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742218b3 AS |
1 | #!./perl |
2 | # | |
3 | # Test inheriting file descriptors across exec (close-on-exec). | |
4 | # | |
5 | # perlvar describes $^F aka $SYSTEM_FD_MAX as follows: | |
6 | # | |
7 | # The maximum system file descriptor, ordinarily 2. System file | |
8 | # descriptors are passed to exec()ed processes, while higher file | |
9 | # descriptors are not. Also, during an open(), system file descriptors | |
10 | # are preserved even if the open() fails. (Ordinary file descriptors | |
11 | # are closed before the open() is attempted.) The close-on-exec | |
12 | # status of a file descriptor will be decided according to the value of | |
13 | # C<$^F> when the corresponding file, pipe, or socket was opened, not | |
14 | # the time of the exec(). | |
15 | # | |
16 | # This documented close-on-exec behaviour is typically implemented in | |
17 | # various places (e.g. pp_sys.c) with code something like: | |
18 | # | |
19 | # #if defined(HAS_FCNTL) && defined(F_SETFD) | |
20 | # fcntl(fd, F_SETFD, fd > PL_maxsysfd); /* ensure close-on-exec */ | |
21 | # #endif | |
22 | # | |
23 | # This behaviour, therefore, is only currently implemented for platforms | |
24 | # where: | |
25 | # | |
26 | # a) HAS_FCNTL and F_SETFD are both defined | |
27 | # b) Integer fds are native OS handles | |
28 | # | |
29 | # ... which is typically just the Unix-like platforms. | |
30 | # | |
31 | # Notice that though integer fds are supported by the C runtime library | |
32 | # on Windows, they are not native OS handles, and so are not inherited | |
33 | # across an exec (though native Windows file handles are). | |
34 | ||
35 | BEGIN { | |
36 | chdir 't' if -d 't'; | |
37 | @INC = '../lib'; | |
742218b3 | 38 | require './test.pl'; |
9c8416b2 | 39 | skip_all_without_config('d_fcntl'); |
742218b3 AS |
40 | } |
41 | ||
42 | use strict; | |
43 | ||
44 | $|=1; | |
45 | ||
742218b3 | 46 | # When in doubt, skip. |
901455ec NC |
47 | skip_all($^O) |
48 | if $^O eq 'VMS' or $^O eq 'MSWin32'; | |
742218b3 AS |
49 | |
50 | sub make_tmp_file { | |
51 | my ($fname, $fcontents) = @_; | |
52 | local *FHTMP; | |
53 | open FHTMP, ">$fname" or die "open '$fname': $!"; | |
54 | print FHTMP $fcontents or die "print '$fname': $!"; | |
55 | close FHTMP or die "close '$fname': $!"; | |
56 | } | |
57 | ||
58 | my $Perl = which_perl(); | |
901455ec | 59 | my $quote = "'"; |
742218b3 | 60 | |
2d90ac95 NC |
61 | my $tmperr = tempfile(); |
62 | my $tmpfile1 = tempfile(); | |
63 | my $tmpfile2 = tempfile(); | |
742218b3 AS |
64 | my $tmpfile1_contents = "tmpfile1 line 1\ntmpfile1 line 2\n"; |
65 | my $tmpfile2_contents = "tmpfile2 line 1\ntmpfile2 line 2\n"; | |
66 | make_tmp_file($tmpfile1, $tmpfile1_contents); | |
67 | make_tmp_file($tmpfile2, $tmpfile2_contents); | |
68 | ||
69 | # $Child_prog is the program run by the child that inherits the fd. | |
70 | # Note: avoid using ' or " in $Child_prog since it is run with -e | |
71 | my $Child_prog = <<'CHILD_PROG'; | |
72 | my $fd = shift; | |
73 | print qq{childfd=$fd\n}; | |
74 | open INHERIT, qq{<&=$fd} or die qq{open $fd: $!}; | |
75 | my $line = <INHERIT>; | |
76 | close INHERIT or die qq{close $fd: $!}; | |
77 | print $line | |
78 | CHILD_PROG | |
79 | $Child_prog =~ tr/\n//d; | |
80 | ||
dcb5c535 | 81 | plan(tests => 22); |
742218b3 AS |
82 | |
83 | sub test_not_inherited { | |
84 | my $expected_fd = shift; | |
85 | ok( -f $tmpfile2, "tmpfile '$tmpfile2' exists" ); | |
dcb5c535 | 86 | my $cmd = qq{$Perl -e $quote$Child_prog$quote $expected_fd}; |
742218b3 AS |
87 | # Expect 'Bad file descriptor' or similar to be written to STDERR. |
88 | local *SAVERR; open SAVERR, ">&STDERR"; # save original STDERR | |
89 | open STDERR, ">$tmperr" or die "open '$tmperr': $!"; | |
90 | my $out = `$cmd`; | |
91 | my $rc = $? >> 8; | |
92 | open STDERR, ">&SAVERR" or die "error: restore STDERR: $!"; | |
93 | close SAVERR or die "error: close SAVERR: $!"; | |
dcb5c535 AS |
94 | # XXX: it seems one cannot rely on a non-zero return code, |
95 | # at least not on Tru64. | |
96 | # cmp_ok( $rc, '!=', 0, | |
97 | # "child return code=$rc (non-zero means cannot inherit fd=$expected_fd)" ); | |
98 | cmp_ok( $out =~ tr/\n//, '==', 1, | |
99 | "child stdout: has 1 newline (rc=$rc, should be non-zero)" ); | |
742218b3 | 100 | is( $out, "childfd=$expected_fd\n", 'child stdout: fd' ); |
742218b3 AS |
101 | } |
102 | ||
103 | sub test_inherited { | |
104 | my $expected_fd = shift; | |
105 | ok( -f $tmpfile1, "tmpfile '$tmpfile1' exists" ); | |
dcb5c535 | 106 | my $cmd = qq{$Perl -e $quote$Child_prog$quote $expected_fd}; |
742218b3 AS |
107 | my $out = `$cmd`; |
108 | my $rc = $? >> 8; | |
109 | cmp_ok( $rc, '==', 0, | |
dcb5c535 | 110 | "child return code=$rc (zero means inherited fd=$expected_fd ok)" ); |
742218b3 AS |
111 | my @lines = split(/^/, $out); |
112 | cmp_ok( $out =~ tr/\n//, '==', 2, 'child stdout: has 2 newlines' ); | |
113 | cmp_ok( scalar(@lines), '==', 2, 'child stdout: split into 2 lines' ); | |
114 | is( $lines[0], "childfd=$expected_fd\n", 'child stdout: fd' ); | |
115 | is( $lines[1], "tmpfile1 line 1\n", 'child stdout: line 1' ); | |
742218b3 AS |
116 | } |
117 | ||
118 | $^F == 2 or print STDERR "# warning: \$^F is $^F (not 2)\n"; | |
119 | ||
dcb5c535 AS |
120 | # Should not be able to inherit > $^F in the default case. |
121 | open FHPARENT2, "<$tmpfile2" or die "open '$tmpfile2': $!"; | |
122 | my $parentfd2 = fileno FHPARENT2; | |
123 | defined $parentfd2 or die "fileno: $!"; | |
124 | cmp_ok( $parentfd2, '>', $^F, "parent open fd=$parentfd2 (\$^F=$^F)" ); | |
125 | test_not_inherited($parentfd2); | |
126 | close FHPARENT2 or die "close '$tmpfile2': $!"; | |
127 | ||
128 | # Should be able to inherit $^F after setting to $parentfd2 | |
129 | # Need to set $^F before open because close-on-exec set at time of open. | |
130 | $^F = $parentfd2; | |
131 | open FHPARENT1, "<$tmpfile1" or die "open '$tmpfile1': $!"; | |
132 | my $parentfd1 = fileno FHPARENT1; | |
133 | defined $parentfd1 or die "fileno: $!"; | |
134 | cmp_ok( $parentfd1, '<=', $^F, "parent open fd=$parentfd1 (\$^F=$^F)" ); | |
135 | test_inherited($parentfd1); | |
136 | close FHPARENT1 or die "close '$tmpfile1': $!"; | |
742218b3 | 137 | |
c7fb9cc8 | 138 | # ... and test that you cannot inherit fd = $^F+n. |
742218b3 | 139 | open FHPARENT1, "<$tmpfile1" or die "open '$tmpfile1': $!"; |
dcb5c535 AS |
140 | open FHPARENT2, "<$tmpfile2" or die "open '$tmpfile2': $!"; |
141 | $parentfd2 = fileno FHPARENT2; | |
142 | defined $parentfd2 or die "fileno: $!"; | |
143 | cmp_ok( $parentfd2, '>', $^F, "parent open fd=$parentfd2 (\$^F=$^F)" ); | |
144 | test_not_inherited($parentfd2); | |
145 | close FHPARENT2 or die "close '$tmpfile2': $!"; | |
742218b3 | 146 | close FHPARENT1 or die "close '$tmpfile1': $!"; |
dcb5c535 | 147 | |
742218b3 | 148 | # ... and now you can inherit after incrementing. |
c7fb9cc8 | 149 | $^F = $parentfd2; |
742218b3 | 150 | open FHPARENT2, "<$tmpfile2" or die "open '$tmpfile2': $!"; |
dcb5c535 AS |
151 | open FHPARENT1, "<$tmpfile1" or die "open '$tmpfile1': $!"; |
152 | $parentfd1 = fileno FHPARENT1; | |
153 | defined $parentfd1 or die "fileno: $!"; | |
154 | cmp_ok( $parentfd1, '<=', $^F, "parent open fd=$parentfd1 (\$^F=$^F)" ); | |
155 | test_inherited($parentfd1); | |
156 | close FHPARENT1 or die "close '$tmpfile1': $!"; | |
742218b3 | 157 | close FHPARENT2 or die "close '$tmpfile2': $!"; |