From b6f1fcb4f2d3cfb1eea95e9e0c6ae11f0659ba3a Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Mon, 7 Sep 2015 23:15:28 -0600
Subject: Pull the mucking with getgrnam into a getgr package.

---
 src/getgr/getgr.go               | 103 +++++++++++++++++++++++++++++++++++++++
 src/nshd/hackers_git/gid.go      |  21 ++++++++
 src/nshd/hackers_git/name2gid.go |  42 ----------------
 3 files changed, 124 insertions(+), 42 deletions(-)
 create mode 100644 src/getgr/getgr.go
 create mode 100644 src/nshd/hackers_git/gid.go
 delete mode 100644 src/nshd/hackers_git/name2gid.go

(limited to 'src')

diff --git a/src/getgr/getgr.go b/src/getgr/getgr.go
new file mode 100644
index 0000000..5470b2c
--- /dev/null
+++ b/src/getgr/getgr.go
@@ -0,0 +1,103 @@
+package getgr
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+//#define _POSIX_SOURCE // for getgrnam_r(3) in grp.h
+//#include <stdlib.h>   // for free(3)
+//#include <unistd.h>   // for sysconf(3)
+//#include <grp.h>      // for getgrnam_r(3)
+//static char *strary(char **ary, unsigned int n) { return ary[n]; }
+import "C"
+
+type Gid uint
+
+type Group struct {
+	Name   string
+	Passwd string
+	Gid    Gid
+	Mem    []string
+}
+
+func strary(c **C.char) (g []string) {
+	g = make([]string, 0)
+	for i := C.uint(0); true; i++ {
+		cstr := C.strary(c, i)
+		if cstr == nil {
+			return
+		}
+		g = append(g, C.GoString(cstr))
+	}
+	panic("not reached")
+}
+
+// A wrapper around C getgrnam_r
+func ByName(name string) (*Group, error) {
+	nameC := C.CString(name)
+	defer C.free(unsafe.Pointer(nameC))
+
+	buflen := C.sysconf(C._SC_GETGR_R_SIZE_MAX)
+	if buflen < 1 {
+		buflen = 1024
+	}
+	buf := make([]byte, buflen)
+	var grp C.struct_group
+	var ret *C.struct_group
+	for {
+		success, errno := C.getgrnam_r(nameC, &grp, (*C.char)(unsafe.Pointer(&buf[0])), C.size_t(buflen), &ret)
+		if success >= 0 {
+			break
+		}
+		if errno == syscall.ERANGE {
+			buflen += 256
+			buf = make([]byte, buflen)
+		} else {
+			return nil, errno
+		}
+	}
+	if ret == nil {
+		return nil, nil
+	}
+	return &Group{
+		Name:   C.GoString(ret.gr_name),
+		Passwd: C.GoString(ret.gr_passwd),
+		Gid:    Gid(ret.gr_gid),
+		Mem:    strary(ret.gr_mem),
+	}, nil
+}
+
+// A wrapper around C getgrgid_r
+func ByGid(gid int32) (*Group, error) {
+	gidC := C.__gid_t(gid)
+
+	buflen := C.sysconf(C._SC_GETGR_R_SIZE_MAX)
+	if buflen < 1 {
+		buflen = 1024
+	}
+	buf := make([]byte, buflen)
+	var grp C.struct_group
+	var ret *C.struct_group
+	for {
+		success, errno := C.getgrgid_r(gidC, &grp, (*C.char)(unsafe.Pointer(&buf[0])), C.size_t(buflen), &ret)
+		if success >= 0 {
+			break
+		}
+		if errno == syscall.ERANGE {
+			buflen += 256
+			buf = make([]byte, buflen)
+		} else {
+			return nil, errno
+		}
+	}
+	if ret == nil {
+		return nil, nil
+	}
+	return &Group{
+		Name:   C.GoString(ret.gr_name),
+		Passwd: C.GoString(ret.gr_passwd),
+		Gid:    Gid(ret.gr_gid),
+		Mem:    strary(ret.gr_mem),
+	}, nil
+}
diff --git a/src/nshd/hackers_git/gid.go b/src/nshd/hackers_git/gid.go
new file mode 100644
index 0000000..ff95309
--- /dev/null
+++ b/src/nshd/hackers_git/gid.go
@@ -0,0 +1,21 @@
+package hackers_git
+
+import "getgr"
+
+func name2gid(name string) int32 {
+	gr, err := getgr.ByName(name)
+	if gr == nil || err != nil {
+		return -1
+	} else {
+		return int32(gr.Gid)
+	}
+}
+
+func gid2name(gid int32) string {
+	gr, err := getgr.ByGid(gid)
+	if gr == nil || err != nil {
+		return ""
+	} else {
+		return gr.Name
+	}
+}
diff --git a/src/nshd/hackers_git/name2gid.go b/src/nshd/hackers_git/name2gid.go
deleted file mode 100644
index c155d29..0000000
--- a/src/nshd/hackers_git/name2gid.go
+++ /dev/null
@@ -1,42 +0,0 @@
-package hackers_git
-
-import (
-	"syscall"
-	"unsafe"
-)
-
-//#define _XOPEN_SOURCE /* for getgrnam_r(3) in grp.h */
-//#include <stdlib.h>   /* for free(3) */
-//#include <unistd.h>   /* for sysconf(3) */
-//#include <grp.h>      /* for getgrnam_r(3) */
-import "C"
-
-func name2gid(name string) (gid int32) {
-	nameC := C.CString(name)
-	defer C.free(unsafe.Pointer(nameC))
-
-	gid = -1
-	buflen := C.sysconf(C._SC_GETGR_R_SIZE_MAX)
-	if buflen < 1 {
-		buflen = 1024
-	}
-	buf := make([]byte, buflen)
-	var grp C.struct_group
-	var ret *C.struct_group
-	for {
-		success, errno := C.getgrnam_r(nameC, &grp, (*C.char)(unsafe.Pointer(&buf[0])), C.size_t(buflen), &ret)
-		if success >= 0 {
-			break
-		}
-		if errno == syscall.ERANGE {
-			buflen += 256
-			buf = make([]byte, buflen)
-		} else {
-			return
-		}
-	}
-	if ret != nil {
-		gid = int32(ret.gr_gid)
-	}
-	return
-}
-- 
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