[CRIU] [PATCH 1/5] crtools: preload libraries

[Pavel Emelyanov]

> @@ -271,6 +275,13 @@ int main(int argc, char *argv[])
>  		case 54:
>  			opts.check_ms_kernel = true;
>  			break;
> +		case 'L':
> +			opts.libdir = strdup(optarg);
> +			if (opts.libdir == NULL) {
> +				pr_perror("Can't allocate memory");
> +				return -1;
> +			}
> +			break;
>  		case 'V':
>  			pr_msg("Version: %s\n", CRIU_VERSION);
>  			if (strcmp(CRIU_GITID, "0"))

Help text missing.

> diff --git a/include/cr_options.h b/include/cr_options.h
> index b90b4e1..5a4676c 100644
> --- a/include/cr_options.h
> +++ b/include/cr_options.h
> @@ -29,6 +29,7 @@ struct cr_options {
>  	char			*pidfile;
>  	struct list_head	veth_pairs;
>  	struct list_head	scripts;
> +	char			*libdir;
>  	bool			use_page_server;
>  	unsigned short		ps_port;
>  	char			*addr;
> diff --git a/include/criu-plugin.h b/include/criu-plugin.h
> new file mode 100644
> index 0000000..44abb2a
> --- /dev/null
> +++ b/include/criu-plugin.h
> @@ -0,0 +1,26 @@
> +/*
> +    This file defines types and macros for CRIU plugins.
> +    Copyright (C) 2013 Parallels, Inc
> +
> +    This program is free software; you can redistribute it and/or modify
> +    it under the terms of the GNU General Public License as published by
> +    the Free Software Foundation; either version 2 of the License, or
> +    (at your option) any later version.
> +
> +    This program is distributed in the hope that it will be useful,
> +    but WITHOUT ANY WARRANTY; without even the implied warranty of
> +    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +    GNU General Public License for more details.
> +
> +    You should have received a copy of the GNU General Public License
> +    along with this program; if not, write to the Free Software
> +    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + */
> +
> +#ifndef __CRIU_PLUGIN_H__
> +#define __CRIU_PLUGIN_H__
> +
> +typedef int (cr_plugin_init_t)(void);
> +typedef void (cr_plugin_fini_t)(void);
> +
> +#endif
> diff --git a/include/plugin.h b/include/plugin.h
> new file mode 100644
> index 0000000..8653a5b
> --- /dev/null
> +++ b/include/plugin.h
> @@ -0,0 +1,22 @@
> +#ifndef __CR_PLUGIN_H__
> +#define __CR_PLUGIN_H__
> +
> +#include "criu-plugin.h"
> +
> +struct cr_plugin_entry {
> +	union {
> +		cr_plugin_fini_t *cr_fini;
> +	};
> +
> +	struct cr_plugin_entry *next;
> +};
> +
> +struct cr_plugins {
> +	struct cr_plugin_entry *cr_fini;
> +};
> +
> +extern struct cr_plugins cr_plugins;

Why should this info be public?

> +
> +void cr_lib_fini(void);
> +int cr_lib_init(void);
> +#endif
> diff --git a/lib.c b/lib.c
> new file mode 100644
> index 0000000..387bb84
> --- /dev/null
> +++ b/lib.c
> @@ -0,0 +1,123 @@
> +#include <stdlib.h>
> +#include <string.h>
> +#include <dirent.h>
> +#include <errno.h>
> +#include <stdio.h>
> +#include <dlfcn.h>
> +
> +#include "cr_options.h"
> +#include "plugin.h"
> +#include "log.h"
> +#include "xmalloc.h"
> +
> +struct cr_plugins cr_plugins;
> +
> +static int cr_lib_load(char *path)
> +{
> +	struct cr_plugin_entry *ce;
> +	cr_plugin_init_t *f_init;
> +	cr_plugin_fini_t *f_fini;
> +	void *h;
> +
> +	h = dlopen(path, RTLD_LAZY);
> +	if (h == NULL) {
> +		pr_err("Unable to load %s: %s", path, dlerror());
> +		return -1;
> +	}
> +
> +	ce = NULL;
> +	f_fini = dlsym(h, "cr_plugin_fini");
> +	if (f_fini) {
> +		ce = xmalloc(sizeof(struct cr_plugin_entry));
> +		if (ce == NULL)
> +			return -1;
> +		ce->cr_fini = f_fini;

In patch #3 you use some fancy macro for this.

> +	}
> +
> +	f_init = dlsym(h, "cr_plugin_init");
> +	if (f_init && f_init()) {
> +		xfree(ce);
> +		return -1;
> +	}
> +
> +	if (ce) {
> +		ce->next = cr_plugins.cr_fini;
> +		cr_plugins.cr_fini = ce;
> +	}
> +
> +	return 0;
> +}
> +
> +void cr_lib_fini(void)
> +{
> +	struct cr_plugin_entry *ce;
> +
> +	while (cr_plugins.cr_fini) {
> +		ce = cr_plugins.cr_fini;
> +		cr_plugins.cr_fini = cr_plugins.cr_fini->next;
> +
> +		ce->cr_fini();
> +		xfree(ce);
> +	}
> +}
> +
> +int cr_lib_init(void)
> +{
> +	int exit_code = -1;
> +	DIR *d;
> +
> +	memset(&cr_plugins, 0, sizeof(cr_plugins));
> +
> +	if (opts.libdir == NULL) {
> +		char *path;
> +
> +		path = getenv("CRIU_LIBS_DIR");
> +		if (path == NULL)

I think we should declare some default library for it.

> +			return 0;
> +
> +		opts.libdir = strdup(path);

Why strdup?

> +		if (opts.libdir == NULL) {
> +			pr_perror("Can't allocate memory");
> +			return -1;
> +		}
> +	}
> +
> +	d = opendir(opts.libdir);
> +	if (d == 0) {
> +		pr_perror("Unable to open directory %s", opts.libdir);
> +		return -1;
> +	}
> +
> +	while (1) {
> +		char path[PATH_MAX];
> +		struct dirent *de;
> +		int len;
> +
> +		errno = 0;
> +		de = readdir(d);
> +		if (de == NULL) {
> +			if (errno == 0)
> +				break;
> +			pr_perror("Unable to read the libraries directory");
> +			goto err;
> +		}
> +
> +		len = strlen(de->d_name);
> +
> +		if (len < 3 || strncmp(de->d_name + len - 3, ".so", 3))
> +			continue;
> +
> +		snprintf(path, sizeof(path), "%s/%s", opts.libdir, de->d_name);
> +
> +		if (cr_lib_load(path))
> +			goto err;
> +	}
> +
> +	exit_code = 0;
> +err:
> +	closedir(d);
> +
> +	cr_lib_fini();
> +
> +	return exit_code;
> +}
>