chore(kernel): add custom pretty printer for std::string

Kernel/.editorconfig

@@ -9,5 +9,9 @@ insert_final_newline = true
 indent_style = tab
 indent_size = 4
 
+[*.py]
+indent_size = 4
+indent_style = space
+
 [Makefile]
 indent_style = tab

Kernel/.gdbinit

@@ -1,91 +0,0 @@
-# Usage: add-symbol-file-all <filename> [<offset>]
-#        remove-symbol-file-all <filename> [<offset>]
-#
-# Credit: https://stackoverflow.com/a/33087762/9352057
-#         CC BY-SA 4.0
-
-python
-import subprocess
-import re
-
-def relocatesections(filename, addr):
-    p = subprocess.Popen(["readelf", "-S", filename], stdout = subprocess.PIPE)
-
-    sections = []
-    textaddr = '0'
-    for line in p.stdout.readlines():
-        line = line.decode("utf-8").strip()
-        if not line.startswith('[') or line.startswith('[Nr]'):
-            continue
-
-        line = re.sub(r' +', ' ', line)
-        line = re.sub(r'\[ *(\d+)\]', '\g<1>', line)
-        fieldsvalue = line.split(' ')
-        fieldsname = ['number', 'name', 'type', 'addr', 'offset', 'size', 'entsize', 'flags', 'link', 'info', 'addralign']
-        sec = dict(zip(fieldsname, fieldsvalue))
-
-        if sec['number'] == '0':
-            continue
-
-        sections.append(sec)
-
-        if sec['name'] == '.text':
-            textaddr = sec['addr']
-
-    return (textaddr, sections)
-
-
-class AddSymbolFileAll(gdb.Command):
-    """The right version for add-symbol-file"""
-
-    def __init__(self):
-        super(AddSymbolFileAll, self).__init__("add-symbol-file-all", gdb.COMMAND_USER)
-        self.dont_repeat()
-
-    def invoke(self, arg, from_tty):
-        argv = gdb.string_to_argv(arg)
-        filename = argv[0]
-
-        if len(argv) > 1:
-            offset = int(str(gdb.parse_and_eval(argv[1])), 0)
-        else:
-            offset = 0
-
-        (textaddr, sections) = relocatesections(filename, offset)
-
-        cmd = "add-symbol-file %s 0x%08x" % (filename, int(textaddr, 16) + offset)
-
-        for s in sections:
-            addr = int(s['addr'], 16)
-            if s['name'] == '.text' or addr == 0:
-                continue
-
-            cmd += " -s %s 0x%08x" % (s['name'], addr + offset)
-
-        gdb.execute(cmd)
-
-class RemoveSymbolFileAll(gdb.Command):
-    """The right version for remove-symbol-file"""
-
-    def __init__(self):
-        super(RemoveSymbolFileAll, self).__init__("remove-symbol-file-all", gdb.COMMAND_USER)
-        self.dont_repeat()
-
-    def invoke(self, arg, from_tty):
-        argv = gdb.string_to_argv(arg)
-        filename = argv[0]
-
-        if len(argv) > 1:
-            offset = int(str(gdb.parse_and_eval(argv[1])), 0)
-        else:
-            offset = 0
-
-        (textaddr, _) = relocatesections(filename, offset)
-
-        cmd = "remove-symbol-file -a 0x%08x" % (int(textaddr, 16) + offset)
-        gdb.execute(cmd)
-
-
-AddSymbolFileAll()
-RemoveSymbolFileAll()
-end

Kernel/gdb_printers.py

@@ -0,0 +1,51 @@
+import gdb
+
+class BasicStringPrinter:
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            data = self.val['_data']
+            size = int(self.val['_size'])
+            capacity = int(self.val['_capacity'])
+            if int(data) == 0:
+                return '<null>'
+            content = data.string(length=size)
+            return f"'{content}' (size={size}, cap={capacity})"
+        except gdb.error:
+            return '<invalid string>'
+
+    def children(self):
+        try:
+            data = self.val['_data']
+            size = int(self.val['_size'])
+            if int(data) == 0:
+                return
+            for i in range(size):
+                yield (f'[{i}]', (data + i).dereference())
+        except gdb.error:
+            return
+
+    def display_hint(self):
+        return 'array'
+
+def lookup_fennix_string(val):
+    try:
+        typename = str(val.type.strip_typedefs())
+        fields = val.type.fields()
+        field_names = [f.name for f in fields]
+        if '_data' in field_names and '_size' in field_names and '_capacity' in field_names:
+            return BasicStringPrinter(val)
+    except:
+        pass
+    return None
+
+gdb.pretty_printers.append(lookup_fennix_string)
+
+def build_pretty_printers():
+    pp = gdb.printing.RegexpCollectionPrettyPrinter("fennix")
+    pp.add_printer('std::string', '^std::string$', BasicStringPrinter)
+    return pp
+
+gdb.printing.register_pretty_printer(None, build_pretty_printers(), replace=True)