From 002bc94e0c345f282bcf3a6bf46f40cdb9de3327 Mon Sep 17 00:00:00 2001 From: Cuong Manh Le Date: Sun, 26 Feb 2023 09:39:07 +0700 Subject: [PATCH] internal/syscall/execenv: refactor handling env variables Discover while working on CL 471335. Change-Id: I006077a5aa93cafb7be47813ab0c4714bb00d774 Reviewed-on: https://go-review.googlesource.com/c/go/+/471435 Reviewed-by: Than McIntosh Reviewed-by: Ian Lance Taylor Reviewed-by: Dmitri Shuralyov Run-TryBot: Cuong Manh Le TryBot-Result: Gopher Robot Reviewed-by: Bryan Mills --- .../syscall/execenv/execenv_windows.go | 24 +++++++------------ 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/src/internal/syscall/execenv/execenv_windows.go b/src/internal/syscall/execenv/execenv_windows.go index a8aa1a644e..46ba12efc5 100644 --- a/src/internal/syscall/execenv/execenv_windows.go +++ b/src/internal/syscall/execenv/execenv_windows.go @@ -25,30 +25,24 @@ func Default(sys *syscall.SysProcAttr) (env []string, err error) { if sys == nil || sys.Token == 0 { return syscall.Environ(), nil } - var block *uint16 - err = windows.CreateEnvironmentBlock(&block, sys.Token, false) + var blockp *uint16 + err = windows.CreateEnvironmentBlock(&blockp, sys.Token, false) if err != nil { return nil, err } - defer windows.DestroyEnvironmentBlock(block) - blockp := uintptr(unsafe.Pointer(block)) - for { + defer windows.DestroyEnvironmentBlock(blockp) + const size = unsafe.Sizeof(*blockp) + for *blockp != 0 { // environment block ends with empty string // find NUL terminator - end := unsafe.Pointer(blockp) + end := unsafe.Add(unsafe.Pointer(blockp), size) for *(*uint16)(end) != 0 { - end = unsafe.Pointer(uintptr(end) + 2) + end = unsafe.Add(end, size) } - n := (uintptr(end) - uintptr(unsafe.Pointer(blockp))) / 2 - if n == 0 { - // environment block ends with empty string - break - } - - entry := (*[(1 << 30) - 1]uint16)(unsafe.Pointer(blockp))[:n:n] + entry := unsafe.Slice(blockp, (uintptr(end)-uintptr(unsafe.Pointer(blockp)))/2) env = append(env, string(utf16.Decode(entry))) - blockp += 2 * (uintptr(len(entry)) + 1) + blockp = (*uint16)(unsafe.Add(end, size)) } return } -- 2.50.0