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Commit 8e62c8a9 authored by Bart Van Assche's avatar Bart Van Assche
Browse files

libcutils: Split uevent_open_socket() 



The best time to attach a BPF filter to a socket is before a socket
starts receiving data. Netlink sockets start receiving data after bind()
has been called. uevent_open_socket() calls socket() and bind(). Hence
split uevent_open_socket() into two functions: one function that calls
socket() and another function that calls bind().

Bug: 203462310
Change-Id: Ia41dee4683358cf9fbb6288fad863cd4f4ac9924
Signed-off-by: default avatarBart Van Assche <bvanassche@google.com>
parent ac68a8b7

libcutils/abi-dumps/arm64/source-based/libcutils.so.lsdump

+76 −142
Original line number Diff line number Diff line
@@ -6,7 +6,6 @@ 
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   "name" : "int[0]",

   "referenced_type" : "_ZTIi",

   "self_type" : "_ZTIA0_i",

   "source_file" : "system/core/libcutils/include/cutils/native_handle.h"

  }

 ],
@@ -17,8 +16,6 @@ 
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   "linker_set_key" : "_ZTIa",

   "name" : "signed char",

   "referenced_type" : "_ZTIa",

   "self_type" : "_ZTIa",

   "size" : 1

  },

  {
@@ -27,8 +24,6 @@ 
   "is_unsigned" : true,

   "linker_set_key" : "_ZTIb",

   "name" : "bool",

   "referenced_type" : "_ZTIb",

   "self_type" : "_ZTIb",

   "size" : 1

  },

  {
@@ -37,25 +32,27 @@ 
   "is_unsigned" : true,

   "linker_set_key" : "_ZTIc",

   "name" : "char",

   "referenced_type" : "_ZTIc",

   "self_type" : "_ZTIc",

   "size" : 1

  },

  {

   "alignment" : 4,

   "linker_set_key" : "_ZTIf",

   "name" : "float",

   "referenced_type" : "_ZTIf",

   "self_type" : "_ZTIf",

   "size" : 4

  },

  {

   "alignment" : 1,

   "is_integral" : true,

   "is_unsigned" : true,

   "linker_set_key" : "_ZTIh",

   "name" : "unsigned char",

   "size" : 1

  },

  {

   "alignment" : 4,

   "is_integral" : true,

   "linker_set_key" : "_ZTIi",

   "name" : "int",

   "referenced_type" : "_ZTIi",

   "self_type" : "_ZTIi",

   "size" : 4

  },

  {
@@ -64,8 +61,6 @@ 
   "is_unsigned" : true,

   "linker_set_key" : "_ZTIj",

   "name" : "unsigned int",

   "referenced_type" : "_ZTIj",

   "self_type" : "_ZTIj",

   "size" : 4

  },

  {
@@ -73,8 +68,6 @@ 
   "is_integral" : true,

   "linker_set_key" : "_ZTIl",

   "name" : "long",

   "referenced_type" : "_ZTIl",

   "self_type" : "_ZTIl",

   "size" : 8

  },

  {
@@ -83,85 +76,55 @@ 
   "is_unsigned" : true,

   "linker_set_key" : "_ZTIm",

   "name" : "unsigned long",

   "referenced_type" : "_ZTIm",

   "self_type" : "_ZTIm",

   "size" : 8

  },

  {

   "linker_set_key" : "_ZTIv",

   "name" : "void",

   "referenced_type" : "_ZTIv",

   "self_type" : "_ZTIv"

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   "name" : "_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m"

   "linker_set_key" : "_ZTIv",

   "name" : "void"

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  {

   "binding" : "weak",

   "name" : "_ZNSt3__16vectorI5EntryNS_9allocatorIS1_EEE24__emplace_back_slow_pathIJS1_EEEvDpOT_"

   "alignment" : 8,

   "is_integral" : true,

   "linker_set_key" : "_ZTIx",

   "name" : "long long",

   "size" : 8

  },

  {

   "binding" : "weak",

   "name" : "_ZNSt3__17getlineIcNS_11char_traitsIcEENS_9allocatorIcEEEERNS_13basic_istreamIT_T0_EES9_RNS_12basic_stringIS6_S7_T1_EES6_"

  },

   "alignment" : 8,

   "is_integral" : true,

   "is_unsigned" : true,

   "linker_set_key" : "_ZTIy",

   "name" : "unsigned long long",

   "size" : 8

  }

 ],

 "elf_functions" :

 [

  {

   "binding" : "weak",

   "name" : "_ZNSt3__1lsINS_11char_traitsIcEEEERNS_13basic_ostreamIcT_EES6_PKc"

   "name" : "_Z23socket_make_sockaddr_unPKciP11sockaddr_unPj"

  },

  {

   "name" : "android_get_control_file"
@@ -487,6 +450,12 @@ 
  {

   "name" : "str_parms_to_str"

  },

  {

   "name" : "uevent_bind"

  },

  {

   "name" : "uevent_create_socket"

  },

  {

   "name" : "uevent_kernel_multicast_recv"

  },
@@ -502,22 +471,6 @@ 
 ],

 "elf_objects" :

 [

  {

   "binding" : "weak",

   "name" : "_ZTCNSt3__114basic_ifstreamIcNS_11char_traitsIcEEEE0_NS_13basic_istreamIcS2_EE"

  },

  {

   "binding" : "weak",

   "name" : "_ZTTNSt3__114basic_ifstreamIcNS_11char_traitsIcEEEE"

  },

  {

   "binding" : "weak",

   "name" : "_ZTVNSt3__113basic_filebufIcNS_11char_traitsIcEEEE"

  },

  {

   "binding" : "weak",

   "name" : "_ZTVNSt3__114basic_ifstreamIcNS_11char_traitsIcEEEE"

  },

  {

   "name" : "atrace_enabled_tags"

  },
@@ -553,8 +506,6 @@ 
   ],

   "linker_set_key" : "_ZTI12IoSchedClass",

   "name" : "IoSchedClass",

   "referenced_type" : "_ZTI12IoSchedClass",

   "self_type" : "_ZTI12IoSchedClass",

   "size" : 4,

   "source_file" : "system/core/libcutils/include/cutils/iosched_policy.h",

   "underlying_type" : "_ZTIj"
@@ -575,9 +526,7 @@ 
     "referenced_type" : "_ZTIPv"

    }

   ],

   "referenced_type" : "_ZTIFbPvS_E",

   "return_type" : "_ZTIb",

   "self_type" : "_ZTIFbPvS_E",

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },

  {
@@ -596,9 +545,7 @@ 
     "referenced_type" : "_ZTIPv"

    }

   ],

   "referenced_type" : "_ZTIFbPvS_S_E",

   "return_type" : "_ZTIb",

   "self_type" : "_ZTIFbPvS_S_E",

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },

  {
@@ -611,9 +558,7 @@ 
     "referenced_type" : "_ZTIPv"

    }

   ],

   "referenced_type" : "_ZTIFiPvE",

   "return_type" : "_ZTIi",

   "self_type" : "_ZTIFiPvE",

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },

  {
@@ -632,9 +577,7 @@ 
     "referenced_type" : "_ZTIPv"

    }

   ],

   "referenced_type" : "_ZTIFvPKcS0_PvE",

   "return_type" : "_ZTIv",

   "self_type" : "_ZTIFvPKcS0_PvE",

   "source_file" : "system/core/libcutils/include/cutils/properties.h"

  }

 ],
@@ -2266,6 +2209,33 @@ 
   "return_type" : "_ZTIPc",

   "source_file" : "system/core/libcutils/include/cutils/str_parms.h"

  },

  {

   "function_name" : "uevent_bind",

   "linker_set_key" : "uevent_bind",

   "parameters" :

   [

    {

     "referenced_type" : "_ZTIi"

    }

   ],

   "return_type" : "_ZTIi",

   "source_file" : "system/core/libcutils/include/cutils/uevent.h"

  },

  {

   "function_name" : "uevent_create_socket",

   "linker_set_key" : "uevent_create_socket",

   "parameters" :

   [

    {

     "referenced_type" : "_ZTIi"

    },

    {

     "referenced_type" : "_ZTIb"

    }

   ],

   "return_type" : "_ZTIi",

   "source_file" : "system/core/libcutils/include/cutils/uevent.h"

  },

  {

   "function_name" : "uevent_kernel_multicast_recv",

   "linker_set_key" : "uevent_kernel_multicast_recv",
@@ -2374,7 +2344,6 @@ 
   "linker_set_key" : "_ZTIP12IoSchedClass",

   "name" : "IoSchedClass *",

   "referenced_type" : "_ZTI12IoSchedClass",

   "self_type" : "_ZTIP12IoSchedClass",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/iosched_policy.h"

  },
@@ -2383,7 +2352,6 @@ 
   "linker_set_key" : "_ZTIP12RecordStream",

   "name" : "RecordStream *",

   "referenced_type" : "_ZTI12RecordStream",

   "self_type" : "_ZTIP12RecordStream",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/record_stream.h"

  },
@@ -2392,7 +2360,6 @@ 
   "linker_set_key" : "_ZTIP13native_handle",

   "name" : "native_handle *",

   "referenced_type" : "_ZTI13native_handle",

   "self_type" : "_ZTIP13native_handle",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/native_handle.h"

  },
@@ -2401,7 +2368,6 @@ 
   "linker_set_key" : "_ZTIP5cnode",

   "name" : "cnode *",

   "referenced_type" : "_ZTI5cnode",

   "self_type" : "_ZTIP5cnode",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/config_utils.h"

  },
@@ -2410,7 +2376,6 @@ 
   "linker_set_key" : "_ZTIP7Hashmap",

   "name" : "Hashmap *",

   "referenced_type" : "_ZTI7Hashmap",

   "self_type" : "_ZTIP7Hashmap",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },
@@ -2419,7 +2384,6 @@ 
   "linker_set_key" : "_ZTIP9fs_config",

   "name" : "fs_config *",

   "referenced_type" : "_ZTI9fs_config",

   "self_type" : "_ZTIP9fs_config",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/private/fs_config.h"

  },
@@ -2428,7 +2392,6 @@ 
   "linker_set_key" : "_ZTIP9str_parms",

   "name" : "str_parms *",

   "referenced_type" : "_ZTI9str_parms",

   "self_type" : "_ZTIP9str_parms",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/str_parms.h"

  },
@@ -2437,7 +2400,6 @@ 
   "linker_set_key" : "_ZTIPFbPvS_E",

   "name" : "bool (*)(void *, void *)",

   "referenced_type" : "_ZTIFbPvS_E",

   "self_type" : "_ZTIPFbPvS_E",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },
@@ -2446,7 +2408,6 @@ 
   "linker_set_key" : "_ZTIPFbPvS_S_E",

   "name" : "bool (*)(void *, void *, void *)",

   "referenced_type" : "_ZTIFbPvS_S_E",

   "self_type" : "_ZTIPFbPvS_S_E",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },
@@ -2455,7 +2416,6 @@ 
   "linker_set_key" : "_ZTIPFiPvE",

   "name" : "int (*)(void *)",

   "referenced_type" : "_ZTIFiPvE",

   "self_type" : "_ZTIPFiPvE",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/hashmap.h"

  },
@@ -2464,7 +2424,6 @@ 
   "linker_set_key" : "_ZTIPFvPKcS0_PvE",

   "name" : "void (*)(const char *, const char *, void *)",

   "referenced_type" : "_ZTIFvPKcS0_PvE",

   "self_type" : "_ZTIPFvPKcS0_PvE",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/properties.h"

  },
@@ -2473,7 +2432,6 @@ 
   "linker_set_key" : "_ZTIPK13native_handle",

   "name" : "const native_handle *",

   "referenced_type" : "_ZTIK13native_handle",

   "self_type" : "_ZTIPK13native_handle",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/native_handle.h"

  },
@@ -2482,7 +2440,6 @@ 
   "linker_set_key" : "_ZTIPK22cutils_socket_buffer_t",

   "name" : "const cutils_socket_buffer_t *",

   "referenced_type" : "_ZTIK22cutils_socket_buffer_t",

   "self_type" : "_ZTIPK22cutils_socket_buffer_t",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/sockets.h"

  },
@@ -2491,7 +2448,6 @@ 
   "linker_set_key" : "_ZTIPK5iovec",

   "name" : "const iovec *",

   "referenced_type" : "_ZTIK5iovec",

   "self_type" : "_ZTIPK5iovec",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/klog.h"

  },
@@ -2500,7 +2456,6 @@ 
   "linker_set_key" : "_ZTIPKc",

   "name" : "const char *",

   "referenced_type" : "_ZTIKc",

   "self_type" : "_ZTIPKc",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/config_utils.h"

  },
@@ -2509,7 +2464,6 @@ 
   "linker_set_key" : "_ZTIPKv",

   "name" : "const void *",

   "referenced_type" : "_ZTIKv",

   "self_type" : "_ZTIPKv",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/sockets.h"

  },
@@ -2518,7 +2472,6 @@ 
   "linker_set_key" : "_ZTIPPv",

   "name" : "void **",

   "referenced_type" : "_ZTIPv",

   "self_type" : "_ZTIPPv",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/record_stream.h"

  },
@@ -2527,7 +2480,6 @@ 
   "linker_set_key" : "_ZTIPc",

   "name" : "char *",

   "referenced_type" : "_ZTIc",

   "self_type" : "_ZTIPc",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/config_utils.h"

  },
@@ -2536,7 +2488,6 @@ 
   "linker_set_key" : "_ZTIPf",

   "name" : "float *",

   "referenced_type" : "_ZTIf",

   "self_type" : "_ZTIPf",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/str_parms.h"

  },
@@ -2545,7 +2496,6 @@ 
   "linker_set_key" : "_ZTIPi",

   "name" : "int *",

   "referenced_type" : "_ZTIi",

   "self_type" : "_ZTIPi",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/iosched_policy.h"

  },
@@ -2554,7 +2504,6 @@ 
   "linker_set_key" : "_ZTIPj",

   "name" : "unsigned int *",

   "referenced_type" : "_ZTIj",

   "self_type" : "_ZTIPj",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/misc.h"

  },
@@ -2563,7 +2512,6 @@ 
   "linker_set_key" : "_ZTIPm",

   "name" : "unsigned long *",

   "referenced_type" : "_ZTIm",

   "self_type" : "_ZTIPm",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/record_stream.h"

  },
@@ -2572,7 +2520,6 @@ 
   "linker_set_key" : "_ZTIPv",

   "name" : "void *",

   "referenced_type" : "_ZTIv",

   "self_type" : "_ZTIPv",

   "size" : 8,

   "source_file" : "system/core/libcutils/include/cutils/misc.h"

  }
@@ -2585,7 +2532,6 @@ 
   "linker_set_key" : "_ZTIK13native_handle",

   "name" : "const native_handle",

   "referenced_type" : "_ZTI13native_handle",

   "self_type" : "_ZTIK13native_handle",

   "size" : 12,

   "source_file" : "system/core/libcutils/include/cutils/native_handle.h"

  },
@@ -2595,7 +2541,6 @@ 
   "linker_set_key" : "_ZTIK22cutils_socket_buffer_t",

   "name" : "const cutils_socket_buffer_t",

   "referenced_type" : "_ZTI22cutils_socket_buffer_t",

   "self_type" : "_ZTIK22cutils_socket_buffer_t",

   "size" : 16,

   "source_file" : "system/core/libcutils/include/cutils/sockets.h"

  },
@@ -2605,7 +2550,6 @@ 
   "linker_set_key" : "_ZTIK5iovec",

   "name" : "const iovec",

   "referenced_type" : "_ZTI5iovec",

   "self_type" : "_ZTIK5iovec",

   "size" : 16,

   "source_file" : "system/core/libcutils/include/cutils/klog.h"

  },
@@ -2615,7 +2559,6 @@ 
   "linker_set_key" : "_ZTIKc",

   "name" : "const char",

   "referenced_type" : "_ZTIc",

   "self_type" : "_ZTIKc",

   "size" : 1,

   "source_file" : "system/core/libcutils/include/cutils/config_utils.h"

  },
@@ -2624,7 +2567,6 @@ 
   "linker_set_key" : "_ZTIKv",

   "name" : "const void",

   "referenced_type" : "_ZTIv",

   "self_type" : "_ZTIKv",

   "source_file" : "system/core/libcutils/include/cutils/sockets.h"

  }

 ],
@@ -2656,8 +2598,6 @@ 
   ],

   "linker_set_key" : "_ZTI13native_handle",

   "name" : "native_handle",

   "referenced_type" : "_ZTI13native_handle",

   "self_type" : "_ZTI13native_handle",

   "size" : 12,

   "source_file" : "system/core/libcutils/include/cutils/native_handle.h"

  },
@@ -2677,8 +2617,6 @@ 
   ],

   "linker_set_key" : "_ZTI22cutils_socket_buffer_t",

   "name" : "cutils_socket_buffer_t",

   "referenced_type" : "_ZTI22cutils_socket_buffer_t",

   "self_type" : "_ZTI22cutils_socket_buffer_t",

   "size" : 16,

   "source_file" : "system/core/libcutils/include/cutils/sockets.h"

  },
@@ -2713,8 +2651,6 @@ 
   ],

   "linker_set_key" : "_ZTI5cnode",

   "name" : "cnode",

   "referenced_type" : "_ZTI5cnode",

   "self_type" : "_ZTI5cnode",

   "size" : 40,

   "source_file" : "system/core/libcutils/include/cutils/config_utils.h"

  },
@@ -2744,8 +2680,6 @@ 
   ],

   "linker_set_key" : "_ZTI9fs_config",

   "name" : "fs_config",

   "referenced_type" : "_ZTI9fs_config",

   "self_type" : "_ZTI9fs_config",

   "size" : 24,

   "source_file" : "system/core/libcutils/include/private/fs_config.h"

  }

libcutils/abi-dumps/arm_arm64/source-based/libcutils.so.lsdump

+64 −144

File changed.

Preview size limit exceeded, changes collapsed.

libcutils/include/cutils/uevent.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 
extern "C" {

#endif



int uevent_create_socket(int buf_sz, bool passcred);

int uevent_bind(int socket);

int uevent_open_socket(int buf_sz, bool passcred);

ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length);

ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer, size_t length, uid_t *uid);

libcutils/uevent.cpp

+49 −13
Original line number Diff line number Diff line
@@ -92,20 +92,22 @@ out: 
    return -1;

}



int uevent_open_socket(int buf_sz, bool passcred) {

    struct sockaddr_nl addr;

    int on = passcred;

/*

 * Creates an unbound netlink socket for receiving uevent messages.

 * @buf_sz: socket receive buffer size.

 * @passcred: whether or not to enable receiving the SCM_CREDENTIALS control

 *	message.

 *

 * Returns: a socket descriptor upon success or -1 upon failure.

 */

int uevent_create_socket(int buf_sz, bool passcred) {

    int s = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);

    if (s < 0) {

        return -1;

    }



    int buf_sz_readback = 0;

    socklen_t optlen = sizeof(buf_sz_readback);

    int s;



    memset(&addr, 0, sizeof(addr));

    addr.nl_family = AF_NETLINK;

    addr.nl_pid = 0;

    addr.nl_groups = 0xffffffff;



    s = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);

    if (s < 0) return -1;



    if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &buf_sz, sizeof(buf_sz)) < 0 ||

          getsockopt(s, SOL_SOCKET, SO_RCVBUF, &buf_sz_readback, &optlen) < 0) {
@@ -123,9 +125,43 @@ int uevent_open_socket(int buf_sz, bool passcred) { 
        }

    }



    int on = passcred;



    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));



    if (bind(s, (struct sockaddr*)&addr, sizeof(addr)) < 0) {

    return s;

}



/*

 * Binds a netlink socket. Binding a netlink socket makes the kernel start

 * sending netlink messages to that netlink socket.

 *

 * Returns: 0 upon success; -1 upon error.

 */

int uevent_bind(int socket) {

    struct sockaddr_nl addr = {

            .nl_family = AF_NETLINK,

            .nl_pid = 0,

            .nl_groups = 0xffffffff,

    };

    return bind(socket, (struct sockaddr*)&addr, sizeof(addr));

}



/*

 * Creates a bound netlink socket for receiving uevent messages.

 * @buf_sz: socket receive buffer size.

 * @passcred: whether or not to enable receiving the SCM_CREDENTIALS control

 *	message.

 *

 * Returns: a socket descriptor upon success or -1 upon failure.

 */

int uevent_open_socket(int buf_sz, bool passcred) {

    int s = uevent_create_socket(buf_sz, passcred);

    if (s < 0) {

        return -1;

    }



    if (uevent_bind(s) < 0) {

        close(s);

        return -1;

    }