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/*!
* @file main.c
* @brief Source of the `sternenblog.cgi` executable
*/
/*!
* @mainpage sternenblog
*
* sternenblog is a file based blog software written in C for CGI.
*
* @section user_doc User documentation
*
* For user documentation and information on
* configuring `sternenblog` refer to
* `man sternenblog.cgi(1)` and config.example.h.
*
* @section dev_doc Developer documentation
*
* @subsection tpl_doc Templating
*
* A template is a single C file implementing all the
* functions declared in template.h. The documentation
* for the header file also includes detailed explanation
* of what every function must do. For inspiration, read through the
* @subpage example_template "default template", `templates/simple.c`.
*
* To change the template sternenblog is using set `TEMPLATE`
* in `config.mk` to the absolute or relative path to your
* template's C file with the `.c` extension omitted.
*
* @subsection xml_doc XML Output Library
*
* sternenblog includes a small library for outputting XML
* which is useful in an CGI environment. You can use this
* library in your template using the following include:
*
* ```
* #include <xml.h>
* ```
*
* Its usage and features are documented in xml.h.
*
* sternenblog uses xml.h internally for generating its
* rss feed and its default template.
*
* @subsection cgi_doc CGI Helpers
*
* cgiutil.h includes a few simple helpers for CGI.
*
* @subsection int_doc Internals
*
* core.h defines the central type of sternenblog, `struct entry`.
* Entries is essentially all sternenblog knows and handles.
* It either builds an index (listing) of them using `make_index()`
* from index.h or gets a single one using `make_entry()` from entry.h
* and serves the result to the user.
*
* This happens either via a RSS feed generated using `blog_rss()`
* or as html pages which are generated by `blog_index()` and
* `blog_entry()` calling the template functions defined in template.h.
*
* For a more detailed explanation than this overview read the documentation
* of main.c and the header files mentioned here. The source code should
* also be a good source of insight if you want to dig deeper.
*
* @page example_template Example template
*
* This is the default template sternenblog uses. It is pretty
* simple and can serve as a good reference point. It utilizes
* sternenblog-specific exposed functions from xml.h and
* `http_status_line()` from cgiutil.h.
*
* @include simple.c
*
*/
#define _POSIX_C_SOURCE 200809L
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <pwd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include "core.h"
#include "config.h"
#include "cgiutil.h"
#include "entry.h"
#include "index.h"
#include "stringutil.h"
#include "timeutil.h"
#include "template.h"
#include "xml.h"
void send_standard_headers(int status, char content_type[]);
/*!
* @brief Outputs the CGI response for the index page of the blog
*
* This function is called if `PATH_INFO` is `/` or empty.
*
* @see template_index_entry
* @see make_index
*/
void blog_index(char script_name[]);
/*!
* @brief Outputs the CGI response for a single entry
*
* Called if no other special routes are found (index, RSS feed).
* If `make_entry()` succeeds, the page for the entry is displayed
* using `template_single_entry()`. If an error occurs,
* `template_error()` is used.
*
* @see make_entry
* @see template_single_entry
* @see template_error
*/
void blog_entry(char script_name[], char path_info[]);
/*!
* @brief Outputs the CGI response for the blog's RSS feed
*
* This function is called if `PATH_INFO` is `/rss.xml`.
*
* @see make_index
* @see blog_atom
*/
void blog_rss(char script_name[]);
/*!
* @brief Outputs the CGI response for the blog's Atom feed
*
* This function is called if `PATH_INFO` is `/atom.xml`.
*
* @see make_index
* @see blog_rss
*/
void blog_atom(char script_name[]);
/*!
* @brief Implements routing of requests
*
* @see blog_index
* @see blog_rss
* @see blog_entry
*/
int main(void) {
char *path_info = getenv("PATH_INFO");
char *script_name = getenv("SCRIPT_NAME");
if(script_name == NULL) {
fputs("Missing SCRIPT_NAME", stderr);
send_standard_headers(500, "text/html");
template_header();
template_error(500);
template_footer();
return EXIT_SUCCESS;
}
if(path_info == NULL || path_info[0] == '\0' || strcmp(path_info, "/") == 0) {
blog_index(script_name);
} else if(strcmp(path_info, "/rss.xml") == 0) {
blog_rss(script_name);
} else if(strcmp(path_info, "/atom.xml") == 0) {
blog_atom(script_name);
} else {
blog_entry(script_name, path_info);
}
return EXIT_SUCCESS;
}
void send_standard_headers(int status, char content_type[]) {
send_header("Status", http_status_line(status));
send_header("Content-type", content_type);
#ifdef BLOG_CACHE_MAX_AGE
// TODO correct sized buffer, no snprintf
char max_age[256];
int result = snprintf(max_age, sizeof max_age, "max-age=%d", BLOG_CACHE_MAX_AGE);
// make sure there won't be a buffer overrun
max_age[sizeof max_age - 1] = '\0';
if(result > 0) {
send_header("Cache-Control", max_age);
}
#endif
terminate_headers();
}
void blog_index(char script_name[]) {
struct entry *entries = NULL;
int count = make_index(BLOG_DIR, script_name, 0, &entries);
if(count < 0) {
send_standard_headers(500, "text/html");
template_header();
template_error(500);
template_footer();
} else {
send_standard_headers(200, "text/html");
template_header();
for(int i = 0; i < count; i++) {
if(entry_get_text(&entries[i]) != -1) {
template_index_entry(entries[i]);
entry_unget_text(&entries[i]);
}
}
template_footer();
free_index(&entries, count);
}
}
void blog_entry(char script_name[], char path_info[]) {
struct entry entry;
int status = make_entry(BLOG_DIR, script_name, path_info, &entry);
if(status == 200 && entry_get_text(&entry) == -1) {
status = 500;
}
send_standard_headers(status, "text/html");
if(status != 200) {
template_header();
template_error(status);
template_footer();
} else {
template_header();
template_single_entry(entry);
template_footer();
}
free_entry(&entry);
}
void blog_rss(char script_name[]) {
// index
struct entry *entries = NULL;
int count = make_index(BLOG_DIR, script_name, 0, &entries);
if(count < 0) {
send_standard_headers(500, "text/plain");
puts("Internal Server Error");
return;
}
send_standard_headers(200, "application/rss+xml");
struct xml_context ctx;
new_xml_context(&ctx);
xml_raw(&ctx, "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>");
xml_open_tag_attrs(&ctx, "rss", 2, "version", "2.0", "xmlns:atom", "http://www.w3.org/2005/Atom");
xml_open_tag(&ctx, "channel");
xml_open_tag(&ctx, "title");
xml_escaped(&ctx, BLOG_TITLE);
xml_close_tag(&ctx, "title");
xml_open_tag(&ctx, "description");
xml_open_cdata(&ctx);
xml_raw(&ctx, BLOG_DESCRIPTION);
xml_close_cdata(&ctx);
xml_close_tag(&ctx, "description");
char *external_url = server_url(BLOG_USE_HTTPS);
if(external_url != NULL) {
xml_open_tag(&ctx, "link");
xml_escaped(&ctx, external_url);
xml_escaped(&ctx, script_name);
xml_close_tag(&ctx, "link");
}
if(count > 0) {
time_t update_time = entries[0].time;
char strtime_update[MAX_TIMESTR_SIZE];
if(flocaltime(strtime_update, RSS_TIME_FORMAT, MAX_TIMESTR_SIZE, &update_time) > 0) {
xml_open_tag(&ctx, "lastBuildDate");
xml_escaped(&ctx, strtime_update);
xml_close_tag(&ctx, "lastBuildDate");
}
}
if(external_url != NULL) {
char *rss_link = catn_alloc(3, external_url, script_name, "/rss.xml");
if(rss_link != NULL) {
xml_empty_tag(&ctx, "atom:link", 3,
"rel", "self",
"href", rss_link,
"type", "application/rss+xml");
free(rss_link);
}
}
for(int i = 0; i < count; i++) {
if(entry_get_text(&entries[i]) != -1) {
xml_open_tag(&ctx, "item");
xml_open_tag(&ctx, "title");
xml_escaped(&ctx, entries[i].title);
xml_close_tag(&ctx, "title");
if(external_url != NULL) {
xml_open_tag(&ctx, "link");
xml_escaped(&ctx, external_url);
xml_escaped(&ctx, entries[i].link);
xml_close_tag(&ctx, "link");
xml_open_tag(&ctx, "guid");
xml_escaped(&ctx, external_url);
xml_escaped(&ctx, entries[i].link);
xml_close_tag(&ctx, "guid");
}
if(entries[i].text_size > 0) {
xml_open_tag(&ctx, "description");
xml_open_cdata(&ctx);
xml_raw(&ctx, entries[i].text);
xml_close_cdata(&ctx);
xml_close_tag(&ctx, "description");
}
char strtime_entry[MAX_TIMESTR_SIZE];
if(flocaltime(strtime_entry, RSS_TIME_FORMAT, MAX_TIMESTR_SIZE, &entries[i].time) > 0) {
xml_open_tag(&ctx, "pubDate");
xml_escaped(&ctx, strtime_entry);
xml_close_tag(&ctx, "pubDate");
}
xml_close_tag(&ctx, "item");
entry_unget_text(&entries[i]);
}
}
xml_close_all(&ctx);
free(external_url);
free_index(&entries, count);
del_xml_context(&ctx);
}
void blog_atom(char script_name[]) {
struct entry *entries = NULL;
int count = make_index(BLOG_DIR, script_name, 0, &entries);
if(count < 0) {
send_standard_headers(500, "text/plain");
puts("Internal Server Error");
free_index(&entries, count);
return;
}
struct xml_context ctx;
new_xml_context(&ctx);
char *external_url = server_url(BLOG_USE_HTTPS);
char *self_url = catn_alloc(3, external_url, script_name, "/atom.xml");
char *html_url = catn_alloc(2, external_url, script_name);
send_standard_headers(200, "application/atom+xml");
xml_raw(&ctx, "<?xml version=\"1.0\" encoding=\"utf-8\"?>");
xml_open_tag_attrs(&ctx, "feed", 1, "xmlns", "http://www.w3.org/2005/Atom");
xml_open_tag(&ctx, "title");
xml_escaped(&ctx, BLOG_TITLE);
xml_close_tag(&ctx, "title");
if(self_url != NULL) {
xml_open_tag(&ctx, "id");
xml_escaped(&ctx, self_url);
xml_close_tag(&ctx, "id");
xml_empty_tag(&ctx, "link", 2, "rel", "self", "href", self_url);
free(self_url);
}
if(html_url != NULL) {
xml_empty_tag(&ctx, "link", 3, "rel", "alternate", "type", "text/html", "href", html_url);
// freed after author element
}
xml_open_tag(&ctx, "author");
xml_open_tag(&ctx, "name");
#ifdef BLOG_AUTHOR
xml_escaped(&ctx, BLOG_AUTHOR);
#else
struct passwd *user;
uid_t uid = geteuid();
user = getpwuid(uid);
xml_escaped(&ctx, user->pw_name);
#endif
xml_close_tag(&ctx, "name");
if(html_url != NULL) {
xml_open_tag(&ctx, "uri");
xml_escaped(&ctx, html_url);
xml_close_tag(&ctx, "uri");
free(html_url);
}
xml_close_tag(&ctx, "author");
if(count > 0) {
time_t update_time = entries[0].time;
char strtime_update[MAX_TIMESTR_SIZE];
if(flocaltime(strtime_update, ATOM_TIME_FORMAT, MAX_TIMESTR_SIZE, &update_time) > 0) {
xml_open_tag(&ctx, "updated");
xml_escaped(&ctx, strtime_update);
xml_close_tag(&ctx, "updated");
}
}
for(int i = 0; i < count; i++) {
if(entry_get_text(&entries[i]) != -1) {
xml_open_tag(&ctx, "entry");
if(external_url != NULL) {
xml_open_tag(&ctx, "id");
xml_escaped(&ctx, external_url);
xml_escaped(&ctx, entries[i].link);
xml_close_tag(&ctx, "id");
}
xml_open_tag(&ctx, "title");
xml_escaped(&ctx, entries[i].title);
xml_close_tag(&ctx, "title");
char strtime_entry[MAX_TIMESTR_SIZE];
if(flocaltime(strtime_entry, ATOM_TIME_FORMAT, MAX_TIMESTR_SIZE, &entries[i].time) > 0) {
xml_open_tag(&ctx, "updated");
xml_escaped(&ctx, strtime_entry);
xml_close_tag(&ctx, "updated");
}
char *entry_url = catn_alloc(2, external_url, entries[i].link);
if(entry_url != NULL) {
xml_empty_tag(&ctx, "link", 3, "rel", "alternate", "type", "text/html", "href", entry_url);
free(entry_url);
}
xml_open_tag_attrs(&ctx, "content", 1, "type", "html");
xml_open_cdata(&ctx);
xml_raw(&ctx, entries[i].text);
xml_close_cdata(&ctx);
xml_close_tag(&ctx, "content");
xml_close_tag(&ctx, "entry");
entry_unget_text(&entries[i]);
}
}
xml_close_tag(&ctx, "feed");
free(external_url);
free_index(&entries, count);
del_xml_context(&ctx);
}
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