[PATCH 2/2] Simplify string concatenation in poke.c.

[Tim Rühsen]

This also removes stack allocation of unchecked input strings,
which could lead to stack overflow.

2020-04-06  Tim Rühsen  <address@hidden>

        * src/poke.c (initialize): Use str_concat instead of
        strlen/xmalloc/strcpy/strcat.
        (initialize_user): Likewise.
---
 ChangeLog  |  6 ++++++
 src/poke.c | 35 ++++++++++++-----------------------
 2 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 92d21ae6..4323a998 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-06  Tim Rühsen  <address@hidden>
+
+       * src/poke.c (initialize): Use str_concat instead of
+       strlen/xmalloc/strcpy/strcat.
+       (initialize_user): Likewise.
+
 2020-04-06  Tim Rühsen  <address@hidden>

        * bootstrap.conf: Add gnulib module stdarg.
diff --git a/src/poke.c b/src/poke.c
index 3508f781..b67720eb 100644
--- a/src/poke.c
+++ b/src/poke.c
@@ -39,6 +39,7 @@
 #include "pk-repl.h"
 #include "pk-term.h"
 #include "poke.h"
+#include "utils.h"

 /* poke can be run either interactively (from a tty) or in batch mode.
    The following predicate records this.  */
@@ -396,13 +397,11 @@ initialize (int argc, char *argv[])
   poke_compiler = pkl_new (poke_vm, poke_datadir);
   /* XXX: use pkl_load here.  */
   {
-    char *poke_std_pk;
+    char *poke_std_pk = str_concat (poke_datadir, "/std.pk", NULL);

-    poke_std_pk = xmalloc (strlen (poke_datadir) + strlen ("/std.pk") + 1);
-    strcpy (poke_std_pk, poke_datadir);
-    strcat (poke_std_pk, "/std.pk");
     if (!pkl_compile_file (poke_compiler, poke_std_pk))
       exit (EXIT_FAILURE);
+
     free (poke_std_pk);
   }

@@ -432,11 +431,7 @@ initialize_user ()
   if (homedir != NULL)
     {
       int ret;
-      char *pokerc;
-
-      pokerc = alloca (strlen (homedir) + strlen ("/.pokerc") + 1);
-      strcpy (pokerc, homedir);
-      strcat (pokerc, "/.pokerc");
+      char *pokerc = str_concat (homedir, "/.pokerc", NULL);

       if (pk_file_readable (pokerc) == NULL)
         {
@@ -446,6 +441,8 @@ initialize_user ()
           else
             return;
         }
+
+      free (pokerc);
     }

   /* If no ~/.pokerc file was found, acknowledge the XDG Base
@@ -468,30 +465,18 @@ initialize_user ()
     if (xdg_config_dirs == NULL)
       xdg_config_dirs = "/etc/xdg";

-    char *config_path = alloca (strlen (xdg_config_dirs)
-                                + 1 /* : */
-                                + strlen (xdg_config_home)
-                                + 1);
-    strcpy (config_path, xdg_config_dirs);
-    strcat (config_path, ":");
-    strcat (config_path, xdg_config_home);
+    char *config_path = str_concat (xdg_config_dirs, ":", xdg_config_home, 
NULL);

     char *dir = strtok (config_path, ":");
     do
       {
-        char *config_filename = NULL;
-
         /* Ignore empty entries.  */
         if (*dir == '\0')
           continue;

         /* Mount the full path and determine whether the resulting
            file is readable. */
-        config_filename = alloca (strlen (dir)
-                                  + strlen ("/poke/pokerc.conf")
-                                  + 1);
-        strcpy (config_filename, dir);
-        strcat (config_filename, "/poke/pokerc.conf");
+        char *config_filename = str_concat (dir, "/poke/pokerc.conf", NULL);

         if (pk_file_readable (config_filename) == NULL)
           {
@@ -501,8 +486,12 @@ initialize_user ()
               exit (EXIT_FAILURE);
             break;
           }
+
+        free (config_filename);
       }
     while ((dir = strtok (NULL, ":")) != NULL);
+
+    free (config_path);
   }
 }

--
2.26.0