fossil: import from plan 9

R=rsc
https://codereview.appspot.com/7988047

src/cmd/fossil/9srv.c

@@ -0,0 +1,242 @@
+#include "stdinc.h"
+
+#include "9.h"
+
+typedef struct Srv Srv;
+struct Srv {
+	int	fd;
+	int	srvfd;
+	char*	service;
+	char*	mntpnt;
+
+	Srv*	next;
+	Srv*	prev;
+};
+
+static struct {
+	VtLock*	lock;
+
+	Srv*	head;
+	Srv*	tail;
+} sbox;
+
+static int
+srvFd(char* name, int mode, int fd, char** mntpnt)
+{
+	int n, srvfd;
+	char *p, buf[10];
+
+	/*
+	 * Drop a file descriptor with given name and mode into /srv.
+	 * Create with ORCLOSE and don't close srvfd so it will be removed
+	 * automatically on process exit.
+	 */
+	p = smprint("/srv/%s", name);
+	if((srvfd = create(p, ORCLOSE|OWRITE, mode)) < 0){
+		vtMemFree(p);
+		p = smprint("#s/%s", name);
+		if((srvfd = create(p, ORCLOSE|OWRITE, mode)) < 0){
+			vtSetError("create %s: %r", p);
+			vtMemFree(p);
+			return -1;
+		}
+	}
+
+	n = snprint(buf, sizeof(buf), "%d", fd);
+	if(write(srvfd, buf, n) < 0){
+		close(srvfd);
+		vtSetError("write %s: %r", p);
+		vtMemFree(p);
+		return -1;
+	}
+
+	*mntpnt = p;
+
+	return srvfd;
+}
+
+static void
+srvFree(Srv* srv)
+{
+	if(srv->prev != nil)
+		srv->prev->next = srv->next;
+	else
+		sbox.head = srv->next;
+	if(srv->next != nil)
+		srv->next->prev = srv->prev;
+	else
+		sbox.tail = srv->prev;
+
+	if(srv->srvfd != -1)
+		close(srv->srvfd);
+	vtMemFree(srv->service);
+	vtMemFree(srv->mntpnt);
+	vtMemFree(srv);
+}
+
+static Srv*
+srvAlloc(char* service, int mode, int fd)
+{
+	Dir *dir;
+	Srv *srv;
+	int srvfd;
+	char *mntpnt;
+
+	vtLock(sbox.lock);
+	for(srv = sbox.head; srv != nil; srv = srv->next){
+		if(strcmp(srv->service, service) != 0)
+			continue;
+		/*
+		 * If the service exists, but is stale,
+		 * free it up and let the name be reused.
+		 */
+		if((dir = dirfstat(srv->srvfd)) != nil){
+			free(dir);
+			vtSetError("srv: already serving '%s'", service);
+			vtUnlock(sbox.lock);
+			return nil;
+		}
+		srvFree(srv);
+		break;
+	}
+
+	if((srvfd = srvFd(service, mode, fd, &mntpnt)) < 0){
+		vtUnlock(sbox.lock);
+		return nil;
+	}
+	close(fd);
+
+	srv = vtMemAllocZ(sizeof(Srv));
+	srv->srvfd = srvfd;
+	srv->service = vtStrDup(service);
+	srv->mntpnt = mntpnt;
+
+	if(sbox.tail != nil){
+		srv->prev = sbox.tail;
+		sbox.tail->next = srv;
+	}
+	else{
+		sbox.head = srv;
+		srv->prev = nil;
+	}
+	sbox.tail = srv;
+	vtUnlock(sbox.lock);
+
+	return srv;
+}
+
+static int
+cmdSrv(int argc, char* argv[])
+{
+	Con *con;
+	Srv *srv;
+	char *usage = "usage: srv [-APWdp] [service]";
+	int conflags, dflag, fd[2], mode, pflag, r;
+
+	dflag = 0;
+	pflag = 0;
+	conflags = 0;
+	mode = 0666;
+
+	ARGBEGIN{
+	default:
+		return cliError(usage);
+	case 'A':
+		conflags |= ConNoAuthCheck;
+		break;
+	case 'I':
+		conflags |= ConIPCheck;
+		break;
+	case 'N':
+		conflags |= ConNoneAllow;
+		break;
+	case 'P':
+		conflags |= ConNoPermCheck;
+		mode = 0600;
+		break;
+	case 'W':
+		conflags |= ConWstatAllow;
+		mode = 0600;
+		break;
+	case 'd':
+		dflag = 1;
+		break;
+	case 'p':
+		pflag = 1;
+		mode = 0600;
+		break;
+	}ARGEND
+
+	if(pflag && (conflags&ConNoPermCheck)){
+		vtSetError("srv: cannot use -P with -p");
+		return 0;
+	}
+
+	switch(argc){
+	default:
+		return cliError(usage);
+	case 0:
+		vtRLock(sbox.lock);
+		for(srv = sbox.head; srv != nil; srv = srv->next)
+			consPrint("\t%s\t%d\n", srv->service, srv->srvfd);
+		vtRUnlock(sbox.lock);
+
+		return 1;
+	case 1:
+		if(!dflag)
+			break;
+
+		vtLock(sbox.lock);
+		for(srv = sbox.head; srv != nil; srv = srv->next){
+			if(strcmp(srv->service, argv[0]) != 0)
+				continue;
+			srvFree(srv);
+			break;
+		}
+		vtUnlock(sbox.lock);
+
+		if(srv == nil){
+			vtSetError("srv: '%s' not found", argv[0]);
+			return 0;
+		}
+
+		return 1;
+	}
+
+	if(pipe(fd) < 0){
+		vtSetError("srv pipe: %r");
+		return 0;
+	}
+	if((srv = srvAlloc(argv[0], mode, fd[0])) == nil){
+		close(fd[0]); close(fd[1]);
+		return 0;
+	}
+
+	if(pflag)
+		r = consOpen(fd[1], srv->srvfd, -1);
+	else{
+		con = conAlloc(fd[1], srv->mntpnt, conflags);
+		if(con == nil)
+			r = 0;
+		else
+			r = 1;
+	}
+	if(r == 0){
+		close(fd[1]);
+		vtLock(sbox.lock);
+		srvFree(srv);
+		vtUnlock(sbox.lock);
+	}
+
+	return r;
+}
+
+int
+srvInit(void)
+{
+	sbox.lock = vtLockAlloc();
+
+	cliAddCmd("srv", cmdSrv);
+
+	return 1;
+}