[PING2][PATCH] iconvconfig: Fix behaviour with --prefix [BZ #28199]

[Siddhesh Poyarekar]

Ping!

On 8/17/21 8:28 AM, Siddhesh Poyarekar wrote:
> Ping!
> 
> On 8/9/21 11:57 AM, Siddhesh Poyarekar via Libc-alpha wrote:
>> The consolidation of configuration parsing broke behaviour with
>> --prefix, where the prefix bled into the modules cache.  Accept a
>> prefix which, when non-NULL, is prepended to the path when looking for
>> configuration files but only the original directory is added to the
>> modules cache.
>>
>> This has no effect on the codegen of gconv_conf since it passes NULL.
>>
>> Reported-by: Patrick McCarty <patrick.mccarty@intel.com>
>> Reported-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
>> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
>> ---
>>   iconv/gconv_conf.c         |  2 +-
>>   iconv/gconv_parseconfdir.h | 21 +++++++++++++++------
>>   iconv/iconvconfig.c        | 16 ++++++++++++----
>>   3 files changed, 28 insertions(+), 11 deletions(-)
>>
>> diff --git a/iconv/gconv_conf.c b/iconv/gconv_conf.c
>> index 62bee28769..cc391d8f93 100644
>> --- a/iconv/gconv_conf.c
>> +++ b/iconv/gconv_conf.c
>> @@ -478,7 +478,7 @@ __gconv_read_conf (void)
>>     __gconv_get_path ();
>>     for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
>> -    gconv_parseconfdir (__gconv_path_elem[cnt].name,
>> +    gconv_parseconfdir (NULL, __gconv_path_elem[cnt].name,
>>               __gconv_path_elem[cnt].len);
>>   #endif
>> diff --git a/iconv/gconv_parseconfdir.h b/iconv/gconv_parseconfdir.h
>> index 2f062689ec..38ffa9353a 100644
>> --- a/iconv/gconv_parseconfdir.h
>> +++ b/iconv/gconv_parseconfdir.h
>> @@ -38,8 +38,9 @@
>>   /* Name of the file containing the module information in the 
>> directories
>>      along the path.  */
>> -static const char gconv_conf_filename[] = "gconv-modules";
>> -static const char gconv_conf_dirname[] = "gconv-modules.d";
>> +#define GCONV_CONF_FILENAME "gconv-modules"
>> +static const char gconv_conf_filename[] = GCONV_CONF_FILENAME;
>> +static const char gconv_conf_dirname[] = GCONV_CONF_FILENAME ".d";
>>   static void add_alias (char *);
>>   static void add_module (char *, const char *, size_t, int);
>> @@ -110,19 +111,27 @@ read_conf_file (const char *filename, const char 
>> *directory, size_t dir_len)
>>     return true;
>>   }
>> +/* Prefix DIR (with length DIR_LEN) with PREFIX if the latter is 
>> non-NULL and
>> +   parse configuration in it.  */
>> +
>>   static __always_inline bool
>> -gconv_parseconfdir (const char *dir, size_t dir_len)
>> +gconv_parseconfdir (const char *prefix, const char *dir, size_t dir_len)
>>   {
>>     /* No slash needs to be inserted between dir and gconv_conf_filename;
>>        dir already ends in a slash.  */
>> -  char *buf = malloc (dir_len + sizeof (gconv_conf_dirname));
>> +  size_t buflen = dir_len + sizeof (gconv_conf_dirname);
>> +  char *buf = malloc (buflen + (prefix != NULL ? strlen (prefix) : 0));
>> +  char *cp = buf;
>>     bool found = false;
>>     if (buf == NULL)
>>       return false;
>> -  char *cp = mempcpy (mempcpy (buf, dir, dir_len), gconv_conf_filename,
>> -              sizeof (gconv_conf_filename));
>> +  if (prefix != NULL)
>> +    cp = stpcpy (cp, prefix);
>> +
>> +  cp = mempcpy (mempcpy (cp, dir, dir_len), gconv_conf_filename,
>> +        sizeof (gconv_conf_filename));
>>     /* Read the gconv-modules configuration file first.  */
>>     found = read_conf_file (buf, dir, dir_len);
>> diff --git a/iconv/iconvconfig.c b/iconv/iconvconfig.c
>> index 783b2bbdbb..273a71f673 100644
>> --- a/iconv/iconvconfig.c
>> +++ b/iconv/iconvconfig.c
>> @@ -653,13 +653,21 @@ add_module (char *rp, const char *directory,
>>   static int
>>   handle_dir (const char *dir)
>>   {
>> +  char *newp = NULL;
>>     size_t dirlen = strlen (dir);
>>     bool found = false;
>> -  char *fulldir = xasprintf ("%s%s%s", dir[0] == '/' ? prefix : "",
>> -                 dir, dir[dirlen - 1] != '/' ? "/" : "");
>> +  /* End directory path with a '/' if it doesn't already.  */
>> +  if (dir[dirlen - 1] != '/')
>> +    {
>> +      newp = xmalloc (dirlen + 2);
>> +      memcpy (newp, dir, dirlen);
>> +      newp[dirlen++] = '/';
>> +      newp[dirlen] = '\0';
>> +      dir = newp;
>> +    }
>> -  found = gconv_parseconfdir (fulldir, strlen (fulldir));
>> +  found = gconv_parseconfdir (dir[0] == '/' ? prefix : NULL, dir, 
>> dirlen);
>>     if (!found)
>>       {
>> @@ -671,7 +679,7 @@ handle_dir (const char *dir)
>>            "configuration files with names ending in .conf.");
>>       }
>> -  free (fulldir);
>> +  free (newp);
>>     return found ? 0 : 1;
>>   }
>>
>