From: Dmitry V. Levin <ldv@altlinux.org>
Date: Mon, 28 Aug 2017 22:37:27 +0000 (+0000)
Subject: Add "flags" field to struct inject_data
X-Git-Tag: v4.19~38
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fe1ab2a53aff62bcbed84b5e14b17740a67f651b;p=strace

Add "flags" field to struct inject_data

Introduce "flags" field to struct inject_data and use it instead
of magic rval and signo constants.
Due to layout of struct inject_data, this new field does not change
sizeof(struct inject_data).

* defs.h (INJECT_F_RETVAL, INJECT_F_SIGNAL): New macros.
(INJECT_OPTS_RVAL_DEFAULT): Remove macro.
(struct inject_data): Add "flags" field.
* filter_qualify.c (parse_inject_token, qualify_inject_common): Check
struct inject_data.flags instead of inject_data.rval
and inject_data.signo, do not initialize inject_opts.data.
* syscall.c (tamper_with_syscall_entering): Check struct
inject_data.flags instead of inject_data.rval and inject_data.signo.
---

diff --git a/defs.h b/defs.h
index 0f276ba2..e37c555b 100644
--- a/defs.h
+++ b/defs.h
@@ -180,7 +180,11 @@ typedef struct ioctlent {
 	unsigned int code;
 } struct_ioctlent;
 
+#define INJECT_F_SIGNAL 1
+#define INJECT_F_RETVAL 2
+
 struct inject_data {
+	uint16_t flags;
 	uint16_t signo;
 	int rval;
 };
@@ -192,7 +196,6 @@ struct inject_opts {
 };
 
 #define MAX_ERRNO_VALUE			4095
-#define INJECT_OPTS_RVAL_DEFAULT	(-(MAX_ERRNO_VALUE + 1))
 
 /* Trace Control Block */
 struct tcb {
diff --git a/filter_qualify.c b/filter_qualify.c
index d3c036cf..f77ceed8 100644
--- a/filter_qualify.c
+++ b/filter_qualify.c
@@ -120,7 +120,7 @@ parse_inject_token(const char *const token, struct inject_opts *const fopts,
 			fopts->step = 0;
 		}
 	} else if ((val = STR_STRIP_PREFIX(token, "error=")) != token) {
-		if (fopts->data.rval != INJECT_OPTS_RVAL_DEFAULT)
+		if (fopts->data.flags & INJECT_F_RETVAL)
 			return false;
 		intval = string_to_uint_upto(val, MAX_ERRNO_VALUE);
 		if (intval < 0)
@@ -128,20 +128,23 @@ parse_inject_token(const char *const token, struct inject_opts *const fopts,
 		if (intval < 1)
 			return false;
 		fopts->data.rval = -intval;
+		fopts->data.flags |= INJECT_F_RETVAL;
 	} else if (!fault_tokens_only
 		   && (val = STR_STRIP_PREFIX(token, "retval=")) != token) {
-		if (fopts->data.rval != INJECT_OPTS_RVAL_DEFAULT)
+		if (fopts->data.flags & INJECT_F_RETVAL)
 			return false;
 		intval = string_to_uint(val);
 		if (intval < 0)
 			return false;
 		fopts->data.rval = intval;
+		fopts->data.flags |= INJECT_F_RETVAL;
 	} else if (!fault_tokens_only
 		   && (val = STR_STRIP_PREFIX(token, "signal=")) != token) {
 		intval = sigstr_to_uint(val);
 		if (intval < 1 || intval > NSIG_BYTES * 8)
 			return false;
 		fopts->data.signo = intval;
+		fopts->data.flags |= INJECT_F_SIGNAL;
 	} else {
 		return false;
 	}
@@ -238,11 +241,7 @@ qualify_inject_common(const char *const str,
 {
 	struct inject_opts opts = {
 		.first = 1,
-		.step = 1,
-		.data = {
-			.rval = INJECT_OPTS_RVAL_DEFAULT,
-			.signo = 0
-		}
+		.step = 1
 	};
 	char *buf = NULL;
 	char *name = parse_inject_expression(str, &buf, &opts, fault_tokens_only);
@@ -251,10 +250,11 @@ qualify_inject_common(const char *const str,
 	}
 
 	/* If neither of retval, error, or signal is specified, then ... */
-	if (opts.data.rval == INJECT_OPTS_RVAL_DEFAULT && !opts.data.signo) {
+	if (!opts.data.flags) {
 		if (fault_tokens_only) {
 			/* in fault= syntax the default error code is ENOSYS. */
 			opts.data.rval = -ENOSYS;
+			opts.data.flags |= INJECT_F_RETVAL;
 		} else {
 			/* in inject= syntax this is not allowed. */
 			error_msg_and_die("invalid %s '%s'", description, str);
diff --git a/syscall.c b/syscall.c
index a622f0bf..b1047feb 100644
--- a/syscall.c
+++ b/syscall.c
@@ -570,9 +570,9 @@ tamper_with_syscall_entering(struct tcb *tcp, unsigned int *signo)
 
 	opts->first = opts->step;
 
-	if (opts->data.signo > 0)
+	if (opts->data.flags & INJECT_F_SIGNAL)
 		*signo = opts->data.signo;
-	if (opts->data.rval != INJECT_OPTS_RVAL_DEFAULT && !arch_set_scno(tcp, -1))
+	if (opts->data.flags & INJECT_F_RETVAL && !arch_set_scno(tcp, -1))
 		tcp->flags |= TCB_TAMPERED;
 
 	return 0;