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avoid harmful '<>' pattern, explicitly read from STDIN

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Fixes problems in CLIHandler using the code pattern:

while (my $line = <>) {
    ...
}

For why this causes only _now_ problems lets first look how <>
behaves:

"The null filehandle <> is special: [...] Input from <> comes either
from standard input, or from each file listed on the command line.
Here's how it works: the first time <> is evaluated, the @ARGV array
is checked, and if it is empty, $ARGV[0] is set to "-" , which when
opened gives you standard input.  The @ARGV array is then processed
as a list of filenames." - 'perldoc perlop'

Recent changes in the CLIHandler code changed how we modfiied @ARGV
Earlier we assumed that the first argument must be the command and
thus shifted it out of @ARGV, now we can have multiple levels of
(sub)commands. This change also changed how we handle @ARGV, we do
not unshift anything but go through the arguments until we got to
the final command and copy the rest of @ARGV as we know that this
must be the commandos arguments.

For '<>' this means that ARGV was still fully populated and perl
tried to open element as a file, which naturally failed.
Thus the change in pve-common only exposed this 'dangerous' code
pattern.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2018-01-22 10:52:11 +01:00 committed by Wolfgang Bumiller
parent 332a2f2bae
commit e5caa02e05
2 changed files with 2 additions and 2 deletions
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2
PVE/API2/Qemu.pm
View File

@ -1849,7 +1849,7 @@ __PACKAGE__->register_method({
# read spice ticket from STDIN
my $spice_ticket;
if ($stateuri && ($stateuri eq 'tcp') && $migratedfrom && ($rpcenv->{type} eq 'cli')) {
if (defined(my $line = <>)) {
if (defined(my $line = <STDIN>)) {
chomp $line;
$spice_ticket = $line;
}

2
PVE/CLI/qm.pm
View File

@ -286,7 +286,7 @@ __PACKAGE__->register_method ({
$tunnel_write->("tunnel online");
$tunnel_write->("ver 1");
while (my $line = <>) {
while (my $line = <STDIN>) {
chomp $line;
if ($line =~ /^quit$/) {
$tunnel_write->("OK");