joe9 / cwfs_partial_line Goto Github PK

Fix: when reading a file being written by pwrite's, loop back to the offset where the null is found

This test takes around 300MB space in /tmp/

; mk clean; mk all ; rm /tmp/test.file /tmp/test.readcontents; touch /tmp/test.file; ./6.reader10 /tmp/test.file /tmp/test.readcontents & echo 'echo kill>/proc/'$apid'/note'; ./6.pwriter10 /tmp/test.file
rm -f *.[0568qv] *.a[0568qv] y.tab.? lex.yy.c y.debug y.output [0568qv].??* writer10 reader10 brdstr10 pwriter10 $CLEANFILES
6c -FTVw writer10.c
6c -FTVw reader10.c
6c -FTVw brdstr10.c
6c -FTVw pwriter10.c
6l  -o 6.writer10 writer10.6
6l  -o 6.reader10 reader10.6
6l  -o 6.pwriter10 pwriter10.6
6l  -o 6.brdstr10 brdstr10.6
echo kill>/proc/27518709/note
iters=53806 n=198 strlen(buf)=176
iters=73726 n=220 strlen(buf)=198
iters=75675 n=220 strlen(buf)=198
iters=77713 n=220 strlen(buf)=198
iters=79835 n=165 strlen(buf)=143
iters=86161 n=242 strlen(buf)=220
iters=88697 n=198 strlen(buf)=176
iters=89770 n=198 strlen(buf)=176
iters=92099 n=231 strlen(buf)=209
iters=93517 n=231 strlen(buf)=209
iters=96050 n=220 strlen(buf)=198
iters=96640 n=198 strlen(buf)=176
iters=100242 n=209 strlen(buf)=187
iters=100430 n=165 strlen(buf)=143
iters=100491 n=198 strlen(buf)=176
iters=101726 n=220 strlen(buf)=198
iters=102100 n=198 strlen(buf)=176
iters=105591 n=209 strlen(buf)=187
iters=113191 n=198 strlen(buf)=176
iters=118188 n=231 strlen(buf)=209
iters=118528 n=220 strlen(buf)=198
iters=118915 n=198 strlen(buf)=176
iters=119760 n=209 strlen(buf)=198
iters=121908 n=209 strlen(buf)=187
iters=121914 n=253 strlen(buf)=231
iters=124651 n=198 strlen(buf)=176
iters=129985 n=220 strlen(buf)=198
iters=130163 n=209 strlen(buf)=187
iters=239103 n=198 strlen(buf)=176
iters=246343 n=198 strlen(buf)=176
iters=258089 n=176 strlen(buf)=154
;

to see the nulls in the written file /tmp/test.readcontents
sed '/iters=53806/q' /tmp/test.readcontents >/tmp/test.clean
ls -ltr /tmp/test.clean # to figure out the size of the file
; dd -bs 1 -skip 14782056 -if test.readcontents | xd -c
0000000   1  2  3  4  5  6  7  8  9 \n  .  i  t  e  r  s
0000010   =  5  3  8  0  6     i  n  p  u  t     o  f  f
0000020   s  e  t  =  1  0  4  7  7  9  4  0     o  u  t
0000030   p  u  t     o  f  f  s  e  t  =  1  4  7  8  2
0000040   0  6  7  ,     n  =  1  9  8     s  t  r  l  e
0000050   n  (  b  u  f  )  =  1  7  6 \n  .  0  1  2  3
0000060   4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8
0000070   9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2
0000080   3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7
0000090   8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1
00000a0   2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6
00000b0   7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0
00000c0   1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5
00000d0   6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n
00000e0   0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4
00000f0   5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9
0000100  \n  0  1  2  3  4  5  6  7  8  9 \n 00 00 00 00
0000110  00 00 00 00 00 00 00  0  1  2  3  4  5  6  7  8
0000120   9 \n  .  i  t  e  r  s  =  5  3  8  0  7     i
0000130   n  p  u  t     o  f  f  s  e  t  =  1  0  4  7
0000140   8  5  0  1     o  u  t  p  u  t     o  f  f  s
0000150   e  t  =  1  4  7  8  2  3  4  7  ,     n  =  5
0000160   6  1     s  t  r  l  e  n  (  b  u  f  )  =  5
0000170   6  1 \n  .  0  1  2  3  4  5  6  7  8  9 \n  0
0000180   1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5
0000190   6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n
00001a0   0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4
00001b0   5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9
00001c0  \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3
00001d0   4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8
00001e0   9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2
00001f0   3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7
0000200   8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1
0000210   2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6
0000220   7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0
0000230   1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5
0000240   6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n
0000250   0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4
0000260   5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9
0000270  \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3
0000280   4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8
0000290   9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2
00002a0   3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7
00002b0   8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1
00002c0   2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6
00002d0   7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0
00002e0   1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5
00002f0   6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n
0000300   0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4
0000310   5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8  9
0000320  \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2  3
0000330   4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7  8
0000340   9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1  2
0000350   3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6  7
0000360   8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0  1
0000370   2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5  6
0000380   7  8  9 \n  0  1  2  3  4  5  6  7  8  9 \n  0
0000390   1  2  3  4  5  6  7  8  9 \n  0  1  2  3  4  5
00003a0   6  7  8  9 \n  .  i  t  e  r  s  =  5  3  8  0
00003b0   8     i  n  p  u  t     o  f  f  s  e  t  =  1