Implements a setflag command for setting or unsetting individual flags in the $eflags register.

pwndbg/__init__.py

@@ -23,6 +23,7 @@ import pwndbg.commands.cpsr
 import pwndbg.commands.dt
 import pwndbg.commands.dumpargs
 import pwndbg.commands.elf
+import pwndbg.commands.flags
 import pwndbg.commands.gdbinit
 import pwndbg.commands.ghidra
 import pwndbg.commands.got

pwndbg/commands/flags.py

@@ -0,0 +1,37 @@
+import argparse
+import gdb
+import pwndbg.commands
+
+parser = argparse.ArgumentParser(description="Modify register flags",
+                                epilog="flags ZF 1")
+parser.add_argument('flag', type=str,
+                    help='Flag for which you want to change the value')
+parser.add_argument('value', type=int,
+                    help='Value to which you want to set the flag - only valid options are 0 and 1')
+
+flags = {
+            "CF": 0,
+            "PF": 2,
+            "AF": 4,
+            "ZF": 6,
+            "SF": 7,
+            "TF": 8,
+            "IF": 9,
+            "DF": 10,
+            "OF": 11,
+        }
+
+@pwndbg.commands.ArgparsedCommand(parser, aliases=["flag"])
+def setflag(flag, value):
+    if value not in [0, 1]:
+        print("can only set flag bit to 0 or 1")
+        return
+
+    if flag.upper() not in flags.keys():
+        print("%s not a valid flag" % flag)
+        return
+
+    if value == 1:
+        gdb.execute("set $eflags |= (1 << %d)" % flags[flag.upper()])
+    elif value == 0:
+        gdb.execute("set $eflags &= ~(1 << %d)" % flags[flag.upper()])