Add fr_debug_get_state() that works on recent versions of macOS

diff --git a/src/lib/util/debug.c b/src/lib/util/debug.c
index 515fd14f5b6cb3182627db2502f16a7d6d97edae..ea7061560de449ba49110d918b519aca146aa006 100644 (file)
--- a/src/lib/util/debug.c
+++ b/src/lib/util/debug.c
@@ -76,6 +76,11 @@
 #  include <sys/resource.h>
 #endif
 
+#ifdef __APPLE__
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif
+
 #ifdef HAVE_EXECINFO
 #  ifndef MAX_BT_FRAMES
 #    define MAX_BT_FRAMES 128
@@ -125,14 +130,15 @@ static TALLOC_CTX *talloc_autofree_ctx;
 #  ifdef __linux__
 #    define _PTRACE(_x, _y) ptrace(_x, _y, NULL, NULL)
 #    define _PTRACE_DETACH(_x) ptrace(PT_DETACH, _x, NULL, NULL)
-#  else
+#  elif !defined(__APPLE__) && !defined(HAVE_SYS_PROCCTL_H)
 #    define _PTRACE(_x, _y) ptrace(_x, _y, NULL, 0)
 #    define _PTRACE_DETACH(_x) ptrace(PT_DETACH, _x, (void *)1, 0)
-#  endif
+#endif
 
 #  ifdef HAVE_CAPABILITY_H
 #    include <sys/capability.h>
 #  endif
+#endif
 
 #ifdef HAVE_SANITIZER_LSAN_INTERFACE_H
 #  include <sanitizer/lsan_interface.h>
@@ -267,6 +273,71 @@ int fr_get_lsan_state(void)
 }
 #endif
 
+#if defined(HAVE_SYS_PROCCTL_H)
+static int fr_get_debug_state(void)
+{
+       int status;
+
+       if (procctl(P_PID, getpid(), PROC_TRACE_STATUS, &status) == -1) {
+               fr_strerror_printf("Cannot get dumpable flag: procctl(PROC_TRACE_STATUS) failed: %s", fr_syserror(errno));
+               return DEBUG_STATE_UNKNOWN;
+       }
+
+       /*
+        *      As FreeBSD docs say about "PROC_TRACE_STATUS":
+        *
+        *      Returns the current tracing status for the specified process in the
+        *      integer variable pointed to by data.  If tracing is disabled, data
+        *      is set to -1.  If tracing is enabled, but no debugger is attached by
+        *      the ptrace(2) syscall, data is set to 0.  If a debugger is attached,
+        *      data is set to the pid of the debugger process.
+        */
+       if (status <= 0) return DEBUG_STATE_NOT_ATTACHED;
+
+       return DEBUG_STATE_ATTACHED;
+}
+#elif defined(__APPLE__)
+/** The ptrace_attach() method no longer works as of macOS 11.4 (we always get eperm)
+ *
+ * Apple published this helpful article here which provides the
+ * magical invocation: https://developer.apple.com/library/archive/qa/qa1361/_index.html
+ *
+ * @return
+ *     - 0 if we're not.
+ *     - 1 if we are.
+ *      - -1
+ */
+int fr_get_debug_state(void)
+{
+       int                 ret;
+       int                 mib[4];
+       struct kinfo_proc   info;
+       size_t              size;
+
+       /*
+        *      Initialize the flags so that, if sysctl fails for some
+        *      reason, we get a predictable result.
+        */
+       info.kp_proc.p_flag = 0;
+
+       /*
+        *      Initialize mib, which tells sysctl the info we want, in this case
+        *      we're looking for information about a specific process ID.
+        */
+       mib[0] = CTL_KERN;
+       mib[1] = KERN_PROC;
+       mib[2] = KERN_PROC_PID;
+       mib[3] = getpid();
+
+       /* Call sysctl */
+       size = sizeof(info);
+       ret = sysctl(mib, NUM_ELEMENTS(mib), &info, &size, NULL, 0);
+       if (ret != 0) return -1;
+
+       /* We're being debugged if the P_TRACED flag is set */
+       return ((info.kp_proc.p_flag & P_TRACED) != 0);
+}
+#elif defined(HAVE_SYS_PTRACE_H)
 /** Determine if we're running under a debugger by attempting to attach using pattach
  *
  * @return
@@ -362,12 +433,9 @@ DIAG_ON(deprecated-declarations)
                 *      If we don't do it in that order the read in the parent triggers
                 *      a SIGKILL.
                 */
-
-               if ((_PTRACE(flags, ppid) == 0)
-#ifdef __APPLE__
-                   || (errno == EPERM)
-#endif
-                   ) {
+               errno = 0;
+               _PTRACE(flags, ppid);
+               if (errno == 0) {
                        /* Wait for the parent to stop */
                        waitpid(ppid, NULL, 0);
 
@@ -377,6 +445,20 @@ DIAG_ON(deprecated-declarations)
                        }
 
                        /* Detach */
+                       _PTRACE_DETACH(ppid);
+                       exit(0);
+               /*
+                *      We could attach because of a permissions issue, we don't know
+                *      whether we're being traced or not.
+                */
+               } else if (errno == EPERM) {
+                       ret = DEBUGGER_STATE_UNKNOWN;
+
+                       /* Tell the parent what happened */
+                       if (write(from_child[1], &ret, sizeof(ret)) < 0) {
+                               fprintf(stderr, "Writing ptrace status to parent failed: %s", fr_syserror(errno));
+                       }
+
                        _PTRACE_DETACH(ppid);
                        exit(0);
                }
@@ -410,29 +492,6 @@ DIAG_ON(deprecated-declarations)
                return ret;
        }
 }
-#elif defined(HAVE_SYS_PROCCTL_H)
-static int fr_get_debug_state(void)
-{
-       int status;
-
-       if (procctl(P_PID, getpid(), PROC_TRACE_STATUS, &status) == -1) {
-               fr_strerror_printf("Cannot get dumpable flag: procctl(PROC_TRACE_STATUS) failed: %s", fr_syserror(errno));
-               return DEBUG_STATE_UNKNOWN;
-       }
-
-       /*
-        *      As FreeBSD docs say about "PROC_TRACE_STATUS":
-        *
-        *      Returns the current tracing status for the specified process in the
-        *      integer variable pointed to by data.  If tracing is disabled, data
-        *      is set to -1.  If tracing is enabled, but no debugger is attached by
-        *      the ptrace(2) syscall, data is set to 0.  If a debugger is attached,
-        *      data is set to the pid of the debugger process.
-        */
-       if (status <= 0) return DEBUG_STATE_NOT_ATTACHED;
-
-       return DEBUG_STATE_ATTACHED;
-}
 #else
 static int fr_get_debug_state(void)
 {