Move implementation of perror_with_name to gdbsupport

gdbsupport/errors.h declares perror_with_name and leaves the
implementation to the clients.

However gdb and gdbserver's implementations are essentially the
same, resulting in unnecessary code duplication.

Fix this by implementing perror_with_name in gdbsupport.  Add an
optional parameter for specifying the errno used to generate the
error message.

Also move the implementation of perror_string to gdbsupport since
perror_with_name requires it.

Approved-By: Tom Tromey <tom@tromey.com>

2 files changed, 34 insertions, 3 deletions

diff --git a/gdbsupport/errors.cc b/gdbsupport/errors.cc
index 566be377e3f..b48ce10eef8 100644
--- a/gdbsupport/errors.cc
+++ b/gdbsupport/errors.cc
@@ -71,6 +71,30 @@ internal_warning_loc (const char *file, int line, const char *fmt, ...)
   va_end (ap);
 }
 
+/* See errors.h.  */
+
+std::string
+perror_string (const char *prefix, int errnum)
+{
+  const char *err;
+
+  if (errnum != 0)
+    err = safe_strerror (errnum);
+  else
+    err = safe_strerror (errno);
+  return std::string (prefix) + ": " + err;
+}
+
+/* See errors.h.  */
+
+void
+perror_with_name (const char *string, int errnum)
+{
+  std::string combined = perror_string (string, errnum);
+
+  error (_("%s."), combined.c_str ());
+}
+
 #if defined (USE_WIN32API) || defined(__CYGWIN__)
 
 /* See errors.h.  */
diff --git a/gdbsupport/errors.h b/gdbsupport/errors.h
index 2304bc1e3d1..20f9152b671 100644
--- a/gdbsupport/errors.h
+++ b/gdbsupport/errors.h
@@ -83,11 +83,18 @@ extern void internal_vwarning (const char *file, int line,
      ATTRIBUTE_PRINTF (3, 0);
 
 
+/* Return a newly allocated string, containing the PREFIX followed
+   by the system error message for errno (separated by a colon).
+   If ERRNUM is given, then use it in place of errno.  */
+
+extern std::string perror_string (const char *prefix, int errnum = 0);
+
 /* Like "error", but the error message is constructed by combining
-   STRING with the system error message for errno.  This function does
-   not return.  This function must be provided by the client.  */
+   STRING with the system error message for errno.  If ERRNUM is given,
+   then use it in place of errno.  This function does not return.  */
 
-extern void perror_with_name (const char *string) ATTRIBUTE_NORETURN;
+extern void perror_with_name (const char *string, int errnum = 0)
+    ATTRIBUTE_NORETURN;
 
 /* Call this function to handle memory allocation failures.  This
    function does not return.  This function must be provided by the