syscall: simplify execve handling on libc platforms

Rather than providing three different execve variables for different
platforms, use a single variable. Provide a small wrapper that handles
conversion to uintptr for the AIX/Solaris case.

Note that this removes special handling for openbsd/mips64, which is
now a dead port.

Updates #61546

Change-Id: I3d6387c31669f64bfb61639536803e595f478647
Reviewed-on: https://go-review.googlesource.com/c/go/+/693880
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>

diff --git a/src/syscall/exec_libc.go b/src/syscall/exec_libc.go
index 0e886508737d1e7310143e9a735d0111747f1a66..2e7e33d9ef2ebdd846be4f91f1d845eb943cd1e4 100644 (file)
--- a/src/syscall/exec_libc.go
+++ b/src/syscall/exec_libc.go
@@ -61,7 +61,13 @@ func write1(fd uintptr, buf uintptr, nbyte uintptr) (n uintptr, err Errno)
 
 // syscall defines this global on our behalf to avoid a build dependency on other platforms
 func init() {
-       execveLibc = execve
+       execveLibc = execveLibcWrapper
+}
+
+func execveLibcWrapper(path *byte, argv **byte, envp **byte) error {
+       return execve(uintptr(unsafe.Pointer(path)),
+               uintptr(unsafe.Pointer(argv)),
+               uintptr(unsafe.Pointer(envp)))
 }
 
 // Fork, dup fd onto 0..len(fd), and exec(argv0, argvv, envv) in child.

diff --git a/src/syscall/exec_unix.go b/src/syscall/exec_unix.go
index 4747fa075834af6337343427df36ba299c451dd9..b830057dff80a322940e300549cb9f277de1adfd 100644 (file)
--- a/src/syscall/exec_unix.go
+++ b/src/syscall/exec_unix.go
@@ -265,9 +265,7 @@ func runtime_AfterExec()
 
 // execveLibc is non-nil on OS using libc syscall, set to execve in exec_libc.go; this
 // avoids a build dependency for other platforms.
-var execveLibc func(path uintptr, argv uintptr, envp uintptr) Errno
-var execveDarwin func(path *byte, argv **byte, envp **byte) error
-var execveOpenBSD func(path *byte, argv **byte, envp **byte) error
+var execveLibc func(path *byte, argv **byte, envp **byte) error
 
 // Exec invokes the execve(2) system call.
 func Exec(argv0 string, argv []string, envv []string) (err error) {
@@ -291,19 +289,12 @@ func Exec(argv0 string, argv []string, envv []string) (err error) {
        }
 
        var err1 error
-       if runtime.GOOS == "solaris" || runtime.GOOS == "illumos" || runtime.GOOS == "aix" {
-               // RawSyscall should never be used on Solaris, illumos, or AIX.
-               err1 = execveLibc(
-                       uintptr(unsafe.Pointer(argv0p)),
-                       uintptr(unsafe.Pointer(&argvp[0])),
-                       uintptr(unsafe.Pointer(&envvp[0])))
-       } else if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
-               // Similarly on Darwin.
-               err1 = execveDarwin(argv0p, &argvp[0], &envvp[0])
-       } else if runtime.GOOS == "openbsd" && runtime.GOARCH != "mips64" {
-               // Similarly on OpenBSD.
-               err1 = execveOpenBSD(argv0p, &argvp[0], &envvp[0])
-       } else {
+       switch runtime.GOOS {
+       case "aix", "darwin", "illumos", "ios", "openbsd", "solaris":
+               // RawSyscall should never be used on these platforms.
+               err1 = execveLibc(argv0p, &argvp[0], &envvp[0])
+
+       default:
                _, _, err1 = RawSyscall(SYS_EXECVE,
                        uintptr(unsafe.Pointer(argv0p)),
                        uintptr(unsafe.Pointer(&argvp[0])),

diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index 5b38aeae31a6fc50d10e450cbf99428888ff9a39..7b4f0d4fb74c480b840b9bc6b33c02e4c5f13564 100644 (file)
--- a/src/syscall/syscall_darwin.go
+++ b/src/syscall/syscall_darwin.go
@@ -228,7 +228,7 @@ func Kill(pid int, signum Signal) (err error) { return kill(pid, int(signum), 1)
 //sys  getcwd(buf []byte) (n int, err error)
 
 func init() {
-       execveDarwin = execve
+       execveLibc = execve
 }
 
 func fdopendir(fd int) (dir uintptr, err error) {

diff --git a/src/syscall/syscall_openbsd_libc.go b/src/syscall/syscall_openbsd_libc.go
index 13311398b9986b09dc232fbf9c30684522bb5723..eca1ad1f98c721fc278ef4079e4fd79f6bb428c6 100644 (file)
--- a/src/syscall/syscall_openbsd_libc.go
+++ b/src/syscall/syscall_openbsd_libc.go
@@ -13,7 +13,7 @@ import (
 var dupTrampoline = abi.FuncPCABI0(libc_dup3_trampoline)
 
 func init() {
-       execveOpenBSD = execve
+       execveLibc = execve
 }
 
 func syscallInternal(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {