c - 收到以下警告 : The ABI of passing struct with a flexible array member has changed in GCC 4. 4

Question

当我尝试运行我的程序时，我收到此警告和一些奇怪的错误。以下结构中的 rmi_pdu 包含我要访问的可变大小的数组。

struct rmi_message_s {  /* Queue element containing Rmi message */
  struct rmi_message_s          *hnext;
  struct rmi_message_s          *hprev;
  uint16_t                      gen_counter;   /* Generation counter */
  time_value                    send_time;
  uint8_t                       retry_count;
  TAILQ_ENTRY(rmi_message_s)    rmi_message_next;
  rmi_message_pdu               rmi_pdu; /* contains a variable sized array */ 
};

typedef struct {
  uint16_t        zero;
  uint16_t        type;
  uint8_t         version;
  uint8_t         len;
  uint8_t         protocol;
  uint16_t        edge_port;
  uint16_t        core_port;
  uint32_t        connexus_id;
  pi_ipv4_addr_t  edge_addr;
  pi_ipv4_addr_t  core_addr;
  uint16_t        gen_count;     /* Integer to identify a stale packet */
  uint8_t         payload[];
} rmi_message_pdu;

问题是当我试图释放我动态分配的内存时。内容在那里，但 free() API 是 abort()ing 。这是核心的样子

in raise () from /lib64/libc.so.6
in abort () from /lib64/libc.so.6
in __libc_message () from /lib64/libc.so.6
in _int_free () from /lib64/libc.so.6
in free () from /lib64/libc.so.6
in free (p=0x2aaabc000fa0) at mallocdbg.cc:188
in rmi_hash_cleanup (rmi_msg=0x2aaabc000fa0) at tcpsvc_rmi.c:126
in rmi_process_response (response_packet=0x27422e00) at tcpsvc_rmi.c:239
in rmi_message_handle (pkt=0x27422e00 "", cnt=28) at tcpsvc_base.c:154
in udpif_worker (arg=0x2b01f7014340) at rumpnet_virtif/if_udp_netbsd_guest.c:573
in threadbouncer (arg=0x2b01f7016428) at rumpkern/emul.c:428
in clone () from /lib64/libc.so.6

这是分配的样子。想要使用 rmi 的调用者会将大小作为参数传递。

struct rmi_message_s *rmi_msg;
rmi_msg = (struct rmi_message_s *) malloc (sizeof(struct rmi_message_s *) + len * sizeof(uint8_t));

len 作为参数传递。

Answer 1

您没有分配足够的内存:

struct rmi_message_s *rmi_msg ;
    rmi_msg = (struct rmi_message_s *) malloc
           (sizeof(struct rmi_message_s) + len * sizeof(uint8_t));

你有 ...sizeof(struct rmi_message_s *)...，但它应该是 ...sizeof(struct rmi_message_s)...