);
@@ -193,7 +253,7 @@ elf_write(const char *file)
 	/* section headers */
 	elf_compute_section_offsets();
 	/* XXX: fix me */
-	elf_shdrs[SEC_SYMTAB].sh_info = 0; /* (elf_symtab.cnt / sizeof(Elf32_Sym)) + 1;*/
+	elf_shdrs[SEC_SYMTAB].sh_info += 1;/*= 0; *//* (elf_symtab.cnt / sizeof(Elf32_Sym)) + 1;*/
 
 	if (fwrite(elf_shdrs, sizeof(Elf32_Shdr), SEC_END, fp) != SEC_END)
 	{

bin/fas2sym/fas.c

@@ -131,9 +131,9 @@ fas_export_symbol_name(uint32_t name_off)
 		return (0); /* anonymous symbol */
 	}
 
-	if (name_off & (1<<31)) /* if in fas strtab */
+	if (name_off & (1u<<31)) /* if in fas strtab */
 	{
-		ptr = fas_strtab + (name_off & ~(1<<31)); /* XXX */
+		ptr = fas_strtab + (name_off & ~(1u<<31)); /* XXX */
 	}
 	else /* otherwhise it's in psrc */
 	{

bin/fas2sym/fas2sym.h

@@ -30,6 +30,9 @@ int elf_write(const char *file);
 void elf_cleanup(void);
 
 /* main.c */
+extern const char *text_begin;
+extern const char *text_end;
+
 void msg_err(const char *fmt, ...);
 void msg_errx(const char *fmt, ...);
 void msg_verbose(int level, const char *fmt, ...);

bin/fas2sym/main.c

@@ -10,6 +10,8 @@
 static const char *prg_name;
 static const char *outfile = "out.sym";
 static int verbose = 0;
+const char *text_begin = NULL;
+const char *text_end = NULL;
 
 static void
 msg_err_common(const char *fmt, va_list ap)
@@ -77,6 +79,15 @@ usage(int retval)
 	else
 	{
 		printf("Usage: %s [-o OUTPUT] file\n", prg_name);
+		printf("OPTIONS:\n");
+		printf("  -o OUTPUT     Set output file (default: %s)\n",
+			outfile);
+		printf("  -t begin,end  XXXX (addr or symbol)\n");
+		/*
+		 * -t start,end (text)
+		 * -b start,end (bss)
+		 * -d start,end (data)
+		 */
 	}
 
 	exit(retval);
@@ -95,10 +106,11 @@ main(int argc, char **argv)
 {
 	int c;
 	int status;
+	char *tmp;
 
 	prg_name = basename(argv[0]);
 
-	while ((c = getopt(argc, argv, "hvVo:")) != -1)
+	while ((c = getopt(argc, argv, "hvVo:t:")) != -1)
 	{
 		switch (c)
 		{
@@ -114,6 +126,19 @@ main(int argc, char **argv)
 		case 'o':
 			outfile = optarg;
 			break;
+		case 't':
+			tmp = strchr(optarg, ',');
+			if (tmp == NULL)
+			{
+				usage(EXIT_FAILURE);
+			}
+
+			*tmp = '\0';
+			text_begin = optarg;
+			text_end = tmp + 1;
+
+			msg_verbose(2, ".text: %s, %s", text_begin, text_end);
+			break;
 		default:
 			usage(EXIT_FAILURE);
 			break;

bin/fasdump/main.c

@@ -185,7 +185,7 @@ print_symbol_section(uint8_t type, uint32_t rel)
 		return;
 	}
 
-	if (rel & (1<<31))
+	if (rel & (1u<<31))
 	{
 		printf("UND ");
 	}
@@ -204,9 +204,9 @@ print_symbol_name(uint32_t off)
 	{
 		return;
 	}
-	if (off & (1<<31))
+	if (off & (1u<<31))
 	{
-		printf("%s", strtab + (off & ~(1<<31)));
+		printf("%s", strtab + (off & ~(1u<<31)));
 	}
 	else
 	{
@@ -230,6 +230,7 @@ print_symbols(void)
 		printf("%-4" PRIu8 " ", symtab[idx].size);
 		print_symbol_section(symtab[idx].type, symtab[idx].reloc);
 		print_symbol_name(symtab[idx].name_off);
+		/*printf(" %" PRIx8, symtab[idx].flags); */
 		printf("\n");
 	}
 	printf("\n");

kernel/Makefile

@@ -42,6 +42,8 @@ SRCS	= kernel.asm \
 			bio.inc \
 			$(ASMINCS)
 
+FAS2SYMFLAGS = -t kmain,kend
+
 .PHONY: const.inc
 const.inc: const.inc.in
 	@$(VERSION_SH)

share/mk/stpd.kernel.mk

@@ -11,7 +11,7 @@ $(KERNEL).sys $(KERNEL).fas &: $(SRCS)
 
 $(KERNEL).sym: $(KERNEL).fas
 	$(MSG_CREATE)
-	@$(FAS2SYM) -o $@ $<
+	@$(FAS2SYM) $(FAS2SYMFLAGS) -o $@ $<
 
 .PHONY: install
 install: $(DESTDIR)/$(KERNEL).sys $(SYMSDIR)/$(KERNEL).sym