1 #include <sys/cdefs.h>
2 #include <sys/proc_internal.h>
3 #include <sys/vnode_internal.h>
4 #include <sys/ubc_internal.h>
5 #include <sys/file_internal.h>
6 #include <sys/vnode.h>
7
8 // From vm_parameter_validation_kern.c
9 void testprintf(const char *format, ...);
10
11 struct file_control_return {
12 void * control;
13 struct fileproc * fp;
14 struct vnode * vp;
15 int fd;
16 };
17 struct file_control_return get_control_from_fd(int fd);
18
19 struct file_control_return
get_control_from_fd(int fd)20 get_control_from_fd(int fd)
21 {
22 struct fileproc *fp = NULL;
23 struct vnode *vp = NULL;
24 size_t file_size;
25 off_t fs;
26 memory_object_control_t file_control = NULL;
27 int error;
28 struct file_control_return ret = {NULL, NULL, NULL, fd};
29
30
31 proc_t p = current_proc();
32
33 /* get file structure from file descriptor */
34 error = fp_get_ftype(p, fd, DTYPE_VNODE, EINVAL, &fp);
35 if (error) {
36 testprintf("%s: [%d(%s)]: fp_get_ftype() failed, error %d\n",
37 __func__, proc_getpid(p), p->p_comm, error);
38 return ret;
39 }
40 ret.fp = fp;
41
42 /* We need at least read permission on the file */
43 if (!(fp->fp_glob->fg_flag & FREAD)) {
44 testprintf("%s: [%d(%s)]: not readable\n",
45 __func__, proc_getpid(p), p->p_comm);
46 return ret;
47 }
48
49 /* Get the vnode from file structure */
50 vp = (struct vnode *)fp_get_data(fp);
51 error = vnode_getwithref(vp);
52 if (error) {
53 testprintf("%s: [%d(%s)]: failed to get vnode, error %d\n",
54 __func__, proc_getpid(p), p->p_comm, error);
55 return ret;
56 }
57 ret.vp = vp;
58
59 /* Make sure the vnode is a regular file */
60 if (vp->v_type != VREG) {
61 testprintf("%s: [%d(%s)]: vnode not VREG\n",
62 __func__, proc_getpid(p), p->p_comm);
63 return ret;
64 }
65
66 /* get vnode size */
67 error = vnode_size(vp, &fs, vfs_context_current());
68 if (error) {
69 return ret;
70 }
71 file_size = fs;
72
73 /* get the file's memory object handle */
74 file_control = ubc_getobject(vp, UBC_HOLDOBJECT);
75 if (file_control == MEMORY_OBJECT_CONTROL_NULL) {
76 testprintf("%s: [%d(%s)]: no memory object\n",
77 __func__, proc_getpid(p), p->p_comm);
78 return ret;
79 }
80 ret.control = file_control;
81
82 return ret;
83 }
84
85 void cleanup_control_related_data(struct file_control_return info);
86
87 void
cleanup_control_related_data(struct file_control_return info)88 cleanup_control_related_data(struct file_control_return info)
89 {
90 if (info.fp != NULL) {
91 /* release the file descriptor */
92 fp_drop(current_proc(), info.fd, info.fp, 0);
93 }
94 if (info.vp != NULL) {
95 (void)vnode_put(info.vp);
96 }
97 }
98