[PATCH 3/4] Remove a use of target_read_string

[Tom Tromey <tromey@adacore.com>]

linux-tdep.c:dump_mapping_p uses target_read_string, but in a way that
does not really make sense.  It's better to use target_read_memory
here.

gdb/ChangeLog
2020-06-02  Tom Tromey  <tromey@adacore.com>

	* linux-tdep.c (dump_mapping_p): Use target_read_memory.
---
 gdb/ChangeLog    |  4 ++++
 gdb/linux-tdep.c | 12 +++---------
 gdb/target.c     |  1 +
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 0f9559355f1..2dcdc630769 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -701,22 +701,16 @@ dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v,
   if (!dump_p && private_p && offset == 0
       && (filterflags & COREFILTER_ELF_HEADERS) != 0)
     {
-      /* Let's check if we have an ELF header.  */
-      gdb::unique_xmalloc_ptr<char> header;
-      int errcode;
-
       /* Useful define specifying the size of the ELF magical
 	 header.  */
 #ifndef SELFMAG
 #define SELFMAG 4
 #endif
 
-      /* Read the first SELFMAG bytes and check if it is ELFMAG.  */
-      if (target_read_string (addr, &header, SELFMAG, &errcode) == SELFMAG
-	  && errcode == 0)
+      /* Let's check if we have an ELF header.  */
+      gdb_byte h[SELFMAG];
+      if (target_read_memory (addr, h, SELFMAG) == 0)
 	{
-	  const char *h = header.get ();
-
 	  /* The EI_MAG* and ELFMAG* constants come from
 	     <elf/common.h>.  */
 	  if (h[EI_MAG0] == ELFMAG0 && h[EI_MAG1] == ELFMAG1
diff --git a/gdb/target.c b/gdb/target.c
index 14c494688e0..897b8fdd32b 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -50,6 +50,7 @@
 #include "terminal.h"
 #include <unordered_map>
 #include "target-connection.h"
+#include "valprint.h"
 
 static void generic_tls_error (void) ATTRIBUTE_NORETURN;
 
-- 
2.21.3