From db9665d4e4ee6f3ebe28741e547167d01651f61e Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 15:40:30 +0000
Subject: [PATCH 1/7] add ostep exercises

---
 sandbox/.gitignore     |  2 --
 sandbox/ostep/Makefile | 18 ++++++++++++++++++
 sandbox/ostep/ex5_1.c  | 25 +++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)
 delete mode 100644 sandbox/.gitignore
 create mode 100644 sandbox/ostep/Makefile
 create mode 100644 sandbox/ostep/ex5_1.c

diff --git a/sandbox/.gitignore b/sandbox/.gitignore
deleted file mode 100644
index b40d66a..0000000
--- a/sandbox/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-msys_server
-server
\ No newline at end of file
diff --git a/sandbox/ostep/Makefile b/sandbox/ostep/Makefile
new file mode 100644
index 0000000..68dfb33
--- /dev/null
+++ b/sandbox/ostep/Makefile
@@ -0,0 +1,18 @@
+CC=gcc
+CCOPTS=#-Wall -Wextra
+LIBS=
+
+SRCS=$(wildcard *.c)
+TARGETS=$(SRCS:.c=)
+
+.PHONY: all clean pristine
+
+all: $(TARGETS)
+
+clean:
+	rm -f $(TARGETS)
+
+pristine: clean
+
+%: %.c
+	$(CC) $(CCOPTS) -o $@ $< $(LIBS)
\ No newline at end of file
diff --git a/sandbox/ostep/ex5_1.c b/sandbox/ostep/ex5_1.c
new file mode 100644
index 0000000..4947639
--- /dev/null
+++ b/sandbox/ostep/ex5_1.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+int main(int argc, char *argv[]){
+
+    printf("hello world (pid:%d)\n", (int) getpid());
+    
+    int rc = fork();
+
+    if (rc < 0) {
+        fprintf(stderr, "fork failed\n");
+        exit(1);
+    } else if (rc == 0) {
+        printf("hello, I am child (pid:%d)\n", (int) getpid());
+	    sleep(1);
+    } else {
+        int wc = wait(NULL);
+        printf("hello, I am parent of %d (wc:%d) (pid:%d)\n",
+	       rc, wc, (int) getpid());
+    }
+
+    return 0;
+}
\ No newline at end of file

From 52ce485b6f6d68132ec165d35746c62a1f630769 Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 15:47:10 +0000
Subject: [PATCH 2/7] simplify folders

---
 {sandbox/ostep => ostep}/Makefile |   2 +-
 ostep/ex5_1                       | Bin 0 -> 16256 bytes
 {sandbox/ostep => ostep}/ex5_1.c  |  10 ++++++----
 3 files changed, 7 insertions(+), 5 deletions(-)
 rename {sandbox/ostep => ostep}/Makefile (83%)
 create mode 100755 ostep/ex5_1
 rename {sandbox/ostep => ostep}/ex5_1.c (65%)

diff --git a/sandbox/ostep/Makefile b/ostep/Makefile
similarity index 83%
rename from sandbox/ostep/Makefile
rename to ostep/Makefile
index 68dfb33..6d01a79 100644
--- a/sandbox/ostep/Makefile
+++ b/ostep/Makefile
@@ -12,7 +12,7 @@ all: $(TARGETS)
 clean:
 	rm -f $(TARGETS)
 
-pristine: clean
+pristine: clean all
 
 %: %.c
 	$(CC) $(CCOPTS) -o $@ $< $(LIBS)
\ No newline at end of file
diff --git a/ostep/ex5_1 b/ostep/ex5_1
new file mode 100755
index 0000000000000000000000000000000000000000..3b572349190354579e48c8223dd094b64fdbdcb2
GIT binary patch
literal 16256
zcmeHOeQXrR6`wo4Oaj;>kbr5!mO^A2ytctO1mtr5I5<}ZTri3vO1Ep@+IP+Q?sB&m
z+fhlKkVc#gsw1kFKO!|zkwTS9rB$njsA){oKof~5sHzI8QbANCTcwS0XzR2I*Y{@L
zTkoyzntuJ)eb(Na_j~U*Gy8V-Zq_^V)o|yIU?3n^=7`S<w6vuP36W#`eky<pi7jF=
ze6AMvi1}d8m6-B}lmf4kOTl7YLHHcd$XkJh68aMg7Oc64sF7DrPA^a%)}l(;$eV{n
zvc38P>L+XVJMC#m2GQiFqZ1ea!rINl+#IQuZgHg9qp7`9q?v~%@=g%%1o2o;QG2X8
zpO_OowopF3x*mKeti8M#@w~cS(FAL317+VeJNlor*G0Uenyf~6b)$j>Yi{rJz{9-!
ztHPIgFSS?hIt)?%SyOsNT_WDo)L55@)+XY~+)(Y%mZsXKMm?L-H_9$xzce^-Ozqsg
zUqChEh*26va75W$ANrP&ALIYJ@>g@~&u=*TV(|EHs>i2KUVrF77sg<}k%KWPSRW4&
zw6VMh4vdlc2s{BL5kzb;92c#(1|FCm<=X~*MRGS-cN8JYut8}haO_X1_|7u;7~mQl
zUI_tEs-AEe{M&$QaCl`s0Hx~LRtB#tg9iX#1BX{|+$|N=LJKJm-zUN_dWTG-FP=0L
z@y9IDZ`tX16i^r^y++nHGqy2c#*-qOu&lJ`OJyDwSvzWFGGfq-+rk=xkG{c7+_pqI
z6HnTG0+~3Vn#9h|j@C9~qrOq!?36b(3ZtWYmjP8+{qd}AWx98@B~nSN+w4hL&~X1i
zDoG6+Dzs!EoJJ5v%N+P~f1-_JD*)bop!t5uRmT_Ns5?m5kDmD^46~q!gN?%9V@_V^
zVvN!E6yxLc`%w{+G{HFAm$oY$$1q+CmMbpYJ?<x5xcnX`!juc=HqbTW!tvf<;p>WZ
z;Qhk#9L3|$2j9c!JLSUh{$x4r!sUHPj+b0G{S-;hxC@5_JMv2xew%{|@wN-U-G%!_
zKLdUS{0#UR@H60Nz|X*cn}PQ$@A+Hg@b!ww=)B7?SB`vb+zuArjvW3)#cQ(a!sagn
zJY87#FsRDa0^?)onV!5_C=|w|jT5-($%~GS6SwKfvyP1us_DreI5tkCrYE0wY@Ccu
zPd?+=IH8)Je1dIgeV1&#UC8#qzNTYuX6<)8_OCtm1&{r@$9~0Q|JZFe{IMf{@r#lC
zyOG1cpX%xkH;gyD5jocUCiJqf{5VA3?9(e(KLsWv@L2O1KqANH{SegyGxl;w?W0(R
z)GjPssa!pRaj%hv_`HnY{3NRNw<7te$k{(_kDQ&E6A7G)T)bs3g9^e_K}F$8pFD5o
zWBx~)4}x3d?%N+Z+`I;hk^D7#QDn6FUN9!k+$t0%qL9pU^EQJWI0#&)edJFLf)fk-
zfd_*@%OAQP$>*+2d>xqib8s%dgQ;>PfBq%x`9vPj^WmFOEMLHg@XX;uGh(<F`gx%i
z1JAyUQ|_PPumJK;6nWwih<z2Yi3g#Cl$<`X0V_B=8ortTdHyX3e%9U6YKIYq(jS^$
z1+tjvKuY+-i5nkDYVPLf{trjPGcEZk+1DrCHM|2cve$3GaK=-VW8E3uSf4L`2K)^8
z8SpdUXTZ;Zp8-Dueg^yu_!;>B$N;|oL5W$3L`oY>WfD=X2HtFKT^C({n|zI>^_lU6
z6{VLGGH!#`p_v0(Z!GSL*6QlCq2_fI=#ER987paPsXlETR6f{?bvun{v%J8nIos-?
zFZl0(Z@gD1;1lMusY2l>=(V6vA`TkgJs!GIDEt)taG(Sp+baS?Re@ED7F3MELnh+*
z5;O$y_hLZ%0{Mz-Efnz`Uk%hh0$MDo+OcHC=PGX>tQZm7tG9k;)7mu%BmWC<j6fW}
z8)Mvt!VutT1W2$g?B^M1?<!*9B~?!c+ZN9cUV<JW;ESIDKLdUS{0#UR@H60Nz|Vl6
z0Y3wN1}Foxj*i#O;d?R^T$_ioNGWHb9=zm|a-Dc9$>#NWtH|a@k7}}cogO}~ps@eX
zw+bn=Pt)QzUSn571zzKJiTu1)?F^DYc#YZ$Ws2pbSrJVfp>=KQsT0=MQ2;(~q41hH
zT&IdsK>*|R)DiCYB^4%kO&zy?58)j5_kub<$g70l9ilv6wTKp8<j(pf6CUHF|6Mx&
z56I^8pz8l;ir060E3Bu7&k*S@(qAH-COtxWjI_6&kFzU6Dq?3_+g7b+e@`xH=d^|f
zy-}~PZOBQp;qi?d_4>y31po6Ias18|HwxY;yiNh|9Hm5R6mTc#Qt@~lgRnZai`J7;
zxX=h6@!*>X=lh7`JD?DNb-gtqh4B4_tE>a!F2VPO@(S@4C}6wZ#l}Zu{Bma<EXTh9
zg;M=5cV6F@^(+&yPjL;ix>P-{$oRX3cbuG)v^$-3^jynj8Nb50-xz-n3Z>RhFM@<<
z9OTjmB@W*%Ar}b68o*1{vkmYnu~Jld;#)C3xK!}>71tIiQ_lga$J=fUaE-|>JqY;H
z;7Y;cm|agHjy)yPTyh)-yb8uceTXBKHUYl_JQ|HF`M)D@ouGK{d7Y&Ah0p}bRi(st
zB~FG*y<7&r066yFTmNOiH5Z?Y@0Y1(9(=J<S2$Gay8vHPgeao{<8k+Z=X>M+GWA3N
zFS$N`UvI{4&{ME5-Ry}Qw%IQL$lAHSKD}4WE@C(A0izd}v1cJNnlkzmsU9<7MD0{2
zYnZtq(VH4bCoJ2F>h+}~a1DOkFf$o**nod4W`;#y#vHJWXl`I&7$`2wfJnP2)Ee4s
zG(d+8W5?c>U11}<yWN1*^X(7qZrRn*1~BZqFv1b?M%woZV`t}{)|O6V&yF4Y!rex9
zOKWEs7~XaNAzs7(G3)l#z5yp1SNt1R)U-_@&x`g36#EVItEK+XaPhi-BbrSaF*6y(
zJpmniASxP98o8_mdlRfAZcymSW{E5JC*VeeqUzPAgd)f=V6Oq^1~(y;+*u%ZIu!A6
zr$Z4?ylJA?h1W*@gSiM+dnSq?p=XB&Y_kWnol!c*CD=$|Wzs@Vrff^^Pv-P=CY81_
z_OJ`;$-%#=Yhkm7ifU=?sKwza!((PPCiLiV5}Huj&M42LRwf%yC5sFLd>JcYB7sWj
zge`P=DmoPP{uG#4$XdNZx2+*CalArwN?v8%iqQy-MWHsfR2^!lDh8LKDRUqWl_@%0
zO`*d*G5|xr#O?fVLpV=_uM+sJQ{vr^$MZyT%UCX>{xlpoH)DReeP<Yp!t*g@3DE=v
zH{ZMe4F6y67XJQb41d?%e4baZ);N%~m;WH(e}TCj_n+s#tZRtJ^IvcOP4MH~m-#$D
zX5EF!1;IXIk@-ANjRS^LA?EXZn>Ej`Aw&vQ$EJ7$N;r3AKF?QK^Y!EYa~$i(fsb=x
zws}6xx}I9{_Mba&3<{W2=JWiVHP6qveed~yi}<ZnA<y?&pCTOjm@_Z`dB89yT)*=>
zM!#qL90Va!yx0F(K;3+ec&tYh&H3b?N!BlT_|K7pHOFxUY_mS?;h!c4>ogNdGmkZn
zkD~t5yoKj4Z=%yB%wq_bRJ!>*KV!|$nH=xU-|NKZ>n}8lB#rOH+``w7u?tYZ_L+ZF
zQy$ih%5*-x?f(`$ZvMEYLRo*$VXA_+{c8X(frFpx`1zUli+bbPW_<&=l`cL%M~u}1
z2*Pp7nzb4K2pl+exqY7B^ZsAn=Zp6r3iJ3nz6cneKlAzd`bZr{!+T1loKNPno)2U<
zUxX;MUTJQJD_|bm_}qXPx37hir>YEJQ*P&TDYZ}G4$l1h97GkcuPAQKV@G+^XNW4S
wpaJtqfN@^T{pasrd>-Y#E2jF4(7-$3shr#8SiIdz@xOyVY#`Mhg2xp903AT~bN~PV

literal 0
HcmV?d00001

diff --git a/sandbox/ostep/ex5_1.c b/ostep/ex5_1.c
similarity index 65%
rename from sandbox/ostep/ex5_1.c
rename to ostep/ex5_1.c
index 4947639..047e18e 100644
--- a/sandbox/ostep/ex5_1.c
+++ b/ostep/ex5_1.c
@@ -6,19 +6,21 @@
 int main(int argc, char *argv[]){
 
     printf("hello world (pid:%d)\n", (int) getpid());
-    
+
+    int x = 100;
+
     int rc = fork();
 
     if (rc < 0) {
         fprintf(stderr, "fork failed\n");
         exit(1);
     } else if (rc == 0) {
-        printf("hello, I am child (pid:%d)\n", (int) getpid());
+        printf("hello, I am child (pid:%d) // x=%d\n", (int) getpid(), x);
 	    sleep(1);
     } else {
         int wc = wait(NULL);
-        printf("hello, I am parent of %d (wc:%d) (pid:%d)\n",
-	       rc, wc, (int) getpid());
+        printf("hello, I am parent of %d (wc:%d) (pid:%d)  // x=%d\n",
+	       rc, wc, (int) getpid(), x);
     }
 
     return 0;

From ab285372661bc3276302ebbb2ee1e4496243de6d Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 16:29:53 +0000
Subject: [PATCH 3/7] do some exercises

---
 ostep/Makefile     |   2 +-
 ostep/ex5_1        | Bin 16256 -> 16128 bytes
 ostep/ex5_1.c      |  48 ++++++++++++++++++++++++++++++---------------
 ostep/ex5_2        | Bin 0 -> 16216 bytes
 ostep/ex5_2.c      |  47 ++++++++++++++++++++++++++++++++++++++++++++
 ostep/ex5_2.output |  11 +++++++++++
 6 files changed, 91 insertions(+), 17 deletions(-)
 create mode 100755 ostep/ex5_2
 create mode 100644 ostep/ex5_2.c
 create mode 100755 ostep/ex5_2.output

diff --git a/ostep/Makefile b/ostep/Makefile
index 6d01a79..a8b6d0e 100644
--- a/ostep/Makefile
+++ b/ostep/Makefile
@@ -10,7 +10,7 @@ TARGETS=$(SRCS:.c=)
 all: $(TARGETS)
 
 clean:
-	rm -f $(TARGETS)
+	rm -f $(TARGETS) & rm -f *.output
 
 pristine: clean all
 
diff --git a/ostep/ex5_1 b/ostep/ex5_1
index 3b572349190354579e48c8223dd094b64fdbdcb2..2ee6ffd8d8a2320418db6542b9762149ed4d9af8 100755
GIT binary patch
delta 2191
zcmZ8iZ%k8H6u-BBXiH$chv1`V?5i6Sw$PR$|EaCh#_F8WL^EA9r3ef*5GN&)O{Ijn
z*f5gfNepf=DW8N-n=%)(#8_tr`e9SDeUM}yV9AnZm<Wy;_Q!SSzIU%WF5&&o@7!~L
z@4VCV&WrWO&LoQDIf-a1paThvlwG!2EjqJ~%(`ut3_7_4GIiTcRA&MSKTlzVI&6JB
zHU<M!k;lvR*l{06n4tG$Rn^%ugt#H>9Obd2JXT;kS8NBHvAe(~KWVGHcy%KG$xo+-
zf4epHxqr`h@Tsv>%|=a@S(c_fpk0}dt(n#zy5NdoJtRFQST+{WX4q#^Xgw?$6?%r*
zpqh#xP;Y|$rUF`}`916ki^d}G)SBQQQvsBkrLwL_XJ_|O(%aM7+IpOX!<`+?N5ehQ
z$cbpUE7Ea{v~{0&pPY<zM4`ugvY!$oCS~M*EI|X=iV5+Ok>27C8^PT-x$moy3z)xw
zyv?%4C2C;RDM`t?k>oWJ{uuXL1NuJqLw8otZsKPdEc$iAij)Q4XDKur$}NiBsJpf6
zbsobyzzjz$3LLiN<lcF~YlUHpLT!_DjnQ^q+GzdIO~~U+$w%;-^v-@Xx{&8NwiEJu
z-iE)B7p~&DtGIa;f9m@G`9GjYF5C4ZdY9W=d5({@G(*F_KhYB!Ha})iw-PN34Vk}Y
z_Ssa_mYK_Q#8}{Mju?Mei?8|?hUE41ER4$=%Fd#T^uB%|H0Wz)W+?t^G$%CVYeSNr
z{Wp_Iw`4MzDf1C{B$xDi;-`NO#e47HWHn8HgWI8aa3wv1Mm)GYczT)iZl4Z5#7(kL
z85#<%43Xgw4GkSwiD$>BFx7=zc8lrjEF%3L9=pj}Hl0LkF!+!To_?5pW_n@wba0VH
ztk!7MMXtRl^6E2@!<xt<iY%hYO(u{oMW1%FySFD7@(XhzWjTCaHSIgv-qG2jo>KdK
zB`w+Hc;rOuv8Z5lov~pv9yT+D#Z0Chp$Rd8cpPyYF@?AnabhWxNg)!rp}tJpVO~|t
ziAR}C6FfzJ2b@mDl|s&9#afTXr}#gQ8dJ;}d`bGmuq`*sa3jZJ#isf!$1eI@^fjvz
zTU%kQ+#x6Ob!OLrjKWO0gC=3A-0hs>?XHgjLLTte7Ng)YY<0QiQQpmbw2(d+a5<a_
zeu&RLa$hR}A>u7d!7Z2HndDyVi*A;H$PFJy<LAKXe%CPW!-2CFlI~J?;J$B{_zTK2
zCMp^R90LKk<x%Y7F~#mqG$<)15-fQXS-k9G_Y}-{6x%s1rVt;#u3`rzFi_#9<8Y-y
zv8$?x)NxjeEW*h73P0TiPVYL{?=7&qG4p(bOhh@wsVW%oD)tcWN(4(B5PlsGz!ltW
z!Cl#4Ct~1;m=9pyt56*NUS%U_3dN*omBJo&U(}wHpt#aic9)k%>jl)A;L_5nW7pV?
z={+WGp2L`pSl~7GznPdJ=lMwGnNXOiRA@fCPKGv@QW&f{SgH^2z>eKJ-`E!Ry1cF`
z5^g=#f@8e7r$?XSgiUcMsNMu`Rd37E$Nc1l>UMgyR;Bb6aMt;$6(V(RS#+Af%P@xC
zbG$nQu7&wJced!6q#26qt7Xwx0#gvFcgv#v1opvLeLrmiXM@`oll13`!J&p4Il-C0
zy)f2*330E$FJK-|ieEPY_QoCfd6VGFS_xu}l1){0O%*OS*4Pemb`WNfi4V^x*nKrN
z(Sb=ggzWjp{GzYs*{d{)L!2!f0={lp{CJW__gcYO>wwsnCPT^yzig?7JhPd-sU_g_
L*U%C;<lpok_p<Ge

delta 2656
zcmZ`*eN0<b6u+;urJW#s2rFf{zOu1_jy?(k1J==f)D@ixW-dC(QadPXU7-w$pm77X
zX=q>>aMUoPal|EJ{6i3pvZ!M&Zfay1F=p_`%vfB~MG^-ik(p^d_r3dS!FWmEIp=qO
z=iIMz@1gT(XGdQKFYrWa4q1?i{=5(LBZ;y#(mx~W@2O<t9`KyFEx^f^B8fq^DXhg`
zcfM?Q+gC^yWf;0RBfP+6zzFvp-z&(hn1ry(ZTY_#?JPz+=o5lzf0%w!7hK-d`;iK+
zWlk)do!eJa4ZR7u>yt31G9AKo(GgS>OUB=n_ew+ALQfWqs&EGC3{40@0j-CiTAjh|
zhWP}ercc2*2emn;guWL;^CYxF`id~B7Hc2FKAvO}!GQ`koh%4(yKCD$?s|WtC*Xg@
zOAdNNP5wGW1O5ZG?v{|JIpl8e_!~(}!0T-y^}*&tq$O16ZEhxQ9)E~<+woK1*6a^?
z!K7((C*Z;o@K63yEdfX3h>Gk%$&P}wX8QF6d-gNz)Bd;cXjH_{W~H1>Y?i5VM;}aS
zj04(dOd3X{;!dS((8JY1gVvZs_fl!ff~g1HU!|Raeq;_aUz$#8r3>Xq9Il0TwMO_+
zo5W4PJZjV0B-5%m?$tQ%17lobjc&k@t$R@<WFeY!2p%y!-{GU9FWl~rMx%XqQ`Y|J
zqjO!j-KE$_d<yv~=ADGlezb2{m)qA@*gvnZCs)|t#@XpK;8$?~wLgPtL*5gB=wiJ!
z#e70qk?W*=91+(^%_mfpErrruJ(`!O{@O%HAH9)c?xe(vOd>xl@r#ealYAB?qK{vj
zw;v(W`siNQaeFpZUEy1yBv+4p0~(R>zoXGe9j^S6rWiivb2^0ZkvUhm^+x0r_Jl9t
z*uUUGxx$yfpd&@Xh+cLs)=_<uGMr1tk1Uaw^KoL6`ILC!96j)_>5W3?&t>PxVdS2t
zSmasMs7tFgvWW(`(BoVTe-plf<ad(EbN>!yj=4Bd`>o_WdXq>M^>N;h%>O0%wl4PU
zz2D<p+7`YeP4-y)WUnJfn)de>$=IpX^yC3S-9e-Hyn#SaXbUz6>V#apVdXh>d8?%B
zB-DHS0dF14D2ca8s1iI4Laomq#}-6UXt(DuVmz<O)9h^w3Bh_H2ZOiO(%7*<1fe|U
z$gN4JD8R|kY<%PQXq4`0+MQ^$7v*}CXDN<yH_9XP(dd`3S6KJ31Cb4gke!Lr{aueL
zeNJ*QLMOZ_tb4o@HRWnkVjBMFv(=7x69rhyLP^IO$B45Ob3SNzU9}@wtC~(q)Qt_L
zu1m^bH+_P=`t$&4+XJKdW`2(Knq-i4!)(5p>jTazT5{Q&K(7{U)AZrNrd-u=c-kuR
z-R!cmhnfsSztwEfv2wx$DPTdA_h%ZWtd$n2d|*V(-5`yu%ner~**C!^9#jq5@v&YF
zBVw+;lWht<TjDjonk|XC(k8%Eff242=uFCDWt@;IR5*OBb78)~XzOEzO6h$S6%~C-
z*=8tsx8#+Mn^I=m#rdGiCUS!?YBQR81%)Ha8Ht%ex6f9|?FUQY8u+y^%~pXcG7u9n
zIF|FbBc7__iL(7luM1`ija&_M;nxR;i;P?wj20TpPavPC(-UN-nmK?JKa&(V7{G*w
z#>bHb9x{upyq+y=mUVw94ReluO_NCFRsWshj5PdRiK&69BBN$C9&t9Un<g7-skFex
z=P1T5r99q+y~`@&*u5f=OO*?uW7qDg?K|9s)<SDBY%Jba=Jqzy>Uf}~MJ|p+Dvq=Y
z##32EjE7*jcq1<r(PikB;+<N#o{nXd__(p7rP&;p3qzYLxoVi*Eb>ZPD{>qxWg>r*
zCA%WCz*8o!QWBJC;q9^#UddubPQxs^D!H!6VX%~UaGfwzF6z&)9XbOu<)!=xvlQ6`
zmI^WU|Cqqi`3LY+h<YV8=HPV2F0L15OU(mY40<K=dcm}%R6ileCprQ9&{B$gH=IUG
z$?`s!L2HoZ{2-X@rLjxfjWv?CcJSDP7QrDI#8AMbEMi{)=Iue1P7MdPmgrsd#lltt
OLt9I^_hDx1#(x0ntYN_b

diff --git a/ostep/ex5_1.c b/ostep/ex5_1.c
index 047e18e..68f0684 100644
--- a/ostep/ex5_1.c
+++ b/ostep/ex5_1.c
@@ -1,27 +1,43 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
-int main(int argc, char *argv[]){
-
-    printf("hello world (pid:%d)\n", (int) getpid());
-
-    int x = 100;
+int main(int argc, char* argv[]) {
+    int* x = (int*)malloc(sizeof(int));
 
     int rc = fork();
 
-    if (rc < 0) {
-        fprintf(stderr, "fork failed\n");
-        exit(1);
-    } else if (rc == 0) {
-        printf("hello, I am child (pid:%d) // x=%d\n", (int) getpid(), x);
-	    sleep(1);
+    if (rc == 0) {
+        for (int i = 0; i <= 10; i++) {
+            printf("child | x=%d\n", (*x)++);
+            usleep(1);
+        }
+
     } else {
-        int wc = wait(NULL);
-        printf("hello, I am parent of %d (wc:%d) (pid:%d)  // x=%d\n",
-	       rc, wc, (int) getpid(), x);
+        for (int i = 0; i <= 10; i++) {
+            printf("parent| x=%d\n", (*x)++);
+            usleep(1);
+        }
+
+        wait(NULL);
     }
 
     return 0;
-}
\ No newline at end of file
+}
+
+/*
+Q: Write a program that calls fork(). Before calling fork(), have the
+main process access a variable (e.g., x) and set its value to something (e.g.,
+100). What value is the variable in the child process? What happens to the
+variable when both the child and parent change the value of x?
+
+A:
+No race condition happens because they don't share memory actually.
+Child process gets its own "private memory" (copy of parent's address space)
+Therefore parent & child modify their own copy of x, indepedently.
+
+Things would break if they were using shared memory.
+
+note: Even if x is a pointer, nothing changes!
+*/
\ No newline at end of file
diff --git a/ostep/ex5_2 b/ostep/ex5_2
new file mode 100755
index 0000000000000000000000000000000000000000..9bf065114c7e0e83a6f978b062289fbefa5cc5d7
GIT binary patch
literal 16216
zcmeHOYit}>6~4R9!+F|Clh#Q{Go)?QQh8!0P6$CJeyu$&b`lat2m~F*-m$%OA7*#9
zv8yIHxKLYZkShe_2R~Y=B0(ULA}Tc%ZJdTCEzl|vs+tNA1|^cMq|`AFnWAPm=iYP1
z<H;^XJcN+uTI=tg?>z3EGk13G?A-h1SX*;65)oWV#3uww+6u+gk>dDAsRB?Zc8F#0
ze}lMFEC6|)<dnWn0ccgZ9G#1$#Fqe~Uj<eQ;D;0~7`cat=vS=tFH{;vQLbe4n~znJ
zgLn`1gOT-Kdm1`J(d2&*SD^tEM!z5CX1G$S#c*u^DKDdh?1v)y9Vfrz<i|Kg?J;sb
zF(>%hLB|oqD$rqJ4EptwUl5y=n_$E?u<XC;#Q&A{_L5(XCc}tZP|>1>klXtd_+eiD
z*}|uJAGKHPJoHok87aMDb28Dny=HSVUYSg!^Zk|mJGNJDuhDZEeT(b@_Dh2gj;WU2
z2Lyx}LypoYqJv82c&J-NdbHpA+YKj<xJ%x<oO|%=zs$`vypx=K3~jLA=z}&`Fdh#P
zl(D`PK4_!zaRh3LL%d|akwPq1)`MbY0c8?6tpJbxDP+I12*0@qKMcGEpJ3SrM4|ZK
z23`vqgWL?CLiY7V_}h!{5#Tq%=ayocUHz8Xok&~B#3Qyim`ymg$mf!_-6u>FMn#vI
zbF8dmrmRF-bR{!6TV(p|w8%NxBtUm2`;a(jB^-gaIAFGmmbTW0Msth4Mc?Mtx7G-=
zwWHmP+gZCOk#p>9M|)#3leRmo&ZG@Z^`tUsYRXim1r6Z<qA(gt<R2o})kuth_LE@4
z*F%17ViAri99_u$_{nd<Fp3Hb>R9-DioYK?*`xG5#QYfDA4=<_n_!;h%exehV-$1E
zW!%U6$MuAdSL0fFO!;_j12r=~9<K*3PZ5u|0lpSdchbk>b;jkCkC*ocQatbD>6Rij
zV?G`d>6KS~{9=z4;-ZgV;^V_=n1L_@VFtnsgc%4k5N6<im4QE&-T9s|biLF#I{$5$
zyBl8}bE57=W9X-)=VX`MZC?a>+P&u?fU*q&?R!x(J^4G=bw{O)6TIokOP-7qyXncZ
zo{ST*>B(n387E-VlTUjxPQ0ckpY&v$08URHVHsL)m#sGm**?fub?nWo{F{LMW<Y*D
zAioljUku34`Q_?&T1PHDXpH>c7`igGw<A_PR{ffBtoCQnOLz4*!17PsdfA4@K!gMy
zt33^jacusN5I#2JtcKJ+jCDxuB6qxO!yww7BLw>qX}|3&2>0DIMy8Cjf7oT5ohdOQ
z=Z#A@omCJZMgdCQ@ostC?2q{$tVOlR-+#aus@;fHW8|u{)HqtZ351E$H(hrk4#_+}
ze?7>N&x5bmKKf4{1SM7ufFBHos*yv#Hb(LnUl@ZE`%*oeO*ovlmSNZn&tvB&z6&8o
zViOZDNxVLE=(@;107hq}QEcWyY#i;b>BiC640uf(07GNsW#ef3%+c6{G4cj*)xe#J
zW4OnmHWV9=3>_Mucla0A9)(Dct4LE2U<w1Q@&ZhG0jAz}-3zfRUQ5#O8jz}`S;Gs!
zop}{oS}$9=0xeyEmd>E-#3X1TCNy#eYVrVIJBR6z*M)Z_plw*f41^g7GZ1DV%s`ld
zFau!*!VH8N2s7~in*n@3q;IzSx54YFOy23sJ0g|q(Ymvll-AXoNX8e>%6(SWPCJW5
zWL?R}tKg9FvHkkHu8Yrb$tl-;0`O75XOIVM1AOy_>;41~-+f|<JhD$j`pYBhmM$zE
zg~v<e@g4thu-}9RO$+6#s=J|z?|=s({ve=OUf#UC;(@Xy2TKRVuC+Tqvi0tbNTdJf
z;By)5_#GGX4pc4z--iShYzzCj0{T^kzgxtXmwzqVxNJemf(UeptU?Gg5N06EK$w9r
z17QZj41^g7GZ1DV%)oy!1GK1-*VW;p2^L(thh?b(Zy_JN9+RcwHic_Q=Jk8)NaiP+
zwIuU8K70<s!umhobTcTQqD6DO7OtEsye985>3NOYv*-kc*S1wCQLH9pAU82g>*4Sf
zF_x1Gyyrt+Yj+3n7pY<9%Sq;bkC7d(#pCwxB%ba5=Bnd^yh;k*1Iptar{jY+pi<_%
z!{exwUnc!uN#^6A@c%L3_1(dMRrF9>N4S^p3xs`ygM_1m!8jiz^SaHJ#>So6y$3q;
zX(z8$SL-!;Rb_Qviq(g=Y|*P~?j!miN5nkN6F1zT6`rREXr7=%YGi=JxR5=b$0)2+
z-An6D$y{i}4+i+H#PfB;_N`Efh_#};PBDC*aUE<#+%EXKP+IsM11i`quYYBJSlX}l
z*2yw|0xE_2U+lPkDC4XW<saq<vsft3i_-oM5gaGyrQ2=ZI(m-swzRMCt~ci2g-W6I
z(@P;C8XNgAEqVBMsq>Lgy%+dGadrY<F4lN?X0Lj*kFF5>eZ_oBkvN|%!Y3(yus;L9
zYaG;v!@#eIt`R)GS@lii@d(Ii9x0vyz8uC$MIBoz%mTj>G#ZV!O{D%F+4Hz!ujj~q
z5hY3f)&$BIB+pi}_;cW~pTRh90k6%Pd9@ow;zZ$#b)#oBTUihM$|&4L0^bjJAwO&8
z)oP0HVt-fGsn#>FK;7z0n2yyWfXF%d?ryzH%r0g(os<cS<I{EyEaMroCz<KAl4jh=
zWOJsK?-yN}RA16|?6_W4*aFw!Crm4wwFXT1*)cmHy0ccwHskqJY5-h(k_nd198>j!
zW*3+>@2hW*nX%nXCaj`w`poY7_SQzAVSj}gGe~PR?Gt88+n$E{HgivN^Zr<e*-_un
z76XsqivK!Z%l`rE_vO9;&lnf}n|9oCEFlkzHVe$r%dG@+7)Ts=s67DClerrL%y=$i
z_FCyUZWd_W16J`w+RW$dIJA_8e`aScN4|2a0&Y?WgohmmoEhATP;h?%Ze<9#`8P<+
zRpEJ%J0RxJYWKt(O6a+Plw)-QI$4FiTuY>3Gen=z(;3Isd(wHmFAIIoIs-ncGY>ya
zS0>^_)i<<O;!u?4y;iPQ=<$IxG@;PRD$T=oHkZhx=Lja~vUbu!2decY9ihuZ(V?pM
zWI)79&h8SrWA}rIV-u`1@|5a!FOA0DI7DMf#Zbdid2k(?vQh~MrrhB~2_3G76by6k
z0{k~CIRAsM2)Ku-65MCU^FLBcTdpJC1s|Mqv464sWN3?p=UGY;Vmnm){=t1^`1`)U
z@b@osc)#}h^L&9(V?)BA|EGcf3(VQL|2(f{<o0Pgc}xE-@W(kV`}4e)aR(+B3ic7J
zeEdBBOaO;d9QNmVG$YTO!9*4c$D;TW)NoG9{yYz5<oP`JpY0eAgFnu3S>|~zV->X&
z>_2zl7*sH)?9cOV#xXMF_JhZd`?t`)f$Vr5&v?@3k2wqaKMfq_gyVbnExLd4^9_ZO
zZE+p(JMi)QYvji`h(^A`w?)Pip!54bMG8i?;}9$}o(lM%A_Zd~I})-V<LQ7u&pQ}r
zuyek`eoW!gMt}c#-o?nzk8B^jeqJGeKL0`^OG11%=PyD3*FlNxvww}ItUXks_dn?W
zE717;do^Xs_yf;VRe1a`eHALp;ls~s{9MfYK!f%yGu{B-GM_&`AB<K435D&HG%GXz
zJ}7YPa{D}Q=Y74re;2PmEbPbU@%zBx@v}caHxF+{Ya#j-c>md-aRE5{{Y4#_Rw?9m
zH~{;xjL!qear-<kEhqn=J+|d9E2w=k_f+hEzsINw`}>i{j^DJ70!~rKct0!mhrfRp
iffM)L?_Wg&w<Qpq+htpv<`?omh&MJUYXc4eQT!b}O7jc=

literal 0
HcmV?d00001

diff --git a/ostep/ex5_2.c b/ostep/ex5_2.c
new file mode 100644
index 0000000..e27e77a
--- /dev/null
+++ b/ostep/ex5_2.c
@@ -0,0 +1,47 @@
+#include <assert.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int main(int argc, char* argv[]) {
+    int fd = open("./ex5_2.output", O_CREAT | O_WRONLY | O_TRUNC, S_IRWXU);
+    int rc = fork();
+
+    if (rc == 0) {
+        char* msg = "msg from child\n";
+
+        for (int i = 0; i < 5; i++) {
+            write(fd, msg, strlen(msg));
+            usleep(100);
+        }
+
+    } else {
+        char* msg = "msg from parent\n";
+        write(fd, msg, strlen(msg));
+
+        for (int i = 0; i < 5; i++) {
+            write(fd, msg, strlen(msg));
+            usleep(200);
+        }
+
+        wait(NULL);
+        close(fd);
+    }
+
+    return 0;
+}
+
+/*
+Q: Write a program that opens a file (with the open() system call)
+and then calls fork() to create a new process. Can both the child
+and parent access the file descriptor returned by open()? What
+happens when they are writing to the file concurrently, i.e., at the
+same time?
+
+A: the order in which the content will be written to the file is
+undeterministic. I needed to introduce loops & delays to force the race
+condition to happen, but it was clear
+*/
\ No newline at end of file
diff --git a/ostep/ex5_2.output b/ostep/ex5_2.output
new file mode 100755
index 0000000..3e61eef
--- /dev/null
+++ b/ostep/ex5_2.output
@@ -0,0 +1,11 @@
+msg from parent
+msg from parent
+msg from child
+msg from parent
+msg from child
+msg from parent
+msg from child
+msg from parent
+msg from child
+msg from parent
+msg from child

From f128d77a4eeac6049b2f277799c875ba8d2b0b49 Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 16:30:08 +0000
Subject: [PATCH 4/7] do some exercises

---
 ostep/ex5_1        | Bin 16128 -> 0 bytes
 ostep/ex5_2        | Bin 16216 -> 0 bytes
 ostep/ex5_2.output |  11 -----------
 3 files changed, 11 deletions(-)
 delete mode 100755 ostep/ex5_1
 delete mode 100755 ostep/ex5_2
 delete mode 100755 ostep/ex5_2.output

diff --git a/ostep/ex5_1 b/ostep/ex5_1
deleted file mode 100755
index 2ee6ffd8d8a2320418db6542b9762149ed4d9af8..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 16128
zcmeHOYit}>6~4R9!%36aNt-qgNET?Kl*$u3u|o(lS;yXFT$~3<EI?|RjJ;!fVIS`9
zEU`lpj7+OqsU;&M2m+*3LTW0I8W2SVsft5r(jWne;720(;UXg0Bv8kskxSJq=ggdM
zGM=s}DoFfbt~C4I^PR`NbLQ^sot=BXl4#o*jYJemh5DpoX{_31;-ZLuOezF%wN)*q
z&$Vienn&^+hjaCD7f9=ttI?TQDSQPX`>o(g8T^1tD<FEv$bPex%K5GasN_7@Z!W7u
z4&wKupFrrn_G0WzCFXp3IEM|W0R4WPo0Bz;TAgg1iG9-EfFS%>WWUqmcUt^_lhPg#
z`Q)7Nu~qUJ#9GpE0S5hg#4m^~uA2gK8(a=tx0COuy?x>ri#cIb5bIr90ny&4$&d5$
z?-pF<{nFlS*P%!950vz(jp<a!mimq9WKBAiE%w#)ZQW9{rCuxKv`tPIxL+|kcueiu
z)2=AYD07lV6&-M8#ADq9qG$UBOYd}T{`QYwSa#?4M~DA%?!tGr?|GGNxZmu<He5I!
zh6u}CUq}brxcT@h)m)D8iuIce<7{OODVCK{b`TdU!*3(5oc-}x?79Et?1yKuZ<xiN
z$7#7Z56!}JK0ZvxyNY3S_L)XkDr=@wM=X^w)9GBNDi+d~)vFAHE_0_*u+6+}WXx1n
zb>;G3REN!!t$OpRtlg#9fG_(NwX3alN3*d>+oUyk_09FlXg#>wNLqQTJ5{i){K4JL
z>0H)2Xm+G6ir<~dWhK7hnwB-BZb#{wR(MAR)%n^-h;JgqcrLC=E#Oh{DdB$d^>5NJ
zh^o(!%mw!ue7{GRy8J1*kANQ#zB2CW!9%{f-Q{_Vac)t@e7t{Lj{A5X$0(CN-W{*5
zX4=Q|ct$xRJm1FgU1HtKKHj;Hi^Hgoms`K1dCkY;+*onh$5SH15@sOGK$w9r17QZj
z41^i@zstbitJeHOAG}$qpO|}Xqf+`)qjt1(Ss(mm<#{I;rG_I!PnFhvnV@Q|V*4J}
zOijFADwReYnJ0)-6IVQ$Cx%lK=RBDwa#IsO@?@SMPE9-qnWAT$=q<{LPxA7Byf`4w
z4ao0k+`D`JZ~EoBzqSrt`Mf^#Cw=hGllu-P>PG7>>BEh`qF$7i|BftgcWG5?zeXY@
zV7T!uV)Ws;Qw$%UwwF_Ce#&)9&4SWc)!G5JJ1<D~mmK?sUobp!S09?x&;4z?er~!#
zk6h5N+_fK|08dGP%F<Yu(@*$w{stOZt%{Gf>w}FQT-ArJ+l%xQja?*+U%Oi>jVCEt
z7v?@ea^wl}_1b6uiNmDiN;~<{#jG7V_D6lFc=;^ndHm<(t`8-q$FERjC~<r6*lks8
zxtO>~N_Atiej+h_LJjK?{Y3lp(88e$bm})2a~CeY%ogKcAh)x8g~v}(Z7^{&GI;Ff
z!s8cjv|UV0vPJnAFZpAv_hLNm#F(TQlN94D`;TuR&S~q?dFT2&<Ix*|Y!a3*17QZj
z41^g7GZ1DV%s`ldFau!*!VH8N_)jyy@0U7zQt4#uXsoYsU2>u7HS<>1h7?&{@d<tx
z>%4QBES31#{}AB_VK3on!coF~gfHAGl|~7<@Vibfkt6$6q^~-%deQvK5qgSbp5N*B
zkk5KHXqoT4+IpC(+|I}wrP3inwWNCIk`<3t-FLWhKy6>O?W3C?c3$tX|KoJLMs|)P
z+frfPrel<N?h6XH^(-B)Q+pSfOf0E>I@-K=Ui1~}5ffnvGZ1DV%s`ldFau!*!VH8N
z2s037Ak4u3HUn6<hjn^bgV!Y8T7>S&LlC`fbIOP;np`O|)&s5<8IL@xM8>*6eoo>7
z{hN17IhN1JB0Q|Q8{>D1RIrxss_3zX?|E0P?h{-gxLgn*ZtA40$HQ8}J~80uIWAb!
z$Ll`1j7Y=aFH6VJ?@`A}DXi^7`@HUz3+&!5x#vfDbtrlT>74H=iAQf#9T|D2$45tg
zM)YrqjPr1#|Mxzz-a8nvR<3tkaG&5I!Ct|j-+Ree_qnUNd0T8ldq**A7h`pGTD?|V
zQ&)7vy5pNRX|?r_2>q`ka^B{sTcw~CUzZ4Jo|VMK#Nd9ya`t@PqO|(8TGp$IxrzxN
z5Ad6X$M**ItyGDqRjNAfGPth1$~vMRRQMjaTBVLsh1<pV5d1Ta{c>-eEqEUH<@!I{
zdA;bwp;7)JM7W3L;=JP6Kcs@=!ud}_-S4fVN0e)h{R;2<1^x}Hlv`K5h!PTmkq;kp
zc)FX!eI!*k5MQlUdijKQBk{|kOBL=z;2W5S;6q*F1mm|8AM@Fvnk0T{bfv<01^*=T
z+=4jCZAuLgU#{J65MNE>VMQDfT-@W>S9|+k){FY2*jESazc2QeWE{HJgZ>L6p8FZJ
ze~I{*#Pq{&oj88Rt&b7!{P7h~z0LMf`V|O#-y?J*EqA`lX5rO=&b(cx<!Gt8*^x4A
zvs)2Su!~(?TBo|Vtlh9PMkg<9FOX$2XLP4?9cJ1{+PQqeFpGVvGneU2Teg+dYRg;j
z8vK-D=JRI1L4Ppj`&C!o%veUUn91~$i%&Ah(w<>z^)(oE)FH#zxxZ<5!bt3CF=#z~
z%jfnq?QU%*n)XW=30<^$%YJ3-YTLV`sm<8CbLWA?LE~W4j<y7O1Q-0rv8w;QR`Od(
z(>9fJ60$YGbL9;IloZmtEB#5Bx$NIa7IH?9nN9MRfY!Zal}u%gV!=wveuSB!tZb4(
zbQB5_&e@n?7__qh=gnIV%I+iJoeMLA&Dj1hQ^i?!HayIr-K`NbD5VwpGq%}5Xy;w*
zL5(&^SovP1WplQrb!UrOZ$8&+<?VhS)lsBBm}^o=p_+EI*6=`c%zMm2kJ6I;S!%*X
zJMU_~WaSH~Ty}<FkS=efO?Hr4Z`xLxb1E8DweB2=Tq#(cO0%s#5_#m2b<Vkjn$;s?
zttUy*Ah|KzLFam)PEDDa6a{nL>AEP5Mtg<^ao|h&K180E(N~#%Yupmt4~Kb~s2y9>
z89zb?&xPPW+rBTh<%0Q-D=D>wDt`aq{xAMt-d}KE1;@Xuet-O~17k204EpoFl{++-
zLjN(}1fqSJ_PwkBCi(MR6aJWw0xLPWRJe~^#rb1im?Dm+BJdxR4g#Mioxeypk9v}7
zJXeH2=7+!s#S;C89gz1?@!S(K=AXb?@elT2XvO=gxXbXzd>A+?hG;){{@)V+9b$+1
zH4yW0_UD`h{huR_bAtHZ?~(j2;kkoMoD#hL-zC=X9}_>|A=l0O#Lpd&uaDn<KomgO
zApm6HnSlR@D1iImC<s5`&jS8qq5!_go%0p=f#MaA{{Ca$1jKV4?1TAxRs3=NRZJ`e
zAqwk^71SAjO$WCR|5%I!D!_VI^ge^_|A91q|Ifx;Q{WFhPq%{c1Nu5ume7IcC_JxX
zzh=-LGVm7pR{8ufk3UsIBo)}X(mfgcJEY*Ti}o?U#{OIEv*qs}7x>{i{(v|>fB55h
z_T)ykruUpKc%SeG&Ld~Pzlw`#t&3;}0pJIj=k3g)eattj#Xo4zZTZVmX<y7e75pFd
z7`Fm{KVt0oP2&=9R66!SQu4eM{lWd0p9j%*zdtqruL}f6yRhYHcRBxc{KH0NRlp%2
Gs(%7VcaZM@

diff --git a/ostep/ex5_2 b/ostep/ex5_2
deleted file mode 100755
index 9bf065114c7e0e83a6f978b062289fbefa5cc5d7..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 16216
zcmeHOYit}>6~4R9!+F|Clh#Q{Go)?QQh8!0P6$CJeyu$&b`lat2m~F*-m$%OA7*#9
zv8yIHxKLYZkShe_2R~Y=B0(ULA}Tc%ZJdTCEzl|vs+tNA1|^cMq|`AFnWAPm=iYP1
z<H;^XJcN+uTI=tg?>z3EGk13G?A-h1SX*;65)oWV#3uww+6u+gk>dDAsRB?Zc8F#0
ze}lMFEC6|)<dnWn0ccgZ9G#1$#Fqe~Uj<eQ;D;0~7`cat=vS=tFH{;vQLbe4n~znJ
zgLn`1gOT-Kdm1`J(d2&*SD^tEM!z5CX1G$S#c*u^DKDdh?1v)y9Vfrz<i|Kg?J;sb
zF(>%hLB|oqD$rqJ4EptwUl5y=n_$E?u<XC;#Q&A{_L5(XCc}tZP|>1>klXtd_+eiD
z*}|uJAGKHPJoHok87aMDb28Dny=HSVUYSg!^Zk|mJGNJDuhDZEeT(b@_Dh2gj;WU2
z2Lyx}LypoYqJv82c&J-NdbHpA+YKj<xJ%x<oO|%=zs$`vypx=K3~jLA=z}&`Fdh#P
zl(D`PK4_!zaRh3LL%d|akwPq1)`MbY0c8?6tpJbxDP+I12*0@qKMcGEpJ3SrM4|ZK
z23`vqgWL?CLiY7V_}h!{5#Tq%=ayocUHz8Xok&~B#3Qyim`ymg$mf!_-6u>FMn#vI
zbF8dmrmRF-bR{!6TV(p|w8%NxBtUm2`;a(jB^-gaIAFGmmbTW0Msth4Mc?Mtx7G-=
zwWHmP+gZCOk#p>9M|)#3leRmo&ZG@Z^`tUsYRXim1r6Z<qA(gt<R2o})kuth_LE@4
z*F%17ViAri99_u$_{nd<Fp3Hb>R9-DioYK?*`xG5#QYfDA4=<_n_!;h%exehV-$1E
zW!%U6$MuAdSL0fFO!;_j12r=~9<K*3PZ5u|0lpSdchbk>b;jkCkC*ocQatbD>6Rij
zV?G`d>6KS~{9=z4;-ZgV;^V_=n1L_@VFtnsgc%4k5N6<im4QE&-T9s|biLF#I{$5$
zyBl8}bE57=W9X-)=VX`MZC?a>+P&u?fU*q&?R!x(J^4G=bw{O)6TIokOP-7qyXncZ
zo{ST*>B(n387E-VlTUjxPQ0ckpY&v$08URHVHsL)m#sGm**?fub?nWo{F{LMW<Y*D
zAioljUku34`Q_?&T1PHDXpH>c7`igGw<A_PR{ffBtoCQnOLz4*!17PsdfA4@K!gMy
zt33^jacusN5I#2JtcKJ+jCDxuB6qxO!yww7BLw>qX}|3&2>0DIMy8Cjf7oT5ohdOQ
z=Z#A@omCJZMgdCQ@ostC?2q{$tVOlR-+#aus@;fHW8|u{)HqtZ351E$H(hrk4#_+}
ze?7>N&x5bmKKf4{1SM7ufFBHos*yv#Hb(LnUl@ZE`%*oeO*ovlmSNZn&tvB&z6&8o
zViOZDNxVLE=(@;107hq}QEcWyY#i;b>BiC640uf(07GNsW#ef3%+c6{G4cj*)xe#J
zW4OnmHWV9=3>_Mucla0A9)(Dct4LE2U<w1Q@&ZhG0jAz}-3zfRUQ5#O8jz}`S;Gs!
zop}{oS}$9=0xeyEmd>E-#3X1TCNy#eYVrVIJBR6z*M)Z_plw*f41^g7GZ1DV%s`ld
zFau!*!VH8N2s7~in*n@3q;IzSx54YFOy23sJ0g|q(Ymvll-AXoNX8e>%6(SWPCJW5
zWL?R}tKg9FvHkkHu8Yrb$tl-;0`O75XOIVM1AOy_>;41~-+f|<JhD$j`pYBhmM$zE
zg~v<e@g4thu-}9RO$+6#s=J|z?|=s({ve=OUf#UC;(@Xy2TKRVuC+Tqvi0tbNTdJf
z;By)5_#GGX4pc4z--iShYzzCj0{T^kzgxtXmwzqVxNJemf(UeptU?Gg5N06EK$w9r
z17QZj41^g7GZ1DV%)oy!1GK1-*VW;p2^L(thh?b(Zy_JN9+RcwHic_Q=Jk8)NaiP+
zwIuU8K70<s!umhobTcTQqD6DO7OtEsye985>3NOYv*-kc*S1wCQLH9pAU82g>*4Sf
zF_x1Gyyrt+Yj+3n7pY<9%Sq;bkC7d(#pCwxB%ba5=Bnd^yh;k*1Iptar{jY+pi<_%
z!{exwUnc!uN#^6A@c%L3_1(dMRrF9>N4S^p3xs`ygM_1m!8jiz^SaHJ#>So6y$3q;
zX(z8$SL-!;Rb_Qviq(g=Y|*P~?j!miN5nkN6F1zT6`rREXr7=%YGi=JxR5=b$0)2+
z-An6D$y{i}4+i+H#PfB;_N`Efh_#};PBDC*aUE<#+%EXKP+IsM11i`quYYBJSlX}l
z*2yw|0xE_2U+lPkDC4XW<saq<vsft3i_-oM5gaGyrQ2=ZI(m-swzRMCt~ci2g-W6I
z(@P;C8XNgAEqVBMsq>Lgy%+dGadrY<F4lN?X0Lj*kFF5>eZ_oBkvN|%!Y3(yus;L9
zYaG;v!@#eIt`R)GS@lii@d(Ii9x0vyz8uC$MIBoz%mTj>G#ZV!O{D%F+4Hz!ujj~q
z5hY3f)&$BIB+pi}_;cW~pTRh90k6%Pd9@ow;zZ$#b)#oBTUihM$|&4L0^bjJAwO&8
z)oP0HVt-fGsn#>FK;7z0n2yyWfXF%d?ryzH%r0g(os<cS<I{EyEaMroCz<KAl4jh=
zWOJsK?-yN}RA16|?6_W4*aFw!Crm4wwFXT1*)cmHy0ccwHskqJY5-h(k_nd198>j!
zW*3+>@2hW*nX%nXCaj`w`poY7_SQzAVSj}gGe~PR?Gt88+n$E{HgivN^Zr<e*-_un
z76XsqivK!Z%l`rE_vO9;&lnf}n|9oCEFlkzHVe$r%dG@+7)Ts=s67DClerrL%y=$i
z_FCyUZWd_W16J`w+RW$dIJA_8e`aScN4|2a0&Y?WgohmmoEhATP;h?%Ze<9#`8P<+
zRpEJ%J0RxJYWKt(O6a+Plw)-QI$4FiTuY>3Gen=z(;3Isd(wHmFAIIoIs-ncGY>ya
zS0>^_)i<<O;!u?4y;iPQ=<$IxG@;PRD$T=oHkZhx=Lja~vUbu!2decY9ihuZ(V?pM
zWI)79&h8SrWA}rIV-u`1@|5a!FOA0DI7DMf#Zbdid2k(?vQh~MrrhB~2_3G76by6k
z0{k~CIRAsM2)Ku-65MCU^FLBcTdpJC1s|Mqv464sWN3?p=UGY;Vmnm){=t1^`1`)U
z@b@osc)#}h^L&9(V?)BA|EGcf3(VQL|2(f{<o0Pgc}xE-@W(kV`}4e)aR(+B3ic7J
zeEdBBOaO;d9QNmVG$YTO!9*4c$D;TW)NoG9{yYz5<oP`JpY0eAgFnu3S>|~zV->X&
z>_2zl7*sH)?9cOV#xXMF_JhZd`?t`)f$Vr5&v?@3k2wqaKMfq_gyVbnExLd4^9_ZO
zZE+p(JMi)QYvji`h(^A`w?)Pip!54bMG8i?;}9$}o(lM%A_Zd~I})-V<LQ7u&pQ}r
zuyek`eoW!gMt}c#-o?nzk8B^jeqJGeKL0`^OG11%=PyD3*FlNxvww}ItUXks_dn?W
zE717;do^Xs_yf;VRe1a`eHALp;ls~s{9MfYK!f%yGu{B-GM_&`AB<K435D&HG%GXz
zJ}7YPa{D}Q=Y74re;2PmEbPbU@%zBx@v}caHxF+{Ya#j-c>md-aRE5{{Y4#_Rw?9m
zH~{;xjL!qear-<kEhqn=J+|d9E2w=k_f+hEzsINw`}>i{j^DJ70!~rKct0!mhrfRp
iffM)L?_Wg&w<Qpq+htpv<`?omh&MJUYXc4eQT!b}O7jc=

diff --git a/ostep/ex5_2.output b/ostep/ex5_2.output
deleted file mode 100755
index 3e61eef..0000000
--- a/ostep/ex5_2.output
+++ /dev/null
@@ -1,11 +0,0 @@
-msg from parent
-msg from parent
-msg from child
-msg from parent
-msg from child
-msg from parent
-msg from child
-msg from parent
-msg from child
-msg from parent
-msg from child

From e54a2ba9189b956d03db891f7e0635a73a9810c2 Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 16:51:51 +0000
Subject: [PATCH 5/7] ex 3

---
 ostep/Makefile |   2 +-
 ostep/ex5_1    | Bin 0 -> 16128 bytes
 ostep/ex5_2    | Bin 0 -> 16216 bytes
 ostep/ex5_3    | Bin 0 -> 16400 bytes
 ostep/ex5_3.c  |  42 ++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100755 ostep/ex5_1
 create mode 100755 ostep/ex5_2
 create mode 100755 ostep/ex5_3
 create mode 100644 ostep/ex5_3.c

diff --git a/ostep/Makefile b/ostep/Makefile
index a8b6d0e..c94cb88 100644
--- a/ostep/Makefile
+++ b/ostep/Makefile
@@ -1,5 +1,5 @@
 CC=gcc
-CCOPTS=#-Wall -Wextra
+CCOPTS=-Wall -Wextra
 LIBS=
 
 SRCS=$(wildcard *.c)
diff --git a/ostep/ex5_1 b/ostep/ex5_1
new file mode 100755
index 0000000000000000000000000000000000000000..2ee6ffd8d8a2320418db6542b9762149ed4d9af8
GIT binary patch
literal 16128
zcmeHOYit}>6~4R9!%36aNt-qgNET?Kl*$u3u|o(lS;yXFT$~3<EI?|RjJ;!fVIS`9
zEU`lpj7+OqsU;&M2m+*3LTW0I8W2SVsft5r(jWne;720(;UXg0Bv8kskxSJq=ggdM
zGM=s}DoFfbt~C4I^PR`NbLQ^sot=BXl4#o*jYJemh5DpoX{_31;-ZLuOezF%wN)*q
z&$Vienn&^+hjaCD7f9=ttI?TQDSQPX`>o(g8T^1tD<FEv$bPex%K5GasN_7@Z!W7u
z4&wKupFrrn_G0WzCFXp3IEM|W0R4WPo0Bz;TAgg1iG9-EfFS%>WWUqmcUt^_lhPg#
z`Q)7Nu~qUJ#9GpE0S5hg#4m^~uA2gK8(a=tx0COuy?x>ri#cIb5bIr90ny&4$&d5$
z?-pF<{nFlS*P%!950vz(jp<a!mimq9WKBAiE%w#)ZQW9{rCuxKv`tPIxL+|kcueiu
z)2=AYD07lV6&-M8#ADq9qG$UBOYd}T{`QYwSa#?4M~DA%?!tGr?|GGNxZmu<He5I!
zh6u}CUq}brxcT@h)m)D8iuIce<7{OODVCK{b`TdU!*3(5oc-}x?79Et?1yKuZ<xiN
z$7#7Z56!}JK0ZvxyNY3S_L)XkDr=@wM=X^w)9GBNDi+d~)vFAHE_0_*u+6+}WXx1n
zb>;G3REN!!t$OpRtlg#9fG_(NwX3alN3*d>+oUyk_09FlXg#>wNLqQTJ5{i){K4JL
z>0H)2Xm+G6ir<~dWhK7hnwB-BZb#{wR(MAR)%n^-h;JgqcrLC=E#Oh{DdB$d^>5NJ
zh^o(!%mw!ue7{GRy8J1*kANQ#zB2CW!9%{f-Q{_Vac)t@e7t{Lj{A5X$0(CN-W{*5
zX4=Q|ct$xRJm1FgU1HtKKHj;Hi^Hgoms`K1dCkY;+*onh$5SH15@sOGK$w9r17QZj
z41^i@zstbitJeHOAG}$qpO|}Xqf+`)qjt1(Ss(mm<#{I;rG_I!PnFhvnV@Q|V*4J}
zOijFADwReYnJ0)-6IVQ$Cx%lK=RBDwa#IsO@?@SMPE9-qnWAT$=q<{LPxA7Byf`4w
z4ao0k+`D`JZ~EoBzqSrt`Mf^#Cw=hGllu-P>PG7>>BEh`qF$7i|BftgcWG5?zeXY@
zV7T!uV)Ws;Qw$%UwwF_Ce#&)9&4SWc)!G5JJ1<D~mmK?sUobp!S09?x&;4z?er~!#
zk6h5N+_fK|08dGP%F<Yu(@*$w{stOZt%{Gf>w}FQT-ArJ+l%xQja?*+U%Oi>jVCEt
z7v?@ea^wl}_1b6uiNmDiN;~<{#jG7V_D6lFc=;^ndHm<(t`8-q$FERjC~<r6*lks8
zxtO>~N_Atiej+h_LJjK?{Y3lp(88e$bm})2a~CeY%ogKcAh)x8g~v}(Z7^{&GI;Ff
z!s8cjv|UV0vPJnAFZpAv_hLNm#F(TQlN94D`;TuR&S~q?dFT2&<Ix*|Y!a3*17QZj
z41^g7GZ1DV%s`ldFau!*!VH8N_)jyy@0U7zQt4#uXsoYsU2>u7HS<>1h7?&{@d<tx
z>%4QBES31#{}AB_VK3on!coF~gfHAGl|~7<@Vibfkt6$6q^~-%deQvK5qgSbp5N*B
zkk5KHXqoT4+IpC(+|I}wrP3inwWNCIk`<3t-FLWhKy6>O?W3C?c3$tX|KoJLMs|)P
z+frfPrel<N?h6XH^(-B)Q+pSfOf0E>I@-K=Ui1~}5ffnvGZ1DV%s`ldFau!*!VH8N
z2s037Ak4u3HUn6<hjn^bgV!Y8T7>S&LlC`fbIOP;np`O|)&s5<8IL@xM8>*6eoo>7
z{hN17IhN1JB0Q|Q8{>D1RIrxss_3zX?|E0P?h{-gxLgn*ZtA40$HQ8}J~80uIWAb!
z$Ll`1j7Y=aFH6VJ?@`A}DXi^7`@HUz3+&!5x#vfDbtrlT>74H=iAQf#9T|D2$45tg
zM)YrqjPr1#|Mxzz-a8nvR<3tkaG&5I!Ct|j-+Ree_qnUNd0T8ldq**A7h`pGTD?|V
zQ&)7vy5pNRX|?r_2>q`ka^B{sTcw~CUzZ4Jo|VMK#Nd9ya`t@PqO|(8TGp$IxrzxN
z5Ad6X$M**ItyGDqRjNAfGPth1$~vMRRQMjaTBVLsh1<pV5d1Ta{c>-eEqEUH<@!I{
zdA;bwp;7)JM7W3L;=JP6Kcs@=!ud}_-S4fVN0e)h{R;2<1^x}Hlv`K5h!PTmkq;kp
zc)FX!eI!*k5MQlUdijKQBk{|kOBL=z;2W5S;6q*F1mm|8AM@Fvnk0T{bfv<01^*=T
z+=4jCZAuLgU#{J65MNE>VMQDfT-@W>S9|+k){FY2*jESazc2QeWE{HJgZ>L6p8FZJ
ze~I{*#Pq{&oj88Rt&b7!{P7h~z0LMf`V|O#-y?J*EqA`lX5rO=&b(cx<!Gt8*^x4A
zvs)2Su!~(?TBo|Vtlh9PMkg<9FOX$2XLP4?9cJ1{+PQqeFpGVvGneU2Teg+dYRg;j
z8vK-D=JRI1L4Ppj`&C!o%veUUn91~$i%&Ah(w<>z^)(oE)FH#zxxZ<5!bt3CF=#z~
z%jfnq?QU%*n)XW=30<^$%YJ3-YTLV`sm<8CbLWA?LE~W4j<y7O1Q-0rv8w;QR`Od(
z(>9fJ60$YGbL9;IloZmtEB#5Bx$NIa7IH?9nN9MRfY!Zal}u%gV!=wveuSB!tZb4(
zbQB5_&e@n?7__qh=gnIV%I+iJoeMLA&Dj1hQ^i?!HayIr-K`NbD5VwpGq%}5Xy;w*
zL5(&^SovP1WplQrb!UrOZ$8&+<?VhS)lsBBm}^o=p_+EI*6=`c%zMm2kJ6I;S!%*X
zJMU_~WaSH~Ty}<FkS=efO?Hr4Z`xLxb1E8DweB2=Tq#(cO0%s#5_#m2b<Vkjn$;s?
zttUy*Ah|KzLFam)PEDDa6a{nL>AEP5Mtg<^ao|h&K180E(N~#%Yupmt4~Kb~s2y9>
z89zb?&xPPW+rBTh<%0Q-D=D>wDt`aq{xAMt-d}KE1;@Xuet-O~17k204EpoFl{++-
zLjN(}1fqSJ_PwkBCi(MR6aJWw0xLPWRJe~^#rb1im?Dm+BJdxR4g#Mioxeypk9v}7
zJXeH2=7+!s#S;C89gz1?@!S(K=AXb?@elT2XvO=gxXbXzd>A+?hG;){{@)V+9b$+1
zH4yW0_UD`h{huR_bAtHZ?~(j2;kkoMoD#hL-zC=X9}_>|A=l0O#Lpd&uaDn<KomgO
zApm6HnSlR@D1iImC<s5`&jS8qq5!_go%0p=f#MaA{{Ca$1jKV4?1TAxRs3=NRZJ`e
zAqwk^71SAjO$WCR|5%I!D!_VI^ge^_|A91q|Ifx;Q{WFhPq%{c1Nu5ume7IcC_JxX
zzh=-LGVm7pR{8ufk3UsIBo)}X(mfgcJEY*Ti}o?U#{OIEv*qs}7x>{i{(v|>fB55h
z_T)ykruUpKc%SeG&Ld~Pzlw`#t&3;}0pJIj=k3g)eattj#Xo4zZTZVmX<y7e75pFd
z7`Fm{KVt0oP2&=9R66!SQu4eM{lWd0p9j%*zdtqruL}f6yRhYHcRBxc{KH0NRlp%2
Gs(%7VcaZM@

literal 0
HcmV?d00001

diff --git a/ostep/ex5_2 b/ostep/ex5_2
new file mode 100755
index 0000000000000000000000000000000000000000..9bf065114c7e0e83a6f978b062289fbefa5cc5d7
GIT binary patch
literal 16216
zcmeHOYit}>6~4R9!+F|Clh#Q{Go)?QQh8!0P6$CJeyu$&b`lat2m~F*-m$%OA7*#9
zv8yIHxKLYZkShe_2R~Y=B0(ULA}Tc%ZJdTCEzl|vs+tNA1|^cMq|`AFnWAPm=iYP1
z<H;^XJcN+uTI=tg?>z3EGk13G?A-h1SX*;65)oWV#3uww+6u+gk>dDAsRB?Zc8F#0
ze}lMFEC6|)<dnWn0ccgZ9G#1$#Fqe~Uj<eQ;D;0~7`cat=vS=tFH{;vQLbe4n~znJ
zgLn`1gOT-Kdm1`J(d2&*SD^tEM!z5CX1G$S#c*u^DKDdh?1v)y9Vfrz<i|Kg?J;sb
zF(>%hLB|oqD$rqJ4EptwUl5y=n_$E?u<XC;#Q&A{_L5(XCc}tZP|>1>klXtd_+eiD
z*}|uJAGKHPJoHok87aMDb28Dny=HSVUYSg!^Zk|mJGNJDuhDZEeT(b@_Dh2gj;WU2
z2Lyx}LypoYqJv82c&J-NdbHpA+YKj<xJ%x<oO|%=zs$`vypx=K3~jLA=z}&`Fdh#P
zl(D`PK4_!zaRh3LL%d|akwPq1)`MbY0c8?6tpJbxDP+I12*0@qKMcGEpJ3SrM4|ZK
z23`vqgWL?CLiY7V_}h!{5#Tq%=ayocUHz8Xok&~B#3Qyim`ymg$mf!_-6u>FMn#vI
zbF8dmrmRF-bR{!6TV(p|w8%NxBtUm2`;a(jB^-gaIAFGmmbTW0Msth4Mc?Mtx7G-=
zwWHmP+gZCOk#p>9M|)#3leRmo&ZG@Z^`tUsYRXim1r6Z<qA(gt<R2o})kuth_LE@4
z*F%17ViAri99_u$_{nd<Fp3Hb>R9-DioYK?*`xG5#QYfDA4=<_n_!;h%exehV-$1E
zW!%U6$MuAdSL0fFO!;_j12r=~9<K*3PZ5u|0lpSdchbk>b;jkCkC*ocQatbD>6Rij
zV?G`d>6KS~{9=z4;-ZgV;^V_=n1L_@VFtnsgc%4k5N6<im4QE&-T9s|biLF#I{$5$
zyBl8}bE57=W9X-)=VX`MZC?a>+P&u?fU*q&?R!x(J^4G=bw{O)6TIokOP-7qyXncZ
zo{ST*>B(n387E-VlTUjxPQ0ckpY&v$08URHVHsL)m#sGm**?fub?nWo{F{LMW<Y*D
zAioljUku34`Q_?&T1PHDXpH>c7`igGw<A_PR{ffBtoCQnOLz4*!17PsdfA4@K!gMy
zt33^jacusN5I#2JtcKJ+jCDxuB6qxO!yww7BLw>qX}|3&2>0DIMy8Cjf7oT5ohdOQ
z=Z#A@omCJZMgdCQ@ostC?2q{$tVOlR-+#aus@;fHW8|u{)HqtZ351E$H(hrk4#_+}
ze?7>N&x5bmKKf4{1SM7ufFBHos*yv#Hb(LnUl@ZE`%*oeO*ovlmSNZn&tvB&z6&8o
zViOZDNxVLE=(@;107hq}QEcWyY#i;b>BiC640uf(07GNsW#ef3%+c6{G4cj*)xe#J
zW4OnmHWV9=3>_Mucla0A9)(Dct4LE2U<w1Q@&ZhG0jAz}-3zfRUQ5#O8jz}`S;Gs!
zop}{oS}$9=0xeyEmd>E-#3X1TCNy#eYVrVIJBR6z*M)Z_plw*f41^g7GZ1DV%s`ld
zFau!*!VH8N2s7~in*n@3q;IzSx54YFOy23sJ0g|q(Ymvll-AXoNX8e>%6(SWPCJW5
zWL?R}tKg9FvHkkHu8Yrb$tl-;0`O75XOIVM1AOy_>;41~-+f|<JhD$j`pYBhmM$zE
zg~v<e@g4thu-}9RO$+6#s=J|z?|=s({ve=OUf#UC;(@Xy2TKRVuC+Tqvi0tbNTdJf
z;By)5_#GGX4pc4z--iShYzzCj0{T^kzgxtXmwzqVxNJemf(UeptU?Gg5N06EK$w9r
z17QZj41^g7GZ1DV%)oy!1GK1-*VW;p2^L(thh?b(Zy_JN9+RcwHic_Q=Jk8)NaiP+
zwIuU8K70<s!umhobTcTQqD6DO7OtEsye985>3NOYv*-kc*S1wCQLH9pAU82g>*4Sf
zF_x1Gyyrt+Yj+3n7pY<9%Sq;bkC7d(#pCwxB%ba5=Bnd^yh;k*1Iptar{jY+pi<_%
z!{exwUnc!uN#^6A@c%L3_1(dMRrF9>N4S^p3xs`ygM_1m!8jiz^SaHJ#>So6y$3q;
zX(z8$SL-!;Rb_Qviq(g=Y|*P~?j!miN5nkN6F1zT6`rREXr7=%YGi=JxR5=b$0)2+
z-An6D$y{i}4+i+H#PfB;_N`Efh_#};PBDC*aUE<#+%EXKP+IsM11i`quYYBJSlX}l
z*2yw|0xE_2U+lPkDC4XW<saq<vsft3i_-oM5gaGyrQ2=ZI(m-swzRMCt~ci2g-W6I
z(@P;C8XNgAEqVBMsq>Lgy%+dGadrY<F4lN?X0Lj*kFF5>eZ_oBkvN|%!Y3(yus;L9
zYaG;v!@#eIt`R)GS@lii@d(Ii9x0vyz8uC$MIBoz%mTj>G#ZV!O{D%F+4Hz!ujj~q
z5hY3f)&$BIB+pi}_;cW~pTRh90k6%Pd9@ow;zZ$#b)#oBTUihM$|&4L0^bjJAwO&8
z)oP0HVt-fGsn#>FK;7z0n2yyWfXF%d?ryzH%r0g(os<cS<I{EyEaMroCz<KAl4jh=
zWOJsK?-yN}RA16|?6_W4*aFw!Crm4wwFXT1*)cmHy0ccwHskqJY5-h(k_nd198>j!
zW*3+>@2hW*nX%nXCaj`w`poY7_SQzAVSj}gGe~PR?Gt88+n$E{HgivN^Zr<e*-_un
z76XsqivK!Z%l`rE_vO9;&lnf}n|9oCEFlkzHVe$r%dG@+7)Ts=s67DClerrL%y=$i
z_FCyUZWd_W16J`w+RW$dIJA_8e`aScN4|2a0&Y?WgohmmoEhATP;h?%Ze<9#`8P<+
zRpEJ%J0RxJYWKt(O6a+Plw)-QI$4FiTuY>3Gen=z(;3Isd(wHmFAIIoIs-ncGY>ya
zS0>^_)i<<O;!u?4y;iPQ=<$IxG@;PRD$T=oHkZhx=Lja~vUbu!2decY9ihuZ(V?pM
zWI)79&h8SrWA}rIV-u`1@|5a!FOA0DI7DMf#Zbdid2k(?vQh~MrrhB~2_3G76by6k
z0{k~CIRAsM2)Ku-65MCU^FLBcTdpJC1s|Mqv464sWN3?p=UGY;Vmnm){=t1^`1`)U
z@b@osc)#}h^L&9(V?)BA|EGcf3(VQL|2(f{<o0Pgc}xE-@W(kV`}4e)aR(+B3ic7J
zeEdBBOaO;d9QNmVG$YTO!9*4c$D;TW)NoG9{yYz5<oP`JpY0eAgFnu3S>|~zV->X&
z>_2zl7*sH)?9cOV#xXMF_JhZd`?t`)f$Vr5&v?@3k2wqaKMfq_gyVbnExLd4^9_ZO
zZE+p(JMi)QYvji`h(^A`w?)Pip!54bMG8i?;}9$}o(lM%A_Zd~I})-V<LQ7u&pQ}r
zuyek`eoW!gMt}c#-o?nzk8B^jeqJGeKL0`^OG11%=PyD3*FlNxvww}ItUXks_dn?W
zE717;do^Xs_yf;VRe1a`eHALp;ls~s{9MfYK!f%yGu{B-GM_&`AB<K435D&HG%GXz
zJ}7YPa{D}Q=Y74re;2PmEbPbU@%zBx@v}caHxF+{Ya#j-c>md-aRE5{{Y4#_Rw?9m
zH~{;xjL!qear-<kEhqn=J+|d9E2w=k_f+hEzsINw`}>i{j^DJ70!~rKct0!mhrfRp
iffM)L?_Wg&w<Qpq+htpv<`?omh&MJUYXc4eQT!b}O7jc=

literal 0
HcmV?d00001

diff --git a/ostep/ex5_3 b/ostep/ex5_3
new file mode 100755
index 0000000000000000000000000000000000000000..6aa7b10e162af3761e13982f485401d73227b187
GIT binary patch
literal 16400
zcmeHOYiu0V6~1f7#6S`|!GSyo83II3Q%~%~2?1o-#C9^S@-U9A2B~y1-W_{a*%!OB
z#6~T3<hqSz+?q;lqbf*2{XtYJ;Yz55NEC;Z0F_D;^-ubc8X{8J0*d24<hCN)bM8H7
zGCS;+w(6gXxz_A=&vzd8&Y6er%-s8x_C32QLLtGWQamV78d|EDFey5>Qw1O_wu{B^
zyH?yGZUA|K<di<F0JN%HtSH86;wu5sZv|FL;O&YQjNC&+^ea~kYJgGHDogaM!Yavr
zyh8n8WWC#-hR#ql`Rif=4WKZ3{V+F~2B{XAmSQ|fc{xSMekh{f5cv&}ALA^w$H@7_
zoZz;d_QQ{jpu@uG_luFAAKR3hV8k}C9Jt~{|C{zY$?upZ!w5e%D_Ssedk=#j=H=fl
ze3-kay>iE4g7VKu=@pw2@!oCCn-bB6L_C!rXc*YOtzlcUo=fYSWf!nt8f<t@?cUcT
zAj}kUltxi8q-2hVx;oOM{gJP~-1di~b?amAo_O)l)#o=&t$A?`+F-xY2W_xmJU&HG
z#(E8GXruCR6l#h?ykNhbL@ZY}fMQt*<@bQoO7IT=SIT~Q8NR&?|M@a}tPH=p3?DAT
zW8O;j^T)tzu=&gDKxlpv<UO#Jiqlnw4*|apwvQFlj0{+2Up!?c;!oHjYg<uqBpY{Z
zVVYJhXJ;L=&x$8Nf-@~*<{S%{q!mwzOy0?fOgv+YoRdx1DUnOqc1HB2vxmVN3?qll
zNbIn3&t&5%r%zxEJUO?C-FrHAwwjyuX1BIk-|E)4Gz+t%d#@R_vvz+x=h)fqy{(CK
z%I>y$6WF!>WI9EiF_mdaL)hI4I0q}`-vYu)V3<QpgB4$gb@BLOyh9BVmtPgX5zp>n
zl3#rKJ8(Kzh;M?7h3}VqpE^VbWq|I7%xlC~hozffp5==VDITvCJXTyTd3f*jHSOVV
zW@Erv55LI6&wF^hF1Z{dejyNiPe9#-hsW!k%W)4c|4)(Pq=#46yHcF;@Yn{INe|Dt
zK;26o9un`CDGz^>%L?(Phlc~_mh&EdiOU9+AOk@Lf(!&12r>|4;QuKDf2z6T@5b=^
z)y7!WuQv%{j7&Kdh4aSn&#KSL-6(AB0(!1+&jEm%wF2#9sF|C2r%)(NNEruKb2ArQ
z83$BzGiO{G2S9T(KXPRp_{_~b>&iIbnVWgqm2sdmH*?gLaey;7^O!5+z-Dg7a%CLQ
z%*{N^GW2$h>}{Kn{RR0M9eaOW{<cpZ_sJtZ`O7{z?~{{0+4jkg`s5z3-1I@m=!GvD
zqnC~0cV|1h+nc7E-ZI8pehzz8SiS`;|J<k7to<s8aDc{J9s$M}uj)d$Z{ArBhwfIa
z!=byeaH(eP5Zaw31p5ure(O4f4cCm(S>wzfA2QC&R~n&n#)WH69R#=nuNyExb>UK<
z%oF?L@f~VGwa9PmF@{@S!>TcQ#aU#GwVVTCdh}YMFdc>DpR0NW<j|ww>$Z>nGe<y)
zl^*ajj=nz&5u(P}f_v&^sP_4$DPw%39*m69H>Q68;YOwg>tPo!FUF?MoW_AEh}}{=
zhx;yTZ%n7ac1(JXj?{tw*vMz$cXVV0{7yd&%F&VAp*s8u{t6lM8x#{COdt}x$bu#?
z<}!-83f#yc-})+^%G37(1s3x#@Ha+BG>B!4DS-Z-{s{a1nlUzxiZR)?G5R)WCP4Gv
zL2&$~bbMnvji%${jnWSLd-_e80W>}<bt9-#{rQP<dI>DVbY5z!eoBGXgD4foSkHXa
z*jOi1=~PX(fZ{E@axvZVx^}N*j1!a~13?CY3<MbnG7w}S$Uu;RAOk@LKFt{j!8aFs
zV5_-BkH~LM_4wh*?2G0$Xb-k%jUpRSn9TKSec5zUi^SrI=$#^CW$l!s^(NAh!**0l
zr!@S+Rlh;gb)A)2J7UKlx1;xKmxoT=le;|h%uTF<4^K(>H0H!p{X%~93azeu0KfU-
ztAOJl77F-|!I*^?41fm#PXW#Yb^^Y0wNRJ>#Dd>cv4o!J5}|?G(CS4Ct0&-n1oAj{
z;3W90M}xM7_{1mfh7H@Phc+gWSW>%d$%@a_+<c^ZNIbOa{?BZ=TYk<%|1ZEc33k#E
zZJ{9Vz;+7wlYm^Xt*2mH34N1u0os?;eyyT)@eP%c5Oj&n0t_+`WFW{ukbxirK?Z^h
z1Q`f25M<y}lmVW{#`D&APFk9B03Uc%p@$CmC?(6qTNJJ&ndishJV`A4gt1DAg6GNc
z{At$z<yt{DHA$1wc&^z&s_-1Mi=^i{VZW!iJST1i$v6+xTgXjhXr36)t(zqye15{h
zbJlKCqBuwd^T(+p-0vx}<GE|x{vE`#-9HLy{~)iDf-iS+e-BbT_`D`%&O1CFN_ji!
z|3)(J2ZjHi0ng+12W+I{9VYA~JVclw93q?`JV`i7I7R4>|4DLnSXu0DZM|Qs@9E8_
zoV?c5q&Mr04NZ9|Ha)p{v)<Uef#`o75%ar1TrK#m@c4y5^AsgmBLh6WOWEV`tq`?h
zlGY=TxzLEe<m0yx&({~*cR(d1R*BlMV)*#uEbEZC)xBPnR){Y_1>5E8mHA`Rez`k8
zmHFqOQmX$iNc&}CSW}jKy_MVF*QI@(h~25|y}za6|4Q25Cj95s@1)}`?)-X=^P#j~
z;a;E2S3yE(DlJnI*8#5;F-rJA@^Ci_7b_nu6K8)J-U7Z>taOhHM~k6-#ZtldJ?2wo
z;v6l*pD4q>P=<f24F8)l{CmJ-|NVKG2VUb&dvGD#5SLc06nwq0st$QP0_3!S6n6n%
z3+L^MFk33T3h|eLhS%w=Cv`p9^Lfr*&A_95oDMRtSGf<{h5q>M+kw~E*@LEx;~}W}
z81U;pPK&3|z5@QM`R+^KDicQ>h-956J&m*Ed*h~K^$Q?!PQI@X-cVkjwr)B}GlCP>
zb6^=woBfG&uaz*PPCA=2t^9z9q?4J1?buPhv9txw&5xT_Hfs%<@G3JqDEhKi(l(>{
zWO5K(Jdz2PPLV0UGBwT4uJ-QkN6cM4`&zp@_U|)I+1{?M9edl&_I+(8%%X35WZ#ax
z9jy=(R&|)|hN-khTbD3*@7cd|#~yS4u3ZP(yUp$$JNLAMhks2#m}m8W!u)+)I^f#k
zynngkpolT;sO4Bf?maCqDAxN{7`V!2q1GC>1ja8~%TT1j_sB&Az8@|k;J86g)M5h&
zRJ`)QjONm2%t}RZRYJ#pu!_c0W<F;}1spB-F?(}4@|7=;O%ql!aK>?oL&<duaw&zc
z7v6Om#VS1Pa@|D{E%e-A(y@90ovgwb*I+S*oy`b6m3C~sKb6-r*>nchdJKA~-aNcP
zZ-_^U+Oe~v0Z(&j9<y>Wp+^T((1b!Kt2B?>*<3uGDiTc4W$lE84phq|9HGm8>rmDE
z(;#9cXGetY*aINqc@NfUc^>F?jL!5}6r!=DVyIJId2k(?vXXHKrrhBu2pz7qBwRuz
zF8}|S!tpHJ+Tee$D*p9>Jf0=BwB<VDU9jO8lKsoAgF{;^JZ@By5Zj>Q_4lub!|w;)
z!uM(BaGc@w=W!0B#)gD`e_SW^R~UnG|9PCw$nDc`^<(|Fz#qrx?9bzP#vx2D6zn5b
zdH;Dl9S07FX6(<;1&sV004B0fI2OfYP{T1c`}4S(Q6o$4Kie@r33?o}v&`dm#xVK&
z`%knOhYIGD{f|>aj8kOD?fdutyX3!<?D)Baan|FHIrIBJ3moQz<GcU&=>H!-uTdD;
zSFR(TfX(Z#kssrv*BI)gcJVo%|9LWCWP1+7GUKGr{}L$}PqHH+`!T-k^XKsiV-Ft~
zpFf9v)#uOSKSq8YW_$njqsGtIkH65!lJFQi68imr0X*iPyLn7ghK$WhbbtN+zXgrg
ze@auPj6ZZeRfW$VrmsL{32glQ$<O(`e${W!GUHY7t?~Htdw_ukAfd3GlCI0le*_9V
zce#CjuHf~^yzUsUKP>FW$NzcYaR1q#-veYep*5_3Q{euxKjRJH?DZF6GHq1I?Qj70
zV|fucBggIYxVD!3{r1?Fw=AXh$=p@3|3;Tl754WcpF3XDFa_+S6J`x4@fnc&!}s4C
if#be={U_+e`@SzYx68KpI9$qq%e~5CmCwN^ihlx2`J2lC

literal 0
HcmV?d00001

diff --git a/ostep/ex5_3.c b/ostep/ex5_3.c
new file mode 100644
index 0000000..fc61065
--- /dev/null
+++ b/ostep/ex5_3.c
@@ -0,0 +1,42 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int main() {
+    int pipe_fds[2];
+    assert(pipe(pipe_fds) >= 0);
+
+    int pipe_read_fd = pipe_fds[0];
+    int pipe_write_fd = pipe_fds[1];
+
+    int rc = fork();
+    assert(rc >= 0);
+
+    if (rc == 0) {
+        sleep(2);  // sleep to prove that nothing happens in parent until child
+                   // writes to pipe
+        char* msg = "msg from child!";
+        write(pipe_write_fd, msg, strlen(msg));
+    } else {
+        char buffer[200];
+        printf("parent blocked on read() ...\n");
+        read(pipe_read_fd, buffer, 200);
+        printf("parent received: “%s”\n", buffer);
+        printf("parent terminating\n");
+    }
+
+    return 0;
+}
+
+/*
+Q: Write another program using fork(). The child process should
+print “hello”; the parent process should print “goodbye”. You should
+try to ensure that the child process always prints first; can you do
+this without calling wait() in the parent?
+
+A: can be achieved using a pipe. parent blocks on read() until child writes to
+it.
+*/
\ No newline at end of file

From bc490b51d311a3dfd0fda62f4a95f862bd3eaa94 Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 16:52:24 +0000
Subject: [PATCH 6/7] cleanup

---
 ostep/ex5_1 | Bin 16128 -> 0 bytes
 ostep/ex5_2 | Bin 16216 -> 0 bytes
 ostep/ex5_3 | Bin 16400 -> 0 bytes
 3 files changed, 0 insertions(+), 0 deletions(-)
 delete mode 100755 ostep/ex5_1
 delete mode 100755 ostep/ex5_2
 delete mode 100755 ostep/ex5_3

diff --git a/ostep/ex5_1 b/ostep/ex5_1
deleted file mode 100755
index 2ee6ffd8d8a2320418db6542b9762149ed4d9af8..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 16128
zcmeHOYit}>6~4R9!%36aNt-qgNET?Kl*$u3u|o(lS;yXFT$~3<EI?|RjJ;!fVIS`9
zEU`lpj7+OqsU;&M2m+*3LTW0I8W2SVsft5r(jWne;720(;UXg0Bv8kskxSJq=ggdM
zGM=s}DoFfbt~C4I^PR`NbLQ^sot=BXl4#o*jYJemh5DpoX{_31;-ZLuOezF%wN)*q
z&$Vienn&^+hjaCD7f9=ttI?TQDSQPX`>o(g8T^1tD<FEv$bPex%K5GasN_7@Z!W7u
z4&wKupFrrn_G0WzCFXp3IEM|W0R4WPo0Bz;TAgg1iG9-EfFS%>WWUqmcUt^_lhPg#
z`Q)7Nu~qUJ#9GpE0S5hg#4m^~uA2gK8(a=tx0COuy?x>ri#cIb5bIr90ny&4$&d5$
z?-pF<{nFlS*P%!950vz(jp<a!mimq9WKBAiE%w#)ZQW9{rCuxKv`tPIxL+|kcueiu
z)2=AYD07lV6&-M8#ADq9qG$UBOYd}T{`QYwSa#?4M~DA%?!tGr?|GGNxZmu<He5I!
zh6u}CUq}brxcT@h)m)D8iuIce<7{OODVCK{b`TdU!*3(5oc-}x?79Et?1yKuZ<xiN
z$7#7Z56!}JK0ZvxyNY3S_L)XkDr=@wM=X^w)9GBNDi+d~)vFAHE_0_*u+6+}WXx1n
zb>;G3REN!!t$OpRtlg#9fG_(NwX3alN3*d>+oUyk_09FlXg#>wNLqQTJ5{i){K4JL
z>0H)2Xm+G6ir<~dWhK7hnwB-BZb#{wR(MAR)%n^-h;JgqcrLC=E#Oh{DdB$d^>5NJ
zh^o(!%mw!ue7{GRy8J1*kANQ#zB2CW!9%{f-Q{_Vac)t@e7t{Lj{A5X$0(CN-W{*5
zX4=Q|ct$xRJm1FgU1HtKKHj;Hi^Hgoms`K1dCkY;+*onh$5SH15@sOGK$w9r17QZj
z41^i@zstbitJeHOAG}$qpO|}Xqf+`)qjt1(Ss(mm<#{I;rG_I!PnFhvnV@Q|V*4J}
zOijFADwReYnJ0)-6IVQ$Cx%lK=RBDwa#IsO@?@SMPE9-qnWAT$=q<{LPxA7Byf`4w
z4ao0k+`D`JZ~EoBzqSrt`Mf^#Cw=hGllu-P>PG7>>BEh`qF$7i|BftgcWG5?zeXY@
zV7T!uV)Ws;Qw$%UwwF_Ce#&)9&4SWc)!G5JJ1<D~mmK?sUobp!S09?x&;4z?er~!#
zk6h5N+_fK|08dGP%F<Yu(@*$w{stOZt%{Gf>w}FQT-ArJ+l%xQja?*+U%Oi>jVCEt
z7v?@ea^wl}_1b6uiNmDiN;~<{#jG7V_D6lFc=;^ndHm<(t`8-q$FERjC~<r6*lks8
zxtO>~N_Atiej+h_LJjK?{Y3lp(88e$bm})2a~CeY%ogKcAh)x8g~v}(Z7^{&GI;Ff
z!s8cjv|UV0vPJnAFZpAv_hLNm#F(TQlN94D`;TuR&S~q?dFT2&<Ix*|Y!a3*17QZj
z41^g7GZ1DV%s`ldFau!*!VH8N_)jyy@0U7zQt4#uXsoYsU2>u7HS<>1h7?&{@d<tx
z>%4QBES31#{}AB_VK3on!coF~gfHAGl|~7<@Vibfkt6$6q^~-%deQvK5qgSbp5N*B
zkk5KHXqoT4+IpC(+|I}wrP3inwWNCIk`<3t-FLWhKy6>O?W3C?c3$tX|KoJLMs|)P
z+frfPrel<N?h6XH^(-B)Q+pSfOf0E>I@-K=Ui1~}5ffnvGZ1DV%s`ldFau!*!VH8N
z2s037Ak4u3HUn6<hjn^bgV!Y8T7>S&LlC`fbIOP;np`O|)&s5<8IL@xM8>*6eoo>7
z{hN17IhN1JB0Q|Q8{>D1RIrxss_3zX?|E0P?h{-gxLgn*ZtA40$HQ8}J~80uIWAb!
z$Ll`1j7Y=aFH6VJ?@`A}DXi^7`@HUz3+&!5x#vfDbtrlT>74H=iAQf#9T|D2$45tg
zM)YrqjPr1#|Mxzz-a8nvR<3tkaG&5I!Ct|j-+Ree_qnUNd0T8ldq**A7h`pGTD?|V
zQ&)7vy5pNRX|?r_2>q`ka^B{sTcw~CUzZ4Jo|VMK#Nd9ya`t@PqO|(8TGp$IxrzxN
z5Ad6X$M**ItyGDqRjNAfGPth1$~vMRRQMjaTBVLsh1<pV5d1Ta{c>-eEqEUH<@!I{
zdA;bwp;7)JM7W3L;=JP6Kcs@=!ud}_-S4fVN0e)h{R;2<1^x}Hlv`K5h!PTmkq;kp
zc)FX!eI!*k5MQlUdijKQBk{|kOBL=z;2W5S;6q*F1mm|8AM@Fvnk0T{bfv<01^*=T
z+=4jCZAuLgU#{J65MNE>VMQDfT-@W>S9|+k){FY2*jESazc2QeWE{HJgZ>L6p8FZJ
ze~I{*#Pq{&oj88Rt&b7!{P7h~z0LMf`V|O#-y?J*EqA`lX5rO=&b(cx<!Gt8*^x4A
zvs)2Su!~(?TBo|Vtlh9PMkg<9FOX$2XLP4?9cJ1{+PQqeFpGVvGneU2Teg+dYRg;j
z8vK-D=JRI1L4Ppj`&C!o%veUUn91~$i%&Ah(w<>z^)(oE)FH#zxxZ<5!bt3CF=#z~
z%jfnq?QU%*n)XW=30<^$%YJ3-YTLV`sm<8CbLWA?LE~W4j<y7O1Q-0rv8w;QR`Od(
z(>9fJ60$YGbL9;IloZmtEB#5Bx$NIa7IH?9nN9MRfY!Zal}u%gV!=wveuSB!tZb4(
zbQB5_&e@n?7__qh=gnIV%I+iJoeMLA&Dj1hQ^i?!HayIr-K`NbD5VwpGq%}5Xy;w*
zL5(&^SovP1WplQrb!UrOZ$8&+<?VhS)lsBBm}^o=p_+EI*6=`c%zMm2kJ6I;S!%*X
zJMU_~WaSH~Ty}<FkS=efO?Hr4Z`xLxb1E8DweB2=Tq#(cO0%s#5_#m2b<Vkjn$;s?
zttUy*Ah|KzLFam)PEDDa6a{nL>AEP5Mtg<^ao|h&K180E(N~#%Yupmt4~Kb~s2y9>
z89zb?&xPPW+rBTh<%0Q-D=D>wDt`aq{xAMt-d}KE1;@Xuet-O~17k204EpoFl{++-
zLjN(}1fqSJ_PwkBCi(MR6aJWw0xLPWRJe~^#rb1im?Dm+BJdxR4g#Mioxeypk9v}7
zJXeH2=7+!s#S;C89gz1?@!S(K=AXb?@elT2XvO=gxXbXzd>A+?hG;){{@)V+9b$+1
zH4yW0_UD`h{huR_bAtHZ?~(j2;kkoMoD#hL-zC=X9}_>|A=l0O#Lpd&uaDn<KomgO
zApm6HnSlR@D1iImC<s5`&jS8qq5!_go%0p=f#MaA{{Ca$1jKV4?1TAxRs3=NRZJ`e
zAqwk^71SAjO$WCR|5%I!D!_VI^ge^_|A91q|Ifx;Q{WFhPq%{c1Nu5ume7IcC_JxX
zzh=-LGVm7pR{8ufk3UsIBo)}X(mfgcJEY*Ti}o?U#{OIEv*qs}7x>{i{(v|>fB55h
z_T)ykruUpKc%SeG&Ld~Pzlw`#t&3;}0pJIj=k3g)eattj#Xo4zZTZVmX<y7e75pFd
z7`Fm{KVt0oP2&=9R66!SQu4eM{lWd0p9j%*zdtqruL}f6yRhYHcRBxc{KH0NRlp%2
Gs(%7VcaZM@

diff --git a/ostep/ex5_2 b/ostep/ex5_2
deleted file mode 100755
index 9bf065114c7e0e83a6f978b062289fbefa5cc5d7..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 16216
zcmeHOYit}>6~4R9!+F|Clh#Q{Go)?QQh8!0P6$CJeyu$&b`lat2m~F*-m$%OA7*#9
zv8yIHxKLYZkShe_2R~Y=B0(ULA}Tc%ZJdTCEzl|vs+tNA1|^cMq|`AFnWAPm=iYP1
z<H;^XJcN+uTI=tg?>z3EGk13G?A-h1SX*;65)oWV#3uww+6u+gk>dDAsRB?Zc8F#0
ze}lMFEC6|)<dnWn0ccgZ9G#1$#Fqe~Uj<eQ;D;0~7`cat=vS=tFH{;vQLbe4n~znJ
zgLn`1gOT-Kdm1`J(d2&*SD^tEM!z5CX1G$S#c*u^DKDdh?1v)y9Vfrz<i|Kg?J;sb
zF(>%hLB|oqD$rqJ4EptwUl5y=n_$E?u<XC;#Q&A{_L5(XCc}tZP|>1>klXtd_+eiD
z*}|uJAGKHPJoHok87aMDb28Dny=HSVUYSg!^Zk|mJGNJDuhDZEeT(b@_Dh2gj;WU2
z2Lyx}LypoYqJv82c&J-NdbHpA+YKj<xJ%x<oO|%=zs$`vypx=K3~jLA=z}&`Fdh#P
zl(D`PK4_!zaRh3LL%d|akwPq1)`MbY0c8?6tpJbxDP+I12*0@qKMcGEpJ3SrM4|ZK
z23`vqgWL?CLiY7V_}h!{5#Tq%=ayocUHz8Xok&~B#3Qyim`ymg$mf!_-6u>FMn#vI
zbF8dmrmRF-bR{!6TV(p|w8%NxBtUm2`;a(jB^-gaIAFGmmbTW0Msth4Mc?Mtx7G-=
zwWHmP+gZCOk#p>9M|)#3leRmo&ZG@Z^`tUsYRXim1r6Z<qA(gt<R2o})kuth_LE@4
z*F%17ViAri99_u$_{nd<Fp3Hb>R9-DioYK?*`xG5#QYfDA4=<_n_!;h%exehV-$1E
zW!%U6$MuAdSL0fFO!;_j12r=~9<K*3PZ5u|0lpSdchbk>b;jkCkC*ocQatbD>6Rij
zV?G`d>6KS~{9=z4;-ZgV;^V_=n1L_@VFtnsgc%4k5N6<im4QE&-T9s|biLF#I{$5$
zyBl8}bE57=W9X-)=VX`MZC?a>+P&u?fU*q&?R!x(J^4G=bw{O)6TIokOP-7qyXncZ
zo{ST*>B(n387E-VlTUjxPQ0ckpY&v$08URHVHsL)m#sGm**?fub?nWo{F{LMW<Y*D
zAioljUku34`Q_?&T1PHDXpH>c7`igGw<A_PR{ffBtoCQnOLz4*!17PsdfA4@K!gMy
zt33^jacusN5I#2JtcKJ+jCDxuB6qxO!yww7BLw>qX}|3&2>0DIMy8Cjf7oT5ohdOQ
z=Z#A@omCJZMgdCQ@ostC?2q{$tVOlR-+#aus@;fHW8|u{)HqtZ351E$H(hrk4#_+}
ze?7>N&x5bmKKf4{1SM7ufFBHos*yv#Hb(LnUl@ZE`%*oeO*ovlmSNZn&tvB&z6&8o
zViOZDNxVLE=(@;107hq}QEcWyY#i;b>BiC640uf(07GNsW#ef3%+c6{G4cj*)xe#J
zW4OnmHWV9=3>_Mucla0A9)(Dct4LE2U<w1Q@&ZhG0jAz}-3zfRUQ5#O8jz}`S;Gs!
zop}{oS}$9=0xeyEmd>E-#3X1TCNy#eYVrVIJBR6z*M)Z_plw*f41^g7GZ1DV%s`ld
zFau!*!VH8N2s7~in*n@3q;IzSx54YFOy23sJ0g|q(Ymvll-AXoNX8e>%6(SWPCJW5
zWL?R}tKg9FvHkkHu8Yrb$tl-;0`O75XOIVM1AOy_>;41~-+f|<JhD$j`pYBhmM$zE
zg~v<e@g4thu-}9RO$+6#s=J|z?|=s({ve=OUf#UC;(@Xy2TKRVuC+Tqvi0tbNTdJf
z;By)5_#GGX4pc4z--iShYzzCj0{T^kzgxtXmwzqVxNJemf(UeptU?Gg5N06EK$w9r
z17QZj41^g7GZ1DV%)oy!1GK1-*VW;p2^L(thh?b(Zy_JN9+RcwHic_Q=Jk8)NaiP+
zwIuU8K70<s!umhobTcTQqD6DO7OtEsye985>3NOYv*-kc*S1wCQLH9pAU82g>*4Sf
zF_x1Gyyrt+Yj+3n7pY<9%Sq;bkC7d(#pCwxB%ba5=Bnd^yh;k*1Iptar{jY+pi<_%
z!{exwUnc!uN#^6A@c%L3_1(dMRrF9>N4S^p3xs`ygM_1m!8jiz^SaHJ#>So6y$3q;
zX(z8$SL-!;Rb_Qviq(g=Y|*P~?j!miN5nkN6F1zT6`rREXr7=%YGi=JxR5=b$0)2+
z-An6D$y{i}4+i+H#PfB;_N`Efh_#};PBDC*aUE<#+%EXKP+IsM11i`quYYBJSlX}l
z*2yw|0xE_2U+lPkDC4XW<saq<vsft3i_-oM5gaGyrQ2=ZI(m-swzRMCt~ci2g-W6I
z(@P;C8XNgAEqVBMsq>Lgy%+dGadrY<F4lN?X0Lj*kFF5>eZ_oBkvN|%!Y3(yus;L9
zYaG;v!@#eIt`R)GS@lii@d(Ii9x0vyz8uC$MIBoz%mTj>G#ZV!O{D%F+4Hz!ujj~q
z5hY3f)&$BIB+pi}_;cW~pTRh90k6%Pd9@ow;zZ$#b)#oBTUihM$|&4L0^bjJAwO&8
z)oP0HVt-fGsn#>FK;7z0n2yyWfXF%d?ryzH%r0g(os<cS<I{EyEaMroCz<KAl4jh=
zWOJsK?-yN}RA16|?6_W4*aFw!Crm4wwFXT1*)cmHy0ccwHskqJY5-h(k_nd198>j!
zW*3+>@2hW*nX%nXCaj`w`poY7_SQzAVSj}gGe~PR?Gt88+n$E{HgivN^Zr<e*-_un
z76XsqivK!Z%l`rE_vO9;&lnf}n|9oCEFlkzHVe$r%dG@+7)Ts=s67DClerrL%y=$i
z_FCyUZWd_W16J`w+RW$dIJA_8e`aScN4|2a0&Y?WgohmmoEhATP;h?%Ze<9#`8P<+
zRpEJ%J0RxJYWKt(O6a+Plw)-QI$4FiTuY>3Gen=z(;3Isd(wHmFAIIoIs-ncGY>ya
zS0>^_)i<<O;!u?4y;iPQ=<$IxG@;PRD$T=oHkZhx=Lja~vUbu!2decY9ihuZ(V?pM
zWI)79&h8SrWA}rIV-u`1@|5a!FOA0DI7DMf#Zbdid2k(?vQh~MrrhB~2_3G76by6k
z0{k~CIRAsM2)Ku-65MCU^FLBcTdpJC1s|Mqv464sWN3?p=UGY;Vmnm){=t1^`1`)U
z@b@osc)#}h^L&9(V?)BA|EGcf3(VQL|2(f{<o0Pgc}xE-@W(kV`}4e)aR(+B3ic7J
zeEdBBOaO;d9QNmVG$YTO!9*4c$D;TW)NoG9{yYz5<oP`JpY0eAgFnu3S>|~zV->X&
z>_2zl7*sH)?9cOV#xXMF_JhZd`?t`)f$Vr5&v?@3k2wqaKMfq_gyVbnExLd4^9_ZO
zZE+p(JMi)QYvji`h(^A`w?)Pip!54bMG8i?;}9$}o(lM%A_Zd~I})-V<LQ7u&pQ}r
zuyek`eoW!gMt}c#-o?nzk8B^jeqJGeKL0`^OG11%=PyD3*FlNxvww}ItUXks_dn?W
zE717;do^Xs_yf;VRe1a`eHALp;ls~s{9MfYK!f%yGu{B-GM_&`AB<K435D&HG%GXz
zJ}7YPa{D}Q=Y74re;2PmEbPbU@%zBx@v}caHxF+{Ya#j-c>md-aRE5{{Y4#_Rw?9m
zH~{;xjL!qear-<kEhqn=J+|d9E2w=k_f+hEzsINw`}>i{j^DJ70!~rKct0!mhrfRp
iffM)L?_Wg&w<Qpq+htpv<`?omh&MJUYXc4eQT!b}O7jc=

diff --git a/ostep/ex5_3 b/ostep/ex5_3
deleted file mode 100755
index 6aa7b10e162af3761e13982f485401d73227b187..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 16400
zcmeHOYiu0V6~1f7#6S`|!GSyo83II3Q%~%~2?1o-#C9^S@-U9A2B~y1-W_{a*%!OB
z#6~T3<hqSz+?q;lqbf*2{XtYJ;Yz55NEC;Z0F_D;^-ubc8X{8J0*d24<hCN)bM8H7
zGCS;+w(6gXxz_A=&vzd8&Y6er%-s8x_C32QLLtGWQamV78d|EDFey5>Qw1O_wu{B^
zyH?yGZUA|K<di<F0JN%HtSH86;wu5sZv|FL;O&YQjNC&+^ea~kYJgGHDogaM!Yavr
zyh8n8WWC#-hR#ql`Rif=4WKZ3{V+F~2B{XAmSQ|fc{xSMekh{f5cv&}ALA^w$H@7_
zoZz;d_QQ{jpu@uG_luFAAKR3hV8k}C9Jt~{|C{zY$?upZ!w5e%D_Ssedk=#j=H=fl
ze3-kay>iE4g7VKu=@pw2@!oCCn-bB6L_C!rXc*YOtzlcUo=fYSWf!nt8f<t@?cUcT
zAj}kUltxi8q-2hVx;oOM{gJP~-1di~b?amAo_O)l)#o=&t$A?`+F-xY2W_xmJU&HG
z#(E8GXruCR6l#h?ykNhbL@ZY}fMQt*<@bQoO7IT=SIT~Q8NR&?|M@a}tPH=p3?DAT
zW8O;j^T)tzu=&gDKxlpv<UO#Jiqlnw4*|apwvQFlj0{+2Up!?c;!oHjYg<uqBpY{Z
zVVYJhXJ;L=&x$8Nf-@~*<{S%{q!mwzOy0?fOgv+YoRdx1DUnOqc1HB2vxmVN3?qll
zNbIn3&t&5%r%zxEJUO?C-FrHAwwjyuX1BIk-|E)4Gz+t%d#@R_vvz+x=h)fqy{(CK
z%I>y$6WF!>WI9EiF_mdaL)hI4I0q}`-vYu)V3<QpgB4$gb@BLOyh9BVmtPgX5zp>n
zl3#rKJ8(Kzh;M?7h3}VqpE^VbWq|I7%xlC~hozffp5==VDITvCJXTyTd3f*jHSOVV
zW@Erv55LI6&wF^hF1Z{dejyNiPe9#-hsW!k%W)4c|4)(Pq=#46yHcF;@Yn{INe|Dt
zK;26o9un`CDGz^>%L?(Phlc~_mh&EdiOU9+AOk@Lf(!&12r>|4;QuKDf2z6T@5b=^
z)y7!WuQv%{j7&Kdh4aSn&#KSL-6(AB0(!1+&jEm%wF2#9sF|C2r%)(NNEruKb2ArQ
z83$BzGiO{G2S9T(KXPRp_{_~b>&iIbnVWgqm2sdmH*?gLaey;7^O!5+z-Dg7a%CLQ
z%*{N^GW2$h>}{Kn{RR0M9eaOW{<cpZ_sJtZ`O7{z?~{{0+4jkg`s5z3-1I@m=!GvD
zqnC~0cV|1h+nc7E-ZI8pehzz8SiS`;|J<k7to<s8aDc{J9s$M}uj)d$Z{ArBhwfIa
z!=byeaH(eP5Zaw31p5ure(O4f4cCm(S>wzfA2QC&R~n&n#)WH69R#=nuNyExb>UK<
z%oF?L@f~VGwa9PmF@{@S!>TcQ#aU#GwVVTCdh}YMFdc>DpR0NW<j|ww>$Z>nGe<y)
zl^*ajj=nz&5u(P}f_v&^sP_4$DPw%39*m69H>Q68;YOwg>tPo!FUF?MoW_AEh}}{=
zhx;yTZ%n7ac1(JXj?{tw*vMz$cXVV0{7yd&%F&VAp*s8u{t6lM8x#{COdt}x$bu#?
z<}!-83f#yc-})+^%G37(1s3x#@Ha+BG>B!4DS-Z-{s{a1nlUzxiZR)?G5R)WCP4Gv
zL2&$~bbMnvji%${jnWSLd-_e80W>}<bt9-#{rQP<dI>DVbY5z!eoBGXgD4foSkHXa
z*jOi1=~PX(fZ{E@axvZVx^}N*j1!a~13?CY3<MbnG7w}S$Uu;RAOk@LKFt{j!8aFs
zV5_-BkH~LM_4wh*?2G0$Xb-k%jUpRSn9TKSec5zUi^SrI=$#^CW$l!s^(NAh!**0l
zr!@S+Rlh;gb)A)2J7UKlx1;xKmxoT=le;|h%uTF<4^K(>H0H!p{X%~93azeu0KfU-
ztAOJl77F-|!I*^?41fm#PXW#Yb^^Y0wNRJ>#Dd>cv4o!J5}|?G(CS4Ct0&-n1oAj{
z;3W90M}xM7_{1mfh7H@Phc+gWSW>%d$%@a_+<c^ZNIbOa{?BZ=TYk<%|1ZEc33k#E
zZJ{9Vz;+7wlYm^Xt*2mH34N1u0os?;eyyT)@eP%c5Oj&n0t_+`WFW{ukbxirK?Z^h
z1Q`f25M<y}lmVW{#`D&APFk9B03Uc%p@$CmC?(6qTNJJ&ndishJV`A4gt1DAg6GNc
z{At$z<yt{DHA$1wc&^z&s_-1Mi=^i{VZW!iJST1i$v6+xTgXjhXr36)t(zqye15{h
zbJlKCqBuwd^T(+p-0vx}<GE|x{vE`#-9HLy{~)iDf-iS+e-BbT_`D`%&O1CFN_ji!
z|3)(J2ZjHi0ng+12W+I{9VYA~JVclw93q?`JV`i7I7R4>|4DLnSXu0DZM|Qs@9E8_
zoV?c5q&Mr04NZ9|Ha)p{v)<Uef#`o75%ar1TrK#m@c4y5^AsgmBLh6WOWEV`tq`?h
zlGY=TxzLEe<m0yx&({~*cR(d1R*BlMV)*#uEbEZC)xBPnR){Y_1>5E8mHA`Rez`k8
zmHFqOQmX$iNc&}CSW}jKy_MVF*QI@(h~25|y}za6|4Q25Cj95s@1)}`?)-X=^P#j~
z;a;E2S3yE(DlJnI*8#5;F-rJA@^Ci_7b_nu6K8)J-U7Z>taOhHM~k6-#ZtldJ?2wo
z;v6l*pD4q>P=<f24F8)l{CmJ-|NVKG2VUb&dvGD#5SLc06nwq0st$QP0_3!S6n6n%
z3+L^MFk33T3h|eLhS%w=Cv`p9^Lfr*&A_95oDMRtSGf<{h5q>M+kw~E*@LEx;~}W}
z81U;pPK&3|z5@QM`R+^KDicQ>h-956J&m*Ed*h~K^$Q?!PQI@X-cVkjwr)B}GlCP>
zb6^=woBfG&uaz*PPCA=2t^9z9q?4J1?buPhv9txw&5xT_Hfs%<@G3JqDEhKi(l(>{
zWO5K(Jdz2PPLV0UGBwT4uJ-QkN6cM4`&zp@_U|)I+1{?M9edl&_I+(8%%X35WZ#ax
z9jy=(R&|)|hN-khTbD3*@7cd|#~yS4u3ZP(yUp$$JNLAMhks2#m}m8W!u)+)I^f#k
zynngkpolT;sO4Bf?maCqDAxN{7`V!2q1GC>1ja8~%TT1j_sB&Az8@|k;J86g)M5h&
zRJ`)QjONm2%t}RZRYJ#pu!_c0W<F;}1spB-F?(}4@|7=;O%ql!aK>?oL&<duaw&zc
z7v6Om#VS1Pa@|D{E%e-A(y@90ovgwb*I+S*oy`b6m3C~sKb6-r*>nchdJKA~-aNcP
zZ-_^U+Oe~v0Z(&j9<y>Wp+^T((1b!Kt2B?>*<3uGDiTc4W$lE84phq|9HGm8>rmDE
z(;#9cXGetY*aINqc@NfUc^>F?jL!5}6r!=DVyIJId2k(?vXXHKrrhBu2pz7qBwRuz
zF8}|S!tpHJ+Tee$D*p9>Jf0=BwB<VDU9jO8lKsoAgF{;^JZ@By5Zj>Q_4lub!|w;)
z!uM(BaGc@w=W!0B#)gD`e_SW^R~UnG|9PCw$nDc`^<(|Fz#qrx?9bzP#vx2D6zn5b
zdH;Dl9S07FX6(<;1&sV004B0fI2OfYP{T1c`}4S(Q6o$4Kie@r33?o}v&`dm#xVK&
z`%knOhYIGD{f|>aj8kOD?fdutyX3!<?D)Baan|FHIrIBJ3moQz<GcU&=>H!-uTdD;
zSFR(TfX(Z#kssrv*BI)gcJVo%|9LWCWP1+7GUKGr{}L$}PqHH+`!T-k^XKsiV-Ft~
zpFf9v)#uOSKSq8YW_$njqsGtIkH65!lJFQi68imr0X*iPyLn7ghK$WhbbtN+zXgrg
ze@auPj6ZZeRfW$VrmsL{32glQ$<O(`e${W!GUHY7t?~Htdw_ukAfd3GlCI0le*_9V
zce#CjuHf~^yzUsUKP>FW$NzcYaR1q#-veYep*5_3Q{euxKjRJH?DZF6GHq1I?Qj70
zV|fucBggIYxVD!3{r1?Fw=AXh$=p@3|3;Tl754WcpF3XDFa_+S6J`x4@fnc&!}s4C
if#be={U_+e`@SzYx68KpI9$qq%e~5CmCwN^ihlx2`J2lC


From cc6bf23a30c84dc485c99879efbacaea79850094 Mon Sep 17 00:00:00 2001
From: linomp-droplet <linomp95@hotmail.com>
Date: Fri, 23 Aug 2024 17:32:34 +0000
Subject: [PATCH 7/7] solve ex 5.8

---
 .vscode/settings.json |  6 ++++
 ostep/Makefile        |  2 +-
 ostep/ex5_8.c         | 74 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 .vscode/settings.json
 create mode 100644 ostep/ex5_8.c

diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..982432c
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,6 @@
+{
+    "files.associations": {
+        "*html": "html",
+        "unistd.h": "c"
+    }
+}
\ No newline at end of file
diff --git a/ostep/Makefile b/ostep/Makefile
index c94cb88..a8b6d0e 100644
--- a/ostep/Makefile
+++ b/ostep/Makefile
@@ -1,5 +1,5 @@
 CC=gcc
-CCOPTS=-Wall -Wextra
+CCOPTS=#-Wall -Wextra
 LIBS=
 
 SRCS=$(wildcard *.c)
diff --git a/ostep/ex5_8.c b/ostep/ex5_8.c
new file mode 100644
index 0000000..698685a
--- /dev/null
+++ b/ostep/ex5_8.c
@@ -0,0 +1,74 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int main() {
+    int status;
+
+    int pipe_fds[2];
+    assert(pipe(pipe_fds) >= 0);
+
+    int pipe_read_fd = pipe_fds[0];
+    int pipe_write_fd = pipe_fds[1];
+
+    pid_t rc1 = fork();
+    assert(rc1 >= 0);
+
+    if (rc1 == 0) {
+        char* out_buffer = "msg from child 1!";
+
+        printf("child 1 is writing...\n");
+        write(pipe_write_fd, out_buffer, strlen(out_buffer));
+
+        close(pipe_write_fd);
+        printf("child 1 terminating...\n");
+
+        exit(0);
+    }
+
+    pid_t rc2 = fork();
+    assert(rc2 >= 0);
+
+    if (rc2 == 0) {
+        printf("child 2 blocked on read()...\n");
+
+        char in_buffer[200];
+        read(pipe_read_fd, in_buffer, 200);
+        printf("child 2 finished reading...\n");
+
+        char out_buffer[400];
+        sprintf(out_buffer, "%s || msg from child 2!", in_buffer);
+
+        printf("child 2 is writing...\n");
+        write(pipe_write_fd, out_buffer, strlen(out_buffer));
+
+        close(pipe_write_fd);
+        printf("child 2 terminating...\n");
+
+        exit(0);
+    }
+
+    // Parent process
+
+    printf("parent waiting for child 1 (pid: %d) ...\n", rc1);
+    waitpid(rc1, &status, 0);
+    printf("parent waiting for child 2 (pid: %d) ...\n", rc1);
+    waitpid(rc2, &status, 0);
+
+    char buffer[200];
+    read(pipe_read_fd, buffer, 200);
+    printf("parent received: “%s”\n", buffer);
+
+    close(pipe_write_fd);
+    printf("parent terminating...\n");
+
+    return 0;
+}
+
+/*
+Q: Write a program that creates two children, and connects the standard output
+of one to the standard input of the other, using the pipe() system call.
+*/