List symbols from symtab

Makefile

@@ -1,6 +1,6 @@
 CC=gcc
 CFLAGS=-MD -MP -ggdb -I./mujs
-LDFLAGS=-lm
+LDFLAGS=-lm -lelf
 SRCS=debugus.c linenoise.c hash.c pmparser.c
 OBJS=$(patsubst %.c,%.o,$(SRCS))
 DEPS=$(patsubst %.c,%.d,$(SRCS))

da.h

@@ -0,0 +1,27 @@
+#ifndef DA_H_
+#define DA_H_
+
+#include <stdlib.h>
+
+#define da_append(da, item) \
+    do { \
+        if ((da)->count == 0) { \
+            (da)->capacity = 1; \
+            (da)->items = malloc(sizeof(item)*sizeof((da)->capacity)); \
+        } else { \
+            if ((da)->count == (da)->capacity) { \
+                (da)->capacity *= 2; \
+                (da)->items = realloc((da)->items, (da)->capacity * sizeof((item))); \
+            } \
+        } \
+        (da)->items[(da)->count++] = (item); \
+    } while(0)
+
+#define da_deinit(da) \
+    do { \
+        if ((da)->count > 0) { \
+            free((da)->items); \
+        } \
+    } while(0)
+
+#endif // DA_H_

debugus.c

@@ -6,6 +6,9 @@
 #include <inttypes.h>
 #include <unistd.h>
 #include <string.h>
+#include <errno.h>
+#include <libelf.h>
+#include <gelf.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/ptrace.h>
@@ -16,6 +19,7 @@
 #include "mujs.h"
 #include "hash.h"
 #include "pmparser.h"
+#include "da.h"
 
 #define LOG_ERR(fmt, ...) fprintf(stderr, "Error: " fmt, ##__VA_ARGS__)
 #define LOG_INF(fmt, ...) fprintf(stdout, "Info:  " fmt, ##__VA_ARGS__)
@@ -139,12 +143,23 @@ 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;
 } Dbg;
 
 void dbg_wait(Dbg *dbg)
@@ -395,6 +410,16 @@ void dbg_js_mem_write(js_State *js)
     js_pushundefined(js);
 }
 
+void dbg_js_list_syms(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_init_js(Dbg *dbg)
 {
     dbg->js   = js_newstate(NULL, NULL, JS_STRICT);
@@ -420,6 +445,7 @@ void dbg_init_js(Dbg *dbg)
     make_js_func(set_reg, 2 /* reg name, value*/);
     make_js_func(mem_read, 1 /*addr*/);
     make_js_func(mem_write, 2 /*addr, value*/);
+    make_js_func(list_syms, 0);
 
     #undef make_js_func
 }
@@ -459,9 +485,65 @@ void dbg_load_script(Dbg *dbg, const char *script_path)
 
     js_dostring(dbg->js, script_buf);
 
+    free(script_buf);
     fclose(script);
 }
 
+void dbg_load_symbols(Dbg *dbg)
+{
+    FILE *bin = fopen(dbg->file, "rb");
+    if (bin == NULL) {
+        LOG_ERR("Cannot load symbols from file\n");
+        return;
+    }
+
+    Elf *elf;
+    Elf_Scn *scn = NULL;
+    GElf_Shdr shdr;
+    Elf_Data *data;
+    GElf_Sym sym;
+
+    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);
+}
+
 void dbg_init(Dbg *dbg, const char *file, pid_t pid)
 {
     memset(dbg, 0, sizeof(*dbg));
@@ -470,7 +552,7 @@ void dbg_init(Dbg *dbg, const char *file, pid_t pid)
     dbg_init_js(dbg);
     dbg_init_load_offset(dbg);
     hashtable_init(&dbg->brks, MAX_BRKS);
-
+    dbg_load_symbols(dbg);
     dbg_load_script(dbg, INIT_SCRIPT);
 }
 
@@ -478,6 +560,7 @@ void dbg_deinit(Dbg *dbg)
 {
     js_freestate(dbg->js);
     hashtable_deinit(&dbg->brks);
+    da_deinit(&dbg->symbols);
 }
 
 void dbg_loop(Dbg *dbg)