1 #include <u.h>
2 #include <libc.h>
3 #include <fcall.h>
4 #include <fs.h>
5 #include "plumb.h"
6 
7 static Fsys *fsplumb;
8 static int pfd = -1;
9 static Fid *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 Fid*
50 plumbopenfid(char *name, int mode)
51 {
52 	if(fsplumb == nil)
53 		fsplumb = nsmount("plumb", "");
54 	if(fsplumb == nil)
55 		return nil;
56 	return fsopen(fsplumb, name, mode);
57 }
58 
59 int
60 plumbsendtofid(Fid *fid, Plumbmsg *m)
61 {
62 	char *buf;
63 	int n;
64 
65 	if(fid == nil){
66 		werrstr("invalid fid");
67 		return -1;
68 	}
69 	buf = plumbpack(m, &n);
70 	if(buf == nil)
71 		return -1;
72 	n = fswrite(fid, buf, n);
73 	free(buf);
74 	return n;
75 }
76 
77 int
78 plumbsend(int fd, Plumbmsg *m)
79 {
80 	if(fd == -1){
81 		werrstr("invalid fd");
82 		return -1;
83 	}
84 	if(fd != pfd){
85 		werrstr("fd is not the plumber");
86 		return -1;
87 	}
88 	return plumbsendtofid(pfid, m);
89 }
90 
91 Plumbmsg*
92 plumbrecv(int fd)
93 {
94 	char *buf;
95 	Plumbmsg *m;
96 	int n, more;
97 
98 	buf = malloc(8192);
99 	if(buf == nil)
100 		return nil;
101 	n = read(fd, buf, 8192);
102 	m = nil;
103 	if(n > 0){
104 		m = plumbunpackpartial(buf, n, &more);
105 		if(m==nil && more>0){
106 			/* we now know how many more bytes to read for complete message */
107 			buf = realloc(buf, n+more);
108 			if(buf == nil)
109 				return nil;
110 			if(readn(fd, buf+n, more) == more)
111 				m = plumbunpackpartial(buf, n+more, nil);
112 		}
113 	}
114 	free(buf);
115 	return m;
116 }
117 
118 Plumbmsg*
119 plumbrecvfid(Fid *fid)
120 {
121 	char *buf;
122 	Plumbmsg *m;
123 	int n, more;
124 
125 	buf = malloc(8192);
126 	if(buf == nil)
127 		return nil;
128 	n = fsread(fid, buf, 8192);
129 	m = nil;
130 	if(n > 0){
131 		m = plumbunpackpartial(buf, n, &more);
132 		if(m==nil && more>0){
133 			/* we now know how many more bytes to read for complete message */
134 			buf = realloc(buf, n+more);
135 			if(buf == nil)
136 				return nil;
137 			if(fsreadn(fid, buf+n, more) == more)
138 				m = plumbunpackpartial(buf, n+more, nil);
139 		}
140 	}
141 	free(buf);
142 	return m;
143 }
144