sqlplus执行错误的问题探究

bisal的个人杂货铺 2020-07-23

1379

今天碰到个很诡异的问题，在装了Oracle Clinet的机器，不同路径下执行指令sqlplus，回显不同。

Oracle Client路径是/opt/app/oracle/instantclient_11_2，包含如下内容，

bash_profile相关配置，

export ORACLE_HOME=/opt/app/oracle/instantclient_11_2
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ORACLE_HOME
export TNS_ADMIN=$ORACLE_HOME
export CLASSPATH=$ORACLE_HOME/ojdbc6.jar:./
export NLS_LANG="AMERICAN_AMERICA.ZHS16GBK"
export PATH=$PATH:$HOME/.local/bin:$HOME/bin:$SELF_ORACLE_HOME

如果在$ORACLE_HOME，执行sqlplus，提示错误，再次执行，会出core，

[test@localhost instantclient_11_2]$ cd opt/app/oracle/instantclient_11_2
[test@localhost instantclient_11_2]$ sqlplus
Error 6 initializing SQL*Plus
SP2-0667: Message file sp1<lang>.msb not found
SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory

如果在其他路径(非$ORACLE_HOME)，执行sqlplus，回显正常，

[test@localhost instantclient_11_2]$ sqlplus
SQL*Plus: Release 11.2.0.4.0 Production on Wed Jul 22 17:48:07 2020
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Enter user-name:

这是为什么？

通过strace发现了其中一些区别，sqlplus执行异常的strace片段，

[test@localhost instantclient_11_2]$ strace sqlplus
execve("/opt/app/oracle/instantclient_11_2/sqlplus", ["sqlplus"], [/* 29 vars */]) = 0
brk(NULL) = 0x1b20000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9cb847c000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("tls/x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("tls/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("libsqlplus.so", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0@\370\1\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0555, st_size=1469542, ...}) = 0
getcwd("/opt/app/oracle/instantclient_11_2", 128) = 54

sqlplus执行正常的strace片段，

[test@localhost instantclient_11_2]$ strace sqlplus
execve("/opt/app/oracle/instantclient_11_2/sqlplus", ["sqlplus"], [/* 28 vars */]) = 0
brk(NULL) = 0x16ec000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fcd72b26000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("tls/x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("tls/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/opt/app/oracle/instantclient_11_2/tls/x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/opt/app/oracle/instantclient_11_2/tls/x86_64", 0x7fff93de3060) = -1 ENOENT (No such file or directory)
open("/opt/app/oracle/instantclient_11_2/tls/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/opt/app/oracle/instantclient_11_2/tls", 0x7fff93de3060) = -1 ENOENT (No such file or directory)
open("/opt/app/oracle/instantclient_11_2/x86_64/libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/opt/app/oracle/instantclient_11_2/x86_64", 0x7fff93de3060) = -1 ENOENT (No such file or directory)
open("/opt/app/oracle/instantclient_11_2/libsqlplus.so", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0@\370\1\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0555, st_size=1469542, ...}) = 0
mmap(NULL, 1985056, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fcd72941000
mprotect(0x7fcd72a17000, 1048576, PROT_NONE) = 0
mmap(0x7fcd72b17000, 57344, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xd6000) = 0x7fcd72b17000
mmap(0x7fcd72b25000, 2592, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fcd72b25000
close(3) = 0

对比一下，可以看到，sqlplus执行异常的strace，打开libsqlplus.so成功，

open("libsqlplus.so", O_RDONLY|O_CLOEXEC) = 3

sqlplus执行正常的strace，打开libsqlplus.so失败，然后打开了带路径的，

open("libsqlplus.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
...
open("/opt/app/oracle/instantclient_11_2/libsqlplus.so", O_RDONLY|O_CLOEXEC) = 3

如果说是解决，在LD_LIBRARY_PATH中开始处增加"."，就是当前路径，此时无论在不在$ORACLE_HOME，sqlplus都可以正常执行，

export LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH:$ORACLE_HOME

但是，原因是什么？

众所周知，LD_LIBRARY_PATH是Linux环境变量名，该环境变量主要用于指定查找共享库(动态链接库，例如此处的libsqlplus.so)时除了默认路径之外的其他路径。

当执行函数动态链接.so时，如果此文件不在缺省目录下/lib和/usr/lib，那么就需要指定环境变量LD_LIBRARY_PATH，有时候我们安装的软件，因为没root权限，不会放到这些系统路径下，因此要改LD_LIBRARY_PATH，指定查找的路径。因此，运行时动态库的搜索路径就需要先后顺序，1. 编译目标代码时指定的动态库搜索路径。2. 环境变量LD_LIBRARY_PATH指定的动态库搜索路径。3 .配置文件/etc/ld.so.conf中指定的动态库搜索路径。4. 默认的动态库搜索路径/lib和/usr/lib。

再回到这个问题，同样在$ORACLE_HOME路径下，执行sqlplus，strace的回显还是一样，但此时执行成功，说明sqlplus的执行路径是没问题的，关键还是LD_LIBRARY_PATH将"."当前路径加入了其中，

[test@localhost instantclient_11_2]$ strace sqlplus
execve("./sqlplus", ["sqlplus"], [/* 28 vars */]) = 0
brk(0) = 0x22c0000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f30b4903000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("./tls/x86_64/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)
open("./tls/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)
open("./x86_64/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)
open("./libsqlplus.so", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0@\370\1\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0555, st_size=1469542, ...}) = 0
getcwd("/opt/app/oracle/instantclient_11_2", 128) = 58