Update 'README.md'

Signed-off-by: Russ Magee <rmagee@gmail.com>

README.md

@@ -3,15 +3,33 @@ goutmp - Minimal bindings to C stdlib pututmpx(), getutmpx() (/var/log/wtmp) and
 Any Go program which allows user shell access should update the standard UNIX files which track user sessions: /var/log/wtmp (for the 'w' and 'who' commands), and /var/log/lastlog (the 'last' and 'lastlog' commands).
 
 ```
-go doc
+$ go doc -all
 package goutmp // import "blitter.com/go/goutmp"
 
 Golang bindings for basic login/utmp accounting
 
-type UtmpEntry struct{ ... }
+FUNCTIONS
+
+func GetHost(addr string) (h string)
+    return remote client hostname or IP if host lookup fails addr is expected to
+    be of the format given by net.Addr.String() eg., "127.0.0.1:80" or
+    "[::1]:80"
+
+func Put_lastlog_entry(app, usr, ptsname, host string)
+    Put the login app, username and originating host/IP to lastlog
 
-func Put_lastlog_entry(app string, usr string, host string)
 func Unput_utmp(entry UtmpEntry)
-func Put_utmp(user string, host string) UtmpEntry
+    Remove a username/host entry from utmp
+
+
+TYPES
+
+type UtmpEntry struct {
+	// Has unexported fields.
+}
+    UtmpEntry wraps the C struct utmp
+
+func Put_utmp(user, ptsName, host string) UtmpEntry
+    Put a username and the originating host/IP to utmp
 ```
 

go.mod

@@ -0,0 +1,3 @@
+module blitter.com/go/goutmp
+
+go 1.17

goutmp_bsd.go

@@ -0,0 +1,136 @@
+// +build freebsd
+
+// Golang bindings for basic login/utmp accounting
+package goutmp
+
+//#include <stdio.h>
+//#include <stdlib.h>
+//#include <sys/file.h>
+//#include <string.h>
+//#include <unistd.h>
+//#include <stdint.h>
+//#include <time.h>
+//#include <pwd.h>
+//
+//#include <utmpx.h>
+//
+//typedef char char_t;
+//
+//void pututmpx(struct utmpx* entry, char* uname, char* ptsname, char* host) {
+//  entry->ut_type = USER_PROCESS;
+//  entry->ut_pid = getpid();
+//  strcpy(entry->ut_line, ptsname + strlen("/dev/"));
+//
+//  strcpy(entry->ut_id, ptsname + strlen("/dev/pts/"));
+//
+//  //entry->ut_time = time(NULL);
+//  strcpy(entry->ut_user, uname);
+//  strcpy(entry->ut_host, host);
+//  //entry->ut_addr = 0;
+//  setutxent();
+//  pututxline(entry);
+//}
+//
+//void unpututmpx(struct utmpx* entry) {
+//  entry->ut_type = DEAD_PROCESS;
+//  entry->ut_line[0] = '\0';
+//  //entry->ut_time = 0;
+//  entry->ut_user[0] = '\0';
+//  setutxent();
+//  pututxline(entry);
+//
+//  endutxent();
+//}
+//
+//#if 0
+//int putlastlogentry(int64_t t, int uid, char* line, char* host) {
+//  int retval = 0;
+//  FILE *f;
+//  struct lastlog l;
+//
+//  strncpy(l.ll_line, line, UT_LINESIZE);
+//  l.ll_line[UT_LINESIZE-1] = '\0';
+//  strncpy(l.ll_host, host, UT_HOSTSIZE);
+//  l.ll_host[UT_HOSTSIZE-1] = '\0';
+//
+//  l.ll_time = (time_t)t;
+//  //printf("l: ll_line '%s', ll_host '%s', ll_time %d\n", l.ll_line, l.ll_host, l.ll_time);
+//
+//  /* Write lastlog entry at fixed offset (uid * sizeof(struct lastlog) */
+//  if( NULL != (f = fopen("/var/log/lastlog", "rw+")) ) {
+//    if( !fseek(f, (uid * sizeof(struct lastlog)), SEEK_SET) ) {
+//      int fd = fileno(f);
+//      if( write(fd, &l, sizeof(l)) == sizeof(l) ) {
+//        retval = 1;
+//        //int32_t stat = system("echo ---- lastlog ----; lastlog");
+//      }
+//    }
+//    fclose(f);
+//  }
+//  return retval;
+//}
+//#else
+//int putlastlogentry(int64_t t, int uid, char* line, char* host) {
+//  return 0;
+//}
+//#endif
+import "C"
+
+import (
+	"fmt"
+	"net"
+	"os/user"
+	"strings"
+	"time"
+)
+
+// UtmpEntry wraps the C struct utmp
+type UtmpEntry struct {
+	entry C.struct_utmpx
+}
+
+// return remote client hostname or IP if host lookup fails
+// addr is expected to be of the format given by net.Addr.String()
+// eg., "127.0.0.1:80" or "[::1]:80"
+func GetHost(addr string) (h string) {
+	if !strings.Contains(addr, "[") {
+		h = strings.Split(addr, ":")[0]
+	} else {
+		h = strings.Split(strings.Split(addr, "[")[1], "]")[0]
+	}
+	hList, e := net.LookupAddr(h)
+	//fmt.Printf("lookupAddr:%v\n", hList)
+	if e == nil {
+		h = hList[0]
+	}
+	return
+}
+
+// Put a username and the originating host/IP to utmp
+func Put_utmp(user, ptsName, host string) UtmpEntry {
+	var entry UtmpEntry
+
+	//log.Println("Put_utmp:host ", host, " user ", user)
+	C.pututmpx(&entry.entry, C.CString(user), C.CString(ptsName), C.CString(host))
+	return entry
+}
+
+// Remove a username/host entry from utmp
+func Unput_utmp(entry UtmpEntry) {
+	C.unpututmpx(&entry.entry)
+}
+
+// Put the login app, username and originating host/IP to lastlog
+func Put_lastlog_entry(app, usr, ptsname, host string) {
+	u, e := user.Lookup(usr)
+	if e != nil {
+		return
+	}
+	var uid uint32
+	fmt.Sscanf(u.Uid, "%d", &uid)
+
+	t := time.Now().Unix()
+	_ = C.putlastlogentry(C.int64_t(t), C.int(uid), C.CString(app), C.CString(host))
+	//stat := C.putlastlogentry(C.int64_t(t), C.int(uid), C.CString(app), C.CString(host))
+	//fmt.Println("stat was:",stat)
+}

goutmp_linux.go

@@ -1,3 +1,5 @@
+// +build linux
+
 // Golang bindings for basic login/utmp accounting
 package goutmp
 
@@ -16,23 +18,15 @@ package goutmp
 //typedef char char_t;
 //
 //
-//void pututmp(struct utmp* entry, char* name, char* host) {
-//  //TODO: if ttyname returns NULL, it's probably a network
-//  // connection and the pty should be passed in to this func.
-//  char* stdinName = ttyname(STDIN_FILENO);
-//  if( !stdinName ) {
-//    stdinName = "/dev/ptyN";
-//  }
-//
+//void pututmp(struct utmp* entry, char* uname, char* ptsname, char* host) {
 //  entry->ut_type = USER_PROCESS;
 //  entry->ut_pid = getpid();
-//  strcpy(entry->ut_line, stdinName + strlen("/dev/"));
-//  /* only correct for ptys named /dev/tty[pqr][0-9a-z] */
+//  strcpy(entry->ut_line, ptsname + strlen("/dev/"));
 //
-//  strcpy(entry->ut_id, stdinName + strlen("/dev/tty"));
+//  strcpy(entry->ut_id, ptsname + strlen("/dev/pts/"));
 //
 //  entry->ut_time = time(NULL);
-//  strcpy(entry->ut_user, name);
+//  strcpy(entry->ut_user, uname);
 //  strcpy(entry->ut_host, host);
 //  entry->ut_addr = 0;
 //  setutent();
@@ -109,11 +103,11 @@ func GetHost(addr string) (h string) {
 }
 
 // Put a username and the originating host/IP to utmp
-func Put_utmp(user string, host string) UtmpEntry {
+func Put_utmp(user, ptsName, host string) UtmpEntry {
 	var entry UtmpEntry
 
 	//log.Println("Put_utmp:host ", host, " user ", user)
-	C.pututmp(&entry.entry, C.CString(user), C.CString(host))
+	C.pututmp(&entry.entry, C.CString(user), C.CString(ptsName), C.CString(host))
 	return entry
 }
 
@@ -123,7 +117,7 @@ func Unput_utmp(entry UtmpEntry) {
 }
 
 // Put the login app, username and originating host/IP to lastlog
-func Put_lastlog_entry(app string, usr string, host string) {
+func Put_lastlog_entry(app, usr, ptsname, host string) {
 	u, e := user.Lookup(usr)
 	if e != nil {
 		return

main/test_bsd.go

@@ -0,0 +1,18 @@
+// +build freebsd
+
+package main
+
+import (
+	"time"
+
+	"blitter.com/go/goutmp"
+)
+
+func main() {
+	user := "bin"
+	host := "test.example.com"
+	utmp := goutmp.Put_utmp(user, "/dev/pts0", host)
+	goutmp.Put_lastlog_entry("xs", user, "/dev/pts0", host)
+	time.Sleep(10 * time.Second)
+	goutmp.Unput_utmp(utmp)
+}

main/test_linux.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package main
 
 import (
@@ -9,8 +11,8 @@ import (
 func main() {
 	user := "bin"
 	host := "test.example.com"
-	utmp := goutmp.Put_utmp(user, host)
-	goutmp.Put_lastlog_entry("hkexsh", user, host)
+	utmp := goutmp.Put_utmp(user, "/dev/pts0", host)
+	goutmp.Put_lastlog_entry("xs", user, "/dev/pts0", host)
 	time.Sleep(10 * time.Second)
 	goutmp.Unput_utmp(utmp)
 }