ref: 6863a7bb8b7c43fa58a6d4b07f36364cc7b29da7
author: sirjofri <sirjofri@sirjofri.de>
date: Thu Mar 27 16:39:27 EDT 2025
adds files
--- /dev/null
+++ b/Readme.md
@@ -1,0 +1,25 @@
+Map Filesystem
+==============
+
+This filesystem provides a cached tile server for Open Street Map tiles.
+
+
+Usage
+-----
+
+- `-s srvname`: post in `/srv`
+- `-m mtpt`: mountpoint (default `/mnt/map`)
+- `-c cache`: cache directory (default `/tmp/mapcache`)
+- `-z maxzoom`: maximum zoom level (default `19`)
+
+Filesystem
+----------
+
+The filesystem has three hierarchy levels and reflects the web interface:
+
+1. Zoom level
+2. X tile coordinate
+3. Y tile coordinate
+
+Reading a full coordinate path (e. g. `5/5/5`) downloads the tile to cache and returns it.
+Deleting a file only deletes the file from the cache. This is useful to flush the cache.
--- /dev/null
+++ b/cache.c
@@ -1,0 +1,122 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include "dat.h"
+#include "fns.h"
+
+Bundle*
+mkbundle(int z, int x, int y)
+{+ Bundle *ret = mallocz(sizeof(Bundle), 1);
+ if (!ret)
+ sysfatal("%r");+ ret->x = x;
+ ret->y = y;
+ ret->z = z;
+ return ret;
+}
+
+void
+filly(File *root, int z, int x)
+{+ int i, m;
+ File *f;
+ char buf[64];
+ Dir *d;
+
+ m = z*2;
+ if (m == 0)
+ m = 1;
+
+ for (i = 0; i < m; i++) {+ snprint(buf, sizeof buf, "%d", i);
+ f = createfile(root, buf, uid, 0444, mkbundle(z, x, i));
+ if (!f)
+ sysfatal("createfile img %r");+
+ snprint(buf, sizeof buf, "%s/%d/%d/%d", cache, z, x, i);
+ d = dirstat(buf);
+ if (!d)
+ continue;
+ f->length = d->length;
+ free(d);
+ }
+}
+
+void
+fillx(File *root, int z)
+{+ int i, m;
+ File *f;
+ char buf[5];
+
+ m = z*2;
+ if (m == 0)
+ m = 1;
+
+ for (i = 0; i < m; i++) {+ snprint(buf, sizeof buf, "%d", i);
+ f = createfile(root, buf, uid, 0777|DMDIR, nil);
+ if (!f)
+ sysfatal("createfile dir %r");+
+ filly(f, z, i);
+ }
+}
+
+void
+inittree(File *root)
+{+ File *f;
+ int i;
+ char buf[3];
+
+ for (i = 0; i <= maxzoom; i++) {+ snprint(buf, sizeof buf, "%d", i);
+ f = createfile(root, buf, uid, 0555|DMDIR, nil);
+ if (!f)
+ sysfatal("createfile zoomdir %r");+ fillx(f, i);
+ }
+}
+
+void
+download(Bundle b, char *file)
+{+ char *cmd = smprint(
+ "mkdir -p `{basename -d '%s'} && "+ "hget https://tile.openstreetmap.org/%d/%d/%d.png | "
+ "png -t9 > '%s'",
+ file, b.z, b.x, b.y, file);
+ execl("/bin/rc", "rc", "-c", cmd, nil);+}
+
+void
+requestfile(File *file, Bundle *b, char *dest)
+{+ int p[2];
+ int pid;
+ Dir *d;
+
+ switch (pid = fork()) {+ case -1:
+ sysfatal("fork: %r");+ default:
+ close(p[1]);
+ break;
+ case 0:
+ download(*b, dest);
+ sysfatal("download: %r");+ }
+
+ while (waitpid() != pid)
+ ;
+
+ d = dirstat(dest);
+ if (d) {+ file->length = d->length;
+ free(d);
+ }
+}
--- /dev/null
+++ b/dat.h
@@ -1,0 +1,11 @@
+extern char* cache;
+extern char* uid;
+extern int maxzoom;
+
+typedef struct Bundle Bundle;
+
+struct Bundle {+ int x;
+ int y;
+ int z;
+};
--- /dev/null
+++ b/fns.h
@@ -1,0 +1,2 @@
+void inittree(File *root);
+void requestfile(File *file, Bundle *b, char *dest);
--- /dev/null
+++ b/mapfs.c
@@ -1,0 +1,112 @@
+#include <u.h>
+#include <libc.h>
+#include <auth.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include "dat.h"
+#include "fns.h"
+
+void
+usage(void)
+{+ fprint(2, "usage: %s [-s srvname] [-m mtpt] [-c cachedir] [-z maxzoom]\n", argv0);
+ exits("usage");+}
+
+char *mtpt = "/mnt/map";
+char *cache = "/tmp/mapcache";
+char *uid;
+int maxzoom = 19;
+
+void
+fsread(Req *r)
+{+ Bundle *b;
+ char *f;
+ int fd;
+
+ if (!r->fid->file->aux) {+ respond(r, "invalid file");
+ return;
+ }
+ b = (Bundle*)r->fid->file->aux;
+
+ f = smprint("%s/%d/%d/%d", cache, b->z, b->x, b->y);+ if (!f)
+ sysfatal("%r");+
+ if (access(f, AEXIST) < 0)
+ requestfile(r->fid->file, b, f);
+
+ fd = open(f, OREAD);
+ free(f);
+ if (fd < 0) {+ responderror(r);
+ return;
+ }
+
+ r->ofcall.count = pread(fd, r->ofcall.data, r->ifcall.count, r->ifcall.offset);
+ respond(r, nil);
+}
+
+void
+fsremove(Req *r)
+{+ Bundle *b;
+ char *f;
+
+ if (!r->fid->file->aux) {+ r->fid->file = nil;
+ respond(r, nil);
+ return;
+ }
+ b = (Bundle*)r->fid->file->aux;
+
+ f = smprint("%s/%d/%d/%d", cache, b->z, b->x, b->y);+ if (!f)
+ sysfatal("%r");+
+ if (access(f, AEXIST) < 0) {+ respond(r, nil);
+ return;
+ }
+
+ remove(f);
+ r->fid->file->length = 0;
+ r->fid->file = nil;
+ respond(r, nil);
+ return;
+}
+
+Srv fs = {+ .read = fsread,
+ .remove = fsremove,
+};
+
+void
+main(int argc, char **argv)
+{+ char *srv = nil;
+
+ ARGBEGIN{+ case 's':
+ srv = EARGF(usage());
+ break;
+ case 'm':
+ mtpt = EARGF(usage());
+ break;
+ case 'c':
+ cache = EARGF(usage());
+ break;
+ case 'z':
+ maxzoom = atoi(EARGF(usage()));
+ break;
+ }ARGEND;
+
+ uid = getuser();
+
+ fs.tree = alloctree(nil, nil, DMDIR|0777, nil);
+ inittree(fs.tree->root);
+ postmountsrv(&fs, srv, mtpt, MREPL|MCREATE);
+}
--- /dev/null
+++ b/mkfile
@@ -1,0 +1,10 @@
+</$objtype/mkfile
+
+TARG=mapfs
+OFILES=\
+ mapfs.$O\
+ cache.$O\
+
+HFILES=fns.h dat.h
+
+</sys/src/cmd/mkone