1
2 /* Sending requests to VFS and handling the replies. */
3
4 #define _SYSTEM 1
5
6 #include <minix/callnr.h>
7 #include <minix/com.h>
8 #include <minix/config.h>
9 #include <minix/const.h>
10 #include <minix/ds.h>
11 #include <minix/endpoint.h>
12 #include <minix/minlib.h>
13 #include <minix/type.h>
14 #include <minix/ipc.h>
15 #include <minix/sysutil.h>
16 #include <minix/syslib.h>
17 #include <minix/type.h>
18 #include <minix/bitmap.h>
19 #include <string.h>
20 #include <errno.h>
21 #include <unistd.h>
22 #include <assert.h>
23 #include <sys/param.h>
24
25 #include "proto.h"
26 #include "glo.h"
27 #include "util.h"
28 #include "region.h"
29 #include "sanitycheck.h"
30
31 #define STATELEN 70
32
33 static struct vfs_request_node {
34 message reqmsg;
35 char reqstate[STATELEN];
36 void *opaque;
37 endpoint_t who;
38 int req_id;
39 vfs_callback_t callback;
40 struct vfs_request_node *next;
41 } *first_queued, *active;
42
activate(void)43 static void activate(void)
44 {
45 assert(!active);
46 assert(first_queued);
47
48 active = first_queued;
49 first_queued = first_queued->next;
50
51 if(asynsend3(VFS_PROC_NR, &active->reqmsg, AMF_NOREPLY) != OK)
52 panic("VM: asynsend to VFS failed");
53 }
54
55 #define ID_MAX LONG_MAX
56
57 /*===========================================================================*
58 * vfs_request *
59 *===========================================================================*/
vfs_request(int reqno,int fd,struct vmproc * vmp,u64_t offset,u32_t len,vfs_callback_t reply_callback,void * cbarg,void * state,int statelen)60 int vfs_request(int reqno, int fd, struct vmproc *vmp, u64_t offset, u32_t len,
61 vfs_callback_t reply_callback, void *cbarg, void *state, int statelen)
62 {
63 /* Perform an asynchronous request to VFS.
64 * We send a message of type VFS_VMCALL to VFS. VFS will respond
65 * with message type VM_VFS_REPLY. We send the request asynchronously
66 * and then handle the reply as it if were a VM_VFS_REPLY request.
67 */
68 message *m;
69 static int reqid = 0;
70 struct vfs_request_node *reqnode;
71
72 reqid++;
73
74 assert(statelen <= STATELEN);
75
76 if(!SLABALLOC(reqnode)) {
77 printf("vfs_request: no memory for request node\n");
78 return ENOMEM;
79 }
80
81 m = &reqnode->reqmsg;
82 memset(m, 0, sizeof(*m));
83 m->m_type = VFS_VMCALL;
84 m->VFS_VMCALL_REQ = reqno;
85 m->VFS_VMCALL_FD = fd;
86 m->VFS_VMCALL_REQID = reqid;
87 m->VFS_VMCALL_ENDPOINT = vmp->vm_endpoint;
88 m->VFS_VMCALL_OFFSET = offset;
89 m->VFS_VMCALL_LENGTH = len;
90
91 reqnode->who = vmp->vm_endpoint;
92 reqnode->req_id = reqid;
93 reqnode->next = first_queued;
94 reqnode->callback = reply_callback;
95 reqnode->opaque = cbarg;
96 if(state) memcpy(reqnode->reqstate, state, statelen);
97 first_queued = reqnode;
98
99 /* Send the request message if none pending. */
100 if(!active)
101 activate();
102
103 return OK;
104 }
105
106 /*===========================================================================*
107 * do_vfs_reply *
108 *===========================================================================*/
do_vfs_reply(message * m)109 int do_vfs_reply(message *m)
110 {
111 /* VFS has handled a VM request and VFS has replied. It must be the
112 * active request.
113 */
114 struct vfs_request_node *orignode = active;
115 vfs_callback_t req_callback;
116 void *cbarg;
117 int n;
118 struct vmproc *vmp;
119
120 assert(active);
121 assert(active->req_id == m->VMV_REQID);
122
123 /* the endpoint may have exited */
124 if(vm_isokendpt(m->VMV_ENDPOINT, &n) != OK)
125 vmp = NULL;
126 else vmp = &vmproc[n];
127
128 req_callback = active->callback;
129 cbarg = active->opaque;
130 active = NULL;
131
132 /* Invoke requested reply-callback within VM. */
133 if(req_callback) req_callback(vmp, m, cbarg, orignode->reqstate);
134
135 SLABFREE(orignode);
136
137 /* Send the next request message if any and not re-activated. */
138 if(first_queued && !active)
139 activate();
140
141 return SUSPEND; /* don't reply to the reply */
142 }
143
144