X-Git-Url: http://git.tuebingen.mpg.de/?p=adu.git;a=blobdiff_plain;f=user.c;h=026d65be741fdc3a100c24f6cce379f8eaa124e0;hp=233764fe40089e387d03b783f01295b180112636;hb=ca20c17a6742464bcf861fe856a4caddf2bfeab2;hpb=4113e8c585d3da46bfa5326b866621cff854a737

diff --git a/user.c b/user.c
index 233764f..026d65b 100644
--- a/user.c
+++ b/user.c
@@ -4,7 +4,7 @@
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file user.c uid User and user ID handling. */
+/** \file user.c \brief User and user ID handling. */
 
 #include "adu.h"
 #include <dirent.h> /* readdir() */
@@ -29,6 +29,7 @@ struct uid_range {
 	uint32_t high;
 };
 
+/** Iterate over all uid ranges. */
 #define FOR_EACH_UID_RANGE(ur, urs) for (ur = urs; ur->low <= ur->high; ur++)
 
 /** Flags for the user hash table. */
@@ -38,6 +39,7 @@ enum uid_info_flags {
 	/** Whether this uid should be taken into account. */
 	UI_FL_ADMISSIBLE = 2,
 };
+
 /*
  * Contains info for each user that owns at least one regular file.
  *
@@ -50,6 +52,9 @@ static struct user_info *uid_hash_table;
 /** This is always a power of two. It is set in create_hash_table(). */
 static uint32_t uid_hash_table_size;
 
+/** The number of used slots in the hash table. */
+static uint32_t num_uids;
+
 /*
  * The columns of the per-user tables.
  *
@@ -138,6 +143,15 @@ out:
 	return ret;
 }
 
+/**
+ * Convert the --uid argument to an array of uid ranges.
+ *
+ * \param orig_arg The argument to the --uid option.
+ * \param ur Result pointer.
+ *
+ * Returns Negative on errors. On success, the number of uid ranges
+ * is returned.
+ */
 int parse_uid_arg(const char *orig_arg, struct uid_range **ur)
 {
 	char *arg, **argv;
@@ -169,6 +183,70 @@ int parse_uid_arg(const char *orig_arg, struct uid_range **ur)
 	return n;
 }
 
+static int uid_is_admissible(uint32_t uid, struct uid_range *urs)
+{
+	struct uid_range *ur;
+	int ret = 1;
+
+	if (!urs) /* empty array means all uids are allowed */
+		return 1;
+	FOR_EACH_UID_RANGE(ur, urs)
+		if (ur->low <= uid && ur->high >= uid)
+			goto out;
+	ret = 0;
+out:
+	DEBUG_LOG("uid %u is %sadmissible\n", (unsigned)uid,
+		ret? "" : "not ");
+	return ret;
+}
+
+/**
+ * Add each given user to the array of admissible users.
+ *
+ * \param users Array of user names to add.
+ * \param num_users Length of \a users.
+ * \param admissible_uids The users which are already admissible.
+ * \param num_uid_ranges The number of intervals of \a admissible_uids.
+ *
+ * For each given user, the function checks whether that user is already
+ * admissible, i.e. its uid is contained in one of the ranges given by \a
+ * admissible_uids. If it is, the function ignores that user. Otherwise, a new
+ * length-one range consisting of that uid only is appended to \a
+ * admissible_uids.
+ *
+ * \return Negative on errors, the new number of uid ranges on success.
+ */
+int append_users(char **users, int num_users,
+		struct uid_range **admissible_uids, int num_uid_ranges)
+{
+	int i;
+	struct uid_range *au = *admissible_uids;
+
+	for (i = 0; i < num_users; i++) {
+		char *u = users[i];
+		struct uid_range *ur;
+		struct passwd *pw = getpwnam(u);
+
+		if (!pw) {
+			ERROR_LOG("user %s not found\n", u);
+			return -ERRNO_TO_ERROR(EINVAL);
+		}
+		if (au && uid_is_admissible(pw->pw_uid, au))
+			continue; /* nothing to do */
+		/* add a range consisting of this uid only */
+		num_uid_ranges++;
+		au = adu_realloc(au, (num_uid_ranges + 1) *
+			sizeof(struct uid_range));
+		*admissible_uids = au;
+		ur = au + num_uid_ranges - 1; /* the new uid range */
+		ur->low = ur->high = pw->pw_uid;
+		/* terminate the list */
+		ur++;
+		ur->low = 1;
+		ur->high = 0;
+	}
+	return num_uid_ranges;
+}
 
 static inline int ui_used(struct user_info *ui)
 {
@@ -195,8 +273,7 @@ static int open_user_table(struct user_info *ui, int create)
 	if (pw && pw->pw_name)
 		ui->pw_name = adu_strdup(pw->pw_name);
 
-	INFO_LOG(".............................uid #%u: %u\n",
-		(unsigned)num_uids, (unsigned)ui->uid);
+	INFO_LOG("opening table for uid %u\n", (unsigned)ui->uid);
 	if (create) {
 		ret = osl(osl_create_table(ui->desc));
 		if (ret < 0)
@@ -220,16 +297,32 @@ err:
 	return ret;
 }
 
+/** Iterate over each user in the uid hash table. */
+#define FOR_EACH_USER(ui) for (ui = uid_hash_table; ui < \
+	uid_hash_table + uid_hash_table_size; ui++)
+
+
+/**
+ * Execute the given function for each admissible user.
+ *
+ * \param func The function to execute.
+ * \param data Arbitrary pointer.
+ *
+ * This function calls \a func for each admissible user in the uid hash table.
+ * The \a data pointer is passed as the second argument to \a func.
+ *
+ * \return As soon as \a func returns a negative value, the loop is terminated
+ * and that negative value is returned. Otherwise, the function returns 1.
+ */
 int for_each_admissible_user(int (*func)(struct user_info *, void *),
 		void *data)
 {
-	struct user_info *ui = uid_hash_table;
-
-	if (!ui)
-		return -ERRNO_TO_ERROR(EFAULT);
+	int i;
 
-	for (; ui < uid_hash_table + uid_hash_table_size; ui++) {
+	assert(uid_hash_table);
+	for (i = 0; i < uid_hash_table_size; i++) {
 		int ret;
+		struct user_info *ui = uid_hash_table + i;
 
 		if (!ui_used(ui) || !ui_admissible(ui))
 			continue;
@@ -240,9 +333,16 @@ int for_each_admissible_user(int (*func)(struct user_info *, void *),
 	return 1;
 }
 
+/** Prime number used for calculating the slot for an uid. */
 #define PRIME1 0xb11924e1
+/** Prime number used for probe all slots. */
 #define PRIME2 0x01000193
 
+/**
+ * Create a hash table large enough of given size.
+ *
+ * \param bits Sets the maximal number of hash table entries to ^bits.
+ */
 void create_hash_table(unsigned bits)
 {
 	uid_hash_table_size = 1 << bits;
@@ -250,41 +350,46 @@ void create_hash_table(unsigned bits)
 		sizeof(struct user_info));
 }
 
-void free_hash_table(void)
-{
-	free(uid_hash_table);
-	uid_hash_table = NULL;
-}
-
-static int close_user_table(struct user_info *ui, __a_unused void *data)
+/**
+ * Close all open user tables and destroy the uid hash table.
+ *
+ * For each used slot in the uid hash table, close the osl user table if it is
+ * open.  Finally, free the uid hash table.
+ */
+void close_user_tables(void)
 {
-	int ret;
+	struct user_info *ui;
 
-	ret = osl(osl_close_table(ui->table, OSL_MARK_CLEAN));
-	if (ret < 0)
-		ERROR_LOG("failed to close user table %u: %s\n",
-			(unsigned) ui->uid, adu_strerror(-ret));
-	free((char *)ui->desc->name);
-	ui->desc->name = NULL;
-	free((char *)ui->desc->dir);
-	ui->desc->dir = NULL;
-	free(ui->pw_name);
-	ui->pw_name = NULL;
-	free(ui->desc);
-	ui->desc = NULL;
-	ui->table = NULL;
-	ui->flags = 0;
-	return 1;
-}
+	FOR_EACH_USER(ui) {
+		int ret;
 
-void close_user_tables(void)
-{
-	for_each_admissible_user(close_user_table, NULL);
+		if (!ui_used(ui))
+			continue;
+		if (!ui->table)
+			continue;
+		INFO_LOG("closing user table for uid %u\n", (unsigned)ui->uid);
+		ret = osl(osl_close_table(ui->table, OSL_MARK_CLEAN));
+		if (ret < 0)
+			ERROR_LOG("failed to close user table %u: %s\n",
+				(unsigned)ui->uid, adu_strerror(-ret));
+		free((char *)ui->desc->name);
+		ui->desc->name = NULL;
+		free((char *)ui->desc->dir);
+		ui->desc->dir = NULL;
+		free(ui->pw_name);
+		ui->pw_name = NULL;
+		free(ui->desc);
+		ui->desc = NULL;
+		ui->table = NULL;
+		ui->flags = 0;
+	}
+	free(uid_hash_table);
+	uid_hash_table = NULL;
 }
 
 /*
  * We use a hash table of size s=2^uid_hash_bits to map the uids into the
- * interval [0..s]. Hash collisions are treated by open addressing, i.e.
+ * interval [0..s-1]. Hash collisions are treated by open addressing, i.e.
  * unused slots in the table are used to store different uids that hash to the
  * same slot.
  *
@@ -296,7 +401,7 @@ void close_user_tables(void)
  * An odd number is sufficient to make sure each entry of the hash table gets
  * probed for probe_num between 0 and s-1 because s is a power of two, hence
  * the second hash value has never a common divisor with the hash table size.
- * IOW: h is invertible in the ring [0..s].
+ * IOW: h is invertible in the ring [0..s-1].
  */
 static uint32_t double_hash(uint32_t uid, uint32_t probe_num)
 {
@@ -304,69 +409,105 @@ static uint32_t double_hash(uint32_t uid, uint32_t probe_num)
 		% uid_hash_table_size;
 }
 
-static int uid_is_admissible(uint32_t uid, struct uid_range *urs)
-{
-	struct uid_range *ur;
-	int ret = 1;
-
-	if (!urs) /* empty array means all uids are allowed */
-		return 1;
-	FOR_EACH_UID_RANGE(ur, urs)
-		if (ur->low <= uid && ur->high >= uid)
-			goto out;
-	ret = 0;
-out:
-	DEBUG_LOG("uid %u is %sadmissible\n", (unsigned)uid,
-		ret? "" : "not ");
-	return ret;
-}
-
-int search_uid(uint32_t uid, struct uid_range *urs,
-		enum search_uid_flags flags, struct user_info **ui_ptr)
+static struct user_info *lookup_uid(uint32_t uid)
 {
 	uint32_t p;
 
 	for (p = 0; p < uid_hash_table_size; p++) {
 		struct user_info *ui = uid_hash_table + double_hash(uid, p);
-
-		if (!ui_used(ui)) {
-			int ret;
-			if (!flags)
-				return -E_BAD_UID;
-			ui->uid = uid;
-			ui->flags |= UI_FL_SLOT_USED;
-			if (!uid_is_admissible(uid, urs))
-				return 0;
-			ui->flags |= UI_FL_ADMISSIBLE;
-			ret = open_user_table(ui, flags & CREATE_USER_TABLE);
-			if (ret < 0)
-				return ret;
-
-			if (ui_ptr)
-				*ui_ptr = ui;
-			return 1;
-		}
-		if (ui->uid != uid)
-			continue;
-		if (ui_ptr)
-			*ui_ptr = ui;
-		return 0;
+		if (!ui_used(ui))
+			return ui;
+		if (ui->uid == uid)
+			return ui;
 	}
-	return flags? -E_HASH_TABLE_OVERFLOW : -E_BAD_UID;
+	return NULL;
+}
+
+/**
+ * Create and open a osl table for the given uid.
+ *
+ * \param uid The user ID.
+ * \param ui_ptr Result pointer
+ *
+ * Find out whether \a uid already exists in the uid hash table.  If yes, just
+ * return the user info struct via \a ui_ptr. Otherwise, insert \a uid into the
+ * uid hash table, create and open the osl user table and also return the user
+ * info struct via \a ui_ptr.
+ *
+ * \return Standard.
+ */
+int create_user_table(uint32_t uid, struct user_info **ui_ptr)
+{
+	struct user_info *ui = lookup_uid(uid);
+
+	if (!ui)
+		return -E_HASH_TABLE_OVERFLOW;
+	*ui_ptr = ui;
+	if (ui_used(ui))
+		return 1;
+	ui->uid = uid;
+	ui->flags |= UI_FL_SLOT_USED;
+	return open_user_table(ui, 1);
 }
 
 static char *get_uid_list_name(void)
 {
 	return make_message("%s/uid_list", conf.database_dir_arg);
 }
-
-void sort_hash_table(int (*comp)(const void *, const void *))
+/**
+ * Open the osl tables for all admissible uids.
+ *
+ * \param admissible_uids Determines which uids are considered admissible.
+ *
+ * Each slot in the hash table contains, among other information, a bit which
+ * specifies whether the uid of the slot is admissible in the current context.
+ *
+ * This function iterates over all entries in the hash table and checks for
+ * each used slot whether the corresponding uid is admissible with respect to
+ * \a admissible_uids. If so, it sets the admissible bit for this slot and
+ * opens the osl table of the uid.
+ *
+ * \return Stamdard.
+ */
+int open_admissible_user_tables(struct uid_range *admissible_uids)
 {
-	qsort(uid_hash_table, uid_hash_table_size, sizeof(struct user_info),
-		comp);
+	struct user_info *ui;
+
+	assert(uid_hash_table);
+	DEBUG_LOG("size: %d\n", uid_hash_table_size);
+	FOR_EACH_USER(ui) {
+		int ret;
+
+		if (!ui_used(ui))
+			continue;
+		if (!uid_is_admissible(ui->uid, admissible_uids)) {
+			DEBUG_LOG("uid %u is not admissible\n", ui->uid);
+			ui->flags &= ~UI_FL_ADMISSIBLE;
+			continue;
+		}
+		ui->flags |= UI_FL_ADMISSIBLE;
+		if (ui->table)
+			continue;
+		ret = open_user_table(ui, 0);
+		if (ret < 0)
+			return ret;
+	}
+	return 1;
 }
 
-int read_uid_file(struct uid_range *admissible_uids)
+/**
+ * Read the file of all possible uids.
+ *
+ * This is called from select/interactive mode. First a large hash table, large
+ * enough to store all uids contained in the uid file is created. Next, the
+ * uids are read from the uid file which was created during the creation of the
+ * database and each uid is inserted into the hash table.
+ *
+ * \sa write_uid_file().
+ *
+ * \return Standard.
+ */
+int read_uid_file(void)
 {
 	size_t size;
 	uint32_t n;
@@ -375,7 +516,7 @@ int read_uid_file(struct uid_range *admissible_uids)
 	unsigned bits;
 
 	if (ret < 0) {
-		INFO_LOG("failed to map %s\n", filename);
+		ERROR_LOG("failed to map %s\n", filename);
 		free(filename);
 		return ret;
 	}
@@ -392,40 +533,53 @@ int read_uid_file(struct uid_range *admissible_uids)
 	create_hash_table(bits);
 	for (n = 0; n < num_uids; n++) {
 		uint32_t uid = read_u32(map + n * sizeof(uid));
-		ret = search_uid(uid, admissible_uids, OPEN_USER_TABLE, NULL);
-		if (ret < 0)
+		struct user_info *ui = lookup_uid(uid);
+		assert(ui);
+		if (ui_used(ui)) { /* impossible */
+			ERROR_LOG("duplicate user id!?\n");
+			ret = -EFAULT;
 			goto out;
+		}
+		ui->uid = uid;
+		ui->flags |= UI_FL_SLOT_USED;
 	}
+	ret = 1;
 out:
 	adu_munmap(map, size);
 	return ret;
 }
 
-static int write_uid(struct user_info *ui, void *data)
-{
-	char **p = data;
-
-	write_u32(*p, ui->uid);
-	*p += sizeof(uint32_t);
-	return 1;
-}
-
+/**
+ * Write the list of uids to permanent storage.
+ *
+ * This is called from create mode after the dir table and all uer tables have
+ * been created. The file simply contains the list of all uids that own at
+ * least one regular file in the base directory and hence an osl table for this
+ * uid exists.
+ *
+ * \sa read_uid_file().
+ *
+ * \return Standard.
+ */
 int write_uid_file(void)
 {
 	char *buf, *p, *filename;
 	size_t size = num_uids * sizeof(uint32_t);
 	int ret;
+	struct user_info *ui;
 
 	if (!num_uids)
 		return 0;
 	buf = p = adu_malloc(size);
-	ret = for_each_admissible_user(write_uid, &p);
-	if (ret < 0)
-		goto out;
+	FOR_EACH_USER(ui) {
+		if (!ui_used(ui))
+			continue;
+		write_u32(p, ui->uid);
+		p += sizeof(uint32_t);
+	}
 	filename = get_uid_list_name();
 	ret = adu_write_file(filename, buf, size);
 	free(filename);
-out:
 	free(buf);
 	return ret;
 }