shithub: neoventi

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error handling skeleton

--- a/main.c

+++ b/main.c

@@ -25,7 +25,6 @@

 		return 0;

 	if(*nmap > MaxAMap)

 		return 0;

-	print("reading %d map entries\n", *nmap);

 	*map = realloc(*map, *nmap * sizeof(MapEntry));

 	for(i = 0; i < *nmap; i += 1){

 		s = Brdline(b, '\n');

@@ -37,7 +36,6 @@

 			sysfatal("corrupt index map: %s", fields[1]);

 		if(stru64int(fields[2], &(*map)[i].stop) < 0)

 			sysfatal("corrupt index map: %s", fields[2]);

-	//	print("amap entry %d: [%llud, %llud)\n", i, (*map)[i].start, (*map)[i].stop);

 	}

 	return 1;

 }

@@ -116,7 +114,6 @@

 	if(Bseek(&bio, tabbase, 0) != tabbase)

 		sysfatal("seek failed: %r");

 	parsemap(&bio, &map, &nmap);

-	print("found %d arenas\n", nmap);

 	arenas = realloc(arenas, sizeof(VtArena) * (nmap + numarenas));

 	if(!arenas)

 		sysfatal("oom");

@@ -232,7 +229,6 @@

 		sysfatal("invalid magic found in index header");

 	if(!Brdu32(&bio, &version) || version != 1)

 		sysfatal("failed to read version or version unsupported");

-	print("Parsing index v1...\n");

 	line = Brdline(&bio, '\n');

 	if(Blinelen(&bio) >= NameSize)

 		sysfatal("invalid or corrupt index: name too big");

@@ -462,8 +458,9 @@

 main(int argc, char **argv)

 {

 	parseargs(argc, argv);

-	print("Initializing neoventi build 2...\n");

+	print("Initializing neoventi build 3... ");

 	init();

 	validate();

+	print("initialized, launching server.\n");

 	serve("tcp!127.1!14011");

 }

--- a/neoventi.h

+++ b/neoventi.h

@@ -30,7 +30,7 @@

 	 * or for when you accidentally {mount /dev/.../arenas /mnt/venti} */

 	PartBlank = 256 * 1024,

 	NameSize = 64,

-	/* FIXME make arena part head a full block? breaking change for new arena partitions, removes

+	/* FIXME(design break) make arena part head a full block? breaking change for new arena partitions, removes

 	 * need for special casing and magic around it. Just read the damn block. */

 	HeadSize = 512,

 	ArenaPartMagic = 0xa9e4a5e7U,

@@ -44,6 +44,7 @@

 typedef struct {

 	int fd;

+	jmp_buf bounce;

 } VtConn;

 typedef struct {

--- a/server.c

+++ b/server.c

@@ -3,22 +3,34 @@

 #include <bio.h>

 #include "neoventi.h"

-// Convenience function: reads a venti packed from conn into buf

+// Handles an error on `conn` handling client request `tbuf`

+// Only the tag must be preserved in the buffer

+static void

+vterr(VtConn conn, char *tbuf, char *msg, ...)

+{

+	va_list args;

+	va_start(args, msg);

+	msg = vsmprint(msg, args);

+	werrstr(msg);

+	free(msg);

+	va_end(args);

+	if(tbuf != nil){

+		// TODO: send Rerror message

+	}

+	longjmp(conn.bounce, 1);

+}

+

+// Convenience function: reads a venti packet from conn into buf

 // Invariant: buf MUST have 0x10002 bytes available! see venti(6)

-static int

+static void

 vtrecv(VtConn conn, char *buf)

 {

 	u16int len;

-	if(read(conn.fd, buf, 2) != 2){

-		werrstr("Failed to read message size: %r");

-		return 0;

-	}

+	if(read(conn.fd, buf, 2) != 2)

+		vterr(conn, nil, "failed to read message size: %r");

 	len = (buf[0] << 8 | buf[1]);

-	if(read(conn.fd, buf + 2, len) != len){

-		werrstr("Failed to read message: %r");

-		return 0;

-	}

-	return 1;

+	if(read(conn.fd, buf + 2, len) != len)

+		vterr(conn, nil, "failed to read message: %r");

 }

 static void

@@ -25,13 +37,14 @@

 vtversion(VtConn conn)

 {

 	char c;

+	// Response is one line of unknown size; discard bytes until EOL

 	if(fprint(conn.fd, "venti-02-neoventi\n") == 18)

 		while(read(conn.fd, &c, 1) == 1)

 			if(c == '\n')

 				return;

+	// If the handshake fails, make it clear there's a problem and give up

 	fprint(conn.fd, "FUCK OFF\n");

-	close(conn.fd);

-	sysfatal("venti handshake failed: %r");

+	vterr(conn, nil, "handshake failed");

 }

 static void

@@ -41,7 +54,6 @@

 	VtArena arena;

 	u64int addr;

 	u16int size;

-	u32int off;

 	u8int blocks;

 	uchar *dbuf;

 	score = (u8int*)buf + 4;

@@ -68,41 +80,48 @@

 	case VtTgoodbye:

 		return 0;

 	case VtTsync:

-		print("we don't support vtsync yet. Hanging up!\n");

-		return 0;

+		vterr(conn, buf, "TODO: sync not supported yet");

 	default:

-		sysfatal("TODO safely hang up vtconns");

+		vterr(conn, buf, "TODO safely hang up vtconns");

 	}

 	return 0;

 }

 static void

-handle(int ctl, char *dir)

+vthello(VtConn conn, char *buf)

 {

-	char buf[0x10002];

-	VtConn conn;

-	conn.fd = accept(ctl, dir);

-	if(conn.fd < 0)

-		sysfatal("failed to accept connection: %r");

-	print("received a connection at %s, fd %d\n", dir, conn.fd);

 	vtversion(conn);

-	if(!vtrecv(conn, buf))

-		sysfatal("msg recv failed: %r");

+	vtrecv(conn, buf);

 	if(buf[2] != VtThello)

-		sysfatal("received message before hello: %d", buf[2]);

+		vterr(conn, buf, "received message before hello: %d", buf[2]);

 	if(buf[4] != 0 || buf[5] != 2 || buf[6] != '0' || buf[7] != '2')

-		sysfatal("unsupported protocol version requested in Thello: %d %d %d %d", buf[4], buf[5], buf[6], buf[7]);

+		vterr(conn, buf, "unsupported protocol version requested in Thello: %d %d %d %d", buf[4], buf[5], buf[6], buf[7]);

 	buf[2] = VtRhello;

 	buf[6] = 'n';

 	buf[7] = 'o';

 	buf[1] = 8;

 	if(write(conn.fd, buf, 10) != 10)

-		sysfatal("failed to rhello: %r");

-	while(vtrecv(conn, buf)){

-		if(!vtconnhandle(conn, buf))

-			break;

+		vterr(conn, buf, "failed to rhello: %r");

+}

+

+static void

+handle(int ctl, char *dir)

+{

+	char buf[0x10002];

+	VtConn conn;

+	if(setjmp(conn.bounce) != 0){

+		fprint(2, "abandoning client: %r\n");

+		close(conn.fd);

+		return;

 	}

-	close(conn.fd);

+	conn.fd = accept(ctl, dir);

+	if(conn.fd < 0)

+		vterr(conn, nil, "failed to accept connection: %r");

+	vthello(conn, buf);

+	while(1){

+		vtrecv(conn, buf);

+		vtconnhandle(conn, buf);

+	}

 }

 void

@@ -115,6 +134,7 @@

 		sysfatal("%r");

 	procsetname("neoventi/server");

 	for(ctl = listen(adir, dir); ctl >= 0; ctl = listen(adir, dir)){

+		// TODO: handle the client in a worker, allow multiple clients

 		handle(ctl, dir);

 		close(ctl);

 	}

-- 

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