From 4c44561d9f97331bb23f900f47a69305091f3ab3 Mon Sep 17 00:00:00 2001 From: Harald van Dijk Date: Fri, 26 Sep 2014 22:27:13 +0800 Subject: [JOBS] Fix off-by-one error for multiple of four job numbers On 29/07/13 23:44, Luigi Tarenga wrote: > hi list, > while writing a script to execute parallel ssh command on many host I found > a strange behavior of dash. I can replicate it with a very simple script but > didn't find any documentation about dash or POSIX that can explain it. > > tested on centos 6.4 (dash 0.5.5.1) and wih dash compiled from source (0.5.7) > the following script reports error: > > #!/bin/dash > > sleep 3 & > sleep 3 & > sleep 3 & > sleep 3 & > > #/bin/true > jobs -l > > wait %1 > wait %2 > wait %3 > wait %4 > > [vortex@lizard ~]$ ./dash-0.5.7/src/dash test.sh > [4] + 4569 Running > [3] - 4568 Running > [2] 4567 Running > [1] 4566 Running > prova: 14: wait: No such job: %4 > [vortex@lizard ~]$ echo $? > 2 Yes, this looks like a bug to me. The number of allocated jobs is always kept as a multiple of four, and the first check in considering whether the job number is valid is "if it's greater than or equal to the number of allocated job, it's invalid". That doesn't look right. That would only be right if jobs were zero-based, but they aren't. If it's exactly equal to the number of available jobs, it can still be valid. It works when adding /bin/true, because four more more jobs end up allocated internally. Signed-off-by: Herbert Xu --- src/jobs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src') diff --git a/src/jobs.c b/src/jobs.c index bf40204..c2c2332 100644 --- a/src/jobs.c +++ b/src/jobs.c @@ -699,7 +699,7 @@ check: if (is_number(p)) { num = atoi(p); - if (num < njobs) { + if (num <= njobs) { jp = jobtab + num - 1; if (jp->used) goto gotit; -- cgit 1.4.1