src/core/condition.c - systemd-stable - Rivoreo Source Code Repositories

 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

 /***
   This file is part of systemd.

   Copyright 2010 Lennart Poettering

   systemd is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2.1 of the License, or
   (at your option) any later version.

   systemd 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/

 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/capability.h>
 #include <sys/statvfs.h>
 #include <fnmatch.h>

 #ifdef HAVE_SELINUX
 #include <selinux/selinux.h>
 #endif

 #include <systemd/sd-id128.h>
 #include "util.h"
 #include "condition.h"
 #include "virt.h"
 #include "path-util.h"

 Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
         Condition *c;

         assert(type < _CONDITION_TYPE_MAX);

         c = new0(Condition, 1);
         if (!c)
                 return NULL;

         c->type = type;
         c->trigger = trigger;
         c->negate = negate;

         if (parameter) {
                 c->parameter = strdup(parameter);
                 if (!c->parameter) {
                         free(c);
                         return NULL;
                 }
         }

         return c;
 }

 void condition_free(Condition *c) {
         assert(c);

         free(c->parameter);
         free(c);
 }

 void condition_free_list(Condition *first) {
         Condition *c, *n;

         LIST_FOREACH_SAFE(conditions, c, n, first)
                 condition_free(c);
 }

 static bool test_kernel_command_line(const char *parameter) {
         char *line, *w, *state, *word = NULL;
         bool equal;
         int r;
         size_t l, pl;
         bool found = false;

         assert(parameter);

         if (detect_container(NULL) > 0)
                 return false;

         r = read_one_line_file("/proc/cmdline", &line);
         if (r < 0) {
                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
                 return false;
         }

         equal = !!strchr(parameter, '=');
         pl = strlen(parameter);

         FOREACH_WORD_QUOTED(w, l, line, state) {

                 free(word);
                 word = strndup(w, l);
                 if (!word)
                         break;

                 if (equal) {
                         if (streq(word, parameter)) {
                                 found = true;
                                 break;
                         }
                 } else {
                         if (startswith(word, parameter) && (word[pl] == '=' || word[pl] == 0)) {
                                 found = true;
                                 break;
                         }
                 }

         }

         free(word);
         free(line);

         return found;
 }

 static bool test_virtualization(const char *parameter) {
         int b;
         Virtualization v;
         const char *id;

         assert(parameter);

         v = detect_virtualization(&id);
         if (v < 0) {
                 log_warning("Failed to detect virtualization, ignoring: %s", strerror(-v));
                 return false;
         }

         /* First, compare with yes/no */
         b = parse_boolean(parameter);

         if (v > 0 && b > 0)
                 return true;

         if (v == 0 && b == 0)
                 return true;

         /* Then, compare categorization */
         if (v == VIRTUALIZATION_VM && streq(parameter, "vm"))
                 return true;

         if (v == VIRTUALIZATION_CONTAINER && streq(parameter, "container"))
                 return true;

         /* Finally compare id */
         return v > 0 && streq(parameter, id);
 }

 static bool test_security(const char *parameter) {
 #ifdef HAVE_SELINUX
         if (streq(parameter, "selinux"))
                 return is_selinux_enabled() > 0;
 #endif
         return false;
 }

 static bool test_capability(const char *parameter) {
         cap_value_t value;
         FILE *f;
         char line[LINE_MAX];
         unsigned long long capabilities = (unsigned long long) -1;

         /* If it's an invalid capability, we don't have it */

         if (cap_from_name(parameter, &value) < 0)
                 return false;

         /* If it's a valid capability we default to assume
          * that we have it */

         f = fopen("/proc/self/status", "re");
         if (!f)
                 return true;

         while (fgets(line, sizeof(line), f)) {
                 truncate_nl(line);

                 if (startswith(line, "CapBnd:")) {
                         (void) sscanf(line+7, "%llx", &capabilities);
                         break;
                 }
         }

         fclose(f);

         return !!(capabilities & (1ULL << value));
 }

 static bool test_host(const char *parameter) {
         sd_id128_t x, y;
         char *h;
         int r;
         bool b;

         if (sd_id128_from_string(parameter, &x) >= 0) {

                 r = sd_id128_get_machine(&y);
                 if (r < 0)
                         return false;

                 return sd_id128_equal(x, y);
         }

         h = gethostname_malloc();
         if (!h)
                 return false;

         b = fnmatch(parameter, h, FNM_CASEFOLD) == 0;
         free(h);

         return b;
 }

 bool condition_test(Condition *c) {
         assert(c);

         switch(c->type) {

         case CONDITION_PATH_EXISTS:
                 return (access(c->parameter, F_OK) >= 0) == !c->negate;

         case CONDITION_PATH_EXISTS_GLOB:
                 return (glob_exists(c->parameter) > 0) == !c->negate;

         case CONDITION_PATH_IS_DIRECTORY: {
                 struct stat st;

                 if (stat(c->parameter, &st) < 0)
                         return c->negate;
                 return S_ISDIR(st.st_mode) == !c->negate;
         }

         case CONDITION_PATH_IS_SYMBOLIC_LINK: {
                 struct stat st;

                 if (lstat(c->parameter, &st) < 0)
                         return c->negate;
                 return S_ISLNK(st.st_mode) == !c->negate;
         }

         case CONDITION_PATH_IS_MOUNT_POINT:
                 return (path_is_mount_point(c->parameter, true) > 0) == !c->negate;

         case CONDITION_PATH_IS_READ_WRITE:
                 return (path_is_read_only_fs(c->parameter) > 0) == c->negate;

         case CONDITION_DIRECTORY_NOT_EMPTY: {
                 int k;

                 k = dir_is_empty(c->parameter);
                 return !(k == -ENOENT || k > 0) == !c->negate;
         }

         case CONDITION_FILE_NOT_EMPTY: {
                 struct stat st;

                 if (stat(c->parameter, &st) < 0)
                         return c->negate;

                 return (S_ISREG(st.st_mode) && st.st_size > 0) == !c->negate;
         }

         case CONDITION_FILE_IS_EXECUTABLE: {
                 struct stat st;

                 if (stat(c->parameter, &st) < 0)
                         return c->negate;

                 return (S_ISREG(st.st_mode) && (st.st_mode & 0111)) == !c->negate;
         }

         case CONDITION_KERNEL_COMMAND_LINE:
                 return test_kernel_command_line(c->parameter) == !c->negate;

         case CONDITION_VIRTUALIZATION:
                 return test_virtualization(c->parameter) == !c->negate;

         case CONDITION_SECURITY:
                 return test_security(c->parameter) == !c->negate;

         case CONDITION_CAPABILITY:
                 return test_capability(c->parameter) == !c->negate;

         case CONDITION_HOST:
                 return test_host(c->parameter) == !c->negate;

         case CONDITION_NULL:
                 return !c->negate;

         default:
                 assert_not_reached("Invalid condition type.");
         }
 }

 bool condition_test_list(Condition *first) {
         Condition *c;
         int triggered = -1;

         /* If the condition list is empty, then it is true */
         if (!first)
                 return true;

         /* Otherwise, if all of the non-trigger conditions apply and
          * if any of the trigger conditions apply (unless there are
          * none) we return true */
         LIST_FOREACH(conditions, c, first) {
                 bool b;

                 b = condition_test(c);

                 if (!c->trigger && !b)
                         return false;

                 if (c->trigger && triggered <= 0)
                         triggered = b;
         }

         return triggered != 0;
 }

 void condition_dump(Condition *c, FILE *f, const char *prefix) {
         assert(c);
         assert(f);

         if (!prefix)
                 prefix = "";

         fprintf(f,
                 "%s\t%s: %s%s%s\n",
                 prefix,
                 condition_type_to_string(c->type),
                 c->trigger ? "|" : "",
                 c->negate ? "!" : "",
                 c->parameter);
 }

 void condition_dump_list(Condition *first, FILE *f, const char *prefix) {
         Condition *c;

         LIST_FOREACH(conditions, c, first)
                 condition_dump(c, f, prefix);
 }

 static const char* const condition_type_table[_CONDITION_TYPE_MAX] = {
         [CONDITION_PATH_EXISTS] = "ConditionPathExists",
         [CONDITION_PATH_EXISTS_GLOB] = "ConditionPathExistsGlob",
         [CONDITION_PATH_IS_DIRECTORY] = "ConditionPathIsDirectory",
         [CONDITION_PATH_IS_SYMBOLIC_LINK] = "ConditionPathIsSymbolicLink",
         [CONDITION_PATH_IS_MOUNT_POINT] = "ConditionPathIsMountPoint",
         [CONDITION_PATH_IS_READ_WRITE] = "ConditionPathIsReadWrite",
         [CONDITION_DIRECTORY_NOT_EMPTY] = "ConditionDirectoryNotEmpty",
         [CONDITION_FILE_NOT_EMPTY] = "ConditionFileNotEmpty",
         [CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine",
         [CONDITION_VIRTUALIZATION] = "ConditionVirtualization",
         [CONDITION_SECURITY] = "ConditionSecurity",
         [CONDITION_HOST] = "ConditionHost",
         [CONDITION_NULL] = "ConditionNull"
 };

 DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType);
	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/

	/***
	This file is part of systemd.

	Copyright 2010 Lennart Poettering

	systemd is free software; you can redistribute it and/or modify it
	under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation; either version 2.1 of the License, or
	(at your option) any later version.

	systemd 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
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	***/

	#include <stdlib.h>
	#include <errno.h>
	#include <string.h>
	#include <unistd.h>
	#include <sys/capability.h>
	#include <sys/statvfs.h>
	#include <fnmatch.h>

	#ifdef HAVE_SELINUX
	#include <selinux/selinux.h>
	#endif

	#include <systemd/sd-id128.h>
	#include "util.h"
	#include "condition.h"
	#include "virt.h"
	#include "path-util.h"

	Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
	Condition *c;

	assert(type < _CONDITION_TYPE_MAX);

	c = new0(Condition, 1);
	if (!c)
	return NULL;

	c->type = type;
	c->trigger = trigger;
	c->negate = negate;

	if (parameter) {
	c->parameter = strdup(parameter);
	if (!c->parameter) {
	free(c);
	return NULL;
	}
	}

	return c;
	}

	void condition_free(Condition *c) {
	assert(c);

	free(c->parameter);
	free(c);
	}

	void condition_free_list(Condition *first) {
	Condition c, n;

	LIST_FOREACH_SAFE(conditions, c, n, first)
	condition_free(c);
	}

	static bool test_kernel_command_line(const char *parameter) {
	char line, w, state, word = NULL;
	bool equal;
	int r;
	size_t l, pl;
	bool found = false;

	assert(parameter);

	if (detect_container(NULL) > 0)
	return false;

	r = read_one_line_file("/proc/cmdline", &line);
	if (r < 0) {
	log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
	return false;
	}

	equal = !!strchr(parameter, '=');
	pl = strlen(parameter);

	FOREACH_WORD_QUOTED(w, l, line, state) {

	free(word);
	word = strndup(w, l);
	if (!word)
	break;

	if (equal) {
	if (streq(word, parameter)) {
	found = true;
	break;
	}
	} else {
	if (startswith(word, parameter) && (word[pl] == '=' \|\| word[pl] == 0)) {
	found = true;
	break;
	}
	}

	}

	free(word);
	free(line);

	return found;
	}

	static bool test_virtualization(const char *parameter) {
	int b;
	Virtualization v;
	const char *id;

	assert(parameter);

	v = detect_virtualization(&id);
	if (v < 0) {
	log_warning("Failed to detect virtualization, ignoring: %s", strerror(-v));
	return false;
	}

	/* First, compare with yes/no */
	b = parse_boolean(parameter);

	if (v > 0 && b > 0)
	return true;

	if (v == 0 && b == 0)
	return true;

	/* Then, compare categorization */
	if (v == VIRTUALIZATION_VM && streq(parameter, "vm"))
	return true;

	if (v == VIRTUALIZATION_CONTAINER && streq(parameter, "container"))
	return true;

	/* Finally compare id */
	return v > 0 && streq(parameter, id);
	}

	static bool test_security(const char *parameter) {
	#ifdef HAVE_SELINUX
	if (streq(parameter, "selinux"))
	return is_selinux_enabled() > 0;
	#endif
	return false;
	}

	static bool test_capability(const char *parameter) {
	cap_value_t value;
	FILE *f;
	char line[LINE_MAX];
	unsigned long long capabilities = (unsigned long long) -1;

	/* If it's an invalid capability, we don't have it */

	if (cap_from_name(parameter, &value) < 0)
	return false;

	/* If it's a valid capability we default to assume
	* that we have it */

	f = fopen("/proc/self/status", "re");
	if (!f)
	return true;

	while (fgets(line, sizeof(line), f)) {
	truncate_nl(line);

	if (startswith(line, "CapBnd:")) {
	(void) sscanf(line+7, "%llx", &capabilities);
	break;
	}
	}

	fclose(f);

	return !!(capabilities & (1ULL << value));
	}

	static bool test_host(const char *parameter) {
	sd_id128_t x, y;
	char *h;
	int r;
	bool b;

	if (sd_id128_from_string(parameter, &x) >= 0) {

	r = sd_id128_get_machine(&y);
	if (r < 0)
	return false;

	return sd_id128_equal(x, y);
	}

	h = gethostname_malloc();
	if (!h)
	return false;

	b = fnmatch(parameter, h, FNM_CASEFOLD) == 0;
	free(h);

	return b;
	}

	bool condition_test(Condition *c) {
	assert(c);

	switch(c->type) {

	case CONDITION_PATH_EXISTS:
	return (access(c->parameter, F_OK) >= 0) == !c->negate;

	case CONDITION_PATH_EXISTS_GLOB:
	return (glob_exists(c->parameter) > 0) == !c->negate;

	case CONDITION_PATH_IS_DIRECTORY: {
	struct stat st;

	if (stat(c->parameter, &st) < 0)
	return c->negate;
	return S_ISDIR(st.st_mode) == !c->negate;
	}

	case CONDITION_PATH_IS_SYMBOLIC_LINK: {
	struct stat st;

	if (lstat(c->parameter, &st) < 0)
	return c->negate;
	return S_ISLNK(st.st_mode) == !c->negate;
	}

	case CONDITION_PATH_IS_MOUNT_POINT:
	return (path_is_mount_point(c->parameter, true) > 0) == !c->negate;

	case CONDITION_PATH_IS_READ_WRITE:
	return (path_is_read_only_fs(c->parameter) > 0) == c->negate;

	case CONDITION_DIRECTORY_NOT_EMPTY: {
	int k;

	k = dir_is_empty(c->parameter);
	return !(k == -ENOENT \|\| k > 0) == !c->negate;
	}

	case CONDITION_FILE_NOT_EMPTY: {
	struct stat st;

	if (stat(c->parameter, &st) < 0)
	return c->negate;

	return (S_ISREG(st.st_mode) && st.st_size > 0) == !c->negate;
	}

	case CONDITION_FILE_IS_EXECUTABLE: {
	struct stat st;

	if (stat(c->parameter, &st) < 0)
	return c->negate;

	return (S_ISREG(st.st_mode) && (st.st_mode & 0111)) == !c->negate;
	}

	case CONDITION_KERNEL_COMMAND_LINE:
	return test_kernel_command_line(c->parameter) == !c->negate;

	case CONDITION_VIRTUALIZATION:
	return test_virtualization(c->parameter) == !c->negate;

	case CONDITION_SECURITY:
	return test_security(c->parameter) == !c->negate;

	case CONDITION_CAPABILITY:
	return test_capability(c->parameter) == !c->negate;

	case CONDITION_HOST:
	return test_host(c->parameter) == !c->negate;

	case CONDITION_NULL:
	return !c->negate;

	default:
	assert_not_reached("Invalid condition type.");
	}
	}

	bool condition_test_list(Condition *first) {
	Condition *c;
	int triggered = -1;

	/* If the condition list is empty, then it is true */
	if (!first)
	return true;

	/* Otherwise, if all of the non-trigger conditions apply and
	* if any of the trigger conditions apply (unless there are
	* none) we return true */
	LIST_FOREACH(conditions, c, first) {
	bool b;

	b = condition_test(c);

	if (!c->trigger && !b)
	return false;

	if (c->trigger && triggered <= 0)
	triggered = b;
	}

	return triggered != 0;
	}

	void condition_dump(Condition c, FILE f, const char *prefix) {
	assert(c);
	assert(f);

	if (!prefix)
	prefix = "";

	fprintf(f,
	"%s\t%s: %s%s%s\n",
	prefix,
	condition_type_to_string(c->type),
	c->trigger ? "\|" : "",
	c->negate ? "!" : "",
	c->parameter);
	}

	void condition_dump_list(Condition first, FILE f, const char *prefix) {
	Condition *c;

	LIST_FOREACH(conditions, c, first)
	condition_dump(c, f, prefix);
	}

	static const char* const condition_type_table[_CONDITION_TYPE_MAX] = {
	[CONDITION_PATH_EXISTS] = "ConditionPathExists",
	[CONDITION_PATH_EXISTS_GLOB] = "ConditionPathExistsGlob",
	[CONDITION_PATH_IS_DIRECTORY] = "ConditionPathIsDirectory",
	[CONDITION_PATH_IS_SYMBOLIC_LINK] = "ConditionPathIsSymbolicLink",
	[CONDITION_PATH_IS_MOUNT_POINT] = "ConditionPathIsMountPoint",
	[CONDITION_PATH_IS_READ_WRITE] = "ConditionPathIsReadWrite",
	[CONDITION_DIRECTORY_NOT_EMPTY] = "ConditionDirectoryNotEmpty",
	[CONDITION_FILE_NOT_EMPTY] = "ConditionFileNotEmpty",
	[CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine",
	[CONDITION_VIRTUALIZATION] = "ConditionVirtualization",
	[CONDITION_SECURITY] = "ConditionSecurity",
	[CONDITION_HOST] = "ConditionHost",
	[CONDITION_NULL] = "ConditionNull"
	};

	DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType);