add blogmirror: static mirror of blog.sillylaird.camasterfront

Reads the blog's RSS feed (full post body lives in content:encoded) and
writes flat mothra-friendly HTML under html/ — an index plus one page per
post at YYYY/MM/DD/slug.html.

Plain ANSI C so it builds with APE pcc on 9front and cc elsewhere; fetches
with hget when present, curl otherwise. mirror.rc regenerates and pushes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YAgU4WFfVJKNK8CkpxhEcg

1 files changed, 424 insertions, 0 deletions

diff --git a/blogmirror.c b/blogmirror.c
new file mode 100644
index 0000000..a479386
--- /dev/null
+++ b/blogmirror.c
@@ -0,0 +1,424 @@
+/*
+ * blogmirror - mirror blog.sillylaird.ca into flat mothra-friendly HTML.
+ *
+ * Reads the blog's RSS 2.0 feed (which carries the full post body in
+ * <content:encoded>) and writes a static tree:
+ *
+ *	index.html			list of posts
+ *	YYYY/MM/DD/slug.html		one page per post
+ *
+ * Plain ANSI C: builds with pcc on 9front (APE) and with cc elsewhere.
+ *
+ *	blogmirror [-u url] [-f file] [-o outdir] [-n maxposts]
+ *
+ * With -f it parses a feed already on disk; otherwise it shells out to
+ * hget(1) (curl elsewhere) to fetch -u into a temporary file first.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#define FEEDURL	"https://blog.sillylaird.ca/feed.xml.php"
+#define SITE	"https://blog.sillylaird.ca/"
+#define TMPFEED	"/tmp/blogmirror.rss"
+
+static char *outdir = "html";
+static int maxposts = 0;		/* 0 = all */
+static int nposts = 0;
+
+static void *
+emalloc(size_t n)
+{
+	void *p = malloc(n);
+	if(p == NULL){
+		fprintf(stderr, "blogmirror: out of memory\n");
+		exit(1);
+	}
+	return p;
+}
+
+static char *
+estrdup(const char *s)
+{
+	char *p = emalloc(strlen(s) + 1);
+	strcpy(p, s);
+	return p;
+}
+
+/* bounded concatenation; returns 0 if it would not fit */
+static int
+cats(char *d, size_t n, const char *s)
+{
+	size_t have = strlen(d), want = strlen(s);
+
+	if(have + want + 1 > n)
+		return 0;
+	memcpy(d + have, s, want + 1);
+	return 1;
+}
+
+/* does this file exist? */
+static int
+exists(const char *path)
+{
+	FILE *f = fopen(path, "rb");
+
+	if(f == NULL)
+		return 0;
+	fclose(f);
+	return 1;
+}
+
+/* read a whole file, NUL terminated */
+static char *
+slurp(const char *path)
+{
+	FILE *f;
+	char *b;
+	long n;
+
+	if((f = fopen(path, "rb")) == NULL)
+		return NULL;
+	fseek(f, 0L, SEEK_END);
+	n = ftell(f);
+	rewind(f);
+	if(n < 0){
+		fclose(f);
+		return NULL;
+	}
+	b = emalloc((size_t)n + 1);
+	if(fread(b, 1, (size_t)n, f) != (size_t)n){
+		fclose(f);
+		free(b);
+		return NULL;
+	}
+	b[n] = '\0';
+	fclose(f);
+	return b;
+}
+
+/* text between open and close, starting at p, not past end.  malloc'd. */
+static char *
+between(char *p, char *end, const char *open, const char *close)
+{
+	char *a, *b, *s;
+	size_t n;
+
+	if((a = strstr(p, open)) == NULL || a >= end)
+		return NULL;
+	a += strlen(open);
+	if((b = strstr(a, close)) == NULL || b > end)
+		return NULL;
+	n = (size_t)(b - a);
+	s = emalloc(n + 1);
+	memcpy(s, a, n);
+	s[n] = '\0';
+	return s;
+}
+
+/* one UTF-8 rune out of a code point */
+static int
+putrune(char *d, long r)
+{
+	if(r < 0x80){
+		d[0] = (char)r;
+		return 1;
+	}
+	if(r < 0x800){
+		d[0] = (char)(0xC0 | (r >> 6));
+		d[1] = (char)(0x80 | (r & 0x3F));
+		return 2;
+	}
+	if(r < 0x10000){
+		d[0] = (char)(0xE0 | (r >> 12));
+		d[1] = (char)(0x80 | ((r >> 6) & 0x3F));
+		d[2] = (char)(0x80 | (r & 0x3F));
+		return 3;
+	}
+	d[0] = (char)(0xF0 | (r >> 18));
+	d[1] = (char)(0x80 | ((r >> 12) & 0x3F));
+	d[2] = (char)(0x80 | ((r >> 6) & 0x3F));
+	d[3] = (char)(0x80 | (r & 0x3F));
+	return 4;
+}
+
+/* &amp; &lt; &gt; &quot; &apos; &#39; &#x2019; -> text, in place */
+static char *
+unxml(char *s)
+{
+	char *r, *w;
+	long v;
+
+	if(s == NULL)
+		return NULL;
+	for(r = w = s; *r != '\0'; ){
+		if(*r != '&'){
+			*w++ = *r++;
+			continue;
+		}
+		if(strncmp(r, "&amp;", 5) == 0){ *w++ = '&'; r += 5; continue; }
+		if(strncmp(r, "&lt;", 4) == 0){ *w++ = '<'; r += 4; continue; }
+		if(strncmp(r, "&gt;", 4) == 0){ *w++ = '>'; r += 4; continue; }
+		if(strncmp(r, "&quot;", 6) == 0){ *w++ = '"'; r += 6; continue; }
+		if(strncmp(r, "&apos;", 6) == 0){ *w++ = '\''; r += 6; continue; }
+		if(r[1] == '#'){
+			char *e;
+			if(r[2] == 'x' || r[2] == 'X')
+				v = strtol(r + 3, &e, 16);
+			else
+				v = strtol(r + 2, &e, 10);
+			if(*e == ';' && v > 0){
+				w += putrune(w, v);
+				r = e + 1;
+				continue;
+			}
+		}
+		*w++ = *r++;
+	}
+	*w = '\0';
+	return s;
+}
+
+/* escape text for HTML output */
+static void
+puthtml(FILE *f, const char *s)
+{
+	if(s == NULL)
+		return;
+	for(; *s != '\0'; s++)
+		switch(*s){
+		case '&': fputs("&amp;", f); break;
+		case '<': fputs("&lt;", f); break;
+		case '>': fputs("&gt;", f); break;
+		case '"': fputs("&quot;", f); break;
+		default: fputc(*s, f); break;
+		}
+}
+
+/* mkdir -p over the directory part of path */
+static void
+mkpath(const char *path)
+{
+	char buf[1024];
+	char *p;
+
+	if(strlen(path) >= sizeof buf)
+		return;
+	strcpy(buf, path);
+	for(p = strchr(buf, '/'); p != NULL; p = strchr(p + 1, '/')){
+		*p = '\0';
+		if(buf[0] != '\0')
+			mkdir(buf, 0777);
+		*p = '/';
+	}
+}
+
+/* blog URL -> repo-relative path, e.g. 2026/05/29/hello-world.html */
+static const char *
+urlpath(const char *link)
+{
+	const char *p = link;
+
+	if(strncmp(p, SITE, strlen(SITE)) == 0)
+		p += strlen(SITE);
+	else if((p = strstr(link, "://")) != NULL){
+		p += 3;
+		p = strchr(p, '/');
+		if(p == NULL)
+			return "";
+		p++;
+	} else
+		p = link;
+	while(*p == '/')
+		p++;
+	return p;
+}
+
+static void
+header(FILE *f, const char *title)
+{
+	fputs("<!DOCTYPE html>\n<html>\n\n<head>\n"
+		"  <meta charset=\"utf-8\">\n  <title>", f);
+	puthtml(f, title);
+	fputs(" \xe2\x80\x93 SillyLaird</title>\n</head>\n\n<body>\n", f);
+}
+
+static void
+footer(FILE *f, const char *up)
+{
+	fputs("\n  <hr>\n\n  <p>\n    <a href=\"", f);
+	fputs(up, f);
+	fputs("index.html\">Blog index</a>\n  </p>\n\n</body>\n\n</html>\n", f);
+}
+
+static void
+writepost(const char *path, const char *title, const char *date,
+	const char *body, const char *link)
+{
+	char file[1024];
+	char up[64];
+	const char *p;
+	FILE *f;
+	int depth;
+
+	if(path[0] == '\0')
+		return;
+	file[0] = '\0';
+	if(!cats(file, sizeof file, outdir) || !cats(file, sizeof file, "/")
+	|| !cats(file, sizeof file, path)){
+		fprintf(stderr, "blogmirror: path too long: %s\n", path);
+		return;
+	}
+	mkpath(file);
+	if((f = fopen(file, "wb")) == NULL){
+		fprintf(stderr, "blogmirror: %s: cannot create\n", file);
+		return;
+	}
+
+	up[0] = '\0';
+	for(depth = 0, p = path; *p != '\0'; p++)
+		if(*p == '/')
+			depth++;
+	for(; depth > 0 && strlen(up) + 3 < sizeof up; depth--)
+		strcat(up, "../");
+
+	header(f, title);
+	fputs("  <h2>", f);
+	puthtml(f, title);
+	fputs("</h2>\n\n  <p><font size=\"-1\">", f);
+	puthtml(f, date);
+	fputs("</font></p>\n\n", f);
+	fputs(body, f);			/* already HTML from the blog */
+	fputs("\n\n  <p><font size=\"-1\">Mirror of <a href=\"", f);
+	puthtml(f, link);
+	fputs("\">", f);
+	puthtml(f, link);
+	fputs("</a></font></p>\n", f);
+	footer(f, up);
+	fclose(f);
+	fprintf(stderr, "%s\n", file);
+}
+
+int
+main(int argc, char *argv[])
+{
+	char *url = FEEDURL;
+	char *feedfile = NULL;
+	char *feed, *p, *end, *item;
+	char cmd[1024];
+	char file[1024];
+	FILE *ix;
+	int i;
+
+	for(i = 1; i < argc; i++){
+		if(strcmp(argv[i], "-u") == 0 && i + 1 < argc)
+			url = argv[++i];
+		else if(strcmp(argv[i], "-f") == 0 && i + 1 < argc)
+			feedfile = argv[++i];
+		else if(strcmp(argv[i], "-o") == 0 && i + 1 < argc)
+			outdir = argv[++i];
+		else if(strcmp(argv[i], "-n") == 0 && i + 1 < argc)
+			maxposts = atoi(argv[++i]);
+		else {
+			fprintf(stderr,
+				"usage: blogmirror [-u url] [-f file] [-o outdir] [-n maxposts]\n");
+			exit(1);
+		}
+	}
+
+	if(feedfile == NULL){
+		cmd[0] = '\0';
+		if(exists("/bin/hget")){		/* 9front */
+			cats(cmd, sizeof cmd, "hget '");
+			cats(cmd, sizeof cmd, url);
+			cats(cmd, sizeof cmd, "' >");
+			cats(cmd, sizeof cmd, TMPFEED);
+		} else {
+			cats(cmd, sizeof cmd, "curl -fsS '");
+			cats(cmd, sizeof cmd, url);
+			cats(cmd, sizeof cmd, "' -o ");
+			cats(cmd, sizeof cmd, TMPFEED);
+		}
+		if(system(cmd) != 0){
+			fprintf(stderr, "blogmirror: fetch failed: %s\n", url);
+			exit(1);
+		}
+		feedfile = TMPFEED;
+	}
+
+	if((feed = slurp(feedfile)) == NULL){
+		fprintf(stderr, "blogmirror: %s: cannot read\n", feedfile);
+		exit(1);
+	}
+
+	mkdir(outdir, 0777);
+	file[0] = '\0';
+	cats(file, sizeof file, outdir);
+	cats(file, sizeof file, "/index.html");
+	if((ix = fopen(file, "wb")) == NULL){
+		fprintf(stderr, "blogmirror: %s: cannot create\n", file);
+		exit(1);
+	}
+	header(ix, "Blog");
+	fputs("  <h2>Blog</h2>\n\n"
+		"  <p>Mirror of <a href=\"" SITE "\">blog.sillylaird.ca</a>.</p>\n\n"
+		"  <table cellspacing=\"0\" cellpadding=\"0\" border=\"0\">\n", ix);
+
+	for(p = feed; (p = strstr(p, "<item>")) != NULL; p = end){
+		char *title, *link, *date, *desc, *body;
+		const char *path;
+
+		if((end = strstr(p, "</item>")) == NULL)
+			break;
+		item = p;
+		title = unxml(between(item, end, "<title>", "</title>"));
+		link  = unxml(between(item, end, "<link>", "</link>"));
+		date  = unxml(between(item, end, "<pubDate>", "</pubDate>"));
+		desc  = unxml(between(item, end, "<description>", "</description>"));
+		body  = between(item, end, "<content:encoded><![CDATA[", "]]></content:encoded>");
+
+		if(title == NULL || link == NULL){
+			free(title); free(link); free(date); free(desc); free(body);
+			continue;
+		}
+		if(date == NULL)
+			date = estrdup("");
+		if(body == NULL)
+			body = estrdup(desc != NULL ? desc : "");
+
+		path = urlpath(link);
+		writepost(path, title, date, body, link);
+
+		fputs("    <tr>\n      <td width=\"10\"></td>\n      <td valign=\"top\">\n"
+			"        <a href=\"", ix);
+		puthtml(ix, path);
+		fputs("\">", ix);
+		puthtml(ix, title);
+		fputs("</a><br>\n"
+			"        <table cellspacing=\"0\" cellpadding=\"0\" border=\"0\">\n"
+			"          <tr>\n            <td width=\"10\"></td>\n            <td>\n"
+			"              <font size=\"-1\">\n                ", ix);
+		puthtml(ix, date);
+		fputs("<br>\n                ", ix);
+		puthtml(ix, desc != NULL ? desc : "");
+		fputs("\n              </font>\n            </td>\n          </tr>\n"
+			"        </table>\n      </td>\n    </tr>\n", ix);
+
+		free(title); free(link); free(date); free(desc); free(body);
+		nposts++;
+		if(maxposts > 0 && nposts >= maxposts)
+			break;
+		end += 7;		/* past </item> */
+	}
+
+	fputs("  </table>\n", ix);
+	footer(ix, "");
+	fclose(ix);
+	free(feed);
+
+	fprintf(stderr, "%s: %d posts\n", file, nposts);
+	return 0;
+}