前导发轫：赛迪网 作者：Alizze
许多人都晓得，经由议定SYS_CONTEXT函数可以失失局部信息，以后用户的ip等信息则可以经由议定上面的敕令来举行获取：
SQL> select sys_context('userenv','host') from dual; SYS_CONTEXT('USERENV','HOST') --------------------------------------------------- WORKGROUP\GQGAI SQL> select sys_context('userenv','ip_address') from dual; SYS_CONTEXT('USERENV','IP_ADDR --------------------------------------------------- 172.16.34.20
假定你须要获取其余session的地址等信息，SYS_CONTEXT函数则只能经由议定LOGON触发器来完成。
在没有触发器记录的前提下，你可以经由议定UTL_INADDR Package来完成。
上面具体引见一下UTL_INADDR包获取ip等信息的事项原理。
起首，在数据库中举行上面的查询：
[oracle@jumper oracle]$ sqlplus "/ as sysdba" SQL*Plus: Release 9.2.0.4.0 - Production on Wed Oct 25 11:24:22 2006 Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved. Connected to: Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production With the Partitioning option JServer Release 9.2.0.4.0 - Production SQL> ! [oracle@jumper oracle]$ ps -ef|grep sql oracle 14700 14663 1 11:24 pts/0 00:00:00 sqlplus oracle 14732 14702 0 11:24 pts/0 00:00:00 grep sql [oracle@jumper oracle]$ ps -ef|grep LO oracle 14701 14700 0 11:24 ? 00:00:00 oracleeygle (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) oracle 14734 14702 0 11:24 pts/0 00:00:00 grep LO [oracle@jumper oracle]$ exit exit SQL> SELECT UTL_INADDR.get_host_address('www.anysql.net') from dual; UTL_INADDR.GET_HOST_ADDRESS('WWW.ANYSQL.NET') --------------------------------------------------------- 208.113.151.109
Linux体系中，你可以经由议定strace跟踪此历程，失失上面的客栈酒店信息:
[oracle@jumper oracle]$ strace -p 14701 Process 14701 attached - interrupt to quit read(7, "\0\313\0\0\6\0\0\0\0\0\3^ \10a\200\0\0\0\0\0\0@\342\22\10"..., 2064) = 203 gettimeofday({1161746697, 269895}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 30000}, ru_stime={0, 10000}, ...}) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 gettimeofday({1161746697, 270542}, NULL) = 0 gettimeofday({1161746697, 270670}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 gettimeofday({1161746697, 271614}, NULL) = 0 gettimeofday({1161746697, 271748}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 gettimeofday({1161746697, 272347}, NULL) = 0 gettimeofday({1161746697, 272699}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 gettimeofday({1161746697, 272989}, NULL) = 0 gettimeofday({1161746697, 273140}, NULL) = 0 gettimeofday({1161746697, 273273}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 10000}, ...}) = 0 gettimeofday({1161746697, 273771}, NULL) = 0 gettimeofday({1161746697, 275526}, NULL) = 0 getpid() = 14701 open("/etc/resolv.conf", O_RDONLY) = 12 fstat64(12, {st_mode=S_IFREG|0644, st_size=46, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6fba000 read(12, "search hurray.com.cn\nnameserver "..., 4096) = 46 read(12, "", 4096) = 0 close(12) = 0 munmap(0xb6fba000, 4096) = 0 socket(PF_UNIX, SOCK_STREAM, 0) = 12 connect(12, {sa_family=AF_UNIX, path="/var/run/.nscd_socket"}, 110) = -1 ENOENT (No such file or directory) close(12) = 0 open("/etc/host.conf", O_RDONLY) = 12 fstat64(12, {st_mode=S_IFREG|0644, st_size=17, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6fba000 read(12, "order hosts,bind\n", 4096) = 17 read(12, "", 4096) = 0 close(12) = 0 munmap(0xb6fba000, 4096) = 0 futex(0xb71a1a20, FUTEX_WAKE, 2147483647) = 0 open("/etc/hosts", O_RDONLY) = 12 fcntl64(12, F_GETFD) = 0 fcntl64(12, F_SETFD, FD_CLOEXEC) = 0 fstat64(12, {st_mode=S_IFREG|0644, st_size=175, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6fba000 read(12, "# Do not remove the following li"..., 4096) = 175 read(12, "", 4096) = 0 close(12) = 0 munmap(0xb6fba000, 4096) = 0 open("/opt/oracle/product/9.2.0/lib/libnss_dns.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/tls/libnss_dns.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/i686/libnss_dns.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/libnss_dns.so.2", O_RDONLY) = 12 read(12, "\177ELF\1\1\1\0\0\0\0\0\0\0\0 \0\3\0\3\0\1\0\0\0\240\16"..., 512) = 512 fstat64(12, {st_mode=S_IFREG|0755, st_size=18632, ...}) = 0 old_mmap(NULL, 17100, PROT_READ |PROT_EXEC, MAP_PRIVATE, 12, 0) = 0xb6fb6000 old_mmap(0xb6fba000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 12, 0x3000) = 0xb6fba000 close(12) = 0 open("/opt/oracle/product/9.2.0/lib/libresolv.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/tls/libresolv.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/i686/libresolv.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/libresolv.so.2", O_RDONLY) = 12 read(12, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320 (\0"..., 512) = 512 fstat64(12, {st_mode=S_IFREG|0755, st_size=76508, ...}) = 0 old_mmap(NULL, 73604, PROT_READ|PROT_EXEC, MAP_PRIVATE, 12, 0) = 0xb6fa4000 old_mmap(0xb6fb3000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 12, 0xf000) = 0xb6fb3000 old_mmap(0xb6fb4000, 8068, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6fb4000 close(12) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 12 connect(12, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("208.113.151.109")}, 28) = 0 send(12, "\324#\1\0\0\1\0\0\0\0\0\0\3www \5anysql\3com\0\0\1\0\1", 31, 0) = 31 gettimeofday({1161746697, 286025}, NULL) = 0 poll([{fd=12, events=POLLIN, revents=POLLIN}], 1, 5000) = 1 ioctl(12, FIONREAD, [74]) = 0 recvfrom(12, "\324#\ 201\200\0\1\0\1\0\1\0\0\3www\5anysql\3com\0\0\1\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("208.113.151.109")}, [16]) = 74 close(12) = 0 gettimeofday({1161746697, 290245}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 20000}, ...}) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 20000}, ...}) = 0 gettimeofday({1161746697, 291553}, NULL) = 0 write(10, "\2\275\0\0\6\0\0\0\0\0\20\31\266\344\217\ 3700\320\341S"..., 701) = 701 read(7, "\0\215\0\0\6\0\0\0\0\0\3^\t@\0\0\0\1\0\0\0 \0\0\0\0\0\0"..., 2064) = 141 gettimeofday({1161746697, 294898}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 20000}, ...}) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 20000}, ...}) = 0 gettimeofday({1161746697, 295496}, NULL) = 0 getrusage(RUSAGE_SELF, {ru_utime={0, 40000}, ru_stime={0, 20000}, ...}) = 0 gettimeofday({1161746697, 295847}, NULL) = 0 gettimeofday({1161746697, 295981}, NULL) = 0 lseek(9, 1024, SEEK_SET) = 1024 read(9, "\30\0$\0007\0@\0J\0V\0`\0i\0t\0~\0\ 232\0\245\0\320\0\330"..., 512) = 512 lseek(9, 47104, SEEK_SET) = 47104 read(9, "\f\0^\5\0\0P\0x\5\0\0\214\0y\5\0\0\ 250\0z\5\0\0\313\0{"..., 512) = 512 gettimeofday({1161746697, 297024}, NULL) = 0 write(10, "\0\202\0\0\6\0\0\0\0\0\4\1\0\0\0\1\ 1\0\0\0{\5\0\0\0\0\1"..., 130) = 130 read(7, Process 14701 detached
在此信息中，你可以创造Oracle递次造访了上面的文件来完成地址定位：
open("/etc/resolv.conf", O_RDONLY) = 12 open("/etc/host.conf", O_RDONLY) = 12 open("/etc/hosts", O_RDONLY) = 12
起首，须要获取域名分解效劳器，然后再凭据host.conf文件确定分解递次，由于缺省hosts文件是优先的，又持续读取/etc/hosts文件。
假定hosts文件存在分解相干，就会前往信息；假定不存在的话，则持续问询DNS效劳器，失失分解地址，假如不克不及分解，则会泛起错误：
SQL> select UTL_INADDR.get_host_address('www.a.com') from dual; select UTL_INADDR.get_host_address('www.a.com') from dual * ERROR at line 1: ORA-29257: host www.a.com unknown ORA-06512: at "SYS.UTL_INADDR", line 35 ORA-06512: at "SYS.UTL_INADDR", line 40 ORA-06512: at line 1
综上所述，年夜师可以创造UTL_INADDR的数据获取曾经不再依赖数据库信息，而SYS_CONTEXT的信息获取依然来自数据库的内部。
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