Add file offset in bcc_procutils_each_module callback

src/cc/bcc_proc.c

@@ -81,7 +81,8 @@ int bcc_procutils_each_module(int pid, bcc_procutils_modulecb callback,
   FILE *procmap;
   int ret;
 
-  snprintf(procmap_filename, sizeof(procmap_filename), "/proc/%ld/maps", (long)pid);
+  snprintf(procmap_filename, sizeof(procmap_filename), "/proc/%ld/maps",
+           (long)pid);
   procmap = fopen(procmap_filename, "r");
 
   if (!procmap)
@@ -90,10 +91,10 @@ int bcc_procutils_each_module(int pid, bcc_procutils_modulecb callback,
   do {
     char endline[4096];
     char perm[8], dev[8];
-    long long begin, end, size, inode;
+    long long begin, end, offset, inode;
 
     ret = fscanf(procmap, "%llx-%llx %s %llx %s %lld", &begin, &end, perm,
-                 &size, dev, &inode);
+                 &offset, dev, &inode);
 
     if (!fgets(endline, sizeof(endline), procmap))
       break;
@@ -105,10 +106,12 @@ int bcc_procutils_each_module(int pid, bcc_procutils_modulecb callback,
       if (newline)
         newline[0] = '\0';
 
-      while (isspace(mapname[0])) mapname++;
+      while (isspace(mapname[0]))
+        mapname++;
 
       if (strchr(perm, 'x') && bcc_mapping_is_file_backed(mapname)) {
-        if (callback(mapname, (uint64_t)begin, (uint64_t)end, true, payload) < 0)
+        if (callback(mapname, (uint64_t)begin, (uint64_t)end, (uint64_t)offset,
+                     true, payload) < 0)
           break;
       }
     }
@@ -122,12 +125,15 @@ int bcc_procutils_each_module(int pid, bcc_procutils_modulecb callback,
   // Try perf-<PID>.map path with process's mount namespace, chroot and NSPID,
   // in case it is generated by the process itself.
   if (bcc_perf_map_path(map_path, sizeof(map_path), pid))
-    callback(map_path, 0, -1, true, payload);
+    if (callback(map_path, 0, -1, 0, true, payload) < 0)
+      return 0;
   // Try perf-<PID>.map path with global root and PID, in case it is generated
   // by other Process. Avoid checking mount namespace for this.
   int res = snprintf(map_path, 4096, "/tmp/perf-%d.map", pid);
   if (res > 0 && res < 4096)
-    callback(map_path, 0, -1, false, payload);
+    if (callback(map_path, 0, -1, 0, false, payload) < 0)
+      return 0;
+
   return 0;
 }
 

src/cc/bcc_proc.h

@@ -24,14 +24,21 @@ extern "C" {
 
 #include <stdint.h>
 
-// Module name, start address, end address, whether to check mount namespace, payload
-typedef int (*bcc_procutils_modulecb)(const char *, uint64_t, uint64_t, bool, void *);
+// Module name, start address, end address, file_offset,
+// whether to check mount namespace, payload
+// Callback returning a negative value indicates to stop the iteration
+typedef int (*bcc_procutils_modulecb)(const char *, uint64_t, uint64_t,
+                                      uint64_t, bool, void *);
 // Symbol name, address, payload
 typedef void (*bcc_procutils_ksymcb)(const char *, uint64_t, void *);
 
 char *bcc_procutils_which_so(const char *libname, int pid);
 char *bcc_procutils_which(const char *binpath);
 int bcc_mapping_is_file_backed(const char *mapname);
+// Iterate over all executable memory mapping sections of a Process.
+// All anonymous and non-file-backed mapping sections, namely those
+// listed in bcc_mapping_is_file_backed, will be ignored.
+// Returns -1 on error, and 0 on success
 int bcc_procutils_each_module(int pid, bcc_procutils_modulecb callback,
                               void *payload);
 int bcc_procutils_each_ksym(bcc_procutils_ksymcb callback, void *payload);

src/cc/bcc_syms.cc

@@ -148,7 +148,7 @@ void ProcSyms::refresh() {
 }
 
 int ProcSyms::_add_module(const char *modname, uint64_t start, uint64_t end,
-                          bool check_mount_ns, void *payload) {
+                          uint64_t offset, bool check_mount_ns, void *payload) {
   ProcSyms *ps = static_cast<ProcSyms *>(payload);
   auto it = std::find_if(
       ps->modules_.begin(), ps->modules_.end(),
@@ -403,8 +403,8 @@ struct mod_st {
   uint64_t start;
 };
 
-static int _find_module(const char *modname, uint64_t start, uint64_t end, bool,
-                        void *p) {
+static int _find_module(const char *modname, uint64_t start, uint64_t end,
+                        uint64_t offset, bool, void *p) {
   struct mod_st *mod = (struct mod_st *)p;
   if (!strcmp(modname, mod->name)) {
     mod->start = start;

src/cc/syms.h

@@ -130,7 +130,8 @@ class ProcSyms : SymbolCache {
 
   static int _add_load_sections(uint64_t v_addr, uint64_t mem_sz,
                                 uint64_t file_offset, void *payload);
-  static int _add_module(const char *, uint64_t, uint64_t, bool, void *);
+  static int _add_module(const char *, uint64_t, uint64_t, uint64_t, bool,
+                         void *);
   void load_exe();
   void load_modules();
 

src/cc/usdt.h

@@ -207,7 +207,8 @@ class Context {
 
   static void _each_probe(const char *binpath, const struct bcc_elf_usdt *probe,
                           void *p);
-  static int _each_module(const char *modpath, uint64_t, uint64_t, bool, void *p);
+  static int _each_module(const char *modpath, uint64_t, uint64_t, uint64_t,
+                          bool, void *p);
 
   void add_probe(const char *binpath, const struct bcc_elf_usdt *probe);
   std::string resolve_bin_path(const std::string &bin_path);

src/cc/usdt/usdt.cc

@@ -217,7 +217,8 @@ void Context::_each_probe(const char *binpath, const struct bcc_elf_usdt *probe,
   ctx->add_probe(binpath, probe);
 }
 
-int Context::_each_module(const char *modpath, uint64_t, uint64_t, bool, void *p) {
+int Context::_each_module(const char *modpath, uint64_t, uint64_t, uint64_t,
+                          bool, void *p) {
   Context *ctx = static_cast<Context *>(p);
   // Modules may be reported multiple times if they contain more than one
   // executable region. We are going to parse the ELF on disk anyway, so we