xref: /illumos-gate/usr/src/cmd/lp/lib/msgs/mconnect.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /* LINTLIBRARY */
31 
32 # include	<unistd.h>
33 # include	<fcntl.h>
34 # include	<errno.h>
35 # include	<sys/utsname.h>
36 # include	<stdlib.h>
37 # include	<sys/types.h>
38 # include	<sys/stat.h>
39 
40 #include "lp.h"
41 #include "msgs.h"
42 
43 #define TURN_OFF(X,F)	(void)Fcntl(X, F_SETFL, (Fcntl(X, F_GETFL, 0) & ~(F)))
44 
45 #if	defined(__STDC__)
46 static int	checklock ( void );
47 #else
48 static int	checklock();
49 #endif
50 
51 /*
52 ** mconnect() - OPEN A MESSAGE PATH
53 */
54 
55 #if	defined(__STDC__)
56 MESG * mconnect ( char * path, int id1, int id2 )
57 #else
58 MESG * mconnect ()
59     char	*path;
60     int		id1;
61     int		id2;
62 #endif
63 {
64     int		fd;
65     int		wronly = 0;
66     int		count = 0;
67     MESG	*md;
68     struct stat	stbuf;
69 
70     /*
71     **	invoked as mconnect(path, 0, 0)
72     **
73     **	Open <path>, if isastream() is true for the returned file
74     **	descriptor, then we're done.
75     */
76 
77     if (path)
78     {
79 	/*
80 	**	Verify that the spooler is running and that the
81 	**	<path> identifies a pipe.
82 	**	This prevents us from getting hung in the open
83 	**	and from thinking the <path> is a non-streams pipe.
84 	*/
85 	if (checklock() == -1)
86 	    return(NULL);
87 Again:	if (stat(path, &stbuf) == -1)
88 	    return(NULL);
89 	if ((stbuf.st_mode & S_IFMT) != S_IFIFO) {
90             if (count++ > 20)
91 		return (NULL);
92 	    sleep(1);
93 	    goto Again;
94 	}
95 
96 	if ((fd = Open(path, O_RDWR, 0)) == -1)
97 	    if ((fd = Open(path, O_WRONLY, 0)) == -1)
98 		return(NULL);
99 	    else
100 		wronly = 1;
101 
102 	if (isastream(fd) && !wronly)
103 	{
104 #if	defined(NOCONNLD)
105 	    int		fds[2];
106 
107 	    if (pipe(fds) != 0)
108 		return(NULL);
109 
110 	    if (ioctl(fd, I_SENDFD, fds[1]) != 0)
111 		return(NULL);
112 
113 	    (void)_Close(fd);
114 
115 	    fd = fds[0];
116 	    (void)_Close(fds[1]);
117 #endif
118 
119 	    if ((md = (MESG *)Malloc(MDSIZE)) == NULL)
120 	    {
121 		errno = ENOMEM;
122 		return(NULL);
123 	    }
124 
125 	    memset(md, 0, sizeof (MESG));
126 	    md->gid = getgid();
127 	    md->on_discon = NULL;
128 	    md->readfd = fd;
129 	    md->state = MDS_IDLE;
130 	    md->type = MD_STREAM;
131 	    md->uid = getuid();
132 	    md->writefd = fd;
133 
134 	    ResetFifoBuffer (md->readfd);
135 	    return(md);
136 	}
137 
138 	return(NULL);
139     }
140 
141     if (id1 > 0 && id2 > 0)
142     {
143 	if ((md = (MESG *)Malloc(MDSIZE)) == NULL)
144 	{
145 	    errno = ENOMEM;
146 	    return(NULL);
147 	}
148 
149 	memset(md, 0, sizeof (MESG));
150 	md->gid = getgid();
151 	md->on_discon = NULL;
152 	md->readfd = id1;
153 	md->state = MDS_IDLE;
154 	md->type = MD_BOUND;
155 	md->uid = getuid();
156 	md->writefd = id2;
157 
158 	ResetFifoBuffer (md->readfd);
159 
160 	return(md);
161     }
162 
163     errno = EINVAL;
164     return(NULL);
165 }
166 
167 #if	defined(__STDC__)
168 static int checklock ( void )
169 #else
170 static int checklock()
171 #endif
172 {
173     int			fd;
174     struct flock	lock;
175 
176     if ((fd = Open(Lp_Schedlock, O_RDONLY, 0666)) == -1)
177 	return (-1);
178 
179     /*
180      * Now, we try to read-lock the lock file. This can only succeed if
181      * the Spooler (lpsched) is down.
182      */
183 
184     lock.l_type = F_RDLCK;
185     lock.l_whence = 0;
186     lock.l_start = 0;
187     lock.l_len = 0;	/* till end of file */
188 
189     if (Fcntl(fd, F_SETLK, &lock) != -1 || errno != EAGAIN)
190     {
191 	(void)Close (fd);
192 	return (-1);
193     }
194 
195     /*
196      * We can get here only when fcntl() == -1 && errno == EAGAIN,
197      * i.e., spooler (lpsched) is running.
198      */
199 
200     (void)Close (fd);
201 
202     return(0);
203 }
204