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scm: Switch compel fd plugin onto common

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Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Pavel Emelyanov
2016-11-02 03:41:57 +03:00
committed by Andrei Vagin
parent e92c326692
commit 6606dc722c
3 changed files with 9 additions and 140 deletions
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18
compel/plugins/fds/fds.c
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@@ -1,3 +1,5 @@
#include <errno.h>
#include "uapi/plugins.h"
#include "uapi/std/syscall.h"
@@ -5,22 +7,14 @@
#include "uapi/plugin-fds.h"
#include "std-priv.h"
#include "log.h"
#include "common/compiler.h"
#include "common/bug.h"
#define __sys(foo) sys_##foo
#define __std(foo) std_##foo
#define __memcpy std_memcpy
#include "../../src/shared/fds.c"
int fds_send(int *fds, int nr_fds)
{
return fds_send_via(std_ctl_sock(), fds, nr_fds);
}
int fds_recv(int *fds, int nr_fds)
{
return fds_recv_via(std_ctl_sock(), fds, nr_fds);
}
#include "common/scm-code.c"
PLUGIN_REGISTER_DUMMY(fds)

18
compel/plugins/include/uapi/plugin-fds.h
View File

@@ -5,23 +5,11 @@
#ifndef __COMPEL_PLUGIN_FDS_H__
#define __COMPEL_PLUGIN_FDS_H__
extern int fds_send(int *fds, int nr_fds);
extern int fds_recv(int *fds, int nr_fds);
#include "common/scm.h"
static inline int fds_send_one(int fd)
static inline int send_fd(int sock, struct sockaddr_un *saddr, int saddr_len, int fd)
{
return fds_send(&fd, 1);
}
static inline int fds_recv_one(void)
{
int fd, ret;
ret = fds_recv(&fd, 1);
if (ret)
fd = -1;
return fd;
return send_fds(sock, saddr, saddr_len, &fd, 1, false);
}
#endif /* __COMPEL_PLUGIN_FDS_H__ */

113
compel/src/shared/fds.c
View File

@@ -1,113 +0,0 @@
#include <sys/socket.h>
#include <sys/un.h>
/*
* Because of kernel doing kmalloc for user data passed
* in SCM messages, and there is kernel's SCM_MAX_FD as a limit
* for descriptors passed at once we're trying to reduce
* the pressue on kernel memory manager and use predefined
* known to work well size of the message buffer.
*/
#define CR_SCM_MSG_SIZE (1024)
#define CR_SCM_MAX_FD (252)
struct scm_fdset {
struct msghdr hdr;
struct iovec iov;
char msg_buf[CR_SCM_MSG_SIZE];
char f;
};
static void scm_fdset_init_chunk(struct scm_fdset *fdset, int nr_fds)
{
struct cmsghdr *cmsg;
fdset->hdr.msg_controllen = CMSG_LEN(sizeof(int) * nr_fds);
cmsg = CMSG_FIRSTHDR(&fdset->hdr);
cmsg->cmsg_len = fdset->hdr.msg_controllen;
}
static int *scm_fdset_init(struct scm_fdset *fdset)
{
struct cmsghdr *cmsg;
BUILD_BUG_ON(sizeof(fdset->msg_buf) < (CMSG_SPACE(sizeof(int) * CR_SCM_MAX_FD)));
fdset->iov.iov_base = &fdset->f;
fdset->iov.iov_len = 1;
fdset->hdr.msg_iov = &fdset->iov;
fdset->hdr.msg_iovlen = 1;
fdset->hdr.msg_name = NULL;
fdset->hdr.msg_namelen = 0;
fdset->hdr.msg_control = &fdset->msg_buf;
fdset->hdr.msg_controllen = CMSG_LEN(sizeof(int) * CR_SCM_MAX_FD);
cmsg = CMSG_FIRSTHDR(&fdset->hdr);
cmsg->cmsg_len = fdset->hdr.msg_controllen;
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
return (int *)CMSG_DATA(cmsg);
}
int fds_send_via(int sock, int *fds, int nr_fds)
{
struct scm_fdset fdset;
int i, min_fd, ret;
int *cmsg_data;
cmsg_data = scm_fdset_init(&fdset);
for (i = 0; i < nr_fds; i += min_fd) {
min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
scm_fdset_init_chunk(&fdset, min_fd);
__std(memcpy(cmsg_data, &fds[i], sizeof(int) * min_fd));
ret = __sys(sendmsg(sock, &fdset.hdr, 0));
if (ret <= 0)
return ret ? : -1;
}
return 0;
}
int fds_recv_via(int sock, int *fds, int nr_fds)
{
struct scm_fdset fdset;
struct cmsghdr *cmsg;
int *cmsg_data;
int ret;
int i, min_fd;
cmsg_data = scm_fdset_init(&fdset);
for (i = 0; i < nr_fds; i += min_fd) {
min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
scm_fdset_init_chunk(&fdset, min_fd);
ret = __sys(recvmsg(sock, &fdset.hdr, 0));
if (ret <= 0)
return ret ? : -1;
cmsg = CMSG_FIRSTHDR(&fdset.hdr);
if (!cmsg || cmsg->cmsg_type != SCM_RIGHTS)
return -1;
if (fdset.hdr.msg_flags & MSG_CTRUNC)
return -2;
min_fd = (cmsg->cmsg_len - sizeof(struct cmsghdr)) / sizeof(int);
/*
* In case if kernel screwed the recepient, most probably
* the caller stack frame will be overwriten, just scream
* and exit.
*/
if (unlikely(min_fd > CR_SCM_MAX_FD))
*(volatile unsigned long *)NULL = 0xdead0000 + __LINE__;
if (unlikely(min_fd <= 0))
return -1;
__std(memcpy(&fds[i], cmsg_data, sizeof(int) * min_fd));
}
return 0;
}