[lxc-devel] [PATCH] Final: Remove MAKEDEV call, add autodev hooks, add environment variables for hook scripts.
Alexander Vladimirov
alexander.idkfa.vladimirov at gmail.com
Fri Jan 11 18:26:16 UTC 2013
2013/1/12 Michael H. Warfield <mhw at wittsend.com>:
> 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
There's a typo at the end of line
> + 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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