It's not always possible to directly access user memory from kernel
mode. While it's in theory a lot more expensive to fetch each character
to be printed separately, mach_print() is only a debugging facility, and
it's not supposed to be used for printing large amounts of data.
---
kern/syscall_subr.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/kern/syscall_subr.c b/kern/syscall_subr.c
index e0057d94..0027be29 100644
--- a/kern/syscall_subr.c
+++ b/kern/syscall_subr.c
@@ -43,6 +43,7 @@
#include <kern/task.h>
#include <kern/thread.h>
#include <machine/spl.h> /* for splsched */
+#include <machine/locore.h> /* for copyin */
#if MACH_FIXPRI
#include <mach/policy.h>
@@ -381,6 +382,14 @@ thread_depress_abort(thread_t thread)
void
mach_print(const char *s)
{
- printf("%s", s);
+ char c;
+ while (TRUE) {
+ if (copyin(s, &c, 1))
+ return;
+ if (c == 0)
+ break;
+ printf("%c", c);
+ s++;
+ }
}
#endif /* MACH_KDB */
--
2.44.0
