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Print function name and file location when caught a SIGSEGV

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This commit is contained in:
Kamil Kowalczyk
2025-03-12 14:25:55 +01:00
parent 6a5b07fa93
commit 3b938a06dd
7 changed files with 131 additions and 46 deletions
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51
debugus.c
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@@ -145,6 +145,14 @@ void brk_disable(Brk *brk)
brk->enabled = false;
}
void symbols_deinit(Symbols *s)
{
for (int i = 0; i < s->count; i++) {
free((char *)s->items[i].name);
}
da_deinit(s);
}
typedef struct {
const char *file;
pid_t pid;
@@ -152,6 +160,8 @@ typedef struct {
HashTable brks;
uintptr_t program_load_offset;
HashTable js_descs;
Symbols symbols;
FILE *binfile;
PLibelfinBinding plibelfin;
} Dbg;
@@ -165,7 +175,26 @@ siginfo_t dbg_get_siginfo(Dbg *dbg)
void dbg_handle_sigsegv(Dbg *dbg, siginfo_t info)
{
unused(dbg);
uint64_t dbg_get_rip(Dbg *dbg);
LOG_ERR("Caught a segfault %d. SKILL ISSUE BRO\n", info.si_code);
uintptr_t rip = (uintptr_t)dbg_get_rip(dbg);
uintptr_t nearest = rip - dbg->symbols.items[0].addr;
for (int i = 0; i < dbg->symbols.count; i++) {
if (rip - dbg->symbols.items[i].addr < nearest) {
nearest = rip - dbg->symbols.items[i].addr;
}
}
uintptr_t addr = rip - nearest;
for (int i = 0; i < dbg->symbols.count; i++) {
if (dbg->symbols.items[i].addr == addr) {
AddrInfo *ai = libelfin_wrap_info_from_rip(dbg->plibelfin, (uint64_t)(addr - dbg->program_load_offset));
if (ai != NULL) {
LOG_INF("%s:%zu in function %s()\n", ai->file, (size_t)ai->line, dbg->symbols.items[i].name);
libelfin_wrap_free_info(ai);
}
break;
}
}
}
void dbg_handle_sigtrap(Dbg *dbg, siginfo_t info)
@@ -538,17 +567,29 @@ void dbg_load_script(Dbg *dbg, const char *script_path)
fclose(script);
}
void dbg_libelfin_wrap_init(Dbg *dbg)
void dbg_init_bin(Dbg *dbg)
{
FILE *bin = fopen(dbg->file, "rb");
if (bin == NULL) {
LOG_ERR("could not open file %s: %s\n", dbg->file, strerror(errno));
return;
}
dbg->binfile = bin;
}
dbg->plibelfin = libelfin_wrap_get_binding(fileno(bin));
void dbg_libelfin_wrap_init(Dbg *dbg)
{
dbg->plibelfin = libelfin_wrap_get_binding(fileno(dbg->binfile), dbg->program_load_offset);
}
fclose(bin);
void dbg_load_symbols(Dbg *dbg)
{
libelfin_wrap_get_syms(dbg->plibelfin, &dbg->symbols);
for (int i = 0; i < dbg->symbols.count; i++) {
Symbol *s = &dbg->symbols.items[i];
LOG_INF("Found symbol %s 0x%"PRIxPTR"\n", s->name, s->addr);
}
}
void dbg_init(Dbg *dbg, const char *file, pid_t pid)
@@ -559,7 +600,9 @@ 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_init_bin(dbg);
dbg_libelfin_wrap_init(dbg);
dbg_load_symbols(dbg);
hashtable_init(&dbg->brks, MAX_BRKS);
dbg_load_script(dbg, INIT_SCRIPT);
}
@@ -569,7 +612,9 @@ void dbg_deinit(Dbg *dbg)
js_freestate(dbg->js);
hashtable_deinit(&dbg->brks);
hashtable_deinit(&dbg->js_descs);
symbols_deinit(&dbg->symbols);
libelfin_wrap_free_binding(dbg->plibelfin);
fclose(dbg->binfile);
}
void dbg_loop(Dbg *dbg)