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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * File descriptor passing |
6 | * |
7 | * (c) 2003 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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18 | * |
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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. |
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23 | * |
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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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <errno.h> |
33 | #include <stdio.h> |
34 | #include <stdlib.h> |
35 | #include <string.h> |
36 | |
37 | #include <sys/types.h> |
38 | #include <sys/time.h> |
39 | #include <unistd.h> |
40 | #include <sys/socket.h> |
41 | #include <sys/uio.h> |
42 | #include <sys/un.h> |
43 | |
44 | #include "fdpass.h" |
45 | |
46 | /*----- Main code ---------------------------------------------------------*/ |
47 | |
48 | /* --- @fdpass_send@ --- * |
49 | * |
50 | * Arguments: @int sock@ = socket to send over |
51 | * @int fd@ = file descriptor to send |
52 | * @const void *p@ = pointer to data to send |
53 | * @size_t sz@ = size of buffer to send |
54 | * |
55 | * Returns: On error, @-1@, otherwise number of bytes transferred from |
56 | * @p@. |
57 | * |
58 | * Use: Sends a copy of file descriptor @fd@ to the other end of |
59 | * @sock@. |
60 | */ |
61 | |
62 | ssize_t fdpass_send(int sock, int fd, const void *p, size_t sz) |
63 | { |
64 | struct iovec iov; |
65 | struct msghdr msg; |
66 | #ifndef HAVE_MSG_ACCRIGHTS |
67 | char buf[CMSG_SPACE(sizeof(fd))]; |
68 | struct cmsghdr *cmsg; |
69 | #endif |
70 | |
71 | iov.iov_base = (/*unconst*/ void *)p; |
72 | iov.iov_len = sz; |
73 | msg.msg_name = 0; |
74 | msg.msg_namelen = 0; |
75 | msg.msg_iov = &iov; |
76 | msg.msg_iovlen = 1; |
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77 | #ifdef HAVE_MSG_ACCRIGHTS |
78 | msg.msg_accrights = &fd; |
79 | msg.msg_accrightslen = sizeof(fd); |
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80 | #else |
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81 | msg.msg_flags = 0; |
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82 | msg.msg_control = buf; |
83 | msg.msg_controllen = sizeof(buf); |
84 | cmsg = CMSG_FIRSTHDR(&msg); |
85 | cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); |
86 | cmsg->cmsg_level = SOL_SOCKET; |
87 | cmsg->cmsg_type = SCM_RIGHTS; |
88 | memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd)); |
89 | #endif |
90 | return (sendmsg(sock, &msg, 0)); |
91 | } |
92 | |
93 | /* --- @fdpass_recv@ --- * |
94 | * |
95 | * Arguments: @int sock@ = socket to send over |
96 | * @int *fd@ = where to put received descriptor |
97 | * @void *p@ = pointer to where to put data |
98 | * @size_t sz@ = size of buffer |
99 | * |
100 | * Returns: On error, @-1@, otherwise number of bytes transferred. |
101 | * |
102 | * Use: Receives a file descriptor. If the call succeeds, and there |
103 | * was a file descriptor, then @fd@ won't be @-1@ on exit; |
104 | * otherwise it will. At most one descriptor will be collected. |
105 | */ |
106 | |
107 | ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz) |
108 | { |
109 | struct iovec iov; |
110 | struct msghdr msg; |
111 | ssize_t rc; |
112 | #ifndef HAVE_MSG_ACCRIGHTS |
113 | char buf[CMSG_SPACE(sizeof(fd))]; |
114 | struct cmsghdr *cmsg; |
115 | int fdtmp; |
116 | #endif |
117 | |
118 | *fd = -1; |
119 | iov.iov_base = p; |
120 | iov.iov_len = sz; |
121 | msg.msg_name = 0; |
122 | msg.msg_namelen = 0; |
123 | msg.msg_iov = &iov; |
124 | msg.msg_iovlen = 1; |
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125 | #ifdef HAVE_MSG_ACCRIGHTS |
126 | msg.msg_accrights = fd; |
127 | msg.msg_accrightslen = sizeof(*fd); |
128 | #else |
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129 | msg.msg_flags = 0; |
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130 | msg.msg_control = buf; |
131 | msg.msg_controllen = sizeof(buf); |
132 | #endif |
133 | if ((rc = recvmsg(sock, &msg, 0)) < 0) |
134 | return (rc); |
135 | #ifdef HAVE_MSG_ACCRIGHTS |
136 | if (msg.msg_accrightslen < sizeof(*fd)) |
137 | *fd = -1; |
138 | #else |
139 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
140 | if (cmsg->cmsg_level == SOL_SOCKET && |
141 | cmsg->cmsg_type == SCM_RIGHTS && |
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142 | cmsg->cmsg_len >= CMSG_LEN(sizeof(fd))) { |
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143 | memcpy(&fdtmp, CMSG_DATA(cmsg), sizeof(fdtmp)); |
144 | if (*fd == -1) |
145 | *fd = fdtmp; |
146 | else |
147 | close(fdtmp); |
148 | } |
149 | } |
150 | #endif |
151 | return (rc); |
152 | } |
153 | |
154 | /*----- That's all, folks -------------------------------------------------*/ |