mirror of
https://github.com/checkpoint-restore/criu
synced 2025-08-22 01:51:51 +00:00
0194ed392f
Brought to you by codespell -w (using codespell v2.1.0). Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
118 lines
3.1 KiB
C
118 lines
3.1 KiB
C
#ifndef __sys
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#error "The __sys macro is required"
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#endif
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static void scm_fdset_init_chunk(struct scm_fdset *fdset, int nr_fds, void *data, unsigned ch_size)
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{
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struct cmsghdr *cmsg;
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static char dummy;
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fdset->hdr.msg_controllen = CMSG_LEN(sizeof(int) * nr_fds);
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cmsg = CMSG_FIRSTHDR(&fdset->hdr);
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cmsg->cmsg_len = fdset->hdr.msg_controllen;
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if (data) {
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fdset->iov.iov_base = data;
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fdset->iov.iov_len = nr_fds * ch_size;
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} else {
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fdset->iov.iov_base = &dummy;
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fdset->iov.iov_len = 1;
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}
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}
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static int *scm_fdset_init(struct scm_fdset *fdset, struct sockaddr_un *saddr, int saddr_len)
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{
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struct cmsghdr *cmsg;
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BUILD_BUG_ON(sizeof(fdset->msg_buf) < (CMSG_SPACE(sizeof(int) * CR_SCM_MAX_FD)));
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fdset->iov.iov_base = (void *)0xdeadbeef;
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fdset->hdr.msg_iov = &fdset->iov;
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fdset->hdr.msg_iovlen = 1;
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fdset->hdr.msg_name = (struct sockaddr *)saddr;
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fdset->hdr.msg_namelen = saddr_len;
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fdset->hdr.msg_control = &fdset->msg_buf;
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fdset->hdr.msg_controllen = CMSG_LEN(sizeof(int) * CR_SCM_MAX_FD);
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cmsg = CMSG_FIRSTHDR(&fdset->hdr);
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cmsg->cmsg_len = fdset->hdr.msg_controllen;
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cmsg->cmsg_level = SOL_SOCKET;
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cmsg->cmsg_type = SCM_RIGHTS;
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return (int *)CMSG_DATA(cmsg);
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}
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int send_fds(int sock, struct sockaddr_un *saddr, int len, int *fds, int nr_fds, void *data, unsigned ch_size)
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{
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/* In musl_libc the msghdr structure has pads which has to be zeroed */
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struct scm_fdset fdset = {};
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int *cmsg_data;
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int i, min_fd, ret;
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cmsg_data = scm_fdset_init(&fdset, saddr, len);
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for (i = 0; i < nr_fds; i += min_fd) {
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min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
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scm_fdset_init_chunk(&fdset, min_fd, data, ch_size);
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memcpy(cmsg_data, &fds[i], sizeof(int) * min_fd);
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ret = __sys(sendmsg)(sock, &fdset.hdr, 0);
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if (ret <= 0)
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return ret ?: -1;
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if (data)
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data += min_fd * ch_size;
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}
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return 0;
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}
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int __recv_fds(int sock, int *fds, int nr_fds, void *data, unsigned ch_size, int flags)
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{
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/* In musl_libc the msghdr structure has pads which has to be zeroed */
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struct scm_fdset fdset = {};
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struct cmsghdr *cmsg;
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int *cmsg_data;
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int ret;
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int i, min_fd;
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cmsg_data = scm_fdset_init(&fdset, NULL, 0);
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for (i = 0; i < nr_fds; i += min_fd) {
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min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
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scm_fdset_init_chunk(&fdset, min_fd, data, ch_size);
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ret = __sys(recvmsg)(sock, &fdset.hdr, flags);
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if (ret <= 0)
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return ret ? __sys_err(ret) : -ENOMSG;
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cmsg = CMSG_FIRSTHDR(&fdset.hdr);
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if (!cmsg || cmsg->cmsg_type != SCM_RIGHTS)
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return -EINVAL;
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if (fdset.hdr.msg_flags & MSG_CTRUNC)
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return -ENFILE;
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min_fd = (cmsg->cmsg_len - sizeof(struct cmsghdr)) / sizeof(int);
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/*
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* In case if kernel screwed the recipient, most probably
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* the caller stack frame will be overwritten, just scream
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* and exit.
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*
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* FIXME Need to sanitize util.h to be able to include it
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* into files which do not have glibc and a couple of
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* sys_write_ helpers. Meawhile opencoded BUG_ON here.
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*/
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BUG_ON(min_fd > CR_SCM_MAX_FD);
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if (unlikely(min_fd <= 0))
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return -EBADFD;
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memcpy(&fds[i], cmsg_data, sizeof(int) * min_fd);
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if (data)
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data += ch_size * min_fd;
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}
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return 0;
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}
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