Rephrase comments to make clear distinction between service runtime and nacl dynamic loader
And, minor renaming.
diff --git a/gdb/nacl-tdep.c b/gdb/nacl-tdep.c
index 099c031..97d0983 100644
--- a/gdb/nacl-tdep.c
+++ b/gdb/nacl-tdep.c
@@ -43,10 +43,10 @@
*******************************************************************************/
-/* The basic idea of the debugger port is to switch from loader symbols to nacl
- symbols when needed. For example, we might want to switch to nacl symbols
- when execution stops in untrusted code. We call this switching gdb states
- between service runtime state and nacl state.
+/* The basic idea of the debugger port is to switch from service runtime symbols
+ to nacl symbols when needed. For example, we might want to switch to nacl
+ symbols when execution stops in untrusted code. We call this switching gdb
+ states between service runtime state and nacl state.
The only way of switching states in this implementation of gdb is overriding
a bunch of global variables. This likely leads to gdb inconsistency, as we
@@ -294,7 +294,7 @@
extern struct so_list *svr4_alloc_so (CORE_ADDR, const char *);
-struct nacl_ld_so_debugger_interface
+struct nacl_dynamic_loader_debugger_interface
{
/* _dl_debug_state - solib event break. */
CORE_ADDR _dl_debug_state;
@@ -311,7 +311,7 @@
We do not read target memory here - it might be not yet initialized! */
static int
-nacl_discover_ld_so_debugger_interface (struct nacl_ld_so_debugger_interface *i)
+nacl_discover_dynamic_loader_debugger_interface (struct nacl_dynamic_loader_debugger_interface *ni)
{
struct minimal_symbol *msymbol;
@@ -321,17 +321,17 @@
msymbol = lookup_minimal_symbol ("_dl_debug_state", NULL, symfile_objfile);
if (!msymbol || !SYMBOL_VALUE_ADDRESS (msymbol))
return 0;
- i->_dl_debug_state = SYMBOL_VALUE_ADDRESS (msymbol);
+ ni->_dl_debug_state = SYMBOL_VALUE_ADDRESS (msymbol);
msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile);
if (!msymbol || !SYMBOL_VALUE_ADDRESS (msymbol))
return 0;
- i->_r_debug = SYMBOL_VALUE_ADDRESS (msymbol);
+ ni->_r_debug = SYMBOL_VALUE_ADDRESS (msymbol);
msymbol = lookup_minimal_symbol ("_dl_argv", NULL, symfile_objfile);
if (!msymbol || !SYMBOL_VALUE_ADDRESS (msymbol))
return 0;
- i->_dl_argv = SYMBOL_VALUE_ADDRESS (msymbol);
+ ni->_dl_argv = SYMBOL_VALUE_ADDRESS (msymbol);
return 1;
}
@@ -340,7 +340,7 @@
struct so_list *
nacl_current_sos (void)
{
- struct nacl_ld_so_debugger_interface ld_so;
+ struct nacl_dynamic_loader_debugger_interface ni;
nacl_init_sandbox_base ();
if (!nacl_sandbox_base)
@@ -349,14 +349,14 @@
if (!nacl_exec_file)
return NULL;
- if (nacl_discover_ld_so_debugger_interface (&ld_so))
+ if (nacl_discover_dynamic_loader_debugger_interface (&ni))
{
CORE_ADDR lm_addr;
struct so_list *head = 0;
struct so_list **link_ptr = &head;
/* for (lm_addr = _r_debug.r_map; lm_addr; lm_addr = lm_addr->l_next) */
- for (lm_addr = read_memory_unsigned_integer (ld_so._r_debug + 4, 4);
+ for (lm_addr = read_memory_unsigned_integer (ni._r_debug + 4, 4);
lm_addr;
lm_addr = read_memory_unsigned_integer (nacl_sandbox_base + lm_addr + 16, 4))
{
@@ -378,7 +378,7 @@
/* Native client dynamic executable. */
xfree (so_name);
- l_name = read_memory_unsigned_integer (ld_so._dl_argv, 4);
+ l_name = read_memory_unsigned_integer (ni._dl_argv, 4);
l_name = read_memory_unsigned_integer (nacl_sandbox_base + l_name, 4);
target_read_string (nacl_sandbox_base + l_name, &so_name, SO_NAME_MAX_PATH_SIZE - 1, &err);
@@ -409,33 +409,53 @@
}
+/* Arrange cooperation with nacl dynamic loader for loading nacl solibs.
+
+ Dynamic loader debugger interface:
+
+ Dynamic loader global structure "_r_debug" contains everything the debugger
+ needs to know. In particular we are interested in 2 fields:
+
+ - "_r_debug.r_map" points to the list of currently loaded solibs;
+
+ - "_r_debug.r_brk" points to the function that is called each time solib is
+ loaded or unloaded. That function is usually called "_dl_debug_state";
+
+ This function might be called when nacl dynamic loader was just loaded by
+ the service runtime but before it started to execute, thus "_r_debug"
+ structure might not be yet initialized.
+
+ Here we set a solib event breakpoint at "_dl_debug_state". */
+
int
nacl_solib_enable_break (void)
{
- struct nacl_ld_so_debugger_interface ld_so;
+ struct nacl_dynamic_loader_debugger_interface ni;
gdb_assert (nacl_gdb_state_p ());
gdb_assert (nacl_sandbox_base);
- if (!nacl_discover_ld_so_debugger_interface (&ld_so))
+ if (!nacl_discover_dynamic_loader_debugger_interface (&ni))
return 0;
- create_solib_event_breakpoint (ld_so._dl_debug_state);
+ create_solib_event_breakpoint (ni._dl_debug_state);
return 1;
}
-/* Arrange cooperation with trusted loader for loading nacl program.
+/* Arrange cooperation with service runtime for loading nacl program.
- Trusted loader debugger interface:
+ Service runtime debugger interface:
- When nacl program is loaded into memory but before it gets control, loader
- calls function named "_ovly_debug_event". The name comes from i386 nacl
- debugger interface, where nacl program loading event was treated as
- an overlay event. For x86_64, we treat it as a solib event instead.
+ When nacl program is loaded into memory but before it gets control, service
+ runtime calls function named "_ovly_debug_event". The name comes from the
+ debugger interface for i386-nacl, where nacl program loading event was
+ treated as an overlay event. For x86_64-nacl, we treat it as a solib event
+ instead.
- At the moment when "_ovly_debug_event" gets called, loader's global variable
- "nacl_global_xlate_base" contains the address of the nacl sandbox base.
+ At the moment when "_ovly_debug_event" gets called, service runtime global
+ variable "nacl_global_xlate_base" contains the address of the nacl sandbox
+ base.
Here we set a solib event breakpoint at "_ovly_debug_event". */
@@ -452,7 +472,7 @@
msymbol = lookup_minimal_symbol ("nacl_global_xlate_base", NULL, symfile_objfile);
if (!msymbol || !SYMBOL_VALUE_ADDRESS (msymbol))
{
- warning (_("failed to find nacl loader debugger interface "
+ warning (_("failed to find service runtime debugger interface "
" (nacl_global_xlate_base)"));
return;
}
@@ -460,7 +480,7 @@
msymbol = lookup_minimal_symbol ("_ovly_debug_event", NULL, symfile_objfile);
if (!msymbol || !SYMBOL_VALUE_ADDRESS (msymbol))
{
- warning (_("failed to find nacl loader debugger interface "
+ warning (_("failed to find service runtime debugger interface "
" (_ovly_debug_event)"));
return;
}
@@ -482,25 +502,24 @@
/* How to use the debugger:
- Primary program being debugged is nacl loader. Specify it as usually:
+ Primary program being debugged is service runtime. Specify it as usually:
file ./sel_ldr
- Set loader command line arguments. For sel_ldr, that should include sel_ldr
- arguments together with nacl program and nacl program arguments:
+ Set service runtime command line arguments. For sel_ldr, that should include
+ sel_ldr arguments together with nacl program and nacl program arguments:
set args -Q -a -c -f ./runnable-ld.so -- ./a.out
Set nacl program to be debugged. This has to be done explicitly, as we are
- not always able to deduce nacl program name from the loader command line,
- for example, chrome picks nacl program name from the html page. For setting
- nacl program, we have a new command:
+ not always able to deduce nacl program name from the service runtime command
+ line, for example, chrome picks nacl program name from the html page. For
+ setting nacl program, we have a new command:
nacl-file ./runnable-ld.so
- While debugging, we can switch views between trusted (loader aka service
- runtime) code and untrusted (nacl program) code. Current view is indicated
- by gdb prompt:
+ While debugging, we can switch views between service runtime (trusted code)
+ and nacl program (untrusted code0. Current view is indicated by gdb prompt:
(sr-gdb) - trusted code view
(nc-gdb) - untrusted code view
diff --git a/gdb/solib.c b/gdb/solib.c
index 5e5b4cb..053e019 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -743,11 +743,11 @@
/* We didn't loaded nacl executable yet - load it now. */
solib_add_1 (pattern, from_tty, target, readsyms);
- /* If we just loaded something, it might be nacl ld.so. Try arranging
- cooperation with it. */
+ /* If we just loaded something, probably it was nacl dynamic loader.
+ Try arranging cooperation with it. */
if (so_list_head && nacl_solib_enable_break ())
{
- /* Yes, it was nacl ld.so. Read solibs it already knows about. */
+ /* It was nacl dynamic loader - read solibs it knows about. */
solib_add_1 (pattern, from_tty, target, readsyms);
}
}
