Automatically load program load offset

debugus.c

@@ -14,6 +14,7 @@
 #include "linenoise.h"
 #include "mujs.h"
 #include "hash.h"
+#include "pmparser.h"
 
 #define LOG_ERR(fmt, ...) fprintf(stderr, "Error: " fmt, ##__VA_ARGS__)
 #define LOG_INF(fmt, ...) fprintf(stdout, "Info:  " fmt, ##__VA_ARGS__)
@@ -33,6 +34,7 @@
 
 typedef struct {
     pid_t pid;
+    pid_t proc_pid;
     uintptr_t addr;
     bool enabled;
     uint8_t data;
@@ -180,12 +182,32 @@ void dbg_init_js(Dbg *dbg)
     #undef make_js_func
 }
 
+void dbg_init_load_offset(Dbg *dbg)
+{
+    procmaps_iterator maps_iter = {0};
+    procmaps_error_t parser_err = PROCMAPS_SUCCESS;
+
+    parser_err = pmparser_parse(dbg->pid, &maps_iter);
+    if (parser_err) {
+        LOG_ERR("Failed to parse /proc/%d/maps (%d)\n", dbg->pid, (int)parser_err);
+        return;
+    }
+
+    // We only need the first one
+    procmaps_struct *mem_region = pmparser_next(&maps_iter);
+
+    dbg->program_load_offset = (uintptr_t)mem_region->addr_start;
+
+    pmparser_free(&maps_iter);
+}
+
 void dbg_init(Dbg *dbg, const char *file, pid_t pid)
 {
     memset(dbg, 0, sizeof(*dbg));
     dbg->file = file;
     dbg->pid  = pid;
     dbg_init_js(dbg);
+    dbg_init_load_offset(dbg);
     hashtable_init(&dbg->brks, MAX_BRKS);
 }