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=== Description (from pull-request) ===
closes #858
lxc-attach uses lxc_console_create() to allocate a pty on the host.
lxc_console_create() in turn calls lxc_console_peer_default() which either
makes the current controlling pty our controlling pty for the container, or
uses whatever the user gave us (e.g. /dev/tty2 etc.). For lxc-attach we always
want the current controlling pty to be used. This commit ensures that we're in
fact always using the current controlling pty. The commit also fixes a segfault
when the user specified lxc.console.path = none.
Signed-off-by: Christian Brauner <christian.brau...@mailbox.org>
From 694be03226af82c2261a2768423347c824dd113f Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@mailbox.org>
Date: Mon, 29 Feb 2016 10:52:43 +0100
Subject: [PATCH] lxc-attach: always allocate current controlling pty
lxc-attach uses lxc_console_create() to allocate a pty on the host.
lxc_console_create() in turn calls lxc_console_peer_default() which either
makes the current controlling pty our controlling pty for the container, or
uses whatever the user gave us (e.g. /dev/tty2 etc.). For lxc-attach we always
want the current controlling pty to be used. This commit ensures that we're in
fact always using the current controlling pty. The commit also fixes a segfault
when the user specified lxc.console.path = none.
Signed-off-by: Christian Brauner <christian.brau...@mailbox.org>
---
src/lxc/lxc_attach.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/src/lxc/lxc_attach.c b/src/lxc/lxc_attach.c
index 8437965..680e82e 100644
--- a/src/lxc/lxc_attach.c
+++ b/src/lxc/lxc_attach.c
@@ -253,10 +253,27 @@ static int get_pty_on_host(struct lxc_container *c,
struct wrapargs *wrap, int *
}
conf = c->lxc_conf;
+ free(conf->console.log_path);
+ conf->console.log_path = NULL;
+
+ /* In the case of lxc-attach our peer console will always be the current
+ * controlling terminal. We clear whatever was set by the user for
+ * lxc.console.path here and set it to "/dev/tty". Doing this will (a)
+ * prevent segfaults when the container has been setup with
+ * lxc.console = none and (b) provide an easy way to ensure that we
+ * always do the currect thing. strdup() must be used since console.path
+ * is free()ed when we call lxc_container_put(). */
+ free(conf->console.path);
+ conf->console.path = NULL;
+ conf->console.path = strdup("/dev/tty");
+ if (!conf->console.path)
+ return -1;
+
/* Create pty on the host. */
if (lxc_console_create(conf) < 0)
return -1;
ts = conf->console.tty_state;
+ conf->console.descr = &descr;
/* Shift ttys to container. */
if (ttys_shift_ids(conf) < 0) {
@@ -375,14 +392,16 @@ int main(int argc, char *argv[])
attach_options.extra_env_vars = extra_env;
attach_options.extra_keep_env = extra_keep;
- struct wrapargs wrap = (struct wrapargs){.command = &command,
- .options = &attach_options};
if (my_args.argc > 0) {
- wrap.command->program = my_args.argv[0];
- wrap.command->argv = (char**)my_args.argv;
+ command.program = my_args.argv[0];
+ command.argv = (char**)my_args.argv;
}
if (isatty(STDIN_FILENO) || isatty(STDOUT_FILENO) ||
isatty(STDERR_FILENO)) {
+ struct wrapargs wrap = (struct wrapargs){
+ .command = &command,
+ .options = &attach_options
+ };
if (isatty(STDIN_FILENO))
wrap.ptyfd = STDIN_FILENO;
else if (isatty(STDOUT_FILENO))
@@ -391,7 +410,7 @@ int main(int argc, char *argv[])
wrap.ptyfd = STDERR_FILENO;
ret = get_pty_on_host(c, &wrap, &pid);
} else {
- if (my_args.argc > 1)
+ if (command.program)
ret = c->attach(c, lxc_attach_run_command, &command,
&attach_options, &pid);
else
ret = c->attach(c, lxc_attach_run_shell, NULL,
&attach_options, &pid);
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