4 files changed, 200 insertions, 33 deletions
diff --git a/pkg/abi/linux/BUILD b/pkg/abi/linux/BUILD
index 9553f164d..716ff22d2 100644
--- a/pkg/abi/linux/BUILD
+++ b/pkg/abi/linux/BUILD
@@ -41,6 +41,7 @@ go_library(
         "poll.go",
         "prctl.go",
         "ptrace.go",
+        "rseq.go",
         "rusage.go",
         "sched.go",
         "seccomp.go",
diff --git a/pkg/abi/linux/netfilter.go b/pkg/abi/linux/netfilter.go
index 269ba5567..33fcc6c95 100644
--- a/pkg/abi/linux/netfilter.go
+++ b/pkg/abi/linux/netfilter.go
@@ -42,6 +42,15 @@ const (
 	NF_RETURN = -NF_REPEAT - 1
 )
 
+// VerdictStrings maps int verdicts to the strings they represent. It is used
+// for debugging.
+var VerdictStrings = map[int32]string{
+	-NF_DROP - 1:   "DROP",
+	-NF_ACCEPT - 1: "ACCEPT",
+	-NF_QUEUE - 1:  "QUEUE",
+	NF_RETURN:      "RETURN",
+}
+
 // Socket options. These correspond to values in
 // include/uapi/linux/netfilter_ipv4/ip_tables.h.
 const (
@@ -179,7 +188,7 @@ const SizeOfXTCounters = 16
 // the user data.
 type XTEntryMatch struct {
 	MatchSize uint16
-	Name      [XT_EXTENSION_MAXNAMELEN]byte
+	Name      ExtensionName
 	Revision  uint8
 	// Data is omitted here because it would cause XTEntryMatch to be an
 	// extra byte larger (see http://www.catb.org/esr/structure-packing/).
@@ -199,7 +208,7 @@ const SizeOfXTEntryMatch = 32
 // the user data.
 type XTEntryTarget struct {
 	TargetSize uint16
-	Name       [XT_EXTENSION_MAXNAMELEN]byte
+	Name       ExtensionName
 	Revision   uint8
 	// Data is omitted here because it would cause XTEntryTarget to be an
 	// extra byte larger (see http://www.catb.org/esr/structure-packing/).
@@ -226,9 +235,9 @@ const SizeOfXTStandardTarget = 40
 // ErrorName. It corresponds to struct xt_error_target in
 // include/uapi/linux/netfilter/x_tables.h.
 type XTErrorTarget struct {
-	Target    XTEntryTarget
-	ErrorName [XT_FUNCTION_MAXNAMELEN]byte
-	_         [2]byte
+	Target XTEntryTarget
+	Name   ErrorName
+	_      [2]byte
 }
 
 // SizeOfXTErrorTarget is the size of an XTErrorTarget.
@@ -237,7 +246,7 @@ const SizeOfXTErrorTarget = 64
 // IPTGetinfo is the argument for the IPT_SO_GET_INFO sockopt. It corresponds
 // to struct ipt_getinfo in include/uapi/linux/netfilter_ipv4/ip_tables.h.
 type IPTGetinfo struct {
-	Name       [XT_TABLE_MAXNAMELEN]byte
+	Name       TableName
 	ValidHooks uint32
 	HookEntry  [NF_INET_NUMHOOKS]uint32
 	Underflow  [NF_INET_NUMHOOKS]uint32
@@ -248,16 +257,11 @@ type IPTGetinfo struct {
 // SizeOfIPTGetinfo is the size of an IPTGetinfo.
 const SizeOfIPTGetinfo = 84
 
-// TableName returns the table name.
-func (info *IPTGetinfo) TableName() string {
-	return tableName(info.Name[:])
-}
-
 // IPTGetEntries is the argument for the IPT_SO_GET_ENTRIES sockopt. It
 // corresponds to struct ipt_get_entries in
 // include/uapi/linux/netfilter_ipv4/ip_tables.h.
 type IPTGetEntries struct {
-	Name [XT_TABLE_MAXNAMELEN]byte
+	Name TableName
 	Size uint32
 	_    [4]byte
 	// Entrytable is omitted here because it would cause IPTGetEntries to
@@ -266,34 +270,22 @@ type IPTGetEntries struct {
 	// Entrytable [0]IPTEntry
 }
 
-// TableName returns the entries' table name.
-func (entries *IPTGetEntries) TableName() string {
-	return tableName(entries.Name[:])
-}
-
 // SizeOfIPTGetEntries is the size of an IPTGetEntries.
 const SizeOfIPTGetEntries = 40
 
-// KernelIPTGetEntries is identical to IPTEntry, but includes the Elems field.
-// This struct marshaled via the binary package to write an KernelIPTGetEntries
-// to userspace.
+// KernelIPTGetEntries is identical to IPTGetEntries, but includes the
+// Entrytable field. This struct marshaled via the binary package to write an
+// KernelIPTGetEntries to userspace.
 type KernelIPTGetEntries struct {
-	Name       [XT_TABLE_MAXNAMELEN]byte
-	Size       uint32
-	_          [4]byte
+	IPTGetEntries
 	Entrytable []KernelIPTEntry
 }
 
-// TableName returns the entries' table name.
-func (entries *KernelIPTGetEntries) TableName() string {
-	return tableName(entries.Name[:])
-}
-
 // IPTReplace is the argument for the IPT_SO_SET_REPLACE sockopt. It
 // corresponds to struct ipt_replace in
 // include/uapi/linux/netfilter_ipv4/ip_tables.h.
 type IPTReplace struct {
-	Name        [XT_TABLE_MAXNAMELEN]byte
+	Name        TableName
 	ValidHooks  uint32
 	NumEntries  uint32
 	Size        uint32
@@ -306,14 +298,45 @@ type IPTReplace struct {
 	// Entries [0]IPTEntry
 }
 
+// KernelIPTReplace is identical to IPTReplace, but includes the Entries field.
+type KernelIPTReplace struct {
+	IPTReplace
+	Entries [0]IPTEntry
+}
+
 // SizeOfIPTReplace is the size of an IPTReplace.
 const SizeOfIPTReplace = 96
 
-func tableName(name []byte) string {
-	for i, c := range name {
+// ExtensionName holds the name of a netfilter extension.
+type ExtensionName [XT_EXTENSION_MAXNAMELEN]byte
+
+// String implements fmt.Stringer.
+func (en ExtensionName) String() string {
+	return goString(en[:])
+}
+
+// TableName holds the name of a netfilter table.
+type TableName [XT_TABLE_MAXNAMELEN]byte
+
+// String implements fmt.Stringer.
+func (tn TableName) String() string {
+	return goString(tn[:])
+}
+
+// ErrorName holds the name of a netfilter error. These can also hold
+// user-defined chains.
+type ErrorName [XT_FUNCTION_MAXNAMELEN]byte
+
+// String implements fmt.Stringer.
+func (en ErrorName) String() string {
+	return goString(en[:])
+}
+
+func goString(cstring []byte) string {
+	for i, c := range cstring {
 		if c == 0 {
-			return string(name[:i])
+			return string(cstring[:i])
 		}
 	}
-	return string(name)
+	return string(cstring)
 }
diff --git a/pkg/abi/linux/rseq.go b/pkg/abi/linux/rseq.go
new file mode 100644
index 000000000..76253ba30
--- /dev/null
+++ b/pkg/abi/linux/rseq.go
@@ -0,0 +1,130 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+// Flags passed to rseq(2).
+//
+// Defined in include/uapi/linux/rseq.h.
+const (
+	// RSEQ_FLAG_UNREGISTER unregisters the current thread.
+	RSEQ_FLAG_UNREGISTER = 1 << 0
+)
+
+// Critical section flags used in RSeqCriticalSection.Flags and RSeq.Flags.
+//
+// Defined in include/uapi/linux/rseq.h.
+const (
+	// RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT inhibits restart on preemption.
+	RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT = 1 << 0
+
+	// RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL inhibits restart on signal
+	// delivery.
+	RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL = 1 << 1
+
+	// RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE inhibits restart on CPU
+	// migration.
+	RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE = 1 << 2
+)
+
+// RSeqCriticalSection describes a restartable sequences critical section. It
+// is equivalent to struct rseq_cs, defined in include/uapi/linux/rseq.h.
+//
+// In userspace, this structure is always aligned to 32 bytes.
+//
+// +marshal
+type RSeqCriticalSection struct {
+	// Version is the version of this structure. Version 0 is defined here.
+	Version uint32
+
+	// Flags are the critical section flags, defined above.
+	Flags uint32
+
+	// Start is the start address of the critical section.
+	Start uint64
+
+	// PostCommitOffset is the offset from Start of the first instruction
+	// outside of the critical section.
+	PostCommitOffset uint64
+
+	// Abort is the abort address. It must be outside the critical section,
+	// and the 4 bytes prior must match the abort signature.
+	Abort uint64
+}
+
+const (
+	// SizeOfRSeqCriticalSection is the size of RSeqCriticalSection.
+	SizeOfRSeqCriticalSection = 32
+
+	// SizeOfRSeqSignature is the size of the signature immediately
+	// preceding RSeqCriticalSection.Abort.
+	SizeOfRSeqSignature = 4
+)
+
+// Special values for RSeq.CPUID, defined in include/uapi/linux/rseq.h.
+const (
+	// RSEQ_CPU_ID_UNINITIALIZED indicates that this thread has not
+	// performed rseq initialization.
+	RSEQ_CPU_ID_UNINITIALIZED = ^uint32(0) // -1
+
+	// RSEQ_CPU_ID_REGISTRATION_FAILED indicates that rseq initialization
+	// failed.
+	RSEQ_CPU_ID_REGISTRATION_FAILED = ^uint32(1) // -2
+)
+
+// RSeq is the thread-local restartable sequences config/status. It
+// is equivalent to struct rseq, defined in include/uapi/linux/rseq.h.
+//
+// In userspace, this structure is always aligned to 32 bytes.
+type RSeq struct {
+	// CPUIDStart contains the current CPU ID if rseq is initialized.
+	//
+	// This field should only be read by the thread which registered this
+	// structure, and must be read atomically.
+	CPUIDStart uint32
+
+	// CPUID contains the current CPU ID or one of the CPU ID special
+	// values defined above.
+	//
+	// This field should only be read by the thread which registered this
+	// structure, and must be read atomically.
+	CPUID uint32
+
+	// RSeqCriticalSection is a pointer to the current RSeqCriticalSection
+	// block, or NULL. It is reset to NULL by the kernel on restart or
+	// non-restarting preempt/signal.
+	//
+	// This field should only be written by the thread which registered
+	// this structure, and must be written atomically.
+	RSeqCriticalSection uint64
+
+	// Flags are the critical section flags that apply to all critical
+	// sections on this thread, defined above.
+	Flags uint32
+}
+
+const (
+	// SizeOfRSeq is the size of RSeq.
+	//
+	// Note that RSeq is naively 24 bytes. However, it has 32-byte
+	// alignment, which in C increases sizeof to 32. That is the size that
+	// the Linux kernel uses.
+	SizeOfRSeq = 32
+
+	// AlignOfRSeq is the standard alignment of RSeq.
+	AlignOfRSeq = 32
+
+	// OffsetOfRSeqCriticalSection is the offset of RSeqCriticalSection in RSeq.
+	OffsetOfRSeqCriticalSection = 8
+)
diff --git a/pkg/abi/linux/time.go b/pkg/abi/linux/time.go
index 546668bca..5c5a58cd4 100644
--- a/pkg/abi/linux/time.go
+++ b/pkg/abi/linux/time.go
@@ -234,6 +234,19 @@ type StatxTimestamp struct {
 	_    int32
 }
 
+// ToNsec returns the nanosecond representation.
+func (sxts StatxTimestamp) ToNsec() int64 {
+	return int64(sxts.Sec)*1e9 + int64(sxts.Nsec)
+}
+
+// ToNsecCapped returns the safe nanosecond representation.
+func (sxts StatxTimestamp) ToNsecCapped() int64 {
+	if sxts.Sec > maxSecInDuration {
+		return math.MaxInt64
+	}
+	return sxts.ToNsec()
+}
+
 // NsecToStatxTimestamp translates nanoseconds to StatxTimestamp.
 func NsecToStatxTimestamp(nsec int64) (ts StatxTimestamp) {
 	return StatxTimestamp{