[lxc-devel] [PATCH] Final: Remove MAKEDEV call, add autodev hooks, add environment variables for hook scripts.
Michael H. Warfield
mhw at WittsEnd.com
Fri Jan 11 16:21:42 UTC 2013
Ok...
My patch to deal with the MAKDEV and hook script stuff after discussion
and valuable input from Serge.
To reiterate - Does several things (that are closely intertwined so
separate patches are not justified)...
1) Removes run_makedev() and the call to it from conf.c per discussion.
2) Adds an lxc.hook.autodev hook.
3) Added a number of environment variables for all the hook scripts to
reference to assist in execution.
4) clearenv and putenv( "container=lxc" ) calls were moved to just after
the "start" hook in the container just prior to actually firing up the
container so we could use environment variables prior to that and have
them flushed them before firing up init.
5) Documentation updated as appropriate.
Patch below my signature block. In addition to signing off, this
message is PGP signed (as are most of my messages) and, as such,
authenticated to me.
Signed-off-by: Michael H. Warfield <mhw at WittsEnd.com>
Regards,
Mike
--
Michael H. Warfield (AI4NB) | (770) 985-6132 | mhw at WittsEnd.com
/\/\|=mhw=|\/\/ | (678) 463-0932 | http://www.wittsend.com/mhw/
NIC whois: MHW9 | An optimist believes we live in the best of all
PGP Key: 0x674627FF | possible worlds. A pessimist is sure of it!
--
diff --git a/doc/lxc.conf.sgml.in b/doc/lxc.conf.sgml.in
index 96dea89..1298143 100644
--- a/doc/lxc.conf.sgml.in
+++ b/doc/lxc.conf.sgml.in
@@ -510,6 +510,10 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
rootfs. If lxc.autodev is set to 1, then after mounting the container's
rootfs LXC will mount a fresh tmpfs under <filename>/dev</filename>
(limited to 100k) and fill in a minimal set of initial devices.
+ This is generally required when starting a container containing
+ a "systemd" based "init" but may be optional at other times. Addional
+ devices in the containers /dev directory may be created through the
+ use of the <option>lxc.hook.autodev</option> hook.
</para>
<variablelist>
<varlistentry>
@@ -737,6 +741,27 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<variablelist>
<varlistentry>
<term>
+ <option>lxc.hook.autodev</option>
+ </term>
+ <listitem>
+ <para>
+ A hook to be run in the container's namespace after
+ mounting has been done and after any mount hooks have
+ run, but before the pivot_root, if
+ <option>lxc.autodev</option> == 1.
+ The purpose of this hook is to assist in populating the
+ /dev directory of the container when using the autodev
+ option for systemd based containers. The container's /dev
+ directory is relative to the
+ ${<option>LXC_ROOTFS_MOUNT</option>} environment
+ variable available when the hook is run.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
<option>lxc.hook.start</option>
</term>
<listitem>
@@ -763,6 +788,103 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
</variablelist>
</refsect2>
+ <refsect2>
+ <title>Startup hooks Environment Variables</title>
+ <para>
+ A number of environment variables are made available to the startup
+ hooks to provide configuration information and assist in the
+ functioning of the hooks. Not all variables are valid in all
+ contexts. In particular, all paths are relative to the host system
+ and, as such, not valid during the <option>lxc.hook.start</option> hook.
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_NAME</option>
+ </term>
+ <listitem>
+ <para>
+ The LXC name of the container. Useful for logging messages
+ in commmon log environments. [<option>-n</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_CONFIG_FILE</option>
+ </term>
+ <listitem>
+ <para>
+ Host relative path to the container configuration file. This
+ gives the container to reference the original, top level,
+ configuration file for the container in order to locate any
+ addotional configuration information not otherwise made
+ available. [<option>-f</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_CONSOLE</option>
+ </term>
+ <listitem>
+ <para>
+ The path to the console output of the container if not NULL.
+ [<option>-c</option>] [<option>lxc.console</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_CONSOLE_LOGPATH</option>
+ </term>
+ <listitem>
+ <para>
+ The path to the console log output of the container if not NULL.
+ [<option>-L</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_ROOTFS_MOUNT</option>
+ </term>
+ <listitem>
+ <para>
+ The mount location to which the container is initially bound.
+ This will be the host relative path to the container rootfs
+ for the container instance being started and is where changes
+ should be made for that instance.
+ [<option>lxc.rootfs.mount</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <option>LXC_ROOTFS_PATH</option>
+ </term>
+ <listitem>
+ <para>
+ The host relative path to the container root which has been
+ mounted to the rootfs.mount location.
+ [<option>lxc.rootfs</option>]
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </refsect2>
+
</refsect1>
<refsect1>
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 1c02850..699011a 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -116,7 +116,7 @@ lxc_log_define(lxc_conf, lxc);
#endif
char *lxchook_names[NUM_LXC_HOOKS] = {
- "pre-start", "pre-mount", "mount", "start", "post-stop" };
+ "pre-start", "pre-mount", "mount", "autodev", "start", "post-stop" };
extern int pivot_root(const char * new_root, const char * put_old);
@@ -913,33 +913,6 @@ static int mount_autodev(char *root)
return 0;
}
-/*
- * Try to run MAKEDEV console in the container. If something fails,
- * continue anyway as it should not be detrimental to the container.
- * This makes sure that things like /dev/vcs* exist.
- * (Pass devpath in to reduce stack usage)
- */
-static void run_makedev(char *devpath)
-{
- int curd;
- int ret;
-
- curd = open(".", O_RDONLY);
- if (curd < 0)
- return;
- ret = chdir(devpath);
- if (ret) {
- close(curd);
- return;
- }
- if (run_buffer("/sbin/MAKEDEV console"))
- INFO("Error running MAKEDEV console in %s", devpath);
- ret = fchdir(curd);
- if (ret)
- INFO("Error returning to original directory: expect breakage");
- close(curd);
-}
-
struct lxc_devs {
char *name;
mode_t mode;
@@ -971,8 +944,7 @@ static int setup_autodev(char *root)
if (ret < 0 || ret >= MAXPATHLEN) {
ERROR("Error calculating container /dev location");
return -1;
- } else
- run_makedev(path);
+ }
INFO("Populating /dev under %s\n", root);
cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
@@ -2553,6 +2525,10 @@ int lxc_setup(const char *name, struct lxc_conf *lxc_conf)
}
if (lxc_conf->autodev) {
+ if (run_lxc_hooks(name, "autodev", lxc_conf)) {
+ ERROR("failed to run autodev hooks for container '%s'.", name);
+ return -1;
+ }
if (setup_autodev(lxc_conf->rootfs.mount)) {
ERROR("failed to populate /dev in the container");
return -1;
@@ -2628,6 +2604,8 @@ int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf)
which = LXCHOOK_PREMOUNT;
else if (strcmp(hook, "mount") == 0)
which = LXCHOOK_MOUNT;
+ else if (strcmp(hook, "autodev") == 0)
+ which = LXCHOOK_AUTODEV;
else if (strcmp(hook, "start") == 0)
which = LXCHOOK_START;
else if (strcmp(hook, "post-stop") == 0)
diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index b576893..45161e1 100644
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -213,8 +213,8 @@ struct lxc_rootfs {
#endif
*/
enum lxchooks {
- LXCHOOK_PRESTART, LXCHOOK_PREMOUNT, LXCHOOK_MOUNT, LXCHOOK_START,
- LXCHOOK_POSTSTOP, NUM_LXC_HOOKS};
+ LXCHOOK_PRESTART, LXCHOOK_PREMOUNT, LXCHOOK_MOUNT, LXCHOOK_AUTODEV,
+ LXCHOOK_START, LXCHOOK_POSTSTOP, NUM_LXC_HOOKS};
extern char *lxchook_names[NUM_LXC_HOOKS];
struct saved_nic {
@@ -257,6 +257,7 @@ struct lxc_conf {
#endif
int maincmd_fd;
int autodev; // if 1, mount and fill a /dev at start
+ char *rcfile; // Copy of the top level rcfile we read
};
int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf);
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 1d87227..8cef8be 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -104,6 +104,7 @@ static struct lxc_config_t config[] = {
{ "lxc.hook.pre-start", config_hook },
{ "lxc.hook.pre-mount", config_hook },
{ "lxc.hook.mount", config_hook },
+ { "lxc.hook.autodev", config_hook },
{ "lxc.hook.start", config_hook },
{ "lxc.hook.post-stop", config_hook },
{ "lxc.network.type", config_network_type },
@@ -821,6 +822,8 @@ static int config_hook(const char *key, const char *value,
return add_hook(lxc_conf, LXCHOOK_PRESTART, copy);
else if (strcmp(key, "lxc.hook.pre-mount") == 0)
return add_hook(lxc_conf, LXCHOOK_PREMOUNT, copy);
+ else if (strcmp(key, "lxc.hook.autodev") == 0)
+ return add_hook(lxc_conf, LXCHOOK_AUTODEV, copy);
else if (strcmp(key, "lxc.hook.mount") == 0)
return add_hook(lxc_conf, LXCHOOK_MOUNT, copy);
else if (strcmp(key, "lxc.hook.start") == 0)
@@ -1265,6 +1268,10 @@ int lxc_config_readline(char *buffer, struct lxc_conf *conf)
int lxc_config_read(const char *file, struct lxc_conf *conf)
{
+ /* Catch only the top level config file name in the structure */
+ if( ! conf->rcfile ) {
+ conf->rcfile = strdup( file );
+ }
return lxc_file_for_each_line(file, parse_line, conf);
}
diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index 184fb04..a97dcca 100644
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -168,15 +168,6 @@ int main(int argc, char *argv[])
my_args.progname, my_args.quiet))
return err;
- if (clearenv()) {
- SYSERROR("failed to clear environment");
- /* don't error out though */
- }
- if (putenv("container=lxc")) {
- SYSERROR("failed to set environment variable");
- return err;
- }
-
/* rcfile is specified in the cli option */
if (my_args.rcfile)
rcfile = (char *)my_args.rcfile;
diff --git a/src/lxc/start.c b/src/lxc/start.c
index 82a74d8..ffc7c5b 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -391,6 +391,34 @@ struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf)
goto out_free_name;
}
+ /* Start of environment variable setup for hooks */
+ if (setenv("LXC_NAME", name, 1)) {
+ SYSERROR("failed to set environment variable for container name");
+ }
+ if (setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
+ SYSERROR("failed to set environment variable for config path");
+ }
+ if (setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
+ SYSERROR("failed to set environment variable for rootfs mount");
+ }
+ if (setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
+ SYSERROR("failed to set environment variable for rootfs mount");
+ }
+ if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
+ SYSERROR("failed to set environment variable for console path");
+ }
+ if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
+ SYSERROR("failed to set environment variable for console log");
+ }
+ {
+ char loglevel[16];
+ snprintf( loglevel, 14, "%d", conf->loglevel );
+ if (setenv("LXC_LOGLEVEL", loglevel, 1)) {
+ SYSERROR("failed to set environment variable for log level mount");
+ }
+ }
+ /* End of environment variable setup for hooks */
+
if (run_lxc_hooks(name, "pre-start", conf)) {
ERROR("failed to run pre-start hooks for container '%s'.", name);
goto out_aborting;
@@ -575,6 +603,21 @@ static int do_start(void *data)
goto out_warn_father;
}
+ /* The clearenv() and putenv() calls have been moved here
+ * to allow us to use enviroment variables passed to the various
+ * hooks, such as the start hook above. Not all of the
+ * variables like CONFIG_PATH or ROOTFS are valid in this
+ * context but others are. */
+ if (clearenv()) {
+ SYSERROR("failed to clear environment");
+ /* don't error out though */
+ }
+
+ if (putenv("container=lxc")) {
+ SYSERROR("failed to set environment variable");
+ return -1;
+ }
+
close(handler->sigfd);
/* after this call, we are in error because this
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