1 /* 2 * linux/ipc/msgutil.c 3 * Copyright (C) 1999, 2004 Manfred Spraul 4 * 5 * This file is released under GNU General Public Licence version 2 or 6 * (at your option) any later version. 7 * 8 * See the file COPYING for more details. 9 */ 10 11 #include <linux/spinlock.h> 12 #include <linux/init.h> 13 #include <linux/security.h> 14 #include <linux/slab.h> 15 #include <linux/ipc.h> 16 #include <linux/msg.h> 17 #include <linux/ipc_namespace.h> 18 #include <linux/utsname.h> 19 #include <linux/proc_fs.h> 20 #include <asm/uaccess.h> 21 22 #include "util.h" 23 24 DEFINE_SPINLOCK(mq_lock); 25 26 /* 27 * The next 2 defines are here bc this is the only file 28 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE 29 * and not CONFIG_IPC_NS. 30 */ 31 struct ipc_namespace init_ipc_ns = { 32 .count = ATOMIC_INIT(1), 33 .user_ns = &init_user_ns, 34 .proc_inum = PROC_IPC_INIT_INO, 35 }; 36 37 atomic_t nr_ipc_ns = ATOMIC_INIT(1); 38 39 struct msg_msgseg { 40 struct msg_msgseg* next; 41 /* the next part of the message follows immediately */ 42 }; 43 44 #define DATALEN_MSG (int)(PAGE_SIZE-sizeof(struct msg_msg)) 45 #define DATALEN_SEG (int)(PAGE_SIZE-sizeof(struct msg_msgseg)) 46 47 struct msg_msg *load_msg(const void __user *src, int len) 48 { 49 struct msg_msg *msg; 50 struct msg_msgseg **pseg; 51 int err; 52 int alen; 53 54 alen = min(len, DATALEN_MSG); 55 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 56 if (msg == NULL) 57 return ERR_PTR(-ENOMEM); 58 59 msg->next = NULL; 60 msg->security = NULL; 61 62 if (copy_from_user(msg + 1, src, alen)) { 63 err = -EFAULT; 64 goto out_err; 65 } 66 67 len -= alen; 68 src = ((char __user *)src) + alen; 69 pseg = &msg->next; 70 while (len > 0) { 71 struct msg_msgseg *seg; 72 alen = min(len, DATALEN_SEG); 73 seg = kmalloc(sizeof(*seg) + alen, 74 GFP_KERNEL); 75 if (seg == NULL) { 76 err = -ENOMEM; 77 goto out_err; 78 } 79 *pseg = seg; 80 seg->next = NULL; 81 if (copy_from_user(seg + 1, src, alen)) { 82 err = -EFAULT; 83 goto out_err; 84 } 85 pseg = &seg->next; 86 len -= alen; 87 src = ((char __user *)src) + alen; 88 } 89 90 err = security_msg_msg_alloc(msg); 91 if (err) 92 goto out_err; 93 94 return msg; 95 96 out_err: 97 free_msg(msg); 98 return ERR_PTR(err); 99 } 100 #ifdef CONFIG_CHECKPOINT_RESTORE 101 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 102 { 103 struct msg_msgseg *dst_pseg, *src_pseg; 104 int len = src->m_ts; 105 int alen; 106 107 BUG_ON(dst == NULL); 108 if (src->m_ts > dst->m_ts) 109 return ERR_PTR(-EINVAL); 110 111 alen = min(len, DATALEN_MSG); 112 memcpy(dst + 1, src + 1, alen); 113 114 len -= alen; 115 dst_pseg = dst->next; 116 src_pseg = src->next; 117 while (len > 0) { 118 alen = min(len, DATALEN_SEG); 119 memcpy(dst_pseg + 1, src_pseg + 1, alen); 120 dst_pseg = dst_pseg->next; 121 len -= alen; 122 src_pseg = src_pseg->next; 123 } 124 125 dst->m_type = src->m_type; 126 dst->m_ts = src->m_ts; 127 128 return dst; 129 } 130 #else 131 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 132 { 133 return ERR_PTR(-ENOSYS); 134 } 135 #endif 136 int store_msg(void __user *dest, struct msg_msg *msg, int len) 137 { 138 int alen; 139 struct msg_msgseg *seg; 140 141 alen = min(len, DATALEN_MSG); 142 if (copy_to_user(dest, msg + 1, alen)) 143 return -1; 144 145 len -= alen; 146 dest = ((char __user *)dest) + alen; 147 seg = msg->next; 148 while (len > 0) { 149 alen = min(len, DATALEN_SEG); 150 if (copy_to_user(dest, seg + 1, alen)) 151 return -1; 152 len -= alen; 153 dest = ((char __user *)dest) + alen; 154 seg = seg->next; 155 } 156 return 0; 157 } 158 159 void free_msg(struct msg_msg *msg) 160 { 161 struct msg_msgseg *seg; 162 163 security_msg_msg_free(msg); 164 165 seg = msg->next; 166 kfree(msg); 167 while (seg != NULL) { 168 struct msg_msgseg *tmp = seg->next; 169 kfree(seg); 170 seg = tmp; 171 } 172 } 173