syscall: fix Exec on solaris

The test added for issue #18146 exposed a long-existing bug in the
Solaris port; notably, that syscall.Exec uses RawSyscall -- which is not
actually functional for the Solaris port (intentionally) and only exists
as a placebo to satisfy build requirements.

Call syscall.execve instead for Solaris.

Fixes #20832

Change-Id: I327d863f4bbbbbb6e5ecf66b82152c4030825d09
Reviewed-on: https://go-review.googlesource.com/47032
Run-TryBot: Shawn Walker-Salas <shawn.walker@oracle.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/syscall/exec_solaris.go b/src/syscall/exec_solaris.go
index 448207ee1b62c508b72838104f16b402053668f6..8052ff186214373e201c93988b1a24749b381bc8 100644 (file)
--- a/src/syscall/exec_solaris.go
+++ b/src/syscall/exec_solaris.go
@@ -41,6 +41,11 @@ func setuid(uid uintptr) (err Errno)
 func setpgid(pid uintptr, pgid uintptr) (err Errno)
 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() {
+       execveSolaris = execve
+}
+
 // Fork, dup fd onto 0..len(fd), and exec(argv0, argvv, envv) in child.
 // If a dup or exec fails, write the errno error to pipe.
 // (Pipe is close-on-exec so if exec succeeds, it will be closed.)

diff --git a/src/syscall/exec_unix.go b/src/syscall/exec_unix.go
index e8ca29ab40389f318e2e9bd5d79c6931682ddd05..9a950ac17fdbe5d4defd619a366916c5816bb38c 100644 (file)
--- a/src/syscall/exec_unix.go
+++ b/src/syscall/exec_unix.go
@@ -246,6 +246,10 @@ func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle
 func runtime_BeforeExec()
 func runtime_AfterExec()
 
+// execveSolaris is non-nil on Solaris, set to execve in exec_solaris.go; this
+// avoids a build dependency for other platforms.
+var execveSolaris func(path uintptr, argv uintptr, envp uintptr) (err Errno)
+
 // Exec invokes the execve(2) system call.
 func Exec(argv0 string, argv []string, envv []string) (err error) {
        argv0p, err := BytePtrFromString(argv0)
@@ -261,10 +265,20 @@ func Exec(argv0 string, argv []string, envv []string) (err error) {
                return err
        }
        runtime_BeforeExec()
-       _, _, err1 := RawSyscall(SYS_EXECVE,
-               uintptr(unsafe.Pointer(argv0p)),
-               uintptr(unsafe.Pointer(&argvp[0])),
-               uintptr(unsafe.Pointer(&envvp[0])))
+
+       var err1 Errno
+       if runtime.GOOS == "solaris" {
+               // RawSyscall should never be used on Solaris.
+               err1 = execveSolaris(
+                       uintptr(unsafe.Pointer(argv0p)),
+                       uintptr(unsafe.Pointer(&argvp[0])),
+                       uintptr(unsafe.Pointer(&envvp[0])))
+       } else {
+               _, _, err1 = RawSyscall(SYS_EXECVE,
+                       uintptr(unsafe.Pointer(argv0p)),
+                       uintptr(unsafe.Pointer(&argvp[0])),
+                       uintptr(unsafe.Pointer(&envvp[0])))
+       }
        runtime_AfterExec()
-       return Errno(err1)
+       return err1
 }