add seqnr to message from kernel, userland needs to quote correct seqnr.

avoids problems where tsleep has been interrupted by a signal.

5 files changed, 41 insertions, 24 deletions

diff --git a/bin/systrace/intercept.c b/bin/systrace/intercept.c
index 2d726d39a5e..3a2d3de4989 100644
--- a/bin/systrace/intercept.c
+++ b/bin/systrace/intercept.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intercept.c,v 1.17 2002/07/19 14:38:57 itojun Exp $	*/
+/*	$OpenBSD: intercept.c,v 1.18 2002/07/22 04:02:39 provos Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -552,8 +552,8 @@ intercept_filename(int fd, pid_t pid, void *addr, int userp)
 }
 
 void
-intercept_syscall(int fd, pid_t pid, int policynr, const char *name, int code,
-    const char *emulation, void *args, int argsize)
+intercept_syscall(int fd, pid_t pid, u_int16_t seqnr, int policynr,
+    const char *name, int code, const char *emulation, void *args, int argsize)
 {
 	short action, flags = 0;
 	struct intercept_syscall *sc;
@@ -609,11 +609,11 @@ intercept_syscall(int fd, pid_t pid, int policynr, const char *name, int code,
 	}
 
 	/* Resume execution of the process */
-	intercept.answer(fd, pid, action, error, flags);
+	intercept.answer(fd, pid, seqnr, action, error, flags);
 }
 
 void
-intercept_syscall_result(int fd, pid_t pid, int policynr,
+intercept_syscall_result(int fd, pid_t pid, u_int16_t seqnr, int policynr,
     const char *name, int code, const char *emulation, void *args, int argsize,
     int result, void *rval)
 {
@@ -644,7 +644,7 @@ intercept_syscall_result(int fd, pid_t pid, int policynr,
 	}
  out:
 	/* Resume execution of the process */
-	intercept.answer(fd, pid, 0, 0, 0);
+	intercept.answer(fd, pid, seqnr, 0, 0, 0);
 }
 
 int
diff --git a/bin/systrace/intercept.h b/bin/systrace/intercept.h
index 9ccc6eb0f4e..01a86e092ad 100644
--- a/bin/systrace/intercept.h
+++ b/bin/systrace/intercept.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intercept.h,v 1.8 2002/07/19 14:38:57 itojun Exp $	*/
+/*	$OpenBSD: intercept.h,v 1.9 2002/07/22 04:02:39 provos Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -49,7 +49,7 @@ struct intercept_system {
 	int (*restcwd)(int);
 	int (*io)(int, pid_t, int, void *, u_char *, size_t);
 	int (*getarg)(int, void *, int, void **);
-	int (*answer)(int, pid_t, short, int, short);
+	int (*answer)(int, pid_t, u_int32_t, short, int, short);
 	int (*newpolicy)(int);
 	int (*assignpolicy)(int, pid_t, int);
 	int (*policy)(int, int, int, short);
@@ -164,9 +164,9 @@ int intercept_existpids(void);
 
 char *intercept_get_string(int, pid_t, void *);
 char *intercept_filename(int, pid_t, void *, int);
-void intercept_syscall(int, pid_t, int, const char *, int, const char *,
-    void *, int);
-void intercept_syscall_result(int, pid_t, int, const char *, int, const char *,
-    void *, int, int, void *);
+void intercept_syscall(int, pid_t, u_int16_t, int, const char *, int,
+    const char *, void *, int);
+void intercept_syscall_result(int, pid_t, u_int16_t, int, const char *, int,
+    const char *, void *, int, int, void *);
 
 #endif /* _INTERCEPT_H_ */
diff --git a/bin/systrace/openbsd-syscalls.c b/bin/systrace/openbsd-syscalls.c
index 93fac028415..42eda506892 100644
--- a/bin/systrace/openbsd-syscalls.c
+++ b/bin/systrace/openbsd-syscalls.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: openbsd-syscalls.c,v 1.8 2002/07/19 14:38:58 itojun Exp $	*/
+/*	$OpenBSD: openbsd-syscalls.c,v 1.9 2002/07/22 04:02:39 provos Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -126,7 +126,7 @@ static int obsd_syscall_number(const char *, const char *);
 static short obsd_translate_policy(short);
 static short obsd_translate_flags(short);
 static int obsd_translate_errno(int);
-static int obsd_answer(int, pid_t, short, int, short);
+static int obsd_answer(int, pid_t, u_int32_t, short, int, short);
 static int obsd_newpolicy(int);
 static int obsd_assignpolicy(int, pid_t, int);
 static int obsd_modifypolicy(int, int, int, short);
@@ -350,11 +350,13 @@ obsd_translate_errno(int errno)
 }
 
 static int
-obsd_answer(int fd, pid_t pid, short policy, int errno, short flags)
+obsd_answer(int fd, pid_t pid, u_int32_t seqnr, short policy, int errno,
+    short flags)
 {
 	struct systrace_answer ans;
 
 	ans.stra_pid = pid;
+	ans.stra_seqnr = seqnr;
 	ans.stra_policy = obsd_translate_policy(policy);
 	ans.stra_flags = obsd_translate_flags(flags);
 	ans.stra_error = obsd_translate_errno(errno);
@@ -515,6 +517,8 @@ obsd_read(int fd)
 
 	char name[SYSTR_EMULEN+1];
 	const char *sysname;
+	u_int16_t seqnr;
+	pid_t pid;
 	int code;
 
 	if (read(fd, &msg, sizeof(msg)) != sizeof(msg))
@@ -526,13 +530,15 @@ obsd_read(int fd)
 	data = icpid->data;
 
 	current = data->current;
-
+	
+	seqnr = msg.msg_seqnr;
+	pid = msg.msg_pid;
 	switch (msg.msg_type) {
 	case SYSTR_MSG_ASK:
 		code = msg.msg_data.msg_ask.code;
-		sysname = obsd_syscall_name(msg.msg_pid, code);
+		sysname = obsd_syscall_name(pid, code);
 
-		intercept_syscall(fd, msg.msg_pid, msg.msg_policy,
+		intercept_syscall(fd, pid, seqnr, msg.msg_policy,
 		    sysname, code, current->name,
 		    (void *)msg.msg_data.msg_ask.args,
 		    msg.msg_data.msg_ask.argsize);
@@ -540,14 +546,14 @@ obsd_read(int fd)
 
 	case SYSTR_MSG_RES:
 		code = msg.msg_data.msg_ask.code;
-		sysname = obsd_syscall_name(msg.msg_pid, code);
+		sysname = obsd_syscall_name(pid, code);
 
 		/* Switch emulation around at the right time */
 		if (data->commit != NULL) {
 			current = obsd_switch_emulation(data);
 		}
 
-		intercept_syscall_result(fd, msg.msg_pid, msg.msg_policy,
+		intercept_syscall_result(fd, pid, seqnr, msg.msg_policy,
 		    sysname, code, current->name,
 		    (void *)msg.msg_data.msg_ask.args,
 		    msg.msg_data.msg_ask.argsize,
@@ -559,7 +565,7 @@ obsd_read(int fd)
 		memcpy(name, msg.msg_data.msg_emul.emul, SYSTR_EMULEN);
 		name[SYSTR_EMULEN] = '\0';
 
-		if (obsd_set_emulation(msg.msg_pid, name) == -1)
+		if (obsd_set_emulation(pid, name) == -1)
 			errx(1, "%s:%d: set_emulation(%s)",
 			    __func__, __LINE__, name);
 
@@ -570,13 +576,13 @@ obsd_read(int fd)
 			current = obsd_switch_emulation(data);
 
 			intercept_syscall_result(fd,
-			    msg.msg_pid, msg.msg_policy,
+			    pid, seqnr, msg.msg_policy,
 			    "execve", 0, current->name,
 			    NULL, 0, 0, NULL);
 			break;
 		}
 
-		if (obsd_answer(fd, msg.msg_pid, 0, 0, 0) == -1)
+		if (obsd_answer(fd, pid, seqnr, 0, 0, 0) == -1)
 			err(1, "%s:%d: answer", __func__, __LINE__);
 		break;
 
diff --git a/sys/dev/systrace.c b/sys/dev/systrace.c
index 3113e2d07fc..f3b964f0661 100644
--- a/sys/dev/systrace.c
+++ b/sys/dev/systrace.c
@@ -85,6 +85,7 @@ struct str_policy {
 #define STR_PROC_WAITANSWER	0x02
 #define STR_PROC_SYSCALLRES	0x04
 #define STR_PROC_REPORT		0x08	/* Report emulation */
+#define STR_PROC_NEEDSEQNR	0x10	/* Answer must quote seqnr */
 
 struct str_process {
 	TAILQ_ENTRY(str_process) next;
@@ -101,6 +102,7 @@ struct str_process {
 	int flags;
 	short answer;
 	short error;
+	u_int16_t seqnr;	/* expected reply sequence number */
 
 	struct str_message msg;
 };
@@ -782,6 +784,12 @@ systrace_answer(struct str_process *strp, struct systrace_answer *ans)
 		goto out;
 	}
 
+	/* Check if answer is in sync with us */
+	if (ans->stra_seqnr != strp->seqnr) {
+		error = ESRCH;
+		goto out;
+	}
+
 	if ((error = systrace_processready(strp)) != 0)
 		goto out;
 
@@ -1306,6 +1314,7 @@ systrace_make_msg(struct str_process *strp, int type)
 	struct proc *p = strp->proc;
 	int st;
 
+	msg->msg_seqnr = ++strp->seqnr;
 	msg->msg_type = type;
 	msg->msg_pid = strp->pid;
 	if (strp->policy)
diff --git a/sys/dev/systrace.h b/sys/dev/systrace.h
index bd1bd369597..d4bd99b6e83 100644
--- a/sys/dev/systrace.h
+++ b/sys/dev/systrace.h
@@ -69,8 +69,8 @@ struct str_msg_child {
 struct str_message {
 	int msg_type;
 	pid_t msg_pid;
+	u_int16_t msg_seqnr;	/* answer has to match seqnr */
 	short msg_policy;
-	short reserved;
 	union {
 		struct str_msg_emul msg_emul;
 		struct str_msg_ask msg_ask;
@@ -80,6 +80,8 @@ struct str_message {
 
 struct systrace_answer {
 	pid_t stra_pid;
+	u_int16_t stra_seqnr;
+	short reserved;
 	int stra_policy;
 	int stra_error;
 	int stra_flags;