new function perror_string extracted out of throw_perror_with_name.

The main purpose of this patch is to extract the part of
throw_perror_with_name that computes a string providing the system
error message combined with a prefix string.  This will become useful
later on to provide a routine which prints a warning using that
perror_string, rather than throwing an error.

gdb/ChangeLog:

        * utils.c (perror_string): New function, extracted out of
        throw_perror_with_name.
        (throw_perror_with_name): Rework to use perror_string.

1 files changed, 22 insertions, 6 deletions

diff --git a/gdb/utils.c b/gdb/utils.c
index 26879ec3721..402fe8ee240 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -957,6 +957,26 @@ add_internal_problem_command (struct internal_problem *problem)
   xfree (show_doc);
 }
 
+/* Return a newly allocated string, containing the PREFIX followed
+   by the system error message for errno (separated by a colon).
+
+   The result must be deallocated after use.  */
+
+static char *
+perror_string (const char *prefix)
+{
+  char *err;
+  char *combined;
+
+  err = safe_strerror (errno);
+  combined = (char *) xmalloc (strlen (err) + strlen (prefix) + 3);
+  strcpy (combined, prefix);
+  strcat (combined, ": ");
+  strcat (combined, err);
+
+  return combined;
+}
+
 /* Print the system error message for errno, and also mention STRING
    as the file name for which the error was encountered.  Use ERRCODE
    for the thrown exception.  Then return to command level.  */
@@ -964,14 +984,10 @@ add_internal_problem_command (struct internal_problem *problem)
 void
 throw_perror_with_name (enum errors errcode, const char *string)
 {
-  char *err;
   char *combined;
 
-  err = safe_strerror (errno);
-  combined = (char *) alloca (strlen (err) + strlen (string) + 3);
-  strcpy (combined, string);
-  strcat (combined, ": ");
-  strcat (combined, err);
+  combined = perror_string (string);
+  make_cleanup (xfree, combined);
 
   /* I understand setting these is a matter of taste.  Still, some people
      may clear errno but not know about bfd_error.  Doing this here is not