759ef658 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: fdpass.c,v 1.1 2003/11/29 11:58:49 mdw Exp $ |
4 | * |
5 | * File descriptor passing |
6 | * |
7 | * (c) 2003 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: fdpass.c,v $ |
33 | * Revision 1.1 2003/11/29 11:58:49 mdw |
34 | * File descriptor passing. |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include <errno.h> |
41 | #include <stdio.h> |
42 | #include <stdlib.h> |
43 | #include <string.h> |
44 | |
45 | #include <sys/types.h> |
46 | #include <sys/time.h> |
47 | #include <unistd.h> |
48 | #include <sys/socket.h> |
49 | #include <sys/uio.h> |
50 | #include <sys/un.h> |
51 | |
52 | #include "fdpass.h" |
53 | |
54 | /*----- Main code ---------------------------------------------------------*/ |
55 | |
56 | /* --- @fdpass_send@ --- * |
57 | * |
58 | * Arguments: @int sock@ = socket to send over |
59 | * @int fd@ = file descriptor to send |
60 | * @const void *p@ = pointer to data to send |
61 | * @size_t sz@ = size of buffer to send |
62 | * |
63 | * Returns: On error, @-1@, otherwise number of bytes transferred from |
64 | * @p@. |
65 | * |
66 | * Use: Sends a copy of file descriptor @fd@ to the other end of |
67 | * @sock@. |
68 | */ |
69 | |
70 | ssize_t fdpass_send(int sock, int fd, const void *p, size_t sz) |
71 | { |
72 | struct iovec iov; |
73 | struct msghdr msg; |
74 | #ifndef HAVE_MSG_ACCRIGHTS |
75 | char buf[CMSG_SPACE(sizeof(fd))]; |
76 | struct cmsghdr *cmsg; |
77 | #endif |
78 | |
79 | iov.iov_base = (/*unconst*/ void *)p; |
80 | iov.iov_len = sz; |
81 | msg.msg_name = 0; |
82 | msg.msg_namelen = 0; |
83 | msg.msg_iov = &iov; |
84 | msg.msg_iovlen = 1; |
85 | msg.msg_flags = 0; |
86 | #ifdef HAVE_MSG_ACCRIGHTS |
87 | msg.msg_accrights = &fd; |
88 | msg.msg_accrightslen = sizeof(fd); |
89 | #else |
90 | msg.msg_control = buf; |
91 | msg.msg_controllen = sizeof(buf); |
92 | cmsg = CMSG_FIRSTHDR(&msg); |
93 | cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); |
94 | cmsg->cmsg_level = SOL_SOCKET; |
95 | cmsg->cmsg_type = SCM_RIGHTS; |
96 | memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd)); |
97 | #endif |
98 | return (sendmsg(sock, &msg, 0)); |
99 | } |
100 | |
101 | /* --- @fdpass_recv@ --- * |
102 | * |
103 | * Arguments: @int sock@ = socket to send over |
104 | * @int *fd@ = where to put received descriptor |
105 | * @void *p@ = pointer to where to put data |
106 | * @size_t sz@ = size of buffer |
107 | * |
108 | * Returns: On error, @-1@, otherwise number of bytes transferred. |
109 | * |
110 | * Use: Receives a file descriptor. If the call succeeds, and there |
111 | * was a file descriptor, then @fd@ won't be @-1@ on exit; |
112 | * otherwise it will. At most one descriptor will be collected. |
113 | */ |
114 | |
115 | ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz) |
116 | { |
117 | struct iovec iov; |
118 | struct msghdr msg; |
119 | ssize_t rc; |
120 | #ifndef HAVE_MSG_ACCRIGHTS |
121 | char buf[CMSG_SPACE(sizeof(fd))]; |
122 | struct cmsghdr *cmsg; |
123 | int fdtmp; |
124 | #endif |
125 | |
126 | *fd = -1; |
127 | iov.iov_base = p; |
128 | iov.iov_len = sz; |
129 | msg.msg_name = 0; |
130 | msg.msg_namelen = 0; |
131 | msg.msg_iov = &iov; |
132 | msg.msg_iovlen = 1; |
133 | msg.msg_flags = 0; |
134 | #ifdef HAVE_MSG_ACCRIGHTS |
135 | msg.msg_accrights = fd; |
136 | msg.msg_accrightslen = sizeof(*fd); |
137 | #else |
138 | msg.msg_control = buf; |
139 | msg.msg_controllen = sizeof(buf); |
140 | #endif |
141 | if ((rc = recvmsg(sock, &msg, 0)) < 0) |
142 | return (rc); |
143 | #ifdef HAVE_MSG_ACCRIGHTS |
144 | if (msg.msg_accrightslen < sizeof(*fd)) |
145 | *fd = -1; |
146 | #else |
147 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
148 | if (cmsg->cmsg_level == SOL_SOCKET && |
149 | cmsg->cmsg_type == SCM_RIGHTS && |
150 | cmsg->cmsg_len >= CMSG_LEN(sizeof(fd))) { |
151 | memcpy(&fdtmp, CMSG_DATA(cmsg), sizeof(fdtmp)); |
152 | if (*fd == -1) |
153 | *fd = fdtmp; |
154 | else |
155 | close(fdtmp); |
156 | } |
157 | } |
158 | #endif |
159 | return (rc); |
160 | } |
161 | |
162 | /*----- That's all, folks -------------------------------------------------*/ |