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 (PAGE_SIZE-sizeof(struct msg_msg)) 45 #define DATALEN_SEG (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 = len; 55 if (alen > DATALEN_MSG) 56 alen = DATALEN_MSG; 57 58 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 59 if (msg == NULL) 60 return ERR_PTR(-ENOMEM); 61 62 msg->next = NULL; 63 msg->security = NULL; 64 65 if (copy_from_user(msg + 1, src, alen)) { 66 err = -EFAULT; 67 goto out_err; 68 } 69 70 len -= alen; 71 src = ((char __user *)src) + alen; 72 pseg = &msg->next; 73 while (len > 0) { 74 struct msg_msgseg *seg; 75 alen = len; 76 if (alen > DATALEN_SEG) 77 alen = DATALEN_SEG; 78 seg = kmalloc(sizeof(*seg) + alen, 79 GFP_KERNEL); 80 if (seg == NULL) { 81 err = -ENOMEM; 82 goto out_err; 83 } 84 *pseg = seg; 85 seg->next = NULL; 86 if (copy_from_user(seg + 1, src, alen)) { 87 err = -EFAULT; 88 goto out_err; 89 } 90 pseg = &seg->next; 91 len -= alen; 92 src = ((char __user *)src) + alen; 93 } 94 95 err = security_msg_msg_alloc(msg); 96 if (err) 97 goto out_err; 98 99 return msg; 100 101 out_err: 102 free_msg(msg); 103 return ERR_PTR(err); 104 } 105 #ifdef CONFIG_CHECKPOINT_RESTORE 106 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 107 { 108 struct msg_msgseg *dst_pseg, *src_pseg; 109 int len = src->m_ts; 110 int alen; 111 112 BUG_ON(dst == NULL); 113 if (src->m_ts > dst->m_ts) 114 return ERR_PTR(-EINVAL); 115 116 alen = len; 117 if (alen > DATALEN_MSG) 118 alen = DATALEN_MSG; 119 120 dst->next = NULL; 121 dst->security = NULL; 122 123 memcpy(dst + 1, src + 1, alen); 124 125 len -= alen; 126 dst_pseg = dst->next; 127 src_pseg = src->next; 128 while (len > 0) { 129 alen = len; 130 if (alen > DATALEN_SEG) 131 alen = DATALEN_SEG; 132 memcpy(dst_pseg + 1, src_pseg + 1, alen); 133 dst_pseg = dst_pseg->next; 134 len -= alen; 135 src_pseg = src_pseg->next; 136 } 137 138 dst->m_type = src->m_type; 139 dst->m_ts = src->m_ts; 140 141 return dst; 142 } 143 #else 144 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 145 { 146 return ERR_PTR(-ENOSYS); 147 } 148 #endif 149 int store_msg(void __user *dest, struct msg_msg *msg, int len) 150 { 151 int alen; 152 struct msg_msgseg *seg; 153 154 alen = len; 155 if (alen > DATALEN_MSG) 156 alen = DATALEN_MSG; 157 if (copy_to_user(dest, msg + 1, alen)) 158 return -1; 159 160 len -= alen; 161 dest = ((char __user *)dest) + alen; 162 seg = msg->next; 163 while (len > 0) { 164 alen = len; 165 if (alen > DATALEN_SEG) 166 alen = DATALEN_SEG; 167 if (copy_to_user(dest, seg + 1, alen)) 168 return -1; 169 len -= alen; 170 dest = ((char __user *)dest) + alen; 171 seg = seg->next; 172 } 173 return 0; 174 } 175 176 void free_msg(struct msg_msg *msg) 177 { 178 struct msg_msgseg *seg; 179 180 security_msg_msg_free(msg); 181 182 seg = msg->next; 183 kfree(msg); 184 while (seg != NULL) { 185 struct msg_msgseg *tmp = seg->next; 186 kfree(seg); 187 seg = tmp; 188 } 189 } 190