Annotation of src/usr.bin/cvs/msg.c, Revision 1.4
1.1 jfb 1: /* $OpenBSD$ */
2: /*
1.2 jfb 3: * Copyright (c) 2002 Matthieu Herrb
4: * Copyright (c) 2001 Niels Provos <provos@citi.umich.edu>
5: * Copyright (c) 2004 Jean-Francois Brousseau
1.1 jfb 6: *
1.2 jfb 7: * Permission to use, copy, modify, and distribute this software for any
8: * purpose with or without fee is hereby granted, provided that the above
9: * copyright notice and this permission notice appear in all copies.
10: *
11: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15: * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
16: * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
17: * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18: *
19: * This code was adapted from the tcpdump source
1.1 jfb 20: */
21:
22: #include <sys/param.h>
1.2 jfb 23: #include <sys/socket.h>
1.1 jfb 24: #include <sys/uio.h>
25:
1.2 jfb 26: #include <errno.h>
1.1 jfb 27: #include <fcntl.h>
28: #include <stdlib.h>
29: #include <unistd.h>
30: #include <string.h>
31:
32: #include "log.h"
33: #include "cvsd.h"
34:
1.2 jfb 35: /*
36: * cvsd_sendfd()
37: *
38: * Pass a file descriptor <fd> to the other endpoint of the socket <sock>.
39: */
1.1 jfb 40:
1.2 jfb 41: int
42: cvsd_sendfd(int sock, int fd)
43: {
44: struct msghdr msg;
45: char tmp[CMSG_SPACE(sizeof(int))];
46: struct cmsghdr *cmsg;
47: struct iovec vec;
48: int result = 0;
49: ssize_t n;
50:
51: memset(&msg, 0, sizeof(msg));
52:
53: if (fd >= 0) {
54: msg.msg_control = (caddr_t)tmp;
55: msg.msg_controllen = CMSG_LEN(sizeof(int));
56: cmsg = CMSG_FIRSTHDR(&msg);
57: cmsg->cmsg_len = CMSG_LEN(sizeof(int));
58: cmsg->cmsg_level = SOL_SOCKET;
59: cmsg->cmsg_type = SCM_RIGHTS;
60: *(int *)CMSG_DATA(cmsg) = fd;
61: } else
62: result = errno;
63:
64: vec.iov_base = &result;
65: vec.iov_len = sizeof(int);
66: msg.msg_iov = &vec;
67: msg.msg_iovlen = 1;
68:
69: if ((n = sendmsg(sock, &msg, 0)) == -1) {
70: cvs_log(LP_ERRNO, "failed to pass file descriptor");
71: return (-1);
72: }
73: if (n != sizeof(int))
74: cvs_log(LP_WARN, "unexpected return count from sendmsg()");
75: return (0);
76: }
77:
78: /*
79: * cvsd_recvfd()
80: *
81: * Receive a file descriptor over the socket <sock>. Returns the descriptor
82: * on success, or -1 on failure.
83: */
84:
85: int
86: cvsd_recvfd(int sock)
87: {
88: struct msghdr msg;
89: char tmp[CMSG_SPACE(sizeof(int))];
90: struct cmsghdr *cmsg;
91: struct iovec vec;
92: ssize_t n;
93: int result;
94: int fd;
95:
96: memset(&msg, 0, sizeof(msg));
97: vec.iov_base = &result;
98: vec.iov_len = sizeof(int);
99: msg.msg_iov = &vec;
100: msg.msg_iovlen = 1;
101: msg.msg_control = tmp;
102: msg.msg_controllen = sizeof(tmp);
103:
104: if ((n = recvmsg(sock, &msg, 0)) == -1)
105: cvs_log(LP_ERRNO, "failed to receive descriptor");
106: if (n != sizeof(int))
107: cvs_log(LP_WARN, "recvmsg: expected received 1 got %ld",
108: (long)n);
109: if (result == 0) {
110: cmsg = CMSG_FIRSTHDR(&msg);
111: if (cmsg->cmsg_type != SCM_RIGHTS)
112: cvs_log(LP_WARN,
113: "unexpected message type in descriptor reception");
114: fd = (*(int *)CMSG_DATA(cmsg));
115: return (fd);
116: } else {
117: errno = result;
118: return (-1);
119: }
120: }
1.1 jfb 121:
122:
123:
124: /*
125: * cvsd_sendmsg()
126: *
127: * Send a message of type <type> along with the first <len> bytes of data
128: * from <data> (which can be up to CVSD_MSG_MAXLEN bytes) on the descriptor
129: * <fd>.
130: * Returns 0 on success, or -1 on failure.
131: */
132:
133: int
134: cvsd_sendmsg(int fd, u_int type, const void *data, size_t len)
135: {
1.2 jfb 136: int cnt;
1.1 jfb 137: struct iovec iov[2];
138: struct cvsd_msg msg;
139:
140: if (len > CVSD_MSG_MAXLEN) {
141: cvs_log(LP_ERR, "message too large");
142: return (-1);
143: }
144:
1.2 jfb 145: memset(&msg, 0, sizeof(msg));
1.1 jfb 146:
1.2 jfb 147: cnt = 1;
1.1 jfb 148: iov[0].iov_base = &msg;
149: iov[0].iov_len = sizeof(msg);
1.2 jfb 150: msg.cm_type = type;
151:
152: if (type != CVSD_MSG_PASSFD) {
153: msg.cm_len = len;
154: iov[1].iov_base = (void *)data;
155: iov[1].iov_len = len;
156: cnt = 2;
157: }
158: else
159: msg.cm_len = sizeof(int); /* dummy */
1.1 jfb 160:
1.2 jfb 161: if (writev(fd, iov, cnt) == -1) {
1.1 jfb 162: cvs_log(LP_ERRNO, "failed to send message");
163: return (-1);
164: }
165:
1.2 jfb 166: if (type == CVSD_MSG_PASSFD) {
167: /* pass the file descriptor for real */
168: cvsd_sendfd(fd, *(int *)data);
169: }
170:
1.1 jfb 171: return (0);
172: }
173:
174:
175: /*
176: * cvsd_recvmsg()
177: *
178: * Read a message from the file descriptor <fd> and store the message data
179: * in the <dst> buffer. The <len> parameter should contain the maximum
180: * length of data that can be stored in <dst>, and will contain the actual
181: * size of data stored on return. The message type is stored in <type>.
1.3 jfb 182: * Returns 1 if a message was read, 0 if the remote end closed the message
183: * socket and no further messages can be read, or -1 on failure.
1.1 jfb 184: */
185:
186: int
187: cvsd_recvmsg(int fd, u_int *type, void *dst, size_t *len)
188: {
1.2 jfb 189: int sfd;
1.1 jfb 190: ssize_t ret;
191: struct cvsd_msg msg;
192:
1.3 jfb 193: if ((ret = read(fd, &msg, sizeof(msg))) == -1) {
1.1 jfb 194: cvs_log(LP_ERRNO, "failed to read message header");
195: return (-1);
196: }
1.3 jfb 197: else if (ret == 0)
198: return (0);
1.1 jfb 199:
200: if (*len < msg.cm_len) {
201: cvs_log(LP_ERR, "buffer size too small for message data");
202: return (-1);
203: }
204:
1.2 jfb 205: if (msg.cm_type == CVSD_MSG_PASSFD) {
206: sfd = cvsd_recvfd(fd);
207: if (sfd == -1)
208: return (-1);
209:
210: *(int *)dst = sfd;
211: *len = sizeof(sfd);
1.1 jfb 212: }
1.2 jfb 213: else {
214: ret = read(fd, dst, msg.cm_len);
215: if (ret == -1) {
216: cvs_log(LP_ERRNO, "failed to read message");
217: return (-1);
218: }
219: else if (ret == 0) {
220: }
221:
222: *len = (size_t)ret;
1.1 jfb 223: }
224:
225: *type = msg.cm_type;
226:
1.4 ! jfb 227: return (1);
1.1 jfb 228: }
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