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authorM. Mohan Kumar <mohan@in.ibm.com>2011-12-14 13:58:44 +0530
committerAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2012-01-04 20:14:28 +0530
commitdaf0b9aca9f67323266af1a92e8ea06f9d7bf408 (patch)
tree6c66baf222b8efb19a1dab88334add4d9275d96c /fsdev/virtfs-proxy-helper.c
parent17bff52b6225419931703aa04cc454c16cf5adad (diff)
hw/9pfs: Open and create files
Add interfaces to open and create files for proxy file system driver. Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Diffstat (limited to 'fsdev/virtfs-proxy-helper.c')
-rw-r--r--fsdev/virtfs-proxy-helper.c179
1 files changed, 176 insertions, 3 deletions
diff --git a/fsdev/virtfs-proxy-helper.c b/fsdev/virtfs-proxy-helper.c
index 5fc2fc41a..e0af257f2 100644
--- a/fsdev/virtfs-proxy-helper.c
+++ b/fsdev/virtfs-proxy-helper.c
@@ -9,6 +9,7 @@
* the COPYING file in the top-level directory.
*/
#include <stdio.h>
+#include <sys/socket.h>
#include <string.h>
#include <sys/un.h>
#include <limits.h>
@@ -27,6 +28,7 @@
#include "qemu-common.h"
#include "virtio-9p-marshal.h"
#include "hw/9pfs/virtio-9p-proxy.h"
+#include "fsdev/virtio-9p-marshal.h"
#define PROGNAME "virtfs-proxy-helper"
@@ -187,6 +189,140 @@ static int read_request(int sockfd, struct iovec *iovec, ProxyHeader *header)
return 0;
}
+static int send_fd(int sockfd, int fd)
+{
+ struct msghdr msg;
+ struct iovec iov;
+ int retval, data;
+ struct cmsghdr *cmsg;
+ union MsgControl msg_control;
+
+ iov.iov_base = &data;
+ iov.iov_len = sizeof(data);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ /* No ancillary data on error */
+ if (fd < 0) {
+ /* fd is really negative errno if the request failed */
+ data = fd;
+ } else {
+ data = V9FS_FD_VALID;
+ msg.msg_control = &msg_control;
+ msg.msg_controllen = sizeof(msg_control);
+
+ cmsg = &msg_control.cmsg;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+ }
+
+ do {
+ retval = sendmsg(sockfd, &msg, 0);
+ } while (retval < 0 && errno == EINTR);
+ if (fd >= 0) {
+ close(fd);
+ }
+ if (retval < 0) {
+ return retval;
+ }
+ return 0;
+}
+
+/*
+ * from man 7 capabilities, section
+ * Effect of User ID Changes on Capabilities:
+ * 4. If the file system user ID is changed from 0 to nonzero (see setfsuid(2))
+ * then the following capabilities are cleared from the effective set:
+ * CAP_CHOWN, CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID,
+ * CAP_LINUX_IMMUTABLE (since Linux 2.2.30), CAP_MAC_OVERRIDE, and CAP_MKNOD
+ * (since Linux 2.2.30). If the file system UID is changed from nonzero to 0,
+ * then any of these capabilities that are enabled in the permitted set
+ * are enabled in the effective set.
+ */
+static int setfsugid(int uid, int gid)
+{
+ /*
+ * We still need DAC_OVERRIDE because we don't change
+ * supplementary group ids, and hence may be subjected DAC rules
+ */
+ cap_value_t cap_list[] = {
+ CAP_DAC_OVERRIDE,
+ };
+
+ setfsgid(gid);
+ setfsuid(uid);
+
+ if (uid != 0 || gid != 0) {
+ return do_cap_set(cap_list, ARRAY_SIZE(cap_list), 0);
+ }
+ return 0;
+}
+
+/*
+ * create a file and send fd on success
+ * return -errno on error
+ */
+static int do_create(struct iovec *iovec)
+{
+ int ret;
+ V9fsString path;
+ int flags, mode, uid, gid, cur_uid, cur_gid;
+
+ v9fs_string_init(&path);
+ ret = proxy_unmarshal(iovec, PROXY_HDR_SZ, "sdddd",
+ &path, &flags, &mode, &uid, &gid);
+ if (ret < 0) {
+ goto unmarshal_err_out;
+ }
+ cur_uid = geteuid();
+ cur_gid = getegid();
+ ret = setfsugid(uid, gid);
+ if (ret < 0) {
+ /*
+ * On failure reset back to the
+ * old uid/gid
+ */
+ ret = -errno;
+ goto err_out;
+ }
+ ret = open(path.data, flags, mode);
+ if (ret < 0) {
+ ret = -errno;
+ }
+
+err_out:
+ setfsugid(cur_uid, cur_gid);
+unmarshal_err_out:
+ v9fs_string_free(&path);
+ return ret;
+}
+
+/*
+ * open a file and send fd on success
+ * return -errno on error
+ */
+static int do_open(struct iovec *iovec)
+{
+ int flags, ret;
+ V9fsString path;
+
+ v9fs_string_init(&path);
+ ret = proxy_unmarshal(iovec, PROXY_HDR_SZ, "sd", &path, &flags);
+ if (ret < 0) {
+ goto err_out;
+ }
+ ret = open(path.data, flags);
+ if (ret < 0) {
+ ret = -errno;
+ }
+err_out:
+ v9fs_string_free(&path);
+ return ret;
+}
+
static void usage(char *prog)
{
fprintf(stderr, "usage: %s\n"
@@ -196,22 +332,59 @@ static void usage(char *prog)
basename(prog));
}
+static int process_reply(int sock, int type, int retval)
+{
+ switch (type) {
+ case T_OPEN:
+ case T_CREATE:
+ if (send_fd(sock, retval) < 0) {
+ return -1;
+ }
+ break;
+ default:
+ return -1;
+ break;
+ }
+ return 0;
+}
+
static int process_requests(int sock)
{
- int retval;
+ int retval = 0;
ProxyHeader header;
struct iovec in_iovec;
in_iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
in_iovec.iov_len = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
while (1) {
+ /*
+ * initialize the header type, so that we send
+ * response to proper request type.
+ */
+ header.type = 0;
retval = read_request(sock, &in_iovec, &header);
if (retval < 0) {
- goto error;
+ goto err_out;
+ }
+
+ switch (header.type) {
+ case T_OPEN:
+ retval = do_open(&in_iovec);
+ break;
+ case T_CREATE:
+ retval = do_create(&in_iovec);
+ break;
+ default:
+ goto err_out;
+ break;
+ }
+
+ if (process_reply(sock, header.type, retval) < 0) {
+ goto err_out;
}
}
(void)socket_write;
-error:
+err_out:
g_free(in_iovec.iov_base);
return -1;
}