sys: check that target consts are defined

Currently when we get target consts with target.ConstMap["name"]
during target initialization, we just get 0 for missing consts.
This is error-prone as we can mis-type a const, or a const may
be undefined only on some archs (as we have common unix code
shared between several OSes).
Check that all the consts are actually defined.
The check detects several violations, to fix them:
1. move mremap to linux as it's only defined on linux
2. move S_IFMT to openbsd, as it's only defined and used on openbsd
3. define missing MAP_ANONYMOUS for freebsd and netbsd
4. fix extract for netbsd

1 files changed, 30 insertions, 20 deletions

diff --git a/sys/linux/init.go b/sys/linux/init.go
index f545abdf4..09fca92fc 100644
--- a/sys/linux/init.go
+++ b/sys/linux/init.go
@@ -14,22 +14,24 @@ func InitTarget(target *prog.Target) {
 	arch := &arch{
 		unix:                      targets.MakeUnixSanitizer(target),
 		clockGettimeSyscall:       target.SyscallMap["clock_gettime"],
-		SYSLOG_ACTION_CONSOLE_OFF: target.ConstMap["SYSLOG_ACTION_CONSOLE_OFF"],
-		SYSLOG_ACTION_CONSOLE_ON:  target.ConstMap["SYSLOG_ACTION_CONSOLE_ON"],
-		SYSLOG_ACTION_SIZE_UNREAD: target.ConstMap["SYSLOG_ACTION_SIZE_UNREAD"],
-		FIFREEZE:                  target.ConstMap["FIFREEZE"],
-		FITHAW:                    target.ConstMap["FITHAW"],
-		EXT4_IOC_SHUTDOWN:         target.ConstMap["EXT4_IOC_SHUTDOWN"],
-		EXT4_IOC_MIGRATE:          target.ConstMap["EXT4_IOC_MIGRATE"],
-		FAN_OPEN_PERM:             target.ConstMap["FAN_OPEN_PERM"],
-		FAN_ACCESS_PERM:           target.ConstMap["FAN_ACCESS_PERM"],
-		PTRACE_TRACEME:            target.ConstMap["PTRACE_TRACEME"],
-		CLOCK_REALTIME:            target.ConstMap["CLOCK_REALTIME"],
-		ARCH_SET_FS:               target.ConstMap["ARCH_SET_FS"],
-		ARCH_SET_GS:               target.ConstMap["ARCH_SET_GS"],
-		AF_NFC:                    target.ConstMap["AF_NFC"],
-		AF_LLC:                    target.ConstMap["AF_LLC"],
-		AF_BLUETOOTH:              target.ConstMap["AF_BLUETOOTH"],
+		MREMAP_MAYMOVE:            target.GetConst("MREMAP_MAYMOVE"),
+		MREMAP_FIXED:              target.GetConst("MREMAP_FIXED"),
+		SYSLOG_ACTION_CONSOLE_OFF: target.GetConst("SYSLOG_ACTION_CONSOLE_OFF"),
+		SYSLOG_ACTION_CONSOLE_ON:  target.GetConst("SYSLOG_ACTION_CONSOLE_ON"),
+		SYSLOG_ACTION_SIZE_UNREAD: target.GetConst("SYSLOG_ACTION_SIZE_UNREAD"),
+		FIFREEZE:                  target.GetConst("FIFREEZE"),
+		FITHAW:                    target.GetConst("FITHAW"),
+		EXT4_IOC_SHUTDOWN:         target.GetConst("EXT4_IOC_SHUTDOWN"),
+		EXT4_IOC_MIGRATE:          target.GetConst("EXT4_IOC_MIGRATE"),
+		FAN_OPEN_PERM:             target.GetConst("FAN_OPEN_PERM"),
+		FAN_ACCESS_PERM:           target.GetConst("FAN_ACCESS_PERM"),
+		PTRACE_TRACEME:            target.GetConst("PTRACE_TRACEME"),
+		CLOCK_REALTIME:            target.GetConst("CLOCK_REALTIME"),
+		ARCH_SET_FS:               target.GetConst("ARCH_SET_FS"),
+		ARCH_SET_GS:               target.GetConst("ARCH_SET_GS"),
+		AF_NFC:                    target.GetConst("AF_NFC"),
+		AF_LLC:                    target.GetConst("AF_LLC"),
+		AF_BLUETOOTH:              target.GetConst("AF_BLUETOOTH"),
 	}
 
 	target.MakeMmap = targets.MakePosixMmap(target)
@@ -70,10 +72,10 @@ func InitTarget(target *prog.Target) {
 	}
 
 	if target.Arch == runtime.GOARCH {
-		KCOV_INIT_TRACE = uintptr(target.ConstMap["KCOV_INIT_TRACE"])
-		KCOV_ENABLE = uintptr(target.ConstMap["KCOV_ENABLE"])
-		KCOV_DISABLE = uintptr(target.ConstMap["KCOV_DISABLE"])
-		KCOV_TRACE_CMP = uintptr(target.ConstMap["KCOV_TRACE_CMP"])
+		KCOV_INIT_TRACE = uintptr(target.GetConst("KCOV_INIT_TRACE"))
+		KCOV_ENABLE = uintptr(target.GetConst("KCOV_ENABLE"))
+		KCOV_DISABLE = uintptr(target.GetConst("KCOV_DISABLE"))
+		KCOV_TRACE_CMP = uintptr(target.GetConst("KCOV_TRACE_CMP"))
 	}
 }
 
@@ -90,6 +92,8 @@ type arch struct {
 
 	clockGettimeSyscall *prog.Syscall
 
+	MREMAP_MAYMOVE            uint64
+	MREMAP_FIXED              uint64
 	SYSLOG_ACTION_CONSOLE_OFF uint64
 	SYSLOG_ACTION_CONSOLE_ON  uint64
 	SYSLOG_ACTION_SIZE_UNREAD uint64
@@ -111,6 +115,12 @@ type arch struct {
 func (arch *arch) sanitizeCall(c *prog.Call) {
 	arch.unix.SanitizeCall(c)
 	switch c.Meta.CallName {
+	case "mremap":
+		// Add MREMAP_FIXED flag, otherwise it produces non-deterministic results.
+		flags := c.Args[3].(*prog.ConstArg)
+		if flags.Val&arch.MREMAP_MAYMOVE != 0 {
+			flags.Val |= arch.MREMAP_FIXED
+		}
 	case "syslog":
 		cmd := c.Args[0].(*prog.ConstArg)
 		cmd.Val = uint64(uint32(cmd.Val))