ref: 2569cbf9bd35798942a1640bf919162efe92d3b8
parent: e061cf22cdf6563a02cd0941da722f8d006f31be
author: Noam Preil <noam@pixelhero.dev>
date: Sat Dec 28 23:45:36 EST 2024
server: vtwrite() of existing data
--- a/notebook
+++ b/notebook
@@ -2448,3 +2448,68 @@
Anyways, confirmed that this is correct :) Commit and next step :D
+Read side first, since it's easier.
+
+Hahah super easy actually
+
+ if(addr.size != len)
+ vterr(conn, buf, "hash collision detected");
+ if(!readclump(buf2, addr))
+ vterr(conn, buf, "clump read failed: %r");
+ if(memcmp(buf2, buf+8, len) != 0)
+ vterr(conn, buf, "hash collision detected");
+
+Have the general structure be
+
+ if(hash exists){+
+ } else if (data is new) {+
+ }
+ send success packet
+
+so now we need that success packet so writes of existing ddata succeed correctly...
+
+ VtRwrite tag[1] score[20]
+
+first two bytes are packet length, then one byte for Rwrite, then one for tag, then 20 for score; 22 byte length.
+
+soo
+
+ah wait no
+
+I was about to write code to manipulate the buffer but I outsmarted myself!
+
+just vtsend lol
+
+memcpy(buf+4, score, 20);
+vtsend(conn, buf, 22, VtRwrite, 0);
+
+annnnd crash.
+
+% lstk
+
+ppanic(fmt=0x30bd1)+0x120 /sys/src/libc/port/malloc.c:162
+ pv=0x30150
+ msg=0x36950
+ v=0x1fffefd90
+ n=0xfffefd9000000030
+D2B(v=0x10131d6f0)+0x6c /sys/src/libc/port/pool.c:926
+ a=0x10131d6e8
+poolfreel(v=0x10131d6f0,p=0x352d0)+0x18 /sys/src/libc/port/pool.c:1152
+ ab=0x30150
+poolfree(p=0x352d0,v=0x10131d6f0)+0x34 /sys/src/libc/port/pool.c:1287
+free()+0x18 /sys/src/libc/port/malloc.c:250
+_schedinit()+0xd0 /sys/src/libthread/sched.c:69
+ p=0xde6d8
+ t=0xde838
+main(argc=0x3,argv=0x1fffeff70)+0x84 /sys/src/libthread/main.c:36
+_callmain+0x24 /sys/src/libc/9sys/callmain.c:20
+acid:
+echo kill > /proc/484831/ctl
+
+okay that's actually useless. acid -lthread and grab stacks()?
+
+<stdin>:2: (error) setproc: open /proc/484718/mem: file does not exist: '/proc/484718'
+
+uh.
\ No newline at end of file
--- a/server.c
+++ b/server.c
@@ -97,13 +97,21 @@
vtwrite(VtConn conn, char *buf, u16int len)
{u8int score[20];
+ uchar buf2[MaxPacketSize];
VtAddress addr;
sha1((uchar*)buf+8, len, score, nil);
if(vtreadlookup(score, &addr)){- vterr(conn, buf, "TODO: handle vtwrite for existing data");
+ if(addr.size != len)
+ vterr(conn, buf, "hash collision detected");
+ if(!readclump(buf2, addr))
+ vterr(conn, buf, "clump read failed: %r");
+ if(memcmp(buf2, buf+8, len) != 0)
+ vterr(conn, buf, "hash collision detected");
} else {vterr(conn, buf, "TODO: insert data");
}
+ memcpy(buf+4, score, 20);
+ vtsend(conn, buf, 22, VtRwrite, 0);
}
static int
@@ -163,7 +171,6 @@
while(offset+2 < sz){// As long as there's a complete packet, process it.
u16int len = U16GET(buf + offset);
- print("Read length from packet: %d\n", len); if(2 + offset + len > sz){// missing part of packet!
break;