Use simple_search_memory in gdbserver

This replaces gdbserver's memory-searching function with
simple_search_memory.

gdbserver/ChangeLog
2020-10-07  Tom Tromey  <tromey@adacore.com>

	* server.cc (handle_search_memory_1): Remove.
	(handle_search_memory): Use simple_search_memory.

diff --git a/gdbserver/ChangeLog b/gdbserver/ChangeLog
index 94f1a75b94da6985a7546f244b61bad1a28aeea2..a341693776cd641723af5194140371a7536e3997 100644 (file)
--- a/gdbserver/ChangeLog
+++ b/gdbserver/ChangeLog
@@ -1,3 +1,8 @@
+2020-10-07  Tom Tromey  <tromey@adacore.com>
+
+       * server.cc (handle_search_memory_1): Remove.
+       (handle_search_memory): Use simple_search_memory.
+
 2020-10-07  Simon Marchi  <simon.marchi@efficios.com>
 
        * Makefile.in (COMPILE): Add CXXFLAGS.

diff --git a/gdbserver/server.cc b/gdbserver/server.cc
index e6314e56506bf507f9adcdf4006d17fca902bd92..86c9a6f22b811cb268516ccc230289da931574ab 100644 (file)
--- a/gdbserver/server.cc
+++ b/gdbserver/server.cc
@@ -49,6 +49,7 @@
 #include "gdbsupport/scope-exit.h"
 #include "gdbsupport/gdb_select.h"
 #include "gdbsupport/scoped_restore.h"
+#include "gdbsupport/search.h"
 
 #define require_running_or_return(BUF)         \
   if (!target_running ())                      \
@@ -1040,89 +1041,6 @@ gdb_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
     }
 }
 
-/* Subroutine of handle_search_memory to simplify it.  */
-
-static int
-handle_search_memory_1 (CORE_ADDR start_addr, CORE_ADDR search_space_len,
-                       gdb_byte *pattern, unsigned pattern_len,
-                       gdb_byte *search_buf,
-                       unsigned chunk_size, unsigned search_buf_size,
-                       CORE_ADDR *found_addrp)
-{
-  /* Prime the search buffer.  */
-
-  if (gdb_read_memory (start_addr, search_buf, search_buf_size)
-      != search_buf_size)
-    {
-      warning ("Unable to access %ld bytes of target "
-              "memory at 0x%lx, halting search.",
-              (long) search_buf_size, (long) start_addr);
-      return -1;
-    }
-
-  /* Perform the search.
-
-     The loop is kept simple by allocating [N + pattern-length - 1] bytes.
-     When we've scanned N bytes we copy the trailing bytes to the start and
-     read in another N bytes.  */
-
-  while (search_space_len >= pattern_len)
-    {
-      gdb_byte *found_ptr;
-      unsigned nr_search_bytes = (search_space_len < search_buf_size
-                                 ? search_space_len
-                                 : search_buf_size);
-
-      found_ptr = (gdb_byte *) memmem (search_buf, nr_search_bytes, pattern,
-                                      pattern_len);
-
-      if (found_ptr != NULL)
-       {
-         CORE_ADDR found_addr = start_addr + (found_ptr - search_buf);
-         *found_addrp = found_addr;
-         return 1;
-       }
-
-      /* Not found in this chunk, skip to next chunk.  */
-
-      /* Don't let search_space_len wrap here, it's unsigned.  */
-      if (search_space_len >= chunk_size)
-       search_space_len -= chunk_size;
-      else
-       search_space_len = 0;
-
-      if (search_space_len >= pattern_len)
-       {
-         unsigned keep_len = search_buf_size - chunk_size;
-         CORE_ADDR read_addr = start_addr + chunk_size + keep_len;
-         int nr_to_read;
-
-         /* Copy the trailing part of the previous iteration to the front
-            of the buffer for the next iteration.  */
-         memcpy (search_buf, search_buf + chunk_size, keep_len);
-
-         nr_to_read = (search_space_len - keep_len < chunk_size
-                       ? search_space_len - keep_len
-                       : chunk_size);
-
-         if (gdb_read_memory (read_addr, search_buf + keep_len,
-                              nr_to_read) != nr_to_read)
-           {
-             warning ("Unable to access %ld bytes of target memory "
-                      "at 0x%lx, halting search.",
-                      (long) nr_to_read, (long) read_addr);
-             return -1;
-           }
-
-         start_addr += chunk_size;
-       }
-    }
-
-  /* Not found.  */
-
-  return 0;
-}
-
 /* Handle qSearch:memory packets.  */
 
 static void
@@ -1132,12 +1050,6 @@ handle_search_memory (char *own_buf, int packet_len)
   CORE_ADDR search_space_len;
   gdb_byte *pattern;
   unsigned int pattern_len;
-  /* NOTE: also defined in find.c testcase.  */
-#define SEARCH_CHUNK_SIZE 16000
-  const unsigned chunk_size = SEARCH_CHUNK_SIZE;
-  /* Buffer to hold memory contents for searching.  */
-  gdb_byte *search_buf;
-  unsigned search_buf_size;
   int found;
   CORE_ADDR found_addr;
   int cmd_name_len = sizeof ("qSearch:memory:") - 1;
@@ -1160,25 +1072,13 @@ handle_search_memory (char *own_buf, int packet_len)
       return;
     }
 
-  search_buf_size = chunk_size + pattern_len - 1;
-
-  /* No point in trying to allocate a buffer larger than the search space.  */
-  if (search_space_len < search_buf_size)
-    search_buf_size = search_space_len;
-
-  search_buf = (gdb_byte *) malloc (search_buf_size);
-  if (search_buf == NULL)
+  auto read_memory = [] (CORE_ADDR addr, gdb_byte *result, size_t len)
     {
-      free (pattern);
-      error ("Unable to allocate memory to perform the search");
-      strcpy (own_buf, "E00");
-      return;
-    }
+      return gdb_read_memory (addr, result, len) == len;
+    };
 
-  found = handle_search_memory_1 (start_addr, search_space_len,
-                                 pattern, pattern_len,
-                                 search_buf, chunk_size, search_buf_size,
-                                 &found_addr);
+  found = simple_search_memory (read_memory, start_addr, search_space_len,
+                               pattern, pattern_len, &found_addr);
 
   if (found > 0)
     sprintf (own_buf, "1,%lx", (long) found_addr);
@@ -1187,7 +1087,6 @@ handle_search_memory (char *own_buf, int packet_len)
   else
     strcpy (own_buf, "E00");
 
-  free (search_buf);
   free (pattern);
 }