exchange/src/mhd/mhd_legal.c

610 lines
16 KiB
C

/*
This file is part of TALER
Copyright (C) 2019, 2020 Taler Systems SA
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file mhd_legal.c
* @brief API for returning legal documents based on client language
* and content type preferences
* @author Christian Grothoff
*/
#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <jansson.h>
#include <microhttpd.h>
#include "taler_util.h"
#include "taler_mhd_lib.h"
/**
* Entry in the terms-of-service array.
*/
struct Terms
{
/**
* Kept in a DLL.
*/
struct Terms *prev;
/**
* Kept in a DLL.
*/
struct Terms *next;
/**
* Mime type of the terms.
*/
const char *mime_type;
/**
* The terms (NOT 0-terminated!), mmap()'ed. Do not free,
* use munmap() instead.
*/
void *terms;
/**
* The desired language.
*/
char *language;
/**
* deflated @e terms, to return if client supports deflate compression.
* malloc()'ed. NULL if @e terms does not compress.
*/
void *compressed_terms;
/**
* Number of bytes in @e terms.
*/
size_t terms_size;
/**
* Number of bytes in @e compressed_terms.
*/
size_t compressed_terms_size;
/**
* Sorting key by format preference in case
* everything else is equal. Higher is preferred.
*/
unsigned int priority;
};
/**
* Prepared responses for legal documents
* (terms of service, privacy policy).
*/
struct TALER_MHD_Legal
{
/**
* DLL of terms of service.
*/
struct Terms *terms_head;
/**
* DLL of terms of service.
*/
struct Terms *terms_tail;
/**
* Etag to use for the terms of service (= version).
*/
char *terms_etag;
};
/**
* Check if @a mime matches the @a accept_pattern.
*
* @param accept_pattern a mime pattern like "text/plain"
* or "image/STAR"
* @param mime the mime type to match
* @return true if @a mime matches the @a accept_pattern
*/
static bool
mime_matches (const char *accept_pattern,
const char *mime)
{
const char *da = strchr (accept_pattern, '/');
const char *dm = strchr (mime, '/');
if ( (NULL == da) ||
(NULL == dm) )
return (0 == strcmp ("*", accept_pattern));
return
( ( (1 == da - accept_pattern) &&
('*' == *accept_pattern) ) ||
( (da - accept_pattern == dm - mime) &&
(0 == strncasecmp (accept_pattern,
mime,
da - accept_pattern)) ) ) &&
( (0 == strcmp (da, "/*")) ||
(0 == strcasecmp (da,
dm)) );
}
bool
TALER_MHD_xmime_matches (const char *accept_pattern,
const char *mime)
{
char *ap = GNUNET_strdup (accept_pattern);
char *sptr;
for (const char *tok = strtok_r (ap, ";", &sptr);
NULL != tok;
tok = strtok_r (NULL, ";", &sptr))
{
if (mime_matches (tok,
mime))
{
GNUNET_free (ap);
return true;
}
}
GNUNET_free (ap);
return false;
}
MHD_RESULT
TALER_MHD_reply_legal (struct MHD_Connection *conn,
struct TALER_MHD_Legal *legal)
{
struct MHD_Response *resp;
struct Terms *t;
if (NULL != legal)
{
const char *etag;
etag = MHD_lookup_connection_value (conn,
MHD_HEADER_KIND,
MHD_HTTP_HEADER_IF_NONE_MATCH);
if ( (NULL != etag) &&
(NULL != legal->terms_etag) &&
(0 == strcasecmp (etag,
legal->terms_etag)) )
{
MHD_RESULT ret;
resp = MHD_create_response_from_buffer (0,
NULL,
MHD_RESPMEM_PERSISTENT);
TALER_MHD_add_global_headers (resp);
ret = MHD_queue_response (conn,
MHD_HTTP_NOT_MODIFIED,
resp);
GNUNET_break (MHD_YES == ret);
MHD_destroy_response (resp);
return ret;
}
}
t = NULL;
if (NULL != legal)
{
const char *mime;
const char *lang;
mime = MHD_lookup_connection_value (conn,
MHD_HEADER_KIND,
MHD_HTTP_HEADER_ACCEPT);
if (NULL == mime)
mime = "text/html";
lang = MHD_lookup_connection_value (conn,
MHD_HEADER_KIND,
MHD_HTTP_HEADER_ACCEPT_LANGUAGE);
if (NULL == lang)
lang = "en";
/* Find best match: must match mime type (if possible), and if
mime type matches, ideally also language */
for (struct Terms *p = legal->terms_head;
NULL != p;
p = p->next)
{
if ( (NULL == t) ||
(TALER_MHD_xmime_matches (mime,
p->mime_type)) )
{
if ( (NULL == t) ||
(! TALER_MHD_xmime_matches (mime,
t->mime_type)) ||
(TALER_language_matches (lang,
p->language) >
TALER_language_matches (lang,
t->language) ) )
t = p;
}
}
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Best match for %s/%s: %s / %s\n",
lang,
mime,
(NULL != t) ? t->mime_type : "<none>",
(NULL != t) ? t->language : "<none>");
}
if (NULL == t)
{
/* Default terms of service if none are configured */
static struct Terms none = {
.mime_type = "text/plain",
.terms = "not configured",
.language = "en",
.terms_size = strlen ("not configured")
};
t = &none;
}
/* try to compress the response */
resp = NULL;
if (MHD_YES ==
TALER_MHD_can_compress (conn))
{
resp = MHD_create_response_from_buffer (t->compressed_terms_size,
t->compressed_terms,
MHD_RESPMEM_PERSISTENT);
if (MHD_NO ==
MHD_add_response_header (resp,
MHD_HTTP_HEADER_CONTENT_ENCODING,
"deflate"))
{
GNUNET_break (0);
MHD_destroy_response (resp);
resp = NULL;
}
}
if (NULL == resp)
{
/* could not generate compressed response, return uncompressed */
resp = MHD_create_response_from_buffer (t->terms_size,
(void *) t->terms,
MHD_RESPMEM_PERSISTENT);
}
TALER_MHD_add_global_headers (resp);
if (NULL != legal)
GNUNET_break (MHD_YES ==
MHD_add_response_header (resp,
MHD_HTTP_HEADER_ETAG,
legal->terms_etag));
GNUNET_break (MHD_YES ==
MHD_add_response_header (resp,
MHD_HTTP_HEADER_CONTENT_TYPE,
t->mime_type));
{
MHD_RESULT ret;
ret = MHD_queue_response (conn,
MHD_HTTP_OK,
resp);
MHD_destroy_response (resp);
return ret;
}
}
/**
* Load all the terms of service from @a path under language @a lang
* from file @a name
*
* @param[in,out] legal where to write the result
* @param path where the terms are found
* @param lang which language directory to crawl
* @param name specific file to access
*/
static void
load_terms (struct TALER_MHD_Legal *legal,
const char *path,
const char *lang,
const char *name)
{
static struct MimeMap
{
const char *ext;
const char *mime;
unsigned int priority;
} mm[] = {
{ .ext = ".html", .mime = "text/html", .priority = 100 },
{ .ext = ".htm", .mime = "text/html", .priority = 99 },
{ .ext = ".txt", .mime = "text/plain", .priority = 50 },
{ .ext = ".pdf", .mime = "application/pdf", .priority = 25 },
{ .ext = ".jpg", .mime = "image/jpeg" },
{ .ext = ".jpeg", .mime = "image/jpeg" },
{ .ext = ".png", .mime = "image/png" },
{ .ext = ".gif", .mime = "image/gif" },
{ .ext = ".epub", .mime = "application/epub+zip", .priority = 10 },
{ .ext = ".xml", .mime = "text/xml", .priority = 10 },
{ .ext = NULL, .mime = NULL }
};
const char *ext = strrchr (name, '.');
const char *mime;
unsigned int priority;
if (NULL == ext)
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Unsupported file `%s' in directory `%s/%s': lacks extension\n",
name,
path,
lang);
return;
}
if ( (NULL == legal->terms_etag) ||
(0 != strncmp (legal->terms_etag,
name,
ext - name - 1)) )
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Filename `%s' does not match Etag `%s' in directory `%s/%s'. Ignoring it.\n",
name,
legal->terms_etag,
path,
lang);
return;
}
mime = NULL;
for (unsigned int i = 0; NULL != mm[i].ext; i++)
if (0 == strcasecmp (mm[i].ext,
ext))
{
mime = mm[i].mime;
priority = mm[i].priority;
break;
}
if (NULL == mime)
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Unsupported file extension `%s' of file `%s' in directory `%s/%s'\n",
ext,
name,
path,
lang);
return;
}
/* try to read the file with the terms of service */
{
struct stat st;
char *fn;
int fd;
GNUNET_asprintf (&fn,
"%s/%s/%s",
path,
lang,
name);
fd = open (fn, O_RDONLY);
if (-1 == fd)
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"open",
fn);
GNUNET_free (fn);
return;
}
if (0 != fstat (fd, &st))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"fstat",
fn);
GNUNET_break (0 == close (fd));
GNUNET_free (fn);
return;
}
if (SIZE_MAX < ((unsigned long long) st.st_size))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"fstat-size",
fn);
GNUNET_break (0 == close (fd));
GNUNET_free (fn);
return;
}
{
void *buf;
size_t bsize;
bsize = (size_t) st.st_size;
buf = mmap (NULL,
bsize,
PROT_READ,
MAP_SHARED,
fd,
0);
if (MAP_FAILED == buf)
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"mmap",
fn);
GNUNET_break (0 == close (fd));
GNUNET_free (fn);
return;
}
GNUNET_break (0 == close (fd));
GNUNET_free (fn);
/* insert into global list of terms of service */
{
struct Terms *t;
t = GNUNET_new (struct Terms);
t->mime_type = mime;
t->terms = buf;
t->language = GNUNET_strdup (lang);
t->terms_size = bsize;
t->priority = priority;
buf = GNUNET_memdup (t->terms,
t->terms_size);
if (TALER_MHD_body_compress (&buf,
&bsize))
{
t->compressed_terms = buf;
t->compressed_terms_size = bsize;
}
else
{
GNUNET_free (buf);
}
{
struct Terms *prev = NULL;
for (struct Terms *pos = legal->terms_head;
NULL != pos;
pos = pos->next)
{
if (pos->priority < priority)
break;
prev = pos;
}
GNUNET_CONTAINER_DLL_insert_after (legal->terms_head,
legal->terms_tail,
prev,
t);
}
}
}
}
}
/**
* Load all the terms of service from @a path under language @a lang.
*
* @param[in,out] legal where to write the result
* @param path where the terms are found
* @param lang which language directory to crawl
*/
static void
load_language (struct TALER_MHD_Legal *legal,
const char *path,
const char *lang)
{
char *dname;
DIR *d;
GNUNET_asprintf (&dname,
"%s/%s",
path,
lang);
d = opendir (dname);
if (NULL == d)
{
GNUNET_free (dname);
return;
}
for (struct dirent *de = readdir (d);
NULL != de;
de = readdir (d))
{
const char *fn = de->d_name;
if (fn[0] == '.')
continue;
load_terms (legal, path, lang, fn);
}
GNUNET_break (0 == closedir (d));
GNUNET_free (dname);
}
struct TALER_MHD_Legal *
TALER_MHD_legal_load (const struct GNUNET_CONFIGURATION_Handle *cfg,
const char *section,
const char *diroption,
const char *tagoption)
{
struct TALER_MHD_Legal *legal;
char *path;
DIR *d;
legal = GNUNET_new (struct TALER_MHD_Legal);
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_string (cfg,
section,
tagoption,
&legal->terms_etag))
{
GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
section,
tagoption);
GNUNET_free (legal);
return NULL;
}
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_filename (cfg,
section,
diroption,
&path))
{
GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
section,
diroption);
GNUNET_free (legal->terms_etag);
GNUNET_free (legal);
return NULL;
}
d = opendir (path);
if (NULL == d)
{
GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING,
section,
diroption,
"Could not open directory");
GNUNET_free (legal->terms_etag);
GNUNET_free (legal);
GNUNET_free (path);
return NULL;
}
for (struct dirent *de = readdir (d);
NULL != de;
de = readdir (d))
{
const char *lang = de->d_name;
if (lang[0] == '.')
continue;
load_language (legal, path, lang);
}
GNUNET_break (0 == closedir (d));
GNUNET_free (path);
return legal;
}
void
TALER_MHD_legal_free (struct TALER_MHD_Legal *legal)
{
struct Terms *t;
if (NULL == legal)
return;
while (NULL != (t = legal->terms_head))
{
GNUNET_free (t->language);
GNUNET_free (t->compressed_terms);
if (0 != munmap (t->terms, t->terms_size))
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"munmap");
GNUNET_CONTAINER_DLL_remove (legal->terms_head,
legal->terms_tail,
t);
GNUNET_free (t);
}
GNUNET_free (legal->terms_etag);
GNUNET_free (legal);
}