1 #include <u.h>
2 #include <libc.h>
3 #include <fcall.h>
4 #include <9pclient.h>
5 #include "plumb.h"
6 
7 static CFsys *fsplumb;
8 static int pfd = -1;
9 static CFid *pfid;
10 
11 int
12 plumbopen(char *name, int omode)
13 {
14 	if(fsplumb == nil)
15 		fsplumb = nsmount("plumb", "");
16 	if(fsplumb == nil)
17 		return -1;
18 	/*
19 	* It's important that when we send something,
20 	* we find out whether it was a valid plumb write.
21 	* (If it isn't, the client might fall back to some
22 	* other mechanism or indicate to the user what happened.)
23 	* We can't use a pipe for this, so we have to use the
24 	* fid interface.  But we need to return a fd.
25 	* Return a fd for /dev/null so that we return a unique
26 	* file descriptor.  In plumbsend we'll look for pfd
27 	* and use the recorded fid instead.
28 	*/
29 	if((omode&3) == OWRITE){
30 		if(pfd != -1){
31 			werrstr("already have plumb send open");
32 			return -1;
33 		}
34 		pfd = open("/dev/null", OWRITE);
35 		if(pfd < 0)
36 			return -1;
37 		pfid = fsopen(fsplumb, name, omode);
38 		if(pfid == nil){
39 			close(pfd);
40 			pfd = -1;
41 			return -1;
42 		}
43 		return pfd;
44 	}
45 
46 	return fsopenfd(fsplumb, name, omode);
47 }
48 
49 CFid*
50 plumbopenfid(char *name, int mode)
51 {
52 	if(fsplumb == nil){
53 		fsplumb = nsmount("plumb", "");
54 		if(fsplumb == nil){
55 			werrstr("mount plumb: %r");
56 			return nil;
57 		}
58 	}
59 	return fsopen(fsplumb, name, mode);
60 }
61 
62 int
63 plumbsendtofid(CFid *fid, Plumbmsg *m)
64 {
65 	char *buf;
66 	int n;
67 
68 	if(fid == nil){
69 		werrstr("invalid fid");
70 		return -1;
71 	}
72 	buf = plumbpack(m, &n);
73 	if(buf == nil)
74 		return -1;
75 	n = fswrite(fid, buf, n);
76 	free(buf);
77 	return n;
78 }
79 
80 int
81 plumbsend(int fd, Plumbmsg *m)
82 {
83 	if(fd == -1){
84 		werrstr("invalid fd");
85 		return -1;
86 	}
87 	if(fd != pfd){
88 		werrstr("fd is not the plumber");
89 		return -1;
90 	}
91 	return plumbsendtofid(pfid, m);
92 }
93 
94 Plumbmsg*
95 plumbrecv(int fd)
96 {
97 	char *buf;
98 	Plumbmsg *m;
99 	int n, more;
100 
101 	buf = malloc(8192);
102 	if(buf == nil)
103 		return nil;
104 	n = read(fd, buf, 8192);
105 	m = nil;
106 	if(n > 0){
107 		m = plumbunpackpartial(buf, n, &more);
108 		if(m==nil && more>0){
109 			/* we now know how many more bytes to read for complete message */
110 			buf = realloc(buf, n+more);
111 			if(buf == nil)
112 				return nil;
113 			if(readn(fd, buf+n, more) == more)
114 				m = plumbunpackpartial(buf, n+more, nil);
115 		}
116 	}
117 	free(buf);
118 	return m;
119 }
120 
121 Plumbmsg*
122 plumbrecvfid(CFid *fid)
123 {
124 	char *buf;
125 	Plumbmsg *m;
126 	int n, more;
127 
128 	buf = malloc(8192);
129 	if(buf == nil)
130 		return nil;
131 	n = fsread(fid, buf, 8192);
132 	m = nil;
133 	if(n > 0){
134 		m = plumbunpackpartial(buf, n, &more);
135 		if(m==nil && more>0){
136 			/* we now know how many more bytes to read for complete message */
137 			buf = realloc(buf, n+more);
138 			if(buf == nil)
139 				return nil;
140 			if(fsreadn(fid, buf+n, more) == more)
141 				m = plumbunpackpartial(buf, n+more, nil);
142 		}
143 	}
144 	free(buf);
145 	return m;
146 }
147