Thread (13 messages) flat view 13 messages, 5 authors, 2016-06-15

Re: [PATCH] Convert open("-|") to qx{} calls

From: Randal L. Schwartz <hidden>
Date: 2016-06-15 22:42:20

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"Alex" == Alex Riesen [off-list ref] writes:
Alex> Is $tmpname safe?
quoted
-       my $sha = <$F>;
+       my $sha = qx{git-hash-object -w $name};
+       !$? or exit $?;
Alex> Is $name safe?
quoted
-       while(<$f>) {
+       foreach (qx{git-ls-tree -r -z $gitrev $srcpath}) {
chomp;
Alex> Is $srcpath safe?
quoted
-                       while(<$F>) {
+                       foreach (qx{git-ls-files -z @o1}) {
Alex> @o1 must contain filenames. Can be dangerous

Convert all of these to use "safe_qx" (perl 5.6 compatible):

    sub safe_qx {
      defined (my $pid = open my $kid, "-|") or die "Cannot fork: $!";
      unless ($pid) { # child does:
        exec @_;
        die "Cannot exec @_: $!";
      }
      my $result = do { local $/; <$kid> };
      close $kid;                   # sets $?
      return $result;
    }

my $result = safe_qx('some shell command');
my $other_result = safe_qx('git-ls-tree', '-r', '-z', $gitrev, $srcpath);

Args are safe, as if being passed to system/exec, so a single arg
can be a shell command, multiargs are passed arg-by-arg to a single
exec target.  $? is set correctly.

-- 
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
[off-list ref] <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
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