1 /* ISC license. */
2
3 #include <skalibs/nonposix.h>
4
5 #include <sys/socket.h>
6 #include <sys/uio.h>
7 #include <string.h>
8 #include <stdint.h>
9 #include <unistd.h>
10 #include <errno.h>
11
12 #include <skalibs/uint16.h>
13 #include <skalibs/uint32.h>
14 #include <skalibs/disize.h>
15 #include <skalibs/allreadwrite.h>
16 #include <skalibs/genalloc.h>
17 #include <skalibs/djbunix.h>
18 #include <skalibs/unixmessage.h>
19 #include <skalibs/posixishard.h>
20
21 union aligner_u
22 {
23 struct cmsghdr cmsghdr ;
24 int i ;
25 } ;
26
27
28 /*
29 XXX: sendmsg/recvmsg is badly, badly specified.
30 XXX: We assume ancillary data is attached to the first byte.
31 */
32
unixmessage_sender_flush(unixmessage_sender_t * b)33 int unixmessage_sender_flush (unixmessage_sender_t *b)
34 {
35 disize last = { .left = b->data.len, .right = genalloc_len(int, &b->fds) } ;
36 disize *offsets = genalloc_s(disize, &b->offsets) ;
37 size_t n = genalloc_len(disize, &b->offsets) ;
38 ssize_t r ;
39
40 if (b->shorty) /* we had a short write, gotta send the remainder first */
41 {
42 disize *next = b->head+1 < n ? offsets + b->head+1 : &last ;
43 size_t len = next->left - offsets[b->head].left ;
44 if (b->shorty <= len)
45 r = fd_write(b->fd, b->data.s + offsets[b->head].left + (len - b->shorty), b->shorty) ;
46 else
47 {
48 size_t nfds = next->right - offsets[b->head].right ;
49 char pack[6] ;
50 struct iovec v[2] =
51 {
52 { .iov_base = pack + 6 - (b->shorty - len), .iov_len = b->shorty - len },
53 { .iov_base = b->data.s + offsets[b->head].left, .iov_len = len }
54 } ;
55 uint32_pack_big(pack, (uint32_t)len) ;
56 uint16_pack_big(pack + 4, (uint16_t)nfds) ;
57 r = fd_writev(b->fd, v, 2) ;
58 }
59 if (r <= 0) return 0 ;
60 b->shorty -= r ;
61 if (b->shorty) return (errno = EWOULDBLOCK, 0) ;
62 }
63
64 for (; b->head < n ; b->head++)
65 {
66 disize *next = b->head+1 < n ? offsets + b->head+1 : &last ;
67 size_t len = next->left - offsets[b->head].left ;
68 size_t nfds = next->right - offsets[b->head].right ;
69 char pack[6] ;
70 struct iovec v[2] =
71 {
72 { .iov_base = pack, .iov_len = 6 },
73 { .iov_base = b->data.s + offsets[b->head].left, .iov_len = len }
74 } ;
75 union aligner_u ancilbuf[1 + CMSG_SPACE(nfds * sizeof(int)) / sizeof(union aligner_u)] ;
76 struct msghdr hdr =
77 {
78 .msg_name = 0,
79 .msg_namelen = 0,
80 .msg_iov = v,
81 .msg_iovlen = 2,
82 .msg_control = nfds ? ancilbuf : 0,
83 .msg_controllen = nfds ? CMSG_SPACE(nfds * sizeof(int)) : 0
84 } ;
85 uint32_pack_big(pack, (uint32_t)len) ;
86 uint16_pack_big(pack + 4, (uint16_t)nfds) ;
87 if (nfds)
88 {
89 struct cmsghdr *cp = CMSG_FIRSTHDR(&hdr) ;
90 size_t i = 0 ;
91 memset(hdr.msg_control, 0, hdr.msg_controllen) ;
92 cp->cmsg_level = SOL_SOCKET ;
93 cp->cmsg_type = SCM_RIGHTS ;
94 cp->cmsg_len = CMSG_LEN(nfds * sizeof(int)) ;
95 for (; i < nfds ; i++)
96 {
97 int fd = genalloc_s(int, &b->fds)[offsets[b->head].right + i] ;
98 ((int *)CMSG_DATA(cp))[i] = fd < 0 ? -(fd+1) : fd ;
99 }
100 }
101 do r = sendmsg(b->fd, &hdr, MSG_NOSIGNAL) ;
102 while (r < 0 && errno == EINTR) ;
103 if (r <= 0) return 0 ;
104 if (nfds)
105 {
106 size_t i = 0 ;
107 for (; i < nfds ; i++)
108 {
109 int fd = genalloc_s(int, &b->fds)[offsets[b->head].right + i] ;
110 if (fd < 0) (*b->closecb)(-(fd+1), b->closecbdata) ;
111 }
112 }
113 if ((size_t)r < 6 + len)
114 {
115 b->shorty = 6 + len - r ;
116 return (errno = EWOULDBLOCK, 0) ;
117 }
118 }
119 b->data.len = 0 ;
120 genalloc_setlen(int, &b->fds, 0) ;
121 genalloc_setlen(disize, &b->offsets, 0) ;
122 b->head = 0 ;
123 return 1 ;
124 }
125