Update.

2000-05-07  Mark Kettenis  <kettenis@gnu.org>

	* nss/nss_db/db-open.c: Cleanup and add comments.  Pretty print.
	Remove duplicate <errno.h> include.  Remove inclusion of
	<libintl.h> and "nsswitch.h".
	(set_cloexec_flag): New function, broken out of dbopen.
	(dbopen): Changed return type to `enum
	nss_status'.  Mostly rewritten to make sure that we do not report
	NSS_STATUS_SUCCESS if something went wrong.  Remove unnecessary casts.
	(internal_setent): Change return type to nss_status.
	Document, and make sure that the function
	behaves accordingly.  Make dynamically loading the database
	library really thread-safe and return NSS_STATUS_UNAVAIL if it
	failed.
	(db_cursor): Return ENOMEM is memory allocation failed.  Remove
	unecessary casts.
	* nss/nss_db/dummy-db.h: Add copyright notice.  Improve
	documentation.
	(struct dbc24, struct dbc27): Use DBT type in parameter lists for
	c_get function member.
	* nss/nss_db/nss_db.h: Add and tweak some comments.
	(DBT): Move typedef before NSS_DBC typedef.
	(NSS_DBC, NSS_DB): Use DBT in function member parameter lists.

1 files changed, 145 insertions, 154 deletions

diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c
index 470af04..6a21a0a 100644
--- a/nss/nss_db/db-open.c
+++ b/nss/nss_db/db-open.c
@@ -20,35 +20,42 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <dlfcn.h>
-#include <errno.h>
 #include <stdlib.h>
-#include <libintl.h>
+#include <string.h>
 #include <bits/libc-lock.h>
 
 #include "dummy-db.h"
-#include "nsswitch.h"
 #include "nss_db.h"
 
 /* This file contains the functions used to open and close the databases
-   read by the rest of libnss_db.  They are not thread safe; the caller
-   must handle locking.
+   read by the rest of libnss_db.  Not all of them are thread safe;
+   make sure the caller does the appropriate locking.
 
    We dynamically load the database library, so that it does not have
-   to be present when glibc is compiled.  Once loaded, libdb is never
-   unloaded again unless this library is unloaded (from the free_mem
-   routine in nsswitch.c) - we catch the unload by providing a shlib
-   destructor.  (XXX Does it work?)  */
-
+   to be present when glibc is compiled.  Once loaded, the database
+   library is never never unloaded again until the libnss_db module is
+   unloaded (from the free_mem routine in nsswitch.c) -- we catch the
+   unload by providing a shlib destructor.  (XXX Does that actually
+   work?)  */
+
+/* Handle for the shared Berkeley DB library.  If non-null, the
+   database library is completely loaded and ready to be used by
+   multithreaded code.  */
 static void *libdb_handle;
+
+/* The version of the Berkeley DB library we are using.  */
 enum {
   nodb,
   db24,
   db27,
   db30
 } libdb_version;
+
+/* Pointer to the db_open function.  For use with DB 2.x.  */
 static int (*libdb_db_open) (const char *, int,
 			     uint32_t, int, void *, void *, void **);
 
+/* Pointer to the db_create function.  For use with DB 3.x.  */
 static int (*libdb_db_create) (void *, void *, uint32_t);
 
 /* Constants which vary from version to version are actually variables
@@ -65,13 +72,17 @@ int db_notfound;
 /* Locks the static variables in this file.  */
 __libc_lock_define_initialized (static, lock)
 
-/* Dynamically load the database library.
+/* Dynamically load the database library.  Return zero if successful,
+   non-zero if no suitable version of the library could be loaded.
+   Must be called with the above lock held if it might run in a
+   multithreaded context.
+
    We try currently:
    - libdb.so.3: the name used by glibc 2.1
    - libdb-3.0.so: the name used by db-3.0.x
    and maybe others in the future.  */
-   
-int
+
+enum nss_status
 load_db (void)
 {
   static const char *libnames[] = { "libdb.so.3", "libdb-3.0.so" };
@@ -83,11 +94,11 @@ load_db (void)
       if (libdb_handle == NULL)
 	continue;
 
-      /* db 3.0 has db_create instead of db_open.  */
+      /* DB 3.0 has db_create instead of db_open.  */
       libdb_db_create = dlsym (libdb_handle, "db_create");
 
       if (libdb_db_create == NULL)
-	/* db 2.x uses db_open.  */
+	/* DB 2.x uses db_open.  */
 	libdb_db_open = dlsym (libdb_handle, "db_open");
 
       if (libdb_db_open != NULL || libdb_db_create != NULL)
@@ -129,6 +140,7 @@ load_db (void)
 		      db_rdonly = DB2x_RDONLY;
 		    }
 		  break;
+
 		case 3:
 		  /* Sanity check: Do we have db_create?  */
 		  if (libdb_db_create != NULL)
@@ -141,12 +153,14 @@ load_db (void)
 		      db_rdonly = DB30_RDONLY;
 		    }
 		  break;
+
 		default:
 		  break;
 		}
 	    }
+
 	  if (libdb_version != nodb)
-	    return 0;
+	    return NSS_STATUS_SUCCESS;
 
 	  /* Clear variables.  */
 	  libdb_db_open = NULL;
@@ -157,7 +171,22 @@ load_db (void)
     }
 
   (void) dlerror ();
-  return 1;
+  return NSS_STATUS_UNAVAIL;
+}
+
+/* Set the `FD_CLOEXEC' flag of FD.  Return 0 on success, or -1 on
+   error with `errno' set. */
+static int
+set_cloexec_flag (int fd)
+{
+  int oldflags = fcntl (fd, F_GETFD, 0);
+
+  if (oldflags < 0)
+    return oldflags;
+
+  oldflags |= FD_CLOEXEC;
+
+  return fcntl (fd, F_SETFD, oldflags);
 }
 
 /* Make sure we don't use the library anymore once we are shutting down.  */
@@ -173,6 +202,9 @@ unload_db (void)
     }
 }
 
+/* Open the database stored in FILE.  If succesful, store the database
+   handle in *DBP and return NSS_STATUS_SUCCESS.  On failure, return
+   the appropriate lookup status.  */
 enum nss_status
 internal_setent (const char *file, NSS_DB **dbp)
 {
@@ -184,26 +216,26 @@ internal_setent (const char *file, NSS_DB **dbp)
 	{
 	  __libc_lock_lock (lock);
 
-	  status = load_db ();
+	  if (libdb_db_open == NULL && libdb_db_create == NULL)
+	    status = load_db ();
 
 	  __libc_lock_unlock (lock);
-
-	  if (status != 0)
-	    return status;
 	}
 
-      status = dbopen (file, db_rdonly, 0, dbp);
+      if (status == NSS_STATUS_SUCCESS)
+	status = dbopen (file, db_rdonly, 0, dbp);
     }
 
   return status;
 }
 
 
-/* Close the database file.  */
+/* Close the database *DBP.  */
 void
 internal_endent (NSS_DB **dbp)
 {
   NSS_DB *db = *dbp;
+
   if (db != NULL)
     {
       DL_CALL_FCT (db->close, (db->db, 0));
@@ -211,188 +243,147 @@ internal_endent (NSS_DB **dbp)
     }
 }
 
+/* Allocate a cursor for database DB and transaction TXN.  On success,
+   store the cursor in *DBCP and return zero.  Otherwise return an
+   error value.  */
 int
 db_cursor (void *db, void *txn, NSS_DBC **dbcp)
 {
-  void *ptr;
-  NSS_DBC *dbc = NULL;
+  NSS_DBC *dbc;
   int ret;
 
+  dbc = (NSS_DBC *) malloc (sizeof (NSS_DBC));
+  if (dbc == NULL)
+    return ENOMEM;
+
   switch (libdb_version)
     {
     case db24:
-      ret = ((struct db24 *) db)->cursor (db, txn, &ptr);
+      ret = ((struct db24 *) db)->cursor (db, txn, &dbc->cursor);
+
+      if (ret == 0)
+	dbc->c_get = ((struct dbc24 *) dbc->cursor)->c_get;
       break;
+
     case db27:
-      ret = ((struct db27 *) db)->cursor (db, txn, &ptr, 0);
+      ret = ((struct db27 *) db)->cursor (db, txn, &dbc->cursor, 0);
+
+      if (ret == 0)
+	dbc->c_get = ((struct dbc27 *) dbc->cursor)->c_get;
       break;
+
     case db30:
-      ret = ((struct db30 *) db)->cursor (db, txn, &ptr, 0);
+      ret = ((struct db30 *) db)->cursor (db, txn, &dbc->cursor, 0);
+
+      if (ret == 0)
+	dbc->c_get = ((struct dbc30 *) dbc->cursor)->c_get;
       break;
+
     default:
       abort ();
     }
 
-  if (ret == 0)
+  if (ret != 0)
     {
-      dbc = (NSS_DBC *) malloc (sizeof (NSS_DBC));
-      if (dbc == NULL)
-	return 1;
-      dbc->cursor = ptr;
-
-      switch (libdb_version)
-	{
-	case db24:
-	  dbc->c_get =
-	    (int (*) (void *, void *, void *, uint32_t))
-	    ((struct dbc24 *) ptr)->c_get;
-	  break;
-	case db27:
-	  dbc->c_get =
-	    (int (*) (void *, void *, void *, uint32_t))
-	    ((struct dbc27 *) ptr)->c_get;
-	  break;
-	case db30:
-	  dbc->c_get =
-	    (int (*) (void *, void *, void *, uint32_t))
-	    ((struct dbc30 *) ptr)->c_get;
-	default:
-	  abort ();
-	}
+      free (dbc);
+      return ret;
     }
 
   *dbcp = dbc;
 
-  return ret;
+  return 0;
 }
 
 
+/* Open the database in FNAME, for access specified by FLAGS.  If
+   opening the database causes the file FNAME to be created, it is
+   created with MODE.  If succesful, store the database handle in *DBP
+   and return NSS_STATUS_SUCCESS.  On failure, return the appropriate
+   lookup status.  */
 int
 dbopen (const char *fname, int oper, int mode, NSS_DB **dbp)
 {
   int err;
-  int result;
   int fd;
-  void *odb;
-  enum nss_status status = NSS_STATUS_SUCCESS;
   NSS_DB *db;
 
+  /* Construct the object we pass up.  */
+  db = (NSS_DB *) calloc (1, sizeof (NSS_DB));
+  if (db == NULL)
+    return NSS_STATUS_UNAVAIL;
+
+  /* Initialize the object.  */
+  db->cursor = db_cursor;
+
   /* Actually open the database.  */
   switch (libdb_version)
     {
     case db24:
     case db27:
       err = DL_CALL_FCT (libdb_db_open,
-			 (fname, DB_BTREE, oper, mode, NULL, NULL, &odb));
+			 (fname, DB_BTREE, oper, mode, NULL, NULL, &db->db));
       if (err != 0)
+	goto fail;
+
+      if (libdb_version)
 	{
-	  __set_errno (err);
-	  *dbp = NULL;
-	  return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+	  db->close = ((struct db24 *) db->db)->close;
+	  db->fd = ((struct db24 *) db->db)->fd;
+	  db->get = ((struct db24 *) db->db)->get;
+	  db->put = ((struct db24 *) db->db)->put;
+	}
+      else
+	{
+	  db->close = ((struct db27 *) db->db)->close;
+	  db->fd = ((struct db27 *) db->db)->fd;
+	  db->get = ((struct db27 *) db->db)->get;
+	  db->put = ((struct db27 *) db->db)->put;
 	}
       break;
+
     case db30:
-      err = DL_CALL_FCT (libdb_db_create, (&odb, NULL, 0));
+      err = DL_CALL_FCT (libdb_db_create, (db->db, NULL, 0));
       if (err != 0)
-	{
-	  __set_errno (err);
-	  *dbp = NULL;
-	  return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
-	}
-      err = ((struct db30 *) odb)->open (odb, fname, NULL, DB_BTREE,
-					oper, mode);
+	goto fail;
+
+      db->close = ((struct db30 *) db->db)->close;
+      db->fd = ((struct db30 *) db->db)->fd;
+      db->get = ((struct db30 *) db->db)->get;
+      db->put = ((struct db30 *) db->db)->put;
+
+      err = ((struct db30 *) db->db)->open (db->db, fname, NULL, DB_BTREE,
+					    oper, mode);
       if (err != 0)
-	{
-	  __set_errno (err);
-	  /* Free all resources.  */
-	  ((struct db30 *) odb)->close (odb, 0);
-	  *dbp = NULL;
-	  return NSS_STATUS_UNAVAIL;
-	}
+	goto fail;
       break;
+
     default:
       abort ();
     }
-      
-  /* Construct the object we pass up.  */
-  db = (NSS_DB *) malloc (sizeof (NSS_DB));
-  if (db != NULL)
-    {
-      db->db = odb;
 
-      /* The functions are at different positions for the different
-	 versions.  Sigh.  */
-      switch (libdb_version)
-	{
-	case db24:
-	  db->close =
-	    (int (*) (void *, uint32_t)) ((struct db24 *) odb)->close;
-	  db->fd =
-	    (int (*) (void *, int *)) ((struct db24 *) odb)->fd;
-	  db->get =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db24 *) odb)->get;
-	  db->put =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db24 *) odb)->put;
-	  break;
-	case db27:
-	  db->close =
-	    (int (*) (void *, uint32_t)) ((struct db27 *) odb)->close;
-	  db->fd =
-	    (int (*) (void *, int *)) ((struct db27 *) odb)->fd;
-	  db->get =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db27 *) odb)->get;
-	  db->put =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db27 *) odb)->put;
-	  break;
-	case db30:
-	  db->close =
-	    (int (*) (void *, uint32_t)) ((struct db30 *) odb)->close;
-	  db->fd =
-	    (int (*) (void *, int *)) ((struct db30 *) odb)->fd;
-	  db->get =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db30 *) odb)->get;
-	  db->put =
-	    (int (*) (void *, void *, void *, void *, uint32_t))
-	    ((struct db30 *) odb)->put;
-	  break;
-	default:
-	  abort ();
-	}
-      db->cursor = db_cursor;
+  /* We have to make sure the file is `closed on exec'.  */
+  err = DL_CALL_FCT (db->fd, (db->db, &fd));
+  if (err != 0)
+    goto fail;
+  if (set_cloexec_flag (fd) < 0)
+    goto fail;
 
-      /* We have to make sure the file is `closed on exec'.  */
-      err = DL_CALL_FCT (db->fd, (odb, &fd));
-      if (err != 0)
-	{
-	  __set_errno (err);
-	  result = -1;
-	}
-      else
-	{
-	  int flags = result = fcntl (fd, F_GETFD, 0);
+  *dbp = db;
 
-	  if (result >= 0)
-	    {
-	      flags |= FD_CLOEXEC;
-	      result = fcntl (fd, F_SETFD, flags);
-	    }
-	}
-      if (result < 0)
-	{
-	  /* Something went wrong.  Close the stream and return a
-	     failure.  */
-	  DL_CALL_FCT (db->close, (odb, 0));
-	  free (db);
-	  status = NSS_STATUS_UNAVAIL;
-	  db = NULL;
-	}
+  return NSS_STATUS_UNAVAIL;
+
+ fail:
+  /* Something went wrong.  Close the database if necessary.  */
+  if (db)
+    {
+      if (db->db && db->close)
+	DL_CALL_FCT (db->close, (db->db, 0));
+      free (db);
     }
-  *dbp = db;
-  
-  return status;
+
+  /* Make sure `errno' is set.  */
+  if (err)
+    __set_errno (err);
+
+  return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
 }