Merge pull request #8 from dscho/home-env

Allow overriding the home directory via the HOME variable

Author: dscho

winsup/cygwin/cygheap.h

@@ -414,7 +414,8 @@ class cygheap_pwdgrp
     NSS_SCHEME_UNIX,
     NSS_SCHEME_DESC,
     NSS_SCHEME_PATH,
-    NSS_SCHEME_FREEATTR
+    NSS_SCHEME_FREEATTR,
+    NSS_SCHEME_ENV
   };
   struct nss_scheme_t {
     nss_scheme_method	method;

winsup/cygwin/uinfo.cc

@@ -780,6 +780,8 @@ cygheap_pwdgrp::nss_init_line (const char *line)
 		    scheme[idx].method = NSS_SCHEME_UNIX;
 		  else if (NSS_CMP ("desc"))
 		    scheme[idx].method = NSS_SCHEME_DESC;
+		  else if (NSS_CMP ("env"))
+		    scheme[idx].method = NSS_SCHEME_ENV;
 		  else if (NSS_NCMP ("/"))
 		    {
 		      const char *e = c + strcspn (c, " \t");
@@ -970,6 +972,40 @@ fetch_from_path (cyg_ldap *pldap, PUSER_INFO_3 ui, cygpsid &sid, PCWSTR str,
   return ret;
 }
 
+static size_t
+fetch_env(LPCWSTR key, char *buf, size_t size)
+{
+  WCHAR wbuf[32767];
+  DWORD max = sizeof wbuf / sizeof *wbuf;
+  DWORD len = GetEnvironmentVariableW (key, wbuf, max);
+
+  if (!len || len >= max)
+    return 0;
+
+  len = sys_wcstombs (buf, size, wbuf, len);
+  return len && len < size ? len : 0;
+}
+
+static char *
+fetch_home_env (void)
+{
+  char home[32767];
+  size_t max = sizeof home / sizeof *home, len;
+
+  if (fetch_env (L"HOME", home, max)
+      || ((len = fetch_env (L"HOMEDRIVE", home, max))
+        && fetch_env (L"HOMEPATH", home + len, max - len))
+      || fetch_env (L"USERPROFILE", home, max))
+    {
+      tmp_pathbuf tp;
+      cygwin_conv_path (CCP_WIN_A_TO_POSIX | CCP_ABSOLUTE,
+	  home, tp.c_get(), NT_MAX_PATH);
+      return strdup(tp.c_get());
+    }
+
+  return NULL;
+}
+
 char *
 cygheap_pwdgrp::get_home (cyg_ldap *pldap, cygpsid &sid, PCWSTR dom,
 			  PCWSTR dnsdomain, PCWSTR name, bool full_qualified)
@@ -1029,6 +1065,10 @@ cygheap_pwdgrp::get_home (cyg_ldap *pldap, cygpsid &sid, PCWSTR dom,
 		}
 	    }
 	  break;
+	case NSS_SCHEME_ENV:
+	  if (RtlEqualSid (sid, cygheap->user.sid ()))
+	    home = fetch_home_env ();
+	  break;
 	}
     }
   return home;
@@ -1042,6 +1082,8 @@ cygheap_pwdgrp::get_home (PUSER_INFO_3 ui, cygpsid &sid, PCWSTR dom,
 
   for (uint16_t idx = 0; !home && idx < NSS_SCHEME_MAX; ++idx)
     {
+      if (!ui && home_scheme[idx].method != NSS_SCHEME_ENV)
+        continue;
       switch (home_scheme[idx].method)
 	{
 	case NSS_SCHEME_FALLBACK:
@@ -1060,6 +1102,10 @@ cygheap_pwdgrp::get_home (PUSER_INFO_3 ui, cygpsid &sid, PCWSTR dom,
 	  home = fetch_from_path (NULL, ui, sid, home_scheme[idx].attrib,
 				  dom, NULL, name, full_qualified);
 	  break;
+	case NSS_SCHEME_ENV:
+	  if (RtlEqualSid (sid, cygheap->user.sid ()))
+	    home = fetch_home_env ();
+	  break;
 	}
     }
   return home;
@@ -1079,6 +1125,7 @@ cygheap_pwdgrp::get_shell (cyg_ldap *pldap, cygpsid &sid, PCWSTR dom,
 	case NSS_SCHEME_FALLBACK:
 	  return NULL;
 	case NSS_SCHEME_WINDOWS:
+	case NSS_SCHEME_ENV:
 	  break;
 	case NSS_SCHEME_CYGWIN:
 	  if (pldap->fetch_ad_account (sid, false, dnsdomain))
@@ -1143,6 +1190,7 @@ cygheap_pwdgrp::get_shell (PUSER_INFO_3 ui, cygpsid &sid, PCWSTR dom,
 	case NSS_SCHEME_CYGWIN:
 	case NSS_SCHEME_UNIX:
 	case NSS_SCHEME_FREEATTR:
+	case NSS_SCHEME_ENV:
 	  break;
 	case NSS_SCHEME_DESC:
 	  shell = fetch_from_description (ui->usri3_comment, L"shell=\"", 7);
@@ -1223,6 +1271,8 @@ cygheap_pwdgrp::get_gecos (cyg_ldap *pldap, cygpsid &sid, PCWSTR dom,
 		sys_wcstombs_alloc (&gecos, HEAP_NOTHEAP, val);
 	    }
 	  break;
+	case NSS_SCHEME_ENV:
+	  break;
 	}
     }
   if (gecos)
@@ -1249,6 +1299,7 @@ cygheap_pwdgrp::get_gecos (PUSER_INFO_3 ui, cygpsid &sid, PCWSTR dom,
 	case NSS_SCHEME_CYGWIN:
 	case NSS_SCHEME_UNIX:
 	case NSS_SCHEME_FREEATTR:
+	case NSS_SCHEME_ENV:
 	  break;
 	case NSS_SCHEME_DESC:
 	  gecos = fetch_from_description (ui->usri3_comment, L"gecos=\"", 7);
@@ -2023,6 +2074,9 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap)
 	{
 	  /* Just some fake. */
 	  sid = csid.create (99, 1, 0);
+	  if (arg.id == cygheap->user.real_uid)
+	    home = cygheap->pg.get_home(NULL, cygheap->user.sid(),
+	      NULL, NULL, false);
 	  break;
 	}
       else if (arg.id >= UNIX_POSIX_OFFSET)
@@ -2076,7 +2130,11 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap)
 	 it to a well-known group here. */
       if (acc_type == SidTypeUser
 	  && (sid_sub_auth_count (sid) <= 3 || sid_id_auth (sid) == 11))
-	acc_type = SidTypeWellKnownGroup;
+	{
+	  acc_type = SidTypeWellKnownGroup;
+	  home = cygheap->pg.get_home (pldap, sid, dom, domain, name,
+				       fully_qualified_name);
+	}
       switch (acc_type)
       	{
 	case SidTypeUser:
@@ -2509,10 +2567,11 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap)
      logon.  Unless it's the SYSTEM account.  This conveniently allows to
      logon interactively as SYSTEM for debugging purposes. */
   else if (acc_type != SidTypeUser && sid != well_known_system_sid)
-    __small_sprintf (linebuf, "%W:*:%u:%u:U-%W\\%W,%s:/:/sbin/nologin",
+    __small_sprintf (linebuf, "%W:*:%u:%u:U-%W\\%W,%s:%s:/sbin/nologin",
 		     posix_name, uid, gid,
 		     dom, name,
-		     sid.string ((char *) sidstr));
+		     sid.string ((char *) sidstr),
+		     home ? home : "/");
   else
     __small_sprintf (linebuf, "%W:*:%u:%u:%s%sU-%W\\%W,%s:%s%W:%s",
 		     posix_name, uid, gid,