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

[Jose E. Marchesi]

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

This is OK for master, assumed str_concat is moved to pk-utils and
renamed.

Thanks! :)

    
    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