Bug #3034
closed
Tail -n 1 don't work on /proc/curproc/map
100%
Description
If i run tail -n 1 /proc/curproc/map it will print 10 last lines.(wc says it is 11 but something is wrong here)
But then if i redirect output to file and then tail it it will print correct number of lines.
tail -n 1 /proc/curproc/map |wc -l
11 143 1111
tail -n 1 /proc/curproc/map > /tmp/tail-bug && tail -n 1 /tmp/tail-bug |wc
1 13 95
uname -a
DragonFly dfly-0 4.6-RELEASE DragonFly v4.6.0rc2-RELEASE #2: Sun Jul 24 14:47:27 EDT 2016 root@www.shiningsilence.com:/usr/obj/home/justin/release/4_6/sys/X86_64_GENERIC x86_64
Updated by daftaupe about 7 years ago
After looking at this issue, it seems that it's because /proc/curproc/map has a size of 0.
In the forward.c code, in that case we're at line 150, calling function rlines : rlines(fp, off, sbp);
But this function starts with a test :
if (!(size = sbp->st_size))
return;
and as the size of the file is 0 it returns immediately and display the whole file instead of the number of lines specified on the cli.
The call of display_lines(fp, off) instead of rlines(fp, off, sbp) seems to fix this issue.
Updated by deef over 4 years ago
- Due date set to 06/17/2020
- Status changed from New to Resolved
- % Done changed from 0 to 100
Fixed in commit d02fa88e+.
Thank you both, cpk for reporting this and daftaupe for analyzing it. :)