[TOMOYO #6 retry 08/21] Utility functions and policy manipulation interface.

[Kentaro Takeda]

Common functions for TOMOYO Linux.

TOMOYO Linux uses /sys/kernel/security/tomoyo interface for configuration.

/sys/kernel/security/tomoyo/domain_policy is the domain-based access policy.
Access control list for files, networks, argv[0], environment variable names,
capabilities and signal is stored in domain_policy.

/sys/kernel/security/tomoyo/system_policy is the system-wide access policy.
Access control list for mount, umount and pivot_root is stored in system_policy.

/sys/kernel/security/tomoyo/exception_policy is the other settings such as
globally readable files, globally usable environment variable names,
domain transition configurations and pre-defined patterned pathnames.

/sys/kernel/security/tomoyo/profile has some profiles, which configure
the access control level of TOMOYO Linux. A profile is assigned to a domain.

Signed-off-by: Kentaro Takeda <takedakn@xxxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
 security/tomoyo/common.c | 2450 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 2450 insertions(+)

--- /dev/null
+++ linux-2.6-mm/security/tomoyo/common.c
@@ -0,0 +1,2450 @@
+/*
+ * security/tomoyo/common.c
+ *
+ * Common functions for TOMOYO Linux.
+ */
+
+#include "tomoyo.h"
+#include "realpath.h"
+
+#define MAX_ACCEPT_ENTRY 2048
+
+static int tmy_read_control(struct file *file,
+			    char __user *buffer,
+			    const int buffer_len);
+
+/*************************  VARIABLES  *************************/
+
+/* /sbin/init started? */
+bool sbin_init_started;
+
+static struct {
+	const char *keyword;
+	unsigned int current_value;
+	const unsigned int max_value;
+} tmy_control[TMY_MAX_CONTROL_INDEX] = {
+	[TMY_COMMENT]             = { "COMMENT",             0, 0 },
+	[TMY_MAC_FOR_FILE]        = { "MAC_FOR_FILE",        0, 3 },
+	[TMY_MAC_FOR_ARGV0]       = { "MAC_FOR_ARGV0",       0, 3 },
+	[TMY_MAC_FOR_ENV]         = { "MAC_FOR_ENV",         0, 3 },
+	[TMY_MAC_FOR_NETWORK]     = { "MAC_FOR_NETWORK",     0, 3 },
+	[TMY_MAC_FOR_SIGNAL]      = { "MAC_FOR_SIGNAL",      0, 3 },
+	[TMY_DENY_CONCEAL_MOUNT]  = { "DENY_CONCEAL_MOUNT",  0, 3 },
+	[TMY_RESTRICT_MOUNT]      = { "RESTRICT_MOUNT",      0, 3 },
+	[TMY_RESTRICT_UMOUNT]     = { "RESTRICT_UNMOUNT",    0, 3 },
+	[TMY_RESTRICT_PIVOT_ROOT] = { "RESTRICT_PIVOT_ROOT", 0, 3 },
+	[TMY_MAX_ACCEPT_ENTRY]    =
+	{ "MAX_ACCEPT_ENTRY", MAX_ACCEPT_ENTRY, INT_MAX },
+	[TMY_MAX_GRANT_LOG]       = { "MAX_GRANT_LOG",       1024, INT_MAX },
+	[TMY_MAX_REJECT_LOG]      = { "MAX_REJECT_LOG",      1024, INT_MAX },
+	[TMY_VERBOSE]             = { "TOMOYO_VERBOSE",      1, 1 },
+	[TMY_ALLOW_ENFORCE_GRACE] = { "ALLOW_ENFORCE_GRACE", 0, 1 },
+};
+
+struct profile {
+	unsigned int value[TMY_MAX_CONTROL_INDEX];
+	const struct path_info *comment;
+};
+
+static struct profile *profile_ptr[TMY_MAX_PROFILES];
+
+/*************************  UTILITY FUNCTIONS  *************************/
+
+/* Is the current process running as root? */
+static int tmy_is_root(void)
+{
+	return !current->uid && !current->euid;
+}
+
+/**
+ * tmy_normalize_line - make a line tidy.
+ * @buffer: the line to make tidy.
+ *
+ * All tokens (such as pathnames) used in TOMOYO Linux contains
+ * only ASCII printable (i.e. 0x21-0x7E) range characters.
+ * This allows policy files and auditing logs split monotonically
+ * using space (i.e. ' ') and new line (i.e. '\n') characters.
+ *
+ * Remove leading and trailing non ASCII printable chracters and
+ * replace one or more non ASCII printable chracters with single space.
+ */
+static void tmy_normalize_line(unsigned char *buffer)
+{
+	unsigned char *sp = buffer;
+	unsigned char *dp = buffer;
+	bool first = 1;
+
+	while (*sp && (*sp <= 0x20 || *sp >= 0x7F))
+		sp++;
+
+	while (*sp) {
+		if (!first)
+			*dp++ = ' ';
+		first = 0;
+		while (*sp > 0x20 && *sp < 0x7F)
+			*dp++ = *sp++;
+		while (*sp && (*sp <= 0x20 || *sp >= 0x7F))
+			sp++;
+	}
+
+	*dp = '\0';
+}
+
+/* Is @c the first letter of "\ooo" expression? */
+static int tmy_char_is_0to3(const unsigned char c)
+{
+	return c >= '0' && c <= '3';
+}
+
+/* Is @c the second or third letter of "\ooo" expression? */
+static int tmy_char_is_0to7(const unsigned char c)
+{
+	return c >= '0' && c <= '7';
+}
+
+/* Is @c a decimal letter? */
+static int tmy_char_is_0to9(const unsigned char c)
+{
+	return c >= '0' && c <= '9';
+}
+
+/* Is @c a hexadecimal letter? */
+static int tmy_char_is_hex(const unsigned char c)
+{
+	return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F')
+		|| (c >= 'a' && c <= 'f');
+}
+
+/* Is @c an alphabet letter? */
+static int tmy_char_is_alpha(const unsigned char c)
+{
+	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
+}
+
+/* Convert \ooo style expression to a byte. */
+static unsigned char tmy_str2chr(const unsigned char c,
+				 const unsigned char d,
+				 const unsigned char e)
+{
+	return (((unsigned char) (c - '0')) << 6) +
+		(((unsigned char) (d - '0')) << 3) +
+		(((unsigned char) (e - '0')));
+}
+
+/* Does the @src starts with @find? */
+static int tmy_strstarts(char **src, const char *find)
+{
+	const int len = strlen(find);
+	char *tmp = *src;
+
+	if (strncmp(tmp, find, len) == 0) {
+		tmp += len;
+		*src = tmp;
+		return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * tmy_correct_path - validate a pathname.
+ * @filename:     the pathname to check
+ * @start_type:   1 if the pathname must start with '/'
+ *                -1 if the pathname must not start with '/'
+ *                0 if it does not matter
+ * @pattern_type: 1 if the pathname must contain patterns
+ *                -1 if the pathname must not contain patterns
+ *                0 if it does not matter
+ * @end_type:     1 if the pathname must end with '/'
+ *                -1 if the pathname must not end with '/'
+ *                0 if it does not matter
+ * @function:     string to display if the @filename is invalid
+ *
+ * Returns true if the pathname is valid.
+ * Returns false otherwise.
+ *
+ * Check whether the given pathname follows the naming rules.
+ */
+bool tmy_correct_path(const char *filename,
+		     const int start_type,
+		     const int pattern_type,
+		     const int end_type,
+		     const char *function)
+{
+	bool contains_pattern = 0;
+	char c;
+	char d;
+	char e;
+	const char *original_filename = filename;
+
+	if (!filename)
+		goto out;
+
+	c = *filename;
+	if (start_type == 1) {
+		/* Must start with '/' */
+		if (c != '/')
+			goto out;
+	} else if (start_type == -1) {
+		/* Must not start with '/' */
+		if (c == '/')
+			goto out;
+	}
+
+	if (c)
+		c = *(strchr(filename, '\0') - 1);
+	if (end_type == 1) {
+		/* Must end with '/' */
+		if (c != '/')
+			goto out;
+	} else if (end_type == -1) {
+		/* Must not end with '/' */
+		if (c == '/')
+			goto out;
+	}
+
+	while ((c = *filename++) != '\0') {
+		if (c == '\\') {
+			unsigned char f;
+			switch ((c = *filename++)) {
+			case '\\':  /* "\\" */
+				continue;
+			case '$':   /* "\$" */
+			case '+':   /* "\+" */
+			case '?':   /* "\?" */
+			case '*':   /* "\*" */
+			case '@':   /* "\@" */
+			case 'x':   /* "\x" */
+			case 'X':   /* "\X" */
+			case 'a':   /* "\a" */
+			case 'A':   /* "\A" */
+			case '-':   /* "\-" */
+				if (pattern_type == -1)
+					goto out; /* Must not contain pattern */
+				contains_pattern = 1;
+				continue;
+			case '0':   /* "\ooo" */
+			case '1':
+			case '2':
+			case '3':
+				d = *filename++;
+				if (!tmy_char_is_0to7(d))
+					goto out;
+				e = *filename++;
+				if (!tmy_char_is_0to7(e))
+					goto out;
+				f = tmy_str2chr(c, d, e);
+				if (f && (f <= 0x20 || f >= 0x7F))
+					/* valid \ooo expression */
+					continue;
+			}
+			goto out;
+		} else if (c <= 0x20 || c >= 0x7F)
+			goto out;
+	}
+
+	if (pattern_type == 1) {
+		/* Must contain pattern */
+		if (!contains_pattern)
+			goto out;
+	}
+
+	return 1;
+
+out: ;
+	printk(KERN_DEBUG "%s: Invalid pathname '%s'\n",
+	       function, original_filename);
+	return 0;
+}
+
+/**
+ * tmy_is_correct_domain - validate a domainname.
+ * @domainname: the domainname to check.
+ * @function:   string to display if the @domainname is invalid.
+ *
+ * Returns true if the domainname is valid.
+ * Returns false otherwise.
+ *
+ * Check whether the given domainname follows the naming rules.
+ */
+bool tmy_is_correct_domain(const unsigned char *domainname,
+			  const char *function)
+{
+	unsigned char c;
+	unsigned char d;
+	unsigned char e;
+	const char *org_domainname = domainname;
+
+	if (!domainname || !tmy_strstarts((char **) &domainname, TMY_ROOT_NAME))
+		goto out;
+
+	if (!*domainname)
+		return 1;
+
+	do {
+		/* 0x20 is a domainname separator. */
+		if (*domainname++ != ' ')
+			goto out;
+		/* Must starts with '/'. */
+		if (*domainname++ != '/')
+			goto out;
+		while ((c = *domainname) != '\0' && c != ' ') {
+			domainname++;
+			if (c == '\\') {
+				unsigned char f;
+				switch ((c = *domainname++)) {
+				case '\\':  /* "\\" */
+					continue;
+				case '0':   /* "\ooo" */
+				case '1':
+				case '2':
+				case '3':
+					d = *domainname++;
+					if (!tmy_char_is_0to7(d))
+						goto out;
+					e = *domainname++;
+					if (!tmy_char_is_0to7(e))
+						goto out;
+					f = tmy_str2chr(c, d, e);
+					if (f && (f <= 0x20 || f >= 0x7F))
+						continue;
+				}
+				goto out;
+			} else if (c < 0x20 || c >= 0x7F)
+				/* 0x20 is a domainname separator. */
+				goto out;
+		}
+	} while (*domainname);
+
+	return 1;
+
+out: ;
+	printk(KERN_DEBUG "%s: Invalid domainname '%s'\n",
+	       function, org_domainname);
+	return 0;
+}
+
+/**
+ * tmy_path_depth - evaluate the number of '/' characters in a token.
+ * @pathname: the token to evaluate.
+ *
+ * Each '/' character but the trailing '/' scores 2.
+ * The trailing '/' scores 1.
+ *
+ * If @pathname ends with '/', the return value is an odd integer.
+ * If @pathname does not end with '/', the return value is an even integer.
+ */
+static int tmy_path_depth(const char *pathname)
+{
+	int i = 0;
+
+	if (pathname) {
+		char *ep = strchr(pathname, '\0');
+
+		if (pathname < ep--) {
+			if (*ep != '/')
+				i++;
+			while (pathname <= ep)
+				if (*ep-- == '/')
+					i += 2;
+		}
+	}
+
+	return i;
+}
+
+/**
+ * tmy_const_part_length - calculate the constant part in a token.
+ * @filename: the token to calculate.
+ *
+ * Returns leading length of @filename that can be compared using strncmp().
+ */
+static int tmy_const_part_length(const char *filename)
+{
+	int len = 0;
+
+	if (filename) {
+		char c;
+
+		while ((c = *filename++) != '\0') {
+			if (c != '\\') {
+				len++;
+				continue;
+			}
+			switch (c = *filename++) {
+			case '\\':  /* "\\" */
+				len += 2;
+				continue;
+			case '0':   /* "\ooo" */
+			case '1':
+			case '2':
+			case '3':
+				if (!tmy_char_is_0to7(*filename++))
+					break;
+				if (!tmy_char_is_0to7(*filename++))
+					break;
+				len += 4;
+				continue;
+			}
+			break;
+		}
+	}
+
+	return len;
+}
+
+/**
+ * tmy_fill_path_info - fill "struct path_info" entry.
+ * @ptr: pointer to "struct path_info".
+ *
+ * Caller stores a token in "struct path_info"->name .
+ * This function will fill rest of "struct path_info" members.
+ */
+void tmy_fill_path_info(struct path_info *ptr)
+{
+	const char *name = ptr->name;
+	const int len = strlen(name);
+	ptr->total_len = len;
+	ptr->const_len = tmy_const_part_length(name);
+	ptr->is_dir = len && (name[len - 1] == '/');
+	ptr->is_patterned = (ptr->const_len < len);
+	ptr->hash = full_name_hash(name, len);
+	ptr->depth = tmy_path_depth(name);
+}
+
+/**
+ * tmy_file_match2 - internal function for tmy_path_match().
+ * @filename:     start address of the token.
+ * @filename_end: end address of the token.
+ * @pattern:      start address of the pattern.
+ * @pattern_end:  end address of the pattern.
+ *
+ * Handle all patterns other than '\-' pattern.
+ * Returns true if matches.
+ * Returns false otherwise.
+ *
+ * @filename and @pattern do not contain '/'.
+ * @filename and @pattern are not '\0'-terminated.
+ * @pattern does not contain '\-'.
+ */
+static bool tmy_file_match2(const char *filename,
+			   const char *filename_end,
+			   const char *pattern,
+			   const char *pattern_end)
+{
+	while (filename < filename_end && pattern < pattern_end) {
+		char c;
+		int i;
+		int j;
+
+		if (*pattern != '\\') {
+			if (*filename++ != *pattern++)
+				goto out;
+			continue;
+		}
+
+		c = *filename;
+		pattern++;
+
+		switch (*pattern) {
+		case '?':
+			if (c == '/')
+				goto out;
+			if (c != '\\')
+				break;
+			/* filename[0] != '\0' */
+			c = filename[1];
+			if (c == '\\')
+				filename++;
+			else if (tmy_char_is_0to3(c) &&
+				 /* filename[1] != '\0' */
+				 tmy_char_is_0to7(filename[2]) &&
+				 /* filename[2] != '\0' */
+				 tmy_char_is_0to7(filename[3]))
+				/* filename[3] != '\0' */
+				filename += 3;
+				/*
+				 * Why not "filename += 4;" here
+				 * because it processed 4 (i.e. "\ooo") bytes?
+				 * - Because "filename++;" is done
+				 * after "break;".
+				 */
+			else
+				goto out;
+			break;
+		case '\\':
+			if (c != '\\')
+				goto out;
+			/* filename[0] != '\0' */
+			if (*++filename != '\\')
+				goto out;
+			break;
+		case '+':
+			if (!tmy_char_is_0to9(c))
+				goto out;
+			break;
+		case 'x':
+			if (!tmy_char_is_hex(c))
+				goto out;
+			break;
+		case 'a':
+			if (!tmy_char_is_alpha(c))
+				goto out;
+			break;
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+			if (c != '\\')
+				goto out;
+			/* filename[0] != '\0' */
+			c = filename[1];
+			if (!tmy_char_is_0to3(c) || c != *pattern)
+				goto out;
+			/* filename[1] != '\0' */
+			c = filename[2];
+			/* pattern[0] != '\0' */
+			if (!tmy_char_is_0to7(c) || c != pattern[1])
+				goto out;
+			/* filename[2] != '\0' */
+			c = filename[3];
+			/* pattern[1] != '\0' */
+			if (!tmy_char_is_0to7(c) || c != pattern[2])
+				goto out;
+			/* filename[3] != '\0' */
+			filename += 3;
+			/* pattern[2] != '\0' */
+			pattern += 2;
+			break;
+		case '*':
+		case '@':
+			for (i = 0; i <= filename_end - filename; i++) {
+				if (tmy_file_match2(filename + i,
+						    filename_end,
+						    pattern + 1,
+						    pattern_end))
+					return 1;
+				c = filename[i];
+				if (c == '.' && *pattern == '@')
+					break;
+				if (c != '\\')
+					continue;
+				/* filename[i] != '\0' */
+				c = filename[i + 1];
+				if (c == '\\')
+					/* filename[i + 1] != '\0' */
+					i++;
+				else if (tmy_char_is_0to3(c) &&
+					 /* filename[i + 1] != '\0' */
+					 tmy_char_is_0to7(filename[i + 2]) &&
+					 /* filename[i + 2] != '\0' */
+					 tmy_char_is_0to7(filename[i + 3]))
+					 /* filename[i + 3] != '\0' */
+					i += 3;
+				else
+					break; /* Bad pattern. */
+			}
+			goto out;
+		default:
+			j = 0;
+			/*
+			 * If j == 0, for() loop does nothing.
+			 * So I can use while() without checking first letter.
+			 */
+			c = *pattern;
+			if (c == '$')
+				while (tmy_char_is_0to9(filename[j]))
+					j++;
+			else if (c == 'X')
+				while (tmy_char_is_hex(filename[j]))
+					j++;
+			else if (c == 'A')
+				while (tmy_char_is_alpha(filename[j]))
+					j++;
+			for (i = 1; i <= j; i++)
+				if (tmy_file_match2(filename + i,
+						    filename_end,
+						    pattern + 1,
+						    pattern_end))
+					return 1;
+			goto out; /* Not matched or bad pattern. */
+		}
+		filename++; /* filename[0] != '\0' */
+		pattern++; /* pattern[0] != '\0' */
+	}
+
+	/* Skip trailing "\*" and "\@" patterns. */
+	while (*pattern == '\\' &&
+	       (*(pattern + 1) == '*' ||
+		*(pattern + 1) == '@'))
+		pattern += 2;
+
+	/* If both are at ending position, they are equals. */
+	return (filename == filename_end && pattern == pattern_end);
+out: ;
+	return 0;
+}
+
+/**
+ * tmy_file_match - internal function for tmy_path_match().
+ * @filename:     start address of the token.
+ * @filename_end: end address of the token.
+ * @pattern:      start address of the pattern.
+ * @pattern_end:  end address of the pattern.
+ *
+ * Handle patterns containing '\-' pattern.
+ * Returns true if matches.
+ * Returns false otherwise.
+ *
+ * @filename and @pattern do not contain '/'.
+ * @filename and @pattern are not '\0'-terminated.
+ */
+static bool tmy_file_match(const char *filename,
+			  const char *filename_end,
+			  const char *pattern,
+			  const char *pattern_end)
+{
+	const char *pattern_start = pattern;
+	bool first = 1;
+	bool result;
+
+	while (pattern < pattern_end - 1) {
+		/* Split at "\-" pattern. */
+		if (*pattern++ != '\\' || *pattern++ != '-')
+			continue;
+		result = tmy_file_match2(filename,
+					 filename_end,
+					 pattern_start,
+					 pattern - 2);
+		/* If before "\-" pattern, invert the result. */
+		if (first)
+			result = !result;
+		/*
+		 * If not matched before first "\-" pattern, return 0.
+		 * If matched after first "\-" pattern, return 0.
+		 */
+		if (result)
+			return 0;
+		first = 0;
+		pattern_start = pattern;
+	}
+
+	result = tmy_file_match2(filename,
+				 filename_end, pattern_start, pattern_end);
+	/* If after first "\-" pattern, invert the result. */
+	return first ? result : !result;
+}
+
+/**
+ * tmy_path_match - do a pattern matching.
+ * @pathname0: pointer to a token to compare.
+ * @pattern0:  pointer to a pattern to compare.
+ *
+ * Returns true if @pathname0 matches to @pattern0 .
+ * Returns false otherwise.
+ *
+ *
+ *  Check whether the given token matches to the given pattern.
+ *
+ *  The following patterns are available.
+ *    \\     \ itself.
+ *    \ooo   Octal representation of a byte.
+ *    \*     More than or equals to 0 character other than '/'.
+ *    \@     More than or equals to 0 character other than '/' or '.'.
+ *    \?     1 byte character other than '/'.
+ *    \$     More than or equals to 1 decimal digit.
+ *    \+     1 decimal digit.
+ *    \X     More than or equals to 1 hexadecimal digit.
+ *    \x     1 hexadecimal digit.
+ *    \A     More than or equals to 1 alphabet character.
+ *    \a     1 alphabet character.
+ *    \-     Subtraction operator.
+ */
+bool tmy_path_match(const struct path_info *pathname0,
+		   const struct path_info *pattern0)
+{
+	const char *pathname = pathname0->name;
+	const char *pattern = pattern0->name;
+	const int len = pattern0->const_len;
+
+	/* If it doesn't contains patterns, I can use tmy_pathcmp() */
+	if (!pattern0->is_patterned)
+		return !tmy_pathcmp(pathname0, pattern0);
+	/* Check the depth of directory. */
+	if (pathname0->depth != pattern0->depth)
+		return 0;
+	/* Use strncmp() for constant part. */
+	if (strncmp(pathname, pattern, len))
+		return 0;
+
+	pathname += len;
+	pattern += len;
+
+	/* Split at '/' character, and compare. */
+	while (*pathname && *pattern) {
+		const char *pathname_delimiter = strchr(pathname, '/');
+		const char *pattern_delimiter = strchr(pattern, '/');
+
+		if (!pathname_delimiter)
+			pathname_delimiter = strchr(pathname, '\0');
+		if (!pattern_delimiter)
+			pattern_delimiter = strchr(pattern, '\0');
+		if (!tmy_file_match(pathname,
+				    pathname_delimiter,
+				    pattern,
+				    pattern_delimiter))
+			return 0;
+
+		pathname = *pathname_delimiter ?
+			pathname_delimiter + 1 :
+			pathname_delimiter;
+		pattern = *pattern_delimiter ?
+			pattern_delimiter + 1 :
+			pattern_delimiter;
+	}
+
+	/* Skip trailing "\*" and "\@" patterns. */
+	while (*pattern == '\\' &&
+	       (*(pattern + 1) == '*' ||
+		*(pattern + 1) == '@'))
+		pattern += 2;
+
+	/* If both are at '\0' position, they are equals. */
+	return (!*pathname && !*pattern);
+}
+
+/**
+ * tmy_io_printf - transactional printf() for "struct io_buffer".
+ * @head: pointer to "struct io_buffer".
+ * @fmt:  format strings for printf().
+ *
+ * Returns zero on success.
+ * Returns nonzero otherwise.
+ *
+ * Transactional printf() to "struct io_buffer" structure.
+ * snprintf() will truncate, but tmy_io_printf() won't.
+ * This is needed because dumping partially truncated tokens
+ * is not acceptable for TOMOYO Linux.
+ */
+int tmy_io_printf(struct io_buffer *head, const char *fmt, ...)
+{
+	va_list args;
+	int len;
+	int pos = head->read_avail;
+	int size = head->readbuf_size - pos;
+
+	if (size <= 0)
+		return -ENOMEM;
+
+	va_start(args, fmt);
+	len = vsnprintf(head->read_buf + pos, size, fmt, args);
+	va_end(args);
+
+	if (pos + len >= head->readbuf_size)
+		return -ENOMEM;
+
+	head->read_avail += len;
+
+	return 0;
+}
+
+/**
+ * tmy_sncatprintf - append version of snprintf().
+ * @buf: pointer to buffer.
+ * @len: sizeof(buffer).
+ *
+ * This function is equivalent to
+ *   snprintf(buf + strlen(buf), len - strlen(buf), fmt, ...) if (*buf).
+ *   snprintf(buf, len, fmt, ...) if (!*buf).
+ */
+int tmy_sncatprintf(char *buf, int len, const char *fmt, ...)
+{
+	va_list args;
+	char *p = memchr(buf, '\0', len);
+	if (p) {
+		len -= (p - buf);
+		buf = p;
+	}
+	va_start(args, fmt);
+	len = vsnprintf(buf, len, fmt, args);
+	va_end(args);
+	return len;
+}
+
+/**
+ * tmy_get_exe - get realpath of current process.
+ *
+ * Returns realpath(3) of current process on success.
+ * Returns NULL on failure.
+ *
+ * This function uses tmy_alloc(), so caller must tmy_free()
+ * if this function didn't return NULL.
+ */
+const char *tmy_get_exe(void)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	const char *cp = NULL;
+	if (!mm)
+		return NULL;
+	down_read(&mm->mmap_sem);
+	for (vma = mm->mmap; vma; vma = vma->vm_next)
+		if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
+			cp = tmy_realpath_dentry(vma->vm_file->f_dentry,
+						 vma->vm_file->f_vfsmnt);
+			break;
+		}
+	up_read(&mm->mmap_sem);
+	return cp;
+}
+
+/**
+ * tmy_lastname - get last part of domainname.
+ *
+ * Returns last part of domainname.
+ */
+const char *tmy_lastname(const struct domain_info *domain)
+{
+	const char *cp0 = domain->domainname->name;
+	const char *cp1 = strrchr(cp0, ' ');
+	if (cp1)
+		return cp1 + 1;
+	return cp0;
+}
+
+/**
+ * tmy_get_msg - get message from mode.
+ * @is_enforce: enforcing flag.
+ *
+ * Returns "ERROR" if enforcing, "WARNING" otherwise.
+ */
+const char *tmy_getmsg(bool is_enforce)
+{
+	return is_enforce ? "ERROR" : "WARNING";
+}
+
+/*************************  DOMAIN POLICY HANDLER  *************************/
+
+/**
+ * tmy_flags - get flags of given access control.
+ * @index: index to retrieve flags.
+ *
+ * Returns current value of given access control.
+ */
+unsigned int tmy_flags(const unsigned int index)
+{
+	const u8 profile =
+		TMY_SECURITY->domain->profile;
+
+	/* All operations might sleep. See tmy_supervisor(). */
+	might_sleep();
+	if (in_interrupt())
+		return 0;
+	return sbin_init_started && index < TMY_MAX_CONTROL_INDEX
+		&& profile_ptr[profile] ?
+		profile_ptr[profile]->value[index] :
+		0;
+}
+
+/**
+ * tmy_quota - check quota.
+ *
+ * Returns true if not quota has not exceeded.
+ * Returns false otherwise.
+ *
+ * This is a safeguard for "learning mode", for appending entries
+ * without limit dulls the system response and consumes much memory.
+ */
+bool tmy_quota(void)
+{
+	unsigned int count = 0;
+	struct acl_info *ptr;
+	struct domain_info * const domain = TMY_SECURITY->domain;
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		if (!ptr->is_deleted)
+			count++;
+	}
+	/* If there are so many entries, don't append any more. */
+	if (count < tmy_flags(TMY_MAX_ACCEPT_ENTRY))
+		return 1;
+	if (!domain->quota_warned) {
+		domain->quota_warned = 1;
+		printk(KERN_INFO
+		       "TOMOYO-WARNING: Domain '%s' has so many ACLs "
+		       "to hold. Stopped learning mode.\n",
+		       domain->domainname->name);
+	}
+	return 0;
+}
+
+/* Create a new profile. */
+static struct profile *tmy_find_new_profile(const unsigned int profile)
+{
+	static DEFINE_MUTEX(profile_lock);
+	struct profile *ptr = NULL;
+
+	mutex_lock(&profile_lock);
+
+	ptr = profile_ptr[profile];
+	if (profile < TMY_MAX_PROFILES && ptr == NULL) {
+		ptr = tmy_alloc_element(sizeof(*ptr));
+		if (ptr != NULL) {
+			int i;
+			for (i = 0; i < TMY_MAX_CONTROL_INDEX; i++)
+				ptr->value[i] = tmy_control[i].current_value;
+			mb(); /* Instead of using spinlock. */
+			profile_ptr[profile] = ptr;
+		}
+	}
+
+	mutex_unlock(&profile_lock);
+
+	return ptr;
+}
+
+/* Loading policy done? */
+static int profile_loaded;
+
+/* Update profile values. */
+static int tmy_set_profile(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	unsigned int i;
+	unsigned int value;
+	char *cp;
+	struct profile *profile;
+
+	if (!tmy_is_root())
+		return -EPERM;
+
+	/* If profile index is not given, assume 0. */
+	i = simple_strtoul(data, &cp, 10);
+	if (data != cp) {
+		if (*cp != '-')
+			return -EINVAL;
+		data = cp + 1;
+	}
+
+	profile = tmy_find_new_profile(i);
+	if (!profile)
+		return -EINVAL;
+	cp = strchr(data, '=');
+	if (!cp)
+		return -EINVAL;
+
+	*cp = '\0';
+	profile_loaded = 1;
+	tmy_update_counter(TMY_UPDATE_PROFILE);
+	if (strcmp(data, tmy_control[TMY_COMMENT].keyword) == 0) {
+		profile->comment = tmy_save_name(cp + 1);
+		return 0;
+	}
+
+	if (sscanf(cp + 1, "%u", &value) != 1)
+		return -EINVAL;
+
+	if (tmy_strstarts(&data, TMY_MAC_FOR_CAPABILITY))
+		return tmy_set_capability_profile(data, value, i);
+
+	for (i = 0; i < TMY_MAX_CONTROL_INDEX; i++) {
+		if (strcmp(data, tmy_control[i].keyword))
+			continue;
+		if (value > tmy_control[i].max_value)
+			value = tmy_control[i].max_value;
+		profile->value[i] = value;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/* Read profile values. */
+static int tmy_read_profile(struct io_buffer *head)
+{
+	int step;
+
+	if (head->read_eof)
+		return 0;
+	if (!tmy_is_root())
+		return -EPERM;
+
+	if (head->read_var1)
+		goto capability;
+
+	for (step = head->read_step;
+	     step < TMY_MAX_PROFILES * TMY_MAX_CONTROL_INDEX;
+	     step++) {
+		const int i = step / TMY_MAX_CONTROL_INDEX;
+		const int j = step % TMY_MAX_CONTROL_INDEX;
+		const struct profile *profile = profile_ptr[i];
+
+		head->read_step = step;
+		if (!profile)
+			continue;
+		if (j != TMY_COMMENT)
+			goto non_comment;
+		if (tmy_io_printf(head, "%u-%s=%s\n",
+				  i, tmy_control[TMY_COMMENT].keyword,
+				  profile->comment ?
+				  profile->comment->name : ""))
+			break;
+		goto comment_ok;
+non_comment: ;
+		if (tmy_io_printf(head, "%u-%s=%u\n",
+				  i, tmy_control[j].keyword,
+				  profile->value[j]))
+			break;
+comment_ok: ;
+	}
+
+	if (step == TMY_MAX_PROFILES * TMY_MAX_CONTROL_INDEX) {
+		head->read_var1 = (void *) "";
+		head->read_step = 0;
+		goto capability;
+	}
+	return 0;
+capability: ;
+	if (tmy_read_capability_profile(head) == 0)
+		head->read_eof = 1;
+	return 0;
+}
+
+/*************************  POLICY MANAGER HANDLER  *************************/
+
+struct policy_manager_entry {
+	struct list_head list;
+	const struct path_info *manager;
+	bool is_domain;
+	bool is_deleted;
+};
+
+static LIST_HEAD(policy_manager_list);
+
+/* Update manager list. */
+static int tmy_add_manager_entry(const char *manager, const bool is_delete)
+{
+	struct policy_manager_entry *new_entry;
+	struct policy_manager_entry *ptr;
+	static DEFINE_MUTEX(mutex);
+	const struct path_info *saved_manager;
+	int error = -ENOMEM;
+
+	bool is_domain = 0;
+	if (!tmy_is_root())
+		return -EPERM;
+	if (tmy_is_domain_def(manager)) {
+		if (!tmy_is_correct_domain(manager, __FUNCTION__))
+			return -EINVAL;
+		is_domain = 1;
+	} else {
+		if (!tmy_correct_path(manager, 1, -1, -1, __FUNCTION__))
+			return -EINVAL;
+	}
+
+	saved_manager = tmy_save_name(manager);
+	if (saved_manager == NULL)
+		return -ENOMEM;
+
+	mutex_lock(&mutex);
+
+	list_for_each_entry(ptr, &policy_manager_list, list) {
+		if (ptr->manager == saved_manager) {
+			ptr->is_deleted = is_delete;
+			error = 0;
+			goto out;
+		}
+	}
+
+	if (is_delete) {
+		error = -ENOENT;
+		goto out;
+	}
+
+	new_entry = tmy_alloc_element(sizeof(*new_entry));
+	if (new_entry == NULL)
+		goto out;
+	new_entry->manager = saved_manager;
+	new_entry->is_domain = is_domain;
+	list_add_tail_mb(&new_entry->list, &policy_manager_list);
+	error = 0;
+out: ;
+
+	mutex_unlock(&mutex);
+
+	if (!error)
+		tmy_update_counter(TMY_UPDATE_MANAGER);
+	return error;
+}
+
+/* Update manager list. */
+static int tmy_add_manager_policy(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	bool is_delete = 0;
+
+	if (!tmy_is_root())
+		return -EPERM;
+	if (tmy_strstarts(&data, TMY_DELETE))
+		is_delete = 1;
+	return tmy_add_manager_entry(data, is_delete);
+}
+
+/* Read manager list.*/
+static int tmy_read_manager_policy(struct io_buffer *head)
+{
+	struct list_head *pos;
+	if (head->read_eof)
+		return 0;
+	if (!tmy_is_root())
+		return -EPERM;
+	list_for_each_cookie(pos, head->read_var2, &policy_manager_list) {
+		struct policy_manager_entry *ptr;
+		ptr = list_entry(pos, struct policy_manager_entry, list);
+		if (!ptr->is_deleted &&
+		    tmy_io_printf(head, "%s\n", ptr->manager->name))
+			break;
+	}
+	if (!head->read_var2)
+		head->read_eof = 1;
+	return 0;
+}
+
+/**
+ * tmy_is_policy_manager - check whether modifying policy is permitted.
+ *
+ * Returns nonzero if modifying policy is permitted.
+ * Returns zero otherwise.
+ *
+ * Only programs or domains registers as manager are permitted to modify
+ * policy via /sys/kernel/security/tomoyo/ interface.
+ * This function checks whether the current process is a policy manager.
+ * But policy manager is not the only processes that can modify policy;
+ * other process are permitted to add policy
+ * if their domains are assigned a profile for learning mode.
+ */
+static int tmy_is_policy_manager(void)
+{
+	struct policy_manager_entry *ptr;
+	const char *exe;
+	const struct path_info *domainname =
+		TMY_SECURITY->domain->domainname;
+	bool found = 0;
+
+	/* Everyone can modify policy before /sbin/init starts. */
+	if (!sbin_init_started)
+		return 1;
+
+	list_for_each_entry(ptr, &policy_manager_list, list) {
+		if (!ptr->is_deleted &&
+		    ptr->is_domain &&
+		    !tmy_pathcmp(domainname, ptr->manager))
+			return 1;
+	}
+
+	exe = tmy_get_exe();
+	if (!exe)
+		return 0;
+
+	list_for_each_entry(ptr, &policy_manager_list, list) {
+		if (!ptr->is_deleted &&
+		    !ptr->is_domain &&
+		    !strcmp(exe, ptr->manager->name)) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		/* Reduce error messages. */
+		static pid_t last_pid;
+		const pid_t pid = current->pid;
+		if (last_pid != pid) {
+			printk(KERN_INFO
+			       "%s is not permitted to update policies.\n",
+			       exe);
+			last_pid = pid;
+		}
+	}
+
+	tmy_free(exe);
+	return found;
+}
+
+/*************************  DOMAIN POLICY HANDLER  *************************/
+
+/* Update domain policy. */
+static int tmy_add_domain_policy(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	char *cp;
+	const struct condition_list *cond = NULL;
+	struct domain_info *domain = head->write_var1;
+	bool is_delete = 0;
+	bool is_select = 0;
+	bool is_undelete = 0;
+	unsigned int profile;
+
+	if (!tmy_is_root())
+		return -EPERM;
+
+	if (tmy_strstarts(&data, TMY_DELETE))
+		is_delete = 1;
+	else if (tmy_strstarts(&data, TMY_SELECT))
+		is_select = 1;
+	else if (tmy_strstarts(&data, TMY_UNDELETE))
+		is_undelete = 1;
+
+	tmy_update_counter(TMY_UPDATE_DOMAINPOLICY);
+
+	if (tmy_is_domain_def(data)) {
+		if (is_delete) {
+			tmy_delete_domain(data);
+			domain = NULL;
+		} else if (is_select)
+			domain = tmy_find_domain(data);
+		else if (is_undelete)
+			domain = tmy_undelete_domain(data);
+		else
+			domain = tmy_new_domain(data, 0);
+		head->write_var1 = domain;
+		return 0;
+	}
+
+	if (!domain)
+		return -EINVAL;
+
+	if (sscanf(data, TMY_USE_PROFILE "%u", &profile) == 1 &&
+	    profile < TMY_MAX_PROFILES) {
+		if (profile_ptr[profile] || !sbin_init_started)
+			domain->profile = (u8) profile;
+		return 0;
+	}
+	cp = tmy_find_condition_part(data);
+	if (cp) {
+		cond = tmy_assign_condition(cp);
+		if (!cond)
+			return -EINVAL;
+	}
+	if (tmy_strstarts(&data, TMY_ALLOW_NETWORK))
+		return tmy_add_network_policy(data, domain, cond, is_delete);
+	else if (tmy_strstarts(&data, TMY_ALLOW_ARGV0))
+		return tmy_add_argv0_policy(data, domain, cond, is_delete);
+	else if (tmy_strstarts(&data, TMY_ALLOW_ENV))
+		return tmy_add_env_policy(data, domain, cond, is_delete);
+	else if (tmy_strstarts(&data, TMY_ALLOW_SIGNAL))
+		return tmy_add_signal_policy(data, domain, cond, is_delete);
+	else if (tmy_strstarts(&data, TMY_ALLOW_CAPABILITY))
+		return tmy_add_capability_policy(data, domain, cond, is_delete);
+	else
+		return tmy_add_file_policy(data, domain, cond, is_delete);
+
+	return -EINVAL;
+}
+
+/* Dump file's open ACL. */
+static inline int print_file_rwx_acl(struct io_buffer *head,
+				     struct acl_info *ptr)
+{
+	struct file_acl *ptr2 = container_of(ptr, struct file_acl, head);
+	const unsigned char b = ptr2->u_is_group;
+
+	if (tmy_io_printf(head, "%d %s%s",
+			  ptr2->perm, b ? "@" : "",
+			  b ? ptr2->u.group->group_name->name :
+			  ptr2->u.filename->name))
+		return -ENOMEM;
+	return 0;
+}
+
+/* Dump argv[0]'s ACL. */
+static inline int print_argv0_acl(struct io_buffer *head,
+				  struct acl_info *ptr)
+{
+	struct argv0_acl *ptr2 = container_of(ptr, struct argv0_acl, head);
+
+	if (tmy_io_printf(head, TMY_ALLOW_ARGV0 "%s %s",
+			  ptr2->filename->name, ptr2->argv0->name))
+		return -ENOMEM;
+	return 0;
+}
+
+/* Dump environment variable's ACL. */
+static inline int print_env_acl(struct io_buffer *head,
+				struct acl_info *ptr)
+{
+	struct env_acl *ptr2 = container_of(ptr, struct env_acl, head);
+
+	if (tmy_io_printf(head, TMY_ALLOW_ENV "%s", ptr2->env->name))
+		return -ENOMEM;
+	return 0;
+}
+
+/* Dump network's ACL. */
+static inline int print_network_acl(struct io_buffer *head,
+				    struct acl_info *ptr)
+{
+	struct net_acl *ptr2 = container_of(ptr, struct net_acl, head);
+	u8 record_type = ptr2->record_type;
+	u32 min_address;
+	u32 max_address;
+	char buf[64];
+	const struct in6_addr *min_address_ptr;
+	const struct in6_addr *max_address_ptr;
+	u16 min_port;
+	u16 max_port;
+
+	if (tmy_io_printf(head, TMY_ALLOW_NETWORK "%s ",
+			  tmy_network2keyword(ptr2->operation_type)))
+		goto out;
+	if (record_type != TMY_TYPE_ADDRESS_GROUP)
+		goto non_address_group;
+
+	if (tmy_io_printf(head, "@%s", ptr2->u.group->group_name->name))
+		goto out;
+	goto print_port;
+
+non_address_group: ;
+	if (record_type != TMY_TYPE_IPv4)
+		goto ipv6_address;
+
+	min_address = ptr2->u.ipv4.min;
+	max_address = ptr2->u.ipv4.max;
+	if (tmy_io_printf(head, NIPQUAD_FMT, HIPQUAD(min_address)))
+		goto out;
+	if (min_address != max_address &&
+	    tmy_io_printf(head, "-" NIPQUAD_FMT, HIPQUAD(max_address)))
+		goto out;
+	goto print_port;
+
+ipv6_address: ;
+	min_address_ptr = ptr2->u.ipv6.min;
+	max_address_ptr = ptr2->u.ipv6.max;
+	tmy_print_ipv6(buf, sizeof(buf), min_address_ptr);
+	if (tmy_io_printf(head, "%s", buf))
+		goto out;
+	if (memcmp(min_address_ptr, max_address_ptr, 16)) {
+		tmy_print_ipv6(buf, sizeof(buf), max_address_ptr);
+		if (tmy_io_printf(head, "-%s", buf))
+			goto out;
+	}
+
+print_port: ;
+	min_port = ptr2->min_port;
+	max_port = ptr2->max_port;
+	if (tmy_io_printf(head, " %u", min_port))
+		goto out;
+	if (min_port != max_port && tmy_io_printf(head, "-%u", max_port))
+		goto out;
+	return 0;
+out: ;
+	return -ENOMEM;
+}
+
+/* Dump signal's ACL. */
+static inline int print_signal_acl(struct io_buffer *head,
+				   struct acl_info *ptr)
+{
+	struct signal_acl *ptr2 = container_of(ptr, struct signal_acl, head);
+
+	if (tmy_io_printf(head, TMY_ALLOW_SIGNAL "%u %s",
+			  ptr2->sig, ptr2->domainname->name))
+		return -ENOMEM;
+	return 0;
+}
+
+/* Dump capability's ACL. */
+static inline int print_capability_acl(struct io_buffer *head,
+				       struct acl_info *ptr)
+{
+	struct capability_acl *ptr2 =
+		container_of(ptr, struct capability_acl, head);
+
+	if (tmy_io_printf(head, TMY_ALLOW_CAPABILITY "%s",
+			  tmy_capability2keyword(ptr2->capability)))
+		return -ENOMEM;
+	return 0;
+}
+
+/* Dump file's non-open ACL. */
+static inline int print_file_other_acl(struct io_buffer *head,
+				       struct acl_info *ptr)
+{
+	const u8 acl_type = ptr->type;
+	const char *keyword = tmy_acltype2keyword(acl_type);
+
+	if (!keyword)
+		return 0; /* This must not happen. */
+
+	if (tmy_acltype2paths(acl_type) == 2) {
+		struct double_acl *ptr2 =
+			container_of(ptr, struct double_acl, head);
+		const bool b1 = ptr2->u1_is_group;
+		const bool b2 = ptr2->u2_is_group;
+
+		if (tmy_io_printf(head,
+				  "allow_%s %s%s %s%s",
+				  keyword,
+				  b1 ? "@" : "",
+				  b1 ? ptr2->u1.group1->group_name->name :
+				  ptr2->u1.filename1->name,
+				  b2 ? "@" : "",
+				  b2 ? ptr2->u2.group2->group_name->name :
+				  ptr2->u2.filename2->name))
+			return -ENOMEM;
+	} else {
+		struct single_acl *ptr2
+			= container_of(ptr, struct single_acl, head);
+		const bool b = ptr2->u_is_group;
+
+		if (tmy_io_printf(head,
+				  "allow_%s %s%s",
+				  keyword,
+				  b ? "@" : "",
+				  b ? ptr2->u.group->group_name->name :
+				  ptr2->u.filename->name))
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+/* Read domain policy. */
+static int tmy_read_domain_policy(struct io_buffer *head)
+{
+	struct list_head *dpos;
+	struct list_head *apos;
+
+	if (head->read_eof)
+		return 0;
+
+	if (head->read_step == 0) {
+		if (!tmy_is_root())
+			return -EPERM;
+		head->read_step = 1;
+	}
+	list_for_each_cookie(dpos, head->read_var1, &domain_list) {
+		struct domain_info *domain;
+		domain = list_entry(dpos, struct domain_info, list);
+		if (head->read_step != 1)
+			goto acl_loop;
+		if (domain->is_deleted)
+			continue;
+		if (tmy_io_printf(head,
+				  "%s\n" TMY_USE_PROFILE "%u\n%s\n",
+				  domain->domainname->name,
+				  domain->profile,
+				  domain->quota_warned ?
+				  "quota_exceeded\n" : ""))
+			return 0;
+		head->read_step = 2;
+acl_loop: ;
+		if (head->read_step == 3)
+			goto tail_mark;
+		list_for_each_cookie(apos, head->read_var2,
+				     &domain->acl_info_list) {
+			struct acl_info *ptr;
+			int pos;
+			u8 acl_type;
+			ptr = list_entry(apos, struct acl_info, list);
+			if (ptr->is_deleted)
+				continue;
+			pos = head->read_avail;
+			acl_type = ptr->type;
+			if (acl_type == TMY_TYPE_FILE_ACL) {
+				if (print_file_rwx_acl(head, ptr))
+					goto print_acl_rollback;
+			} else if (acl_type == TMY_TYPE_ARGV0_ACL) {
+				if (print_argv0_acl(head, ptr))
+					goto print_acl_rollback;
+			} else if (acl_type == TMY_TYPE_ENV_ACL) {
+				if (print_env_acl(head, ptr))
+					goto print_acl_rollback;
+			} else if (acl_type == TMY_TYPE_IP_NETWORK_ACL) {
+				if (print_network_acl(head, ptr))
+					goto print_acl_rollback;
+			} else if (acl_type == TMY_TYPE_SIGNAL_ACL) {
+				if (print_signal_acl(head, ptr))
+					goto print_acl_rollback;
+			} else if (acl_type == TMY_TYPE_CAPABILITY_ACL) {
+				if (print_capability_acl(head, ptr))
+					goto print_acl_rollback;
+			} else
+				if (print_file_other_acl(head, ptr))
+					goto print_acl_rollback;
+			if (tmy_dump_condition(head, ptr->cond)) {
+print_acl_rollback: ;
+				head->read_avail = pos;
+				return 0;
+			}
+		}
+		head->read_step = 3;
+tail_mark: ;
+		if (tmy_io_printf(head, "\n"))
+			return 0;
+		head->read_step = 1;
+	}
+	head->read_eof = 1;
+	return 0;
+}
+
+/* Read domainname and its profile values. */
+static int tmy_read_domain_profile(struct io_buffer *head)
+{
+	struct list_head *pos;
+	if (head->read_eof)
+		return 0;
+	if (!tmy_is_root())
+		return -EPERM;
+	list_for_each_cookie(pos, head->read_var1, &domain_list) {
+		struct domain_info *domain;
+		domain = list_entry(pos, struct domain_info, list);
+		if (domain->is_deleted)
+			continue;
+		if (tmy_io_printf(head, "%u %s\n",
+				  domain->profile, domain->domainname->name))
+			return 0;
+	}
+	head->read_eof = 1;
+	return 0;
+}
+
+/* Set PID to report. Non manager process is permitted to call this function. */
+static int tmy_write_pid(struct io_buffer *head)
+{
+	head->read_step = (int) simple_strtoul(head->write_buf, NULL, 10);
+	head->read_eof = 0;
+	return 0;
+}
+
+/* Read domainname and its profile values. */
+static int tmy_read_pid(struct io_buffer *head)
+{
+	const int pid = head->read_step;
+	struct task_struct *p;
+	struct domain_info *domain = NULL;
+
+	/* If PID is not set via tmy_write_pid(), do nothing. */
+	if (head->read_avail || head->read_eof)
+		return 0;
+
+	/***** CRITICAL SECTION START *****/
+	read_lock(&tasklist_lock);
+	p = find_task_by_pid(pid);
+	if (p) {
+		/* "struct task_struct"->security is not NULL. */
+		domain = ((struct tmy_security *) p->security)->domain;
+	}
+	read_unlock(&tasklist_lock);
+	/***** CRITICAL SECTION END *****/
+
+	if (domain)
+		tmy_io_printf(head, "%d %u %s",
+			      pid, domain->profile, domain->domainname->name);
+	head->read_eof = 1;
+
+	return 0;
+}
+
+/* Update profile values for domains. */
+static int tmy_update_domain_profile(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	char *cp = strchr(data, ' ');
+	struct domain_info *domain;
+	unsigned int profile;
+
+	if (!tmy_is_root())
+		return -EPERM;
+	if (!cp)
+		return -EINVAL;
+
+	*cp = '\0';
+	domain = tmy_find_domain(cp + 1);
+	profile = simple_strtoul(data, NULL, 10);
+	if (domain && profile < TMY_MAX_PROFILES &&
+	    (profile_ptr[profile] || !sbin_init_started))
+		domain->profile = (u8) profile;
+	tmy_update_counter(TMY_UPDATE_DOMAINPOLICY);
+
+	return 0;
+}
+
+/*************************  SYSTEM POLICY HANDLER  *************************/
+
+/* Update system policy. */
+static int tmy_add_system_policy(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	bool is_delete = 0;
+
+	if (!tmy_is_root())
+		return -EPERM;
+
+	tmy_update_counter(TMY_UPDATE_SYSTEMPOLICY);
+
+	if (tmy_strstarts(&data, TMY_DELETE))
+		is_delete = 1;
+	if (tmy_strstarts(&data, TMY_ALLOW_MOUNT))
+		return tmy_add_mount_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_DENY_UNMOUNT))
+		return tmy_add_no_umount_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_ALLOW_PIVOT_ROOT))
+		return tmy_add_pivot_root_policy(data, is_delete);
+
+	return -EINVAL;
+}
+
+/* Read system policy. */
+static int tmy_read_system_policy(struct io_buffer *head)
+{
+	if (head->read_eof)
+		return 0;
+	switch (head->read_step) {
+	case 0:
+		if (!tmy_is_root())
+			return -EPERM;
+		head->read_step = 1;
+	case 1:
+		if (tmy_read_mount_policy(head))
+			break;
+		head->read_step = 2;
+	case 2:
+		if (tmy_read_no_umount_policy(head))
+			break;
+		head->read_step = 3;
+	case 3:
+		if (tmy_read_pivot_root_policy(head))
+			break;
+		head->read_eof = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*************************  EXCEPTION POLICY HANDLER  *************************/
+/* Update exception policy. */
+static int tmy_add_exception_policy(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	bool is_delete = 0;
+
+	if (!tmy_is_root())
+		return -EPERM;
+
+	tmy_update_counter(TMY_UPDATE_EXCEPTIONPOLICY);
+
+	if (tmy_strstarts(&data, TMY_DELETE))
+		is_delete = 1;
+	if (tmy_strstarts(&data, TMY_KEEP_DOMAIN))
+		return tmy_add_domain_keeper_policy(data, 0, is_delete);
+	if (tmy_strstarts(&data, TMY_NO_KEEP_DOMAIN))
+		return tmy_add_domain_keeper_policy(data, 1, is_delete);
+	if (tmy_strstarts(&data, TMY_INITIALIZE_DOMAIN))
+		return tmy_add_domain_initializer_policy(data, 0, is_delete);
+	if (tmy_strstarts(&data, TMY_NO_INITIALIZE_DOMAIN))
+		return tmy_add_domain_initializer_policy(data, 1, is_delete);
+	if (tmy_strstarts(&data, TMY_ALIAS))
+		return tmy_add_alias_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_AGGREGATOR))
+		return tmy_add_aggregator_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_ALLOW_READ))
+		return tmy_add_globally_readable_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_ALLOW_ENV))
+		return tmy_add_globally_usable_env_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_FILE_PATTERN))
+		return tmy_add_pattern_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_PATH_GROUP))
+		return tmy_add_group_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_DENY_REWRITE))
+		return tmy_add_no_rewrite_policy(data, is_delete);
+	if (tmy_strstarts(&data, TMY_ADDRESS_GROUP))
+		return tmy_add_address_group_policy(data, is_delete);
+
+	return -EINVAL;
+}
+
+/* Read exception policy. */
+static int tmy_read_exception_policy(struct io_buffer *head)
+{
+	if (head->read_eof)
+		return 0;
+	switch (head->read_step) {
+	case 0:
+		if (!tmy_is_root())
+			return -EPERM;
+		head->read_step = 1;
+	case 1:
+		if (tmy_read_domain_keeper_policy(head))
+			break;
+		head->read_step = 2;
+	case 2:
+		if (tmy_read_globally_readable_policy(head))
+			break;
+		head->read_step = 3;
+	case 3:
+		if (tmy_read_globally_usable_env_policy(head))
+			break;
+		head->read_step = 4;
+	case 4:
+		if (tmy_read_domain_initializer_policy(head))
+			break;
+		head->read_step = 5;
+	case 5:
+		if (tmy_read_alias_policy(head))
+			break;
+		head->read_step = 6;
+	case 6:
+		if (tmy_read_aggregator_policy(head))
+			break;
+		head->read_step = 7;
+	case 7:
+		if (tmy_read_pattern_policy(head))
+			break;
+		head->read_step = 8;
+	case 8:
+		if (tmy_read_no_rewrite_policy(head))
+			break;
+		head->read_step = 9;
+	case 9:
+		if (tmy_read_path_group_policy(head))
+			break;
+		head->read_step = 10;
+	case 10:
+		if (tmy_read_address_group_policy(head))
+			break;
+		head->read_eof = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*************************  POLICY LOADER  *************************/
+
+/**
+ * tmy_load_policy - load policy and activate access control.
+ * @filename: program to be executed.
+ *
+ * This function calls /sbin/tomoyo-init using call_usermodehelper()
+ * to load policy
+ * if "execution of /sbin/init is requested" and "/sbin/tomoyo-init exists".
+ */
+void tmy_load_policy(const char *filename)
+{
+	if (sbin_init_started)
+		return;
+	if (strcmp(filename, "/sbin/init") != 0)
+		return;
+
+	/*
+	 * Don't activate MAC if the path '/sbin/tomoyo-init' doesn't exist.
+	 * If initrd.img includes /sbin/init but real-root-dev has not
+	 * mounted on / yet, activating MAC will block the system
+	 * since policies are not loaded yet.
+	 * So let do_execve() call this function everytime.
+	 */
+	if (!profile_loaded) {
+		const char *tmy_loader = "/sbin/tomoyo-init";
+		struct nameidata nd;
+		char *argv[2];
+		char *envp[3];
+
+		if (path_lookup(tmy_loader, LOOKUP_FOLLOW, &nd)) {
+			printk("TOMOYO: Not activating Mandatory Access Control"
+			       " now since %s doesn't exist.\n", tmy_loader);
+			return;
+		}
+		path_put(&nd.path);
+		argv[0] = (char *) tmy_loader;
+		argv[1] = NULL;
+		envp[0] = "HOME=/";
+		envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+		envp[2] = NULL;
+		call_usermodehelper(argv[0], argv, envp, 1);
+	}
+
+	printk(KERN_INFO "TOMOYO: %s   2007/12/28\n", TOMOYO_VERSION_CODE);
+
+	if (!profile_loaded)
+		panic("TOMOYO: No profiles loaded.\n");
+
+	printk(KERN_INFO "TOMOYO: Mandatory Access Control activated.\n");
+	sbin_init_started = 1;
+
+	{ /* Check all profiles currently assigned to domains are defined. */
+		struct domain_info *domain;
+		list_for_each_entry(domain, &domain_list, list) {
+			const u8 profile = domain->profile;
+			if (profile_ptr[profile])
+				continue;
+			panic("TOMOYO: Profile %u (used by '%s') "
+			      "not defined.\n",
+			      profile,
+			      domain->domainname->name);
+		}
+	}
+}
+
+
+/*************************  MAC Decision Delayer  *************************/
+
+static DECLARE_WAIT_QUEUE_HEAD(query_wait);
+
+static DEFINE_SPINLOCK(query_lock);
+
+struct query_entry {
+	struct list_head list;
+	char *query;
+	int query_len;
+	unsigned int serial;
+	int timer;
+	int answer;
+};
+
+static LIST_HEAD(query_list);
+static atomic_t queryd_watcher = ATOMIC_INIT(0);
+
+/**
+ * tmy_supervisor - ask for supervisors decision.
+ * @fmt: format strings for printf().
+ *
+ * Returns zero if administrator allowed.
+ * Returns nonzero otherwise.
+ *
+ * This is one of TOMOYO Linux's feature.
+ * Normally, access requests that violates policy is rejected immediately.
+ * But this behavior is inconvenient when developing policy.
+ * TOMOYO Linux allows administrators handle access requests that violated
+ * policy in enforce mode to adjust policy.
+ *
+ * This function blocks a process who is requesting access that violated policy
+ * and tell it via /sys/kernel/security/tomoyo/query and wait for supervisor's
+ * decision.
+ */
+int tmy_supervisor(const char *fmt, ...)
+{
+	va_list args;
+	int error = -EPERM;
+	int pos;
+	int len;
+	static unsigned int serial;
+	struct query_entry *query_entry;
+
+	if (!tmy_flags(TMY_ALLOW_ENFORCE_GRACE))
+		return -EPERM;
+	if (!atomic_read(&queryd_watcher))
+		return -EPERM;
+
+	va_start(args, fmt);
+	len = vsnprintf((char *) &pos, sizeof(pos) - 1, fmt, args) + 32;
+	va_end(args);
+
+	query_entry = tmy_alloc(sizeof(*query_entry));
+	if (!query_entry)
+		goto out;
+	query_entry->query = tmy_alloc(len);
+	if (!query_entry->query)
+		goto out;
+
+	INIT_LIST_HEAD(&query_entry->list);
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	query_entry->serial = serial++;
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	pos = snprintf(query_entry->query, len - 1,
+		       "Q%u\n", query_entry->serial);
+	va_start(args, fmt);
+	vsnprintf(query_entry->query + pos, len - 1 - pos, fmt, args);
+	query_entry->query_len = strlen(query_entry->query) + 1;
+	va_end(args);
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	list_add_tail(&query_entry->list, &query_list);
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	tmy_update_counter(TMY_UPDATE_QUERY);
+
+	/* Give 10 seconds for supervisor's opinion. */
+	for (query_entry->timer = 0;
+	     atomic_read(&queryd_watcher) &&
+		     tmy_flags(TMY_ALLOW_ENFORCE_GRACE) &&
+		     query_entry->timer < 100;
+	     query_entry->timer++) {
+		wake_up(&query_wait);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ / 10);
+		if (query_entry->answer)
+			break;
+	}
+
+	tmy_update_counter(TMY_UPDATE_QUERY);
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	list_del(&query_entry->list);
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	switch (query_entry->answer) {
+	case 1:
+		/* Granted by administrator. */
+		error = 0;
+		break;
+	case 0:
+		/* Timed out. */
+		break;
+	default:
+		/* Rejected by administrator. */
+		break;
+	}
+
+out: ;
+	if (query_entry)
+		tmy_free(query_entry->query);
+	tmy_free(query_entry);
+	return error;
+}
+
+/* Check for pending access requests. */
+static int tmy_poll_query(struct file *file, poll_table *wait)
+{
+	bool found;
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	found = !list_empty(&query_list);
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	if (found)
+		return POLLIN | POLLRDNORM;
+	poll_wait(file, &query_wait, wait);
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	found = !list_empty(&query_list);
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	if (found)
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+
+/* Read pending access requests. */
+static int tmy_read_query(struct io_buffer *head)
+{
+	struct list_head *tmp;
+	int pos = 0;
+	int len = 0;
+	char *buf;
+
+	if (head->read_avail)
+		return 0;
+	if (head->read_buf) {
+		tmy_free(head->read_buf);
+		head->read_buf = NULL;
+		head->readbuf_size = 0;
+	}
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	list_for_each(tmp, &query_list) {
+		struct query_entry *ptr
+			= list_entry(tmp, struct query_entry, list);
+		if (pos++ == head->read_step) {
+			len = ptr->query_len;
+			break;
+		}
+	}
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	if (!len) {
+		head->read_step = 0;
+		return 0;
+	}
+	buf = tmy_alloc(len);
+	if (buf) {
+		pos = 0;
+
+		/***** CRITICAL SECTION START *****/
+		spin_lock(&query_lock);
+		list_for_each(tmp, &query_list) {
+			struct query_entry *ptr
+				= list_entry(tmp, struct query_entry, list);
+			if (pos++ == head->read_step) {
+				/* Some query can be skiipped because
+				 * query_list can change, but I don't care.
+				 */
+				if (len == ptr->query_len)
+					memmove(buf, ptr->query, len);
+				break;
+			}
+		}
+		spin_unlock(&query_lock);
+		/***** CRITICAL SECTION END *****/
+
+		if (buf[0]) {
+			head->readbuf_size = len;
+			head->read_avail = len;
+			head->read_buf = buf;
+			head->read_step++;
+		} else
+			tmy_free(buf);
+	}
+
+	return 0;
+}
+
+/* Reply to pending access requests. */
+static int tmy_write_answer(struct io_buffer *head)
+{
+	char *data = head->write_buf;
+	struct list_head *tmp;
+	unsigned int serial;
+	unsigned int answer;
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	list_for_each(tmp, &query_list) {
+		struct query_entry *ptr
+			= list_entry(tmp, struct query_entry, list);
+		ptr->timer = 0;
+	}
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	if (sscanf(data, "A%u=%u", &serial, &answer) != 2)
+		return -EINVAL;
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&query_lock);
+	list_for_each(tmp, &query_list) {
+		struct query_entry *ptr
+			= list_entry(tmp, struct query_entry, list);
+		if (ptr->serial != serial)
+			continue;
+		if (!ptr->answer)
+			ptr->answer = answer;
+		break;
+	}
+	spin_unlock(&query_lock);
+	/***** CRITICAL SECTION END *****/
+
+	return 0;
+}
+
+/******************  /sys/kernel/security INTERFACE HANDLER  ******************/
+
+/* Policy updates counter. */
+static unsigned int updates_counter[TMY_MAX_UPDATES_COUNTER];
+static DEFINE_SPINLOCK(updates_counter_lock);
+
+/**
+ * tmy_update_counter - notify userland that policy is changed.
+ * @index: index to update counter.
+ *
+ * This is for userland process who is monitoring policy changes.
+ */
+void tmy_update_counter(const unsigned char index)
+{
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&updates_counter_lock);
+	if (index < TMY_MAX_UPDATES_COUNTER)
+		updates_counter[index]++;
+	spin_unlock(&updates_counter_lock);
+	/***** CRITICAL SECTION END *****/
+}
+
+/* Read policy update counter. */
+static int tmy_read_updates_counter(struct io_buffer *head)
+{
+	unsigned int counter[TMY_MAX_UPDATES_COUNTER];
+	if (head->read_eof)
+		return 0;
+
+	/***** CRITICAL SECTION START *****/
+	spin_lock(&updates_counter_lock);
+	memmove(counter, updates_counter, sizeof(updates_counter));
+	memset(updates_counter, 0, sizeof(updates_counter));
+	spin_unlock(&updates_counter_lock);
+	/***** CRITICAL SECTION END *****/
+
+	tmy_io_printf(head,
+		      "/sys/kernel/security/tomoyo/system_policy:    %10u\n"
+		      "/sys/kernel/security/tomoyo/domain_policy:    %10u\n"
+		      "/sys/kernel/security/tomoyo/exception_policy: %10u\n"
+		      "/sys/kernel/security/tomoyo/profile:          %10u\n"
+		      "/sys/kernel/security/tomoyo/query:            %10u\n"
+		      "/sys/kernel/security/tomoyo/manager:          %10u\n"
+		      "/sys/kernel/security/tomoyo/grant_log:        %10u\n"
+		      "/sys/kernel/security/tomoyo/reject_log:       %10u\n",
+		      counter[TMY_UPDATE_SYSTEMPOLICY],
+		      counter[TMY_UPDATE_DOMAINPOLICY],
+		      counter[TMY_UPDATE_EXCEPTIONPOLICY],
+		      counter[TMY_UPDATE_PROFILE],
+		      counter[TMY_UPDATE_QUERY],
+		      counter[TMY_UPDATE_MANAGER],
+		      counter[TMY_UPDATE_GRANT_LOG],
+		      counter[TMY_UPDATE_REJECT_LOG]);
+
+	head->read_eof = 1;
+
+	return 0;
+}
+
+/* Read how much memory is used. */
+static int tmy_read_memory_counter(struct io_buffer *head)
+{
+	int shared;
+	int private;
+	int dynamic;
+
+	if (head->read_eof)
+		return 0;
+	shared = tmy_get_memory_used_for_save_name();
+	private = tmy_get_memory_used_for_elements();
+	dynamic = tmy_get_memory_used_for_dynamic();
+	if (tmy_io_printf(head,
+			  "Shared:  %10u\n"
+			  "Private: %10u\n"
+			  "Dynamic: %10u\n"
+			  "Total:   %10u\n",
+			  shared,
+			  private,
+			  dynamic,
+			  shared + private + dynamic) == 0)
+		head->read_eof = 1;
+	return 0;
+}
+
+/* Read TOMOYO Linux's version. */
+static int tmy_read_version(struct io_buffer *head)
+{
+	if (!head->read_eof) {
+		tmy_io_printf(head, TOMOYO_VERSION_CODE "\n");
+		head->read_eof = 1;
+	}
+	return 0;
+}
+
+/* Read current process's domainname. */
+static int tmy_read_self_domain(struct io_buffer *head)
+{
+	if (!head->read_eof) {
+		tmy_io_printf(head,
+			      "%s",
+			      TMY_SECURITY->domain->domainname->name);
+		head->read_eof = 1;
+	}
+
+	return 0;
+}
+
+/* This is /sys/kernel/security/tomoyo/ interface. */
+static int tmy_open_control(const int type, struct file *file)
+{
+	struct io_buffer *head = tmy_alloc(sizeof(*head));
+
+	if (!head)
+		return -ENOMEM;
+	mutex_init(&head->read_mutex);
+	mutex_init(&head->write_mutex);
+
+	switch (type) {
+	case TMY_DOMAINPOLICY:
+		head->write = tmy_add_domain_policy;
+		head->read = tmy_read_domain_policy;
+		break;
+	case TMY_SYSTEMPOLICY:
+		head->write = tmy_add_system_policy;
+		head->read = tmy_read_system_policy;
+		break;
+	case TMY_EXCEPTIONPOLICY:
+		head->write = tmy_add_exception_policy;
+		head->read = tmy_read_exception_policy;
+		break;
+	case TMY_DOMAIN_STATUS:
+		head->write = tmy_update_domain_profile;
+		head->read = tmy_read_domain_profile;
+		break;
+	case TMY_PROCESS_STATUS:
+		head->write = tmy_write_pid;
+		head->read = tmy_read_pid;
+		break;
+	case TMY_SELFDOMAIN:
+		head->read = tmy_read_self_domain;
+		break;
+	case TMY_MEMINFO:
+		head->read = tmy_read_memory_counter;
+		head->readbuf_size = 128;
+		break;
+	case TMY_PROFILE:
+		head->write = tmy_set_profile;
+		head->read = tmy_read_profile;
+		break;
+	case TMY_QUERY:
+		head->poll = tmy_poll_query;
+		head->write = tmy_write_answer;
+		head->read = tmy_read_query;
+		break;
+	case TMY_MANAGER:
+		head->write = tmy_add_manager_policy;
+		head->read = tmy_read_manager_policy;
+		break;
+	case TMY_UPDATESCOUNTER:
+		head->read = tmy_read_updates_counter;
+		break;
+	case TMY_VERSION:
+		head->read = tmy_read_version;
+		break;
+	case TMY_GRANT_LOG:
+		head->read = tmy_read_grant_log;
+		head->poll = tmy_poll_grant_log;
+		break;
+	case TMY_REJECT_LOG:
+		head->read = tmy_read_reject_log;
+		head->poll = tmy_poll_reject_log;
+		break;
+	}
+
+	if (type != TMY_QUERY) {
+		if (!head->readbuf_size)
+			head->readbuf_size = PAGE_SIZE * 2;
+		head->read_buf = tmy_alloc(head->readbuf_size);
+		if (!head->read_buf) {
+			tmy_free(head);
+			return -ENOMEM;
+		}
+	}
+
+	if (head->write) {
+		head->writebuf_size = PAGE_SIZE * 2;
+		head->write_buf = tmy_alloc(head->writebuf_size);
+		if (!head->write_buf) {
+			tmy_free(head->read_buf);
+			tmy_free(head);
+			return -ENOMEM;
+		}
+	}
+
+	file->private_data = head;
+
+	if (type == TMY_SELFDOMAIN)
+		tmy_read_control(file, NULL, 0);
+	else if (head->write == tmy_write_answer)
+		atomic_inc(&queryd_watcher);
+
+	return 0;
+}
+
+/* Copy read data to userland buffer. */
+static int tmy_copy_to_user(struct io_buffer *head, char __user *buffer,
+			    int buffer_len)
+{
+	int len = head->read_avail;
+	char *cp = head->read_buf;
+
+	if (len > buffer_len)
+		len = buffer_len;
+	if (len) {
+		if (copy_to_user(buffer, cp, len))
+			return -EFAULT;
+		head->read_avail -= len;
+		memmove(cp, cp + len, head->read_avail);
+	}
+
+	return len;
+}
+
+/* Check for pending requests. */
+static int tmy_poll_control(struct file *file, poll_table *wait)
+{
+	struct io_buffer *head = (struct io_buffer *) file->private_data;
+	if (!head->poll)
+		return -ENOSYS;
+	return head->poll(file, wait);
+}
+
+/* Read policy. */
+static int tmy_read_control(struct file *file, char __user *buffer,
+			    const int buffer_len)
+{
+	int len = 0;
+	struct io_buffer *head = (struct io_buffer *) file->private_data;
+
+	if (!head->read)
+		return -ENOSYS;
+	if (!access_ok(VERIFY_WRITE, buffer, buffer_len))
+		return -EFAULT;
+	if (mutex_lock_interruptible(&head->read_mutex))
+		return -EINTR;
+	len = head->read(head);
+	if (len >= 0)
+		len = tmy_copy_to_user(head, buffer, buffer_len);
+	mutex_unlock(&head->read_mutex);
+
+	return len;
+}
+
+/* Update policy. */
+static int tmy_write_control(struct file *file, const char __user *buffer,
+			     const int buffer_len)
+{
+	struct io_buffer *head = (struct io_buffer *) file->private_data;
+	int error = buffer_len;
+	int avail_len = buffer_len;
+	char *cp0 = head->write_buf;
+
+	if (!head->write)
+		return -ENOSYS;
+	if (!access_ok(VERIFY_READ, buffer, buffer_len))
+		return -EFAULT;
+	if (!tmy_is_root())
+		return -EPERM;
+	if (head->write != tmy_write_pid && !tmy_is_policy_manager())
+		/* Forbid updating policies for non manager programs. */
+		return -EPERM;
+
+	if (mutex_lock_interruptible(&head->write_mutex))
+		return -EINTR;
+	while (avail_len > 0) {
+		char c;
+		if (head->write_avail >= head->writebuf_size - 1) {
+			error = -ENOMEM;
+			break;
+		} else if (get_user(c, buffer)) {
+			error = -EFAULT;
+			break;
+		}
+		buffer++;
+		avail_len--;
+		cp0[head->write_avail++] = c;
+		if (c != '\n')
+			continue;
+		cp0[head->write_avail - 1] = '\0';
+		head->write_avail = 0;
+		tmy_normalize_line(cp0);
+		head->write(head);
+	}
+	mutex_unlock(&head->write_mutex);
+
+	return error;
+}
+
+/* Close /sys/kernel/security/tomoyo/ interface. */
+static int tmy_close_control(struct file *file)
+{
+	struct io_buffer *head = file->private_data;
+
+	if (head->write == tmy_write_answer)
+		atomic_dec(&queryd_watcher);
+
+	tmy_free(head->read_buf);
+	head->read_buf = NULL;
+	tmy_free(head->write_buf);
+	head->write_buf = NULL;
+	tmy_free(head);
+	head = NULL;
+	file->private_data = NULL;
+	return 0;
+}
+
+/* open() operation for /sys/kernel/security/tomoyo/ interface. */
+static int tmy_open(struct inode *inode, struct file *file)
+{
+	return tmy_open_control(((u8 *) file->f_dentry->d_inode->i_private)
+				- ((u8 *) NULL), file);
+}
+
+/* close() operation for /sys/kernel/security/tomoyo/ interface. */
+static int tmy_release(struct inode *inode, struct file *file)
+{
+	return tmy_close_control(file);
+}
+
+/* poll() operation for /sys/kernel/security/tomoyo/ interface. */
+static unsigned int tmy_poll(struct file *file, poll_table *wait)
+{
+	return tmy_poll_control(file, wait);
+}
+
+/* read() operation for /sys/kernel/security/tomoyo/ interface. */
+static ssize_t tmy_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	return tmy_read_control(file, buf, count);
+}
+
+/* write() operation for /sys/kernel/security/tomoyo/ interface. */
+static ssize_t tmy_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	return tmy_write_control(file, buf, count);
+}
+
+static struct file_operations tmy_operations = {
+	.open 	 = tmy_open,
+	.release = tmy_release,
+	.poll 	 = tmy_poll,
+	.read 	 = tmy_read,
+	.write 	 = tmy_write
+};
+
+/* Associate /sys/kernel/security/tomoyo/ interface with key. */
+static void __init tmy_create_entry(const char *name,
+			     const mode_t mode,
+			     struct dentry *parent,
+			     const int key)
+{
+	securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
+			       &tmy_operations);
+}
+
+/**
+ * tmy_interface_init - initialize /sys/kernel/security/tomoyo/ interface.
+ */
+static int __init tmy_interface_init(void)
+{
+	struct dentry *tmy_dir;
+	tmy_dir = securityfs_create_dir("tomoyo", NULL);
+	tmy_create_entry("query",            0600, tmy_dir,
+			 TMY_QUERY);
+	tmy_create_entry("domain_policy",    0600, tmy_dir,
+			 TMY_DOMAINPOLICY);
+	tmy_create_entry("system_policy",    0600, tmy_dir,
+			 TMY_SYSTEMPOLICY);
+	tmy_create_entry("exception_policy", 0600, tmy_dir,
+			 TMY_EXCEPTIONPOLICY);
+	tmy_create_entry(".domain_status",   0600, tmy_dir,
+			 TMY_DOMAIN_STATUS);
+	tmy_create_entry(".process_status",  0400, tmy_dir,
+			 TMY_PROCESS_STATUS);
+	tmy_create_entry("self_domain",      0400, tmy_dir,
+			 TMY_SELFDOMAIN);
+	tmy_create_entry("meminfo",          0400, tmy_dir,
+			 TMY_MEMINFO);
+	tmy_create_entry("profile",          0600, tmy_dir,
+			 TMY_PROFILE);
+	tmy_create_entry("manager",          0600, tmy_dir,
+			 TMY_MANAGER);
+	tmy_create_entry(".updates_counter", 0400, tmy_dir,
+			 TMY_UPDATESCOUNTER);
+	tmy_create_entry("version",          0400, tmy_dir,
+			 TMY_VERSION);
+	tmy_create_entry("grant_log",        0400, tmy_dir,
+			 TMY_GRANT_LOG);
+	tmy_create_entry("reject_log",       0400, tmy_dir,
+			 TMY_REJECT_LOG);
+	return 0;
+}
+
+postcore_initcall(tmy_interface_init);

-- 
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