Move to short lived TALLOC_CTX* for allocating printer

objects from the print handle cache.   Fixes bug that
caused smbd to consume large amounts of RAM when

(a) a printer handle was kept open over an extended
    period of time, and
(b) the client issued frequent requests that resulted
    in a call to get_a_printer()
(This used to be commit 10b9976e0ab961dc34c9426f0a497e0f81a5e17f)

diff --git a/source3/printing/nt_printing.c b/source3/printing/nt_printing.c
index bf8e1432c6430d4e4bcb82124fc0b88a10bae8ed..c28f8e8189408e8307da8757c470f361671bb31d 100644 (file)
--- a/source3/printing/nt_printing.c
+++ b/source3/printing/nt_printing.c
@@ -3917,6 +3917,16 @@ NT_PRINTER_INFO_LEVEL_2* dup_printer_2( TALLOC_CTX *ctx, NT_PRINTER_INFO_LEVEL_2
 
 /****************************************************************************
  Get a NT_PRINTER_INFO_LEVEL struct. It returns malloced memory.
+
+ Previously the code had a memory allocation problem because it always
+ used the TALLOC_CTX from the Printer_entry*.   This context lasts 
+ as a long as the original handle is open.  So if the client made a lot 
+ of getprinter[data]() calls, the memory usage would climb.  Now we use
+ a short lived TALLOC_CTX for printer_info_2 objects returned.  We 
+ still use the Printer_entry->ctx for maintaining the cache copy though
+ since that object must live as long as the handle by definition.  
+                                                    --jerry
+
 ****************************************************************************/
 
 WERROR get_a_printer( Printer_entry *print_hnd, NT_PRINTER_INFO_LEVEL **pp_printer, uint32 level, 
@@ -3947,7 +3957,11 @@ WERROR get_a_printer( Printer_entry *print_hnd, NT_PRINTER_INFO_LEVEL **pp_print
                                && (print_hnd->printer_type==PRINTER_HANDLE_IS_PRINTER) 
                                && print_hnd->printer_info )
                        {
-                               if ( !(printer->info_2 = dup_printer_2(print_hnd->ctx, print_hnd->printer_info->info_2)) ) {
+                               /* get_talloc_ctx() works here because we need a short 
+                                  lived talloc context */
+
+                               if ( !(printer->info_2 = dup_printer_2(get_talloc_ctx(), print_hnd->printer_info->info_2)) ) 
+                               {
                                        DEBUG(0,("get_a_printer: unable to copy cached printer info!\n"));
                                        
                                        SAFE_FREE(printer);
@@ -3962,10 +3976,11 @@ WERROR get_a_printer( Printer_entry *print_hnd, NT_PRINTER_INFO_LEVEL **pp_print
                                break;
                        }
 
-                       /* no cache for this handle; see if we can match one from another handle */
-                       
+                       /* no cache for this handle; see if we can match one from another handle.
+                          Make sure to use a short lived talloc ctx */
+
                        if ( print_hnd )
-                               result = find_printer_in_print_hnd_cache(print_hnd->ctx, &printer->info_2, sharename);
+                               result = find_printer_in_print_hnd_cache(get_talloc_ctx(), &printer->info_2, sharename);
                        
                        /* fail to disk if we don't have it with any open handle */
 
@@ -3983,6 +3998,9 @@ WERROR get_a_printer( Printer_entry *print_hnd, NT_PRINTER_INFO_LEVEL **pp_print
                                                print_hnd->printer_info = (NT_PRINTER_INFO_LEVEL *)malloc(sizeof(NT_PRINTER_INFO_LEVEL));
 
                                        if ( print_hnd->printer_info ) {
+                                               /* make sure to use the handle's talloc ctx here since 
+                                                  the printer_2 object must last until the handle is closed */
+
                                                print_hnd->printer_info->info_2 = dup_printer_2(print_hnd->ctx, printer->info_2);
                                                
                                                /* don't fail the lookup just because the cache update failed */