1// +build linux,cgo 2 3package psx // import "kernel.org/pub/linux/libs/security/libcap/psx" 4 5import ( 6 "runtime" 7 "sync" 8 "syscall" 9) 10 11// #cgo LDFLAGS: -lpthread -Wl,-wrap,pthread_create 12// 13// #include <errno.h> 14// #include "psx_syscall.h" 15// 16// long __errno_too(long set_errno) { 17// long v = errno; 18// if (set_errno >= 0) { 19// errno = set_errno; 20// } 21// return v; 22// } 23import "C" 24 25// setErrno returns the current C.errno value and, if v >= 0, sets the 26// CGo errno for a random pthread to value v. If you want some 27// consistency, this needs to be called from runtime.LockOSThread() 28// code. This function is only defined for testing purposes. The psx.c 29// code should properly handle the case that a non-zero errno is saved 30// and restored independently of what these Syscall[36]() functions 31// observe. 32func setErrno(v int) int { 33 return int(C.__errno_too(C.long(v))) 34} 35 36var makeFatal sync.Once 37 38// forceFatal configures the psx_syscall mechanism to PSX_ERROR. 39func forceFatal() { 40 makeFatal.Do(func() { 41 C.psx_set_sensitivity(C.PSX_ERROR) 42 }) 43} 44 45//go:uintptrescapes 46 47// Syscall3 performs a 3 argument syscall. Syscall3 differs from 48// syscall.[Raw]Syscall() insofar as it is simultaneously executed on 49// every thread of the combined Go and CGo runtimes. It works 50// differently depending on whether CGO_ENABLED is 1 or 0 at compile 51// time. 52// 53// If CGO_ENABLED=1 it uses the libpsx function C.psx_syscall3(). 54// 55// If CGO_ENABLED=0 it redirects to the go1.16+ 56// syscall.AllThreadsSyscall() function. 57func Syscall3(syscallnr, arg1, arg2, arg3 uintptr) (uintptr, uintptr, syscall.Errno) { 58 forceFatal() 59 // We lock to the OSThread here because we may need errno to 60 // be the one for this thread. 61 runtime.LockOSThread() 62 defer runtime.UnlockOSThread() 63 64 v := C.psx_syscall3(C.long(syscallnr), C.long(arg1), C.long(arg2), C.long(arg3)) 65 var errno syscall.Errno 66 if v < 0 { 67 errno = syscall.Errno(C.__errno_too(-1)) 68 } 69 return uintptr(v), uintptr(v), errno 70} 71 72//go:uintptrescapes 73 74// Syscall6 performs a 6 argument syscall on every thread of the 75// combined Go and CGo runtimes. Other than the number of syscall 76// arguments, its behavior is identical to that of Syscall3() - see 77// above for the full documentation. 78func Syscall6(syscallnr, arg1, arg2, arg3, arg4, arg5, arg6 uintptr) (uintptr, uintptr, syscall.Errno) { 79 forceFatal() 80 // We lock to the OSThread here because we may need errno to 81 // be the one for this thread. 82 runtime.LockOSThread() 83 defer runtime.UnlockOSThread() 84 85 v := C.psx_syscall6(C.long(syscallnr), C.long(arg1), C.long(arg2), C.long(arg3), C.long(arg4), C.long(arg5), C.long(arg6)) 86 var errno syscall.Errno 87 if v < 0 { 88 errno = syscall.Errno(C.__errno_too(-1)) 89 } 90 return uintptr(v), uintptr(v), errno 91} 92