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Best way to access $_SERVER variables from c?

php.internals

Glenn Richmond

19 years ago

Hi All,

I apologize if this is an extremely straight-forward question, but I'm
trying to access the SERVER_NAME  variable from PHP source (a tweak to
protect against accessing disallowed directory paths in a shared
environment without enabling safe mode). I've got the following code:

if
(zend_hash_find(PG(http_globals)[TRACK_VARS_SERVER]->value.ht,
"SERVER_NAME", sizeof("SERVER_NAME"), (void **) &server_name) !=
FAILURE) {
// Got server name
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Base directory:
%s, %s, %s", basedir, path, server_name);
return 0;
} else {
// Unable to find server name
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Unable to find
server_name hash.");
return 0;
}


However, the value that is reported as SERVER_NAME appears to be
giberish (the call succeeds, but the value doesn't make sense). I'm
getting "lEÊ·èEÊ·EÊ·" for the value of the server name. Any idea what
is going on here? I've also tried the get_env function without success,
but I'm guessing this is only valid when running as a CGI script as
opposed to mod_php5.

Note that I'm just using the php_error_docref as debugging output at
this point.

Regards,

Glenn.

Glenn Richmond

19 years ago

ok, worked it out - after a day and a half of trying to get it working,
it hits me just after I post! Didn't realize the values were coming back
as php hashes. For future newbie reference, here's the working code:

zval **server_name = NULL;
char* lookup_server_name;

if (strcmp(basedir, "VIRTUAL_DOCUMENT_ROOT") == 0) {
if (!PG(http_globals)[TRACK_VARS_SERVER] ||
zend_hash_find(PG(http_globals)[TRACK_VARS_SERVER]->value.ht,
"SERVER_NAME", sizeof("SERVER_NAME"), (void **) &server_name) == FAILURE) {
// Unable to find server name
php_error_docref(NULL TSRMLS_CC, E_WARNING, "SERVER_NAME
variable is not set, cannot determine server name.");
return 0;
} else {
// Convert the hash to a string
convert_to_string_ex(server_name);
// Convert the hash value to a char* for c processing
lookup_server_name = estrndup(Z_STRVAL_PP(server_name),
Z_STRLEN_PP(server_name));
// Non-zero result, error occured
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Base directory:
%s, %s, %s", basedir, path, lookup_server_name);
return 0;
}
}

Glenn Richmond wrote:

Pierre Joye

19 years ago

Hi Glenn,

On 11/21/06, Glenn Richmond <glenn.richmond@ilisys.com.au> wrote:

> ok, worked it out - after a day and a half of trying to get it working,
> it hits me just after I post! Didn't realize the values were coming back
> as php hashes. For future newbie reference, here's the working code:
>
> zval **server_name = NULL;
> char* lookup_server_name;
>
>     if (strcmp(basedir, "VIRTUAL_DOCUMENT_ROOT") == 0) {
>         if (!PG(http_globals)[TRACK_VARS_SERVER] ||
> zend_hash_find(PG(http_globals)[TRACK_VARS_SERVER]->value.ht,
> "SERVER_NAME", sizeof("SERVER_NAME"), (void **) &server_name) == FAILURE)

You can use the HASH_OF macro, a bit cleaner :

if (zend_hash_find(HASH_OF(PG(http_globals)[TRACK_VARS_SERVER]),
"SERVER_NAME", sizeof("SERVER_NAME"), (void **) &server_name) ==
SUCCESS) {
...
}

--Pierre