libsandbox: enable tracing for multiple personalities

Initial support for tracing non-default personalities.  For example,
tracing a 32bit binary from a 64bit environment.

URL: http://bugs.gentoo.org/264399
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Reported-by: Patrick Lauer <patrick@gentoo.org>

2 files changed, 92 insertions, 10 deletions

diff --git a/libsandbox/trace/common.c b/libsandbox/trace/common.c
index 20fcb7e..390e343 100644
--- a/libsandbox/trace/common.c
+++ b/libsandbox/trace/common.c
@@ -1,3 +1,18 @@
+struct syscall_entry {
+	const int nr, sys;
+	const char *name;
+};
+
 static int trace_sysnum(void);
 static long trace_raw_ret(void *vregs);
 static unsigned long trace_arg(void *vregs, int num);
+
+#ifndef SB_SCHIZO
+static const struct syscall_entry syscall_table[] = {
+#define S(s) { SB_SYS_##s, SB_NR_##s, #s },
+#include "trace_syscalls.h"
+#undef S
+	{ SB_NR_UNDEF, SB_NR_UNDEF, NULL },
+};
+# define trace_check_personality() syscall_table
+#endif
diff --git a/libsandbox/trace/linux/x86_64.c b/libsandbox/trace/linux/x86_64.c
index 1f40036..96e732e 100644
--- a/libsandbox/trace/linux/x86_64.c
+++ b/libsandbox/trace/linux/x86_64.c
@@ -1,3 +1,41 @@
+#ifdef SB_SCHIZO
+
+static const struct syscall_entry syscall_table_32[] = {
+#define S(s) { SB_SYS_x86_##s, SB_NR_##s, #s },
+#include "trace_syscalls_x86.h"
+#undef S
+	{ SB_NR_UNDEF, SB_NR_UNDEF, NULL },
+};
+static const struct syscall_entry syscall_table_64[] = {
+#define S(s) { SB_SYS_x86_64_##s, SB_NR_##s, #s },
+#include "trace_syscalls_x86_64.h"
+#undef S
+	{ SB_NR_UNDEF, SB_NR_UNDEF, NULL },
+};
+
+static bool pers_is_32(void)
+{
+	switch (do_peekuser(8 * CS)) {
+		case 0x23: return true;
+		case 0x33: return false;
+		default:   sb_abort();
+	}
+}
+
+static const struct syscall_entry *trace_check_personality(void)
+{
+	return pers_is_32() ? syscall_table_32 : syscall_table_64;
+}
+
+#else
+
+static bool pers_is_32(void)
+{
+	return false;
+}
+
+#endif
+
 static int trace_sysnum(void)
 {
 	return do_peekuser(8 * ORIG_RAX);
@@ -6,19 +44,48 @@ static int trace_sysnum(void)
 static long trace_raw_ret(void *vregs)
 {
 	struct user_regs_struct *regs = vregs;
-	return regs->rax;
+	return pers_is_32() ? (int)regs->rax : regs->rax;
 }
 
 static unsigned long trace_arg(void *vregs, int num)
 {
 	struct user_regs_struct *regs = vregs;
-	switch (num) {
-		case 1: return regs->rdi;
-		case 2: return regs->rsi;
-		case 3: return regs->rdx;
-		case 4: return regs->r10;
-		case 5: return regs->r8;
-		case 6: return regs->r9;
-		default: return -1;
-	}
+	if (pers_is_32())
+		switch (num) {
+			case 1: return regs->rbx;
+			case 2: return regs->rcx;
+			case 3: return regs->rdx;
+			case 4: return regs->rsi;
+			case 5: return regs->rdi;
+			case 6: return regs->rbp;
+			default: return -1;
+		}
+	else
+		switch (num) {
+			case 1: return regs->rdi;
+			case 2: return regs->rsi;
+			case 3: return regs->rdx;
+			case 4: return regs->r10;
+			case 5: return regs->r8;
+			case 6: return regs->r9;
+			default: return -1;
+		}
+}
+
+#ifdef DEBUG
+static void trace_dump_regs(void *vregs)
+{
+	struct user_regs_struct *regs = vregs;
+	sb_printf("{ ");
+#define D(r) sb_printf(#r":%lu ", regs->r)
+	D(rax);
+	D(rdi);
+	D(rsi);
+	D(rdx);
+	D(r10);
+	D(r8);
+	D(r9);
+#undef D
+	sb_printf("}");
 }
+#endif