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libelfin wrapper WIP!

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kamkow1
2025-03-12 00:31:47 +01:00
parent b9ec1900b4
commit 6363c89afc
4 changed files with 91 additions and 76 deletions
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12
Makefile
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@@ -1,6 +1,7 @@
CC=gcc
CFLAGS=-MD -MP -ggdb -I./mujs
LDFLAGS=-lm -lelf
CXX=g++
CFLAGS=-MD -MP -gdwarf -I./mujs
LDFLAGS=-lm -ldwarf++ -lelf++ -lstdc++
SRCS=debugus.c linenoise.c hash.c pmparser.c
OBJS=$(patsubst %.c,%.o,$(SRCS))
DEPS=$(patsubst %.c,%.d,$(SRCS))
@@ -10,7 +11,7 @@ all: debugus .debugusrc1.js test
test: test.o
$(CC) -gdwarf -o $@ $^
debugus: $(OBJS) ./mujs/build/debug/libmujs.o
debugus: $(OBJS) ./mujs/build/debug/libmujs.o ./libelfin_wrap.o
$(CC) -o $@ $^ $(LDFLAGS)
.debugusrc1.js: test .debugusrc1.js.txt
@@ -19,9 +20,12 @@ debugus: $(OBJS) ./mujs/build/debug/libmujs.o
./mujs/build/debug/libmujs.o:
make -C mujs -j$(shell nproc)
./libelfin_wrap.o: ./libelfin_wrap.cpp
$(CXX) $(CFLAGS) -c -o $@ $<
-include $(DEPS)
clean: $(OBJS) test.o $(DEPS)
clean: $(OBJS) test.o $(DEPS) .debugusrc1.js
rm -f $^
make -C mujs clean

87
debugus.c
View File

@@ -8,8 +8,6 @@
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <libelf.h>
#include <gelf.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
@@ -22,6 +20,7 @@
#include "hash.h"
#include "pmparser.h"
#include "da.h"
#include "libelfin_wrap.h"
#define LOG_ERR(fmt, ...) fprintf(stderr, "Error: " fmt, ##__VA_ARGS__)
#define LOG_INF(fmt, ...) fprintf(stdout, "Info: " fmt, ##__VA_ARGS__)
@@ -146,23 +145,12 @@ void brk_disable(Brk *brk)
brk->enabled = false;
}
typedef struct {
const char *name;
uintptr_t addr;
} Symbol;
typedef struct {
Symbol *items;
size_t count, capacity;
} Symbols;
typedef struct {
const char *file;
pid_t pid;
js_State *js;
HashTable brks;
uintptr_t program_load_offset;
Symbols symbols;
HashTable js_descs;
} Dbg;
@@ -184,11 +172,20 @@ void dbg_handle_sigtrap(Dbg *dbg, siginfo_t info)
void dbg_set_rip(Dbg *dbg, uint64_t v);
uint64_t dbg_get_rip(Dbg *dbg);
AddrInfo *ai;
switch (info.si_code) {
case SI_KERNEL:
case TRAP_BRKPT:
dbg_set_rip(dbg, dbg_get_rip(dbg) - 1);
LOG_INF("Hit breakpoint at 0x%"PRIxPTR"\n", dbg_get_rip(dbg));
ai = libelfin_wrap_info_from_rip(dbg_get_rip(dbg));
if (ai != NULL) {
LOG_INF("Hit breakpoint at 0x%"PRIxPTR", %s:%zu\n", dbg_get_rip(dbg),
ai->file, (size_t)ai->line);
libelfin_wrap_free_info(ai);
} else {
LOG_INF("Hit breakpoint at 0x%"PRIxPTR"\n", dbg_get_rip(dbg));
}
return;
case TRAP_TRACE:
return;
@@ -450,16 +447,6 @@ void dbg_js_mwr(js_State *js)
js_pushundefined(js);
}
void dbg_js_lsm(js_State *js)
{
Dbg *dbg = getdbg();
for (int i = 0; i < dbg->symbols.count; i++) {
Symbol *sym = &dbg->symbols.items[i];
LOG_INF("Symbol %s at %"PRIxPTR"\n", sym->name, sym->addr);
}
js_pushundefined(js);
}
void dbg_js_help(js_State *js)
{
Dbg *dbg = getdbg();
@@ -499,7 +486,6 @@ void dbg_init_js(Dbg *dbg)
make_js_func(sr, 2, "Set register value, ARGS=Register name:string,Register value:hex string");
make_js_func(mrd, 1, "Read memory at address, ARGS=Address:hex string");
make_js_func(mwr, 2, "Write memory at address, ARGS=Address:hex string,Value:hex string");
make_js_func(lsm, 0, "List all symbols, ARGS=None");
make_js_func(help, 0, "Print help information, ARGS=None");
#undef make_js_func
@@ -544,58 +530,16 @@ void dbg_load_script(Dbg *dbg, const char *script_path)
fclose(script);
}
void dbg_load_symbols(Dbg *dbg)
void dbg_libelfin_wrap_init(Dbg *dbg)
{
FILE *bin = fopen(dbg->file, "rb");
if (bin == NULL) {
LOG_ERR("Cannot load symbols from file\n");
LOG_ERR("could not open file %s: %s\n", dbg->file, strerror(errno));
return;
}
Elf *elf;
Elf_Scn *scn = NULL;
GElf_Shdr shdr;
Elf_Data *data;
GElf_Sym sym;
libelfin_wrap_init(fileno(bin));
elf_version(EV_CURRENT);
elf = elf_begin(fileno(bin), ELF_C_READ, NULL);
if (elf == NULL) {
LOG_ERR("Could not parse elf\n");
fclose(bin);
return;
}
while ((scn = elf_nextscn(elf, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
if (shdr.sh_type == SHT_SYMTAB) {
break;
}
}
data = elf_getdata(scn, NULL);
int count = shdr.sh_size / shdr.sh_entsize;
for (int i = 0; i < count; i++) {
gelf_getsym(data, i, &sym);
if (sym.st_info != 2 /*func*/) {
char *name = elf_strptr(elf, shdr.sh_link, sym.st_name);
size_t len = strlen(name);
if (len == 0 || sym.st_value == 0x0) {
continue;
}
char *n = malloc(len+1);
strcpy(n, name);
n[len] = '\0';
Symbol symbol = { .name = name, .addr = dbg->program_load_offset + (uintptr_t)sym.st_value };
da_append(&dbg->symbols, symbol);
}
}
elf_end(elf);
fclose(bin);
}
@@ -607,8 +551,8 @@ void dbg_init(Dbg *dbg, const char *file, pid_t pid)
hashtable_init(&dbg->js_descs, MAX_JS_FUNCS);
dbg_init_js(dbg);
dbg_init_load_offset(dbg);
dbg_libelfin_wrap_init(dbg);
hashtable_init(&dbg->brks, MAX_BRKS);
dbg_load_symbols(dbg);
dbg_load_script(dbg, INIT_SCRIPT);
}
@@ -617,7 +561,6 @@ void dbg_deinit(Dbg *dbg)
js_freestate(dbg->js);
hashtable_deinit(&dbg->brks);
hashtable_deinit(&dbg->js_descs);
da_deinit(&dbg->symbols);
}
void dbg_loop(Dbg *dbg)

43
libelfin_wrap.cpp Normal file
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@@ -0,0 +1,43 @@
#include <libelfin/dwarf/dwarf++.hh>
#include <libelfin/elf/elf++.hh>
#include "libelfin_wrap.h"
static elf::elf gelf;
static dwarf::dwarf gdwarf;
DEBUGUS_EXTERNC void libelfin_wrap_init(int fd)
{
gelf = elf::elf{elf::create_mmap_loader(fd)};
gdwarf = dwarf::dwarf{dwarf::elf::create_loader(gelf)};
}
DEBUGUS_EXTERNC AddrInfo *libelfin_wrap_info_from_rip(uint64_t rip)
{
for (auto &cu : gdwarf.compilation_units()) {
if (die_pc_range(cu.root()).contains(rip)) {
auto &lt = cu.get_line_table();
auto it = lt.find_address(rip);
if (it == lt.end()) {
printf("ADDR NOT FOUND\n");
return NULL;
} else {
AddrInfo *ai = (AddrInfo *)malloc(sizeof(*ai));
ai->addr = rip;
ai->line = it->line;
ai->file = (const char*)malloc(strlen(it->file->path.c_str())+1);
strcpy((char*)ai->file, it->file->path.c_str());
return ai;
}
}
}
printf("NO CUS\n");
return NULL;
}
DEBUGUS_EXTERNC void libelfin_wrap_free_info(AddrInfo *ai)
{
free((void*)ai->file);
free((void*)ai);
}

25
libelfin_wrap.h Normal file
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@@ -0,0 +1,25 @@
#ifndef LIBELFIN_WRAP_H_
#define LIBELFIN_WRAP_H_
#ifdef __cplusplus
# define DEBUGUS_EXTERNC extern "C"
#else
# define DEBUGUS_EXTERNC
#endif // __cplusplus
#include <stddef.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
ssize_t line;
const char *file;
uint64_t addr;
} AddrInfo;
DEBUGUS_EXTERNC void libelfin_wrap_init(int fd);
DEBUGUS_EXTERNC AddrInfo *libelfin_wrap_info_from_rip(uint64_t rip);
DEBUGUS_EXTERNC void libelfin_wrap_free_info(AddrInfo *ai);
#endif // LIBELFIN_WRAP_H_