[Libguestfs] [PATCH nbdkit 9/9] eval, sh: Define $nbdkit_safe_stdio = 0|1 in scripts.

--- plugins/eval/nbdkit-eval-plugin.pod | 11 +++-------- plugins/sh/nbdkit-sh-plugin.pod | 18 +++++++++++++++++- plugins/sh/call.c | 8 ++++++-- tests/test-single-sh.sh | 4 ++++ 4 files changed, 30 insertions(+), 11 deletions(-) diff --git a/plugins/eval/nbdkit-eval-plugin.pod b/plugins/eval/nbdkit-eval-plugin.pod index 602fd3aa..a016aa78 100644 --- a/plugins/eval/nbdkit-eval-plugin.pod +++ b/plugins/eval/nbdkit-eval-plugin.pod @@ -154,14 +154,9 @@ defaults to the script "exit 2". =head1 ENVIRONMENT VARIABLES -=over 4 - -=item C<tmpdir> - -This is defined to the name of a temporary directory which can be used -by the script snippets. It is deleted when nbdkit exits. - -=back +For environment variables that are set by the plugin running the +script snippets, see +L<nbdkit-sh-plugin(3)/Environment variables passed to the script>. =head1 FILES diff --git a/plugins/sh/nbdkit-sh-plugin.pod b/plugins/sh/nbdkit-sh-plugin.pod index 20a2b785..33bae6e4 100644 --- a/plugins/sh/nbdkit-sh-plugin.pod +++ b/plugins/sh/nbdkit-sh-plugin.pod @@ -119,7 +119,14 @@ These exit codes are reserved for future use. =back -=head2 Temporary directory +=head2 Environment variables passed to the script + +When running the script, certain environment variables are set by the +plugin: + +=over 4 + +=item C<$tmpdir> A fresh script is invoked for each method call (ie. scripts are stateless), so if the script needs to store state it has to store it @@ -131,6 +138,15 @@ the script. This directory persists for the lifetime of nbdkit and is deleted when nbdkit exits. The name of the directory is passed to each script invocation in the C<$tmpdir> environment variable. +=item C<$nbdkit_stdio_safe> + +This is set to C<1> or C<0> depending on whether or not the script can +safely use stdin/stdout (eg. for reading passwords from the user). +See also the discussion of C<nbdkit_stdio_safe> in +L<nbdkit-plugin(3)>. + +=back + =head2 Handles Handles are arbitrary strings, but it is best to limit them to short diff --git a/plugins/sh/call.c b/plugins/sh/call.c index b0aaf754..ddb7045b 100644 --- a/plugins/sh/call.c +++ b/plugins/sh/call.c @@ -107,6 +107,7 @@ call3 (const char *wbuf, size_t wbuflen, /* sent to stdin */ { const char *argv0 = argv[0]; /* script name, used in error messages */ CLEANUP_FREE_STRING_LIST char **env = NULL; + const char *stdio_safe_str = nbdkit_stdio_safe () ? "1" : "0"; pid_t pid = -1; int status; int ret = ERROR; @@ -123,8 +124,11 @@ call3 (const char *wbuf, size_t wbuflen, /* sent to stdin */ debug_call (argv); - /* Copy the environment, and add $tmpdir. */ - env = copy_environ (environ, "tmpdir", tmpdir, NULL); + /* Copy the environment, and add $tmpdir and some other variables. */ + env = copy_environ (environ, + "tmpdir", tmpdir, + "nbdkit_stdio_safe", stdio_safe_str, + NULL); if (env == NULL) goto error; diff --git a/tests/test-single-sh.sh b/tests/test-single-sh.sh index a1586868..b4cfc9f0 100755 --- a/tests/test-single-sh.sh +++ b/tests/test-single-sh.sh @@ -57,6 +57,10 @@ if test -f single-sh.log; then fi cat >single-sh.script <<\EOF +if test "$nbdkit_stdio_safe" != "0"; then + echo "unexpected value for nbdkit_stdio_safe ($nbdkit_stdio_safe)" 1>&2 + exit 1 +fi case $1 in get_size) echo 1m ;; pread) dd if=/dev/zero count=$3 iflag=count_bytes ;; -- 2.25.0