change to plumb better

1 files changed, 144 insertions, 0 deletions

diff --git a/src/libplumb/fid.c b/src/libplumb/fid.c
new file mode 100644
index 00000000..86093c05
--- /dev/null
+++ b/src/libplumb/fid.c
@@ -0,0 +1,144 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <fs.h>
+#include "plumb.h"
+
+static Fsys *fsplumb;
+static int pfd = -1;
+static Fid *pfid;
+
+int
+plumbopen(char *name, int omode)
+{
+	if(fsplumb == nil)
+		fsplumb = nsmount("plumb", "");
+	if(fsplumb == nil)
+		return -1;
+	/*
+	* It's important that when we send something,
+	* we find out whether it was a valid plumb write.
+	* (If it isn't, the client might fall back to some
+	* other mechanism or indicate to the user what happened.)
+	* We can't use a pipe for this, so we have to use the
+	* fid interface.  But we need to return a fd.
+	* Return a fd for /dev/null so that we return a unique
+	* file descriptor.  In plumbsend we'll look for pfd
+	* and use the recorded fid instead.
+	*/
+	if((omode&3) == OWRITE){
+		if(pfd != -1){
+			werrstr("already have plumb send open");
+			return -1;
+		}
+		pfd = open("/dev/null", OWRITE);
+		if(pfd < 0)
+			return -1;
+		pfid = fsopen(fsplumb, name, omode);
+		if(pfid == nil){
+			close(pfd);
+			pfd = -1;
+			return -1;
+		}
+		return pfd;
+	}
+
+	return fsopenfd(fsplumb, name, omode);
+}
+
+Fid*
+plumbopenfid(char *name, int mode)
+{
+	if(fsplumb == nil)
+		fsplumb = nsmount("plumb", "");
+	if(fsplumb == nil)
+		return nil;
+	return fsopen(fsplumb, name, mode);
+}
+
+int
+plumbsendtofid(Fid *fid, Plumbmsg *m)
+{
+	char *buf;
+	int n;
+
+	if(fid == nil){
+		werrstr("invalid fid");
+		return -1;
+	}
+	buf = plumbpack(m, &n);
+	if(buf == nil)
+		return -1;
+	n = fswrite(fid, buf, n);
+	free(buf);
+	return n;
+}
+
+int
+plumbsend(int fd, Plumbmsg *m)
+{
+	if(fd == -1){
+		werrstr("invalid fd");
+		return -1;
+	}
+	if(fd != pfd){
+		werrstr("fd is not the plumber");
+		return -1;
+	}
+	return plumbsendtofid(pfid, m);
+}
+
+Plumbmsg*
+plumbrecv(int fd)
+{
+	char *buf;
+	Plumbmsg *m;
+	int n, more;
+
+	buf = malloc(8192);
+	if(buf == nil)
+		return nil;
+	n = read(fd, buf, 8192);
+	m = nil;
+	if(n > 0){
+		m = plumbunpackpartial(buf, n, &more);
+		if(m==nil && more>0){
+			/* we now know how many more bytes to read for complete message */
+			buf = realloc(buf, n+more);
+			if(buf == nil)
+				return nil;
+			if(readn(fd, buf+n, more) == more)
+				m = plumbunpackpartial(buf, n+more, nil);
+		}
+	}
+	free(buf);
+	return m;
+}
+
+Plumbmsg*
+plumbrecvfid(Fid *fid)
+{
+	char *buf;
+	Plumbmsg *m;
+	int n, more;
+
+	buf = malloc(8192);
+	if(buf == nil)
+		return nil;
+	n = fsread(fid, buf, 8192);
+	m = nil;
+	if(n > 0){
+		m = plumbunpackpartial(buf, n, &more);
+		if(m==nil && more>0){
+			/* we now know how many more bytes to read for complete message */
+			buf = realloc(buf, n+more);
+			if(buf == nil)
+				return nil;
+			if(fsreadn(fid, buf+n, more) == more)
+				m = plumbunpackpartial(buf, n+more, nil);
+		}
+	}
+	free(buf);
+	return m;
+}
+