Re: [platform-testers] new snapshot available: grep-3.4-almost.19-ff30

[Bruno Haible]

Paul Eggert wrote:
> I suspect that the 'splice' system call is not working correctly on Alpine 
> 3.10, 
> when copying from a pipe to /dev/null. To test this hypotheses, try something 
> like this:
> 
> export LC_ALL=C
> mkfifo fifo
> awk 'BEGIN {while (1) print "x"}' </dev/null >fifo &
> timeout 1 strace -o tr src/grep x <fifo >/dev/null
> echo $?
> 
> On my platform (Fedora 31 x86-64), this outputs "124" and "tr" ends like this:
> 
> fstat(1, {st_mode=S_IFCHR|0666, st_rdev=makedev(0x1, 0x3), ...}) = 0
> stat("/dev/null", {st_mode=S_IFCHR|0666, st_rdev=makedev(0x1, 0x3), ...}) = 0
> fstat(0, {st_mode=S_IFIFO|0664, st_size=0, ...}) = 0
> lseek(0, 0, SEEK_CUR)                   = -1 ESPIPE (Illegal seek)
> read(0, "x\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\nx\n"..., 98304) = 65536
> splice(0, NULL, 1, NULL, 98304, SPLICE_F_MOVE) = 4096
> splice(0, NULL, 1, NULL, 98304, SPLICE_F_MOVE) = 4096
> ... [many more duplicates like this]
> splice(0, NULL, 1, NULL, 98304, SPLICE_F_MOVE) = 4096
> splice(0, NULL, 1, NULL, 98304, SPLICE_F_MOVE) = ? ERESTARTSYS (To be 
> restarted 
> if SA_RESTART is set)
> --- SIGTERM {si_signo=SIGTERM, si_code=SI_USER, si_pid=1615171, si_uid=1000} 
> --\
> -
> +++ killed by SIGTERM +++
> 
> 
> What does it do on Alpine 3.10?

The 'timeout 1 strace -o tr src/grep x <fifo >/dev/null' command does not
terminate within ca. 10 seconds. When I interrupt it with Ctrl-C, it leaves
the attached file 'tr'.

(This is with grep-3.4-almost.31, with which the grep-dev-null-out test still
fails.)

Bruno

tr.gz
Description: application/gzip