1 2 #define _SYSTEM 1 3 4 #include <minix/callnr.h> 5 #include <minix/com.h> 6 #include <minix/config.h> 7 #include <minix/const.h> 8 #include <minix/ds.h> 9 #include <minix/endpoint.h> 10 #include <minix/minlib.h> 11 #include <minix/type.h> 12 #include <minix/ipc.h> 13 #include <minix/sysutil.h> 14 #include <minix/syslib.h> 15 #include <minix/debug.h> 16 #include <minix/bitmap.h> 17 18 #include <string.h> 19 #include <errno.h> 20 #include <env.h> 21 #include <assert.h> 22 23 #include "glo.h" 24 #include "vm.h" 25 #include "proto.h" 26 #include "util.h" 27 #include "sanitycheck.h" 28 #include "region.h" 29 30 /*===========================================================================* 31 * do_fork * 32 *===========================================================================*/ 33 int do_fork(message *msg) 34 { 35 int r, proc, childproc; 36 struct vmproc *vmp, *vmc; 37 pt_t origpt; 38 vir_bytes msgaddr; 39 40 SANITYCHECK(SCL_FUNCTIONS); 41 42 if(vm_isokendpt(msg->VMF_ENDPOINT, &proc) != OK) { 43 printf("VM: bogus endpoint VM_FORK %d\n", msg->VMF_ENDPOINT); 44 SANITYCHECK(SCL_FUNCTIONS); 45 return EINVAL; 46 } 47 48 childproc = msg->VMF_SLOTNO; 49 if(childproc < 0 || childproc >= NR_PROCS) { 50 printf("VM: bogus slotno VM_FORK %d\n", msg->VMF_SLOTNO); 51 SANITYCHECK(SCL_FUNCTIONS); 52 return EINVAL; 53 } 54 55 vmp = &vmproc[proc]; /* parent */ 56 vmc = &vmproc[childproc]; /* child */ 57 assert(vmc->vm_slot == childproc); 58 59 /* The child is basically a copy of the parent. */ 60 origpt = vmc->vm_pt; 61 *vmc = *vmp; 62 vmc->vm_slot = childproc; 63 region_init(&vmc->vm_regions_avl); 64 vmc->vm_endpoint = NONE; /* In case someone tries to use it. */ 65 vmc->vm_pt = origpt; 66 67 #if VMSTATS 68 vmc->vm_bytecopies = 0; 69 #endif 70 71 if(pt_new(&vmc->vm_pt) != OK) { 72 return ENOMEM; 73 } 74 75 SANITYCHECK(SCL_DETAIL); 76 77 if(map_proc_copy(vmc, vmp) != OK) { 78 printf("VM: fork: map_proc_copy failed\n"); 79 pt_free(&vmc->vm_pt); 80 return(ENOMEM); 81 } 82 83 /* Only inherit these flags. */ 84 vmc->vm_flags &= VMF_INUSE; 85 86 /* Deal with ACLs. */ 87 acl_fork(vmc); 88 89 /* Tell kernel about the (now successful) FORK. */ 90 if((r=sys_fork(vmp->vm_endpoint, childproc, 91 &vmc->vm_endpoint, PFF_VMINHIBIT, &msgaddr)) != OK) { 92 panic("do_fork can't sys_fork: %d", r); 93 } 94 95 if((r=pt_bind(&vmc->vm_pt, vmc)) != OK) 96 panic("fork can't pt_bind: %d", r); 97 98 { 99 vir_bytes vir; 100 /* making these messages writable is an optimisation 101 * and its return value needn't be checked. 102 */ 103 vir = msgaddr; 104 if (handle_memory_once(vmc, vir, sizeof(message), 1) != OK) 105 panic("do_fork: handle_memory for child failed\n"); 106 vir = msgaddr; 107 if (handle_memory_once(vmp, vir, sizeof(message), 1) != OK) 108 panic("do_fork: handle_memory for parent failed\n"); 109 } 110 111 /* Inform caller of new child endpoint. */ 112 msg->VMF_CHILD_ENDPOINT = vmc->vm_endpoint; 113 114 SANITYCHECK(SCL_FUNCTIONS); 115 return OK; 116 } 117 118