diff options
Diffstat (limited to 'login/utmpd/database.c')
| -rw-r--r-- | login/utmpd/database.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/login/utmpd/database.c b/login/utmpd/database.c new file mode 100644 index 0000000000..e31e0d9dae --- /dev/null +++ b/login/utmpd/database.c @@ -0,0 +1,516 @@ +/* Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <stdlib.h> +#include <sys/stat.h> +#include <time.h> +#include <unistd.h> +#include <utmp.h> + + +#include "utmpd-private.h" +#include "xtmp.h" + + +/* Prototypes for the local functions. */ +static int initialize_database (utmp_database *database); +static int store_state_entry (utmp_database *database, int old_position, + const struct utmp *old_entry); +static int store_process_entry (utmp_database *database, int old_position, + const struct utmp *old_entry); +static int replace_entry (utmp_database *database, int old_position, + int new_position, const struct utmp *entry); +static int store_entry (utmp_database *database, int position, + const struct utmp *entry); +static int proc_utmp_eq (const struct utmp *entry, const struct utmp *match); +static int get_mtime (const char *file, time_t *timer); + + +/* Open the database specified by FILE and merge it with the + contents of the old format file specified by OLD_FILE. Returns a + pointer to a newly allocated structure describing the database, or + NULL on error. */ +utmp_database * +open_database (const char *file, const char *old_file) +{ + utmp_database *database; + + /* Allocate memory. */ + database = (utmp_database *) malloc (sizeof (utmp_database)); + if (database == NULL) + return NULL; + + memset (database, 0, sizeof (utmp_database)); + + /* Open database. */ + database->fd = open (file, O_RDWR); + if (database->fd < 0) + goto fail; + + database->old_fd = open (old_file, O_RDWR); + if (database->old_fd < 0) + goto fail; + + if ((file && !(database->file = strdup (file))) + || (old_file && !(database->old_file = strdup (old_file)))) + goto fail; + + if (initialize_database (database) < 0 + || synchronize_database (database) < 0) + goto fail; + + return database; + +fail: + close_database (database); + return NULL; +} + +/* Synchronize DATABASE. */ +int +synchronize_database (utmp_database *database) +{ + assert (database); + + /* Check if there is a file in the old format, that we have to + synchronize with. */ + if (database->old_file) + { + time_t curtime; + time_t mtime; + + curtime = time (NULL); + + if (get_mtime (database->old_file, &mtime) < 0) + return -1; + + if (mtime >= database->mtime) + { + int position = 0; + struct utmp entry; + struct utmp old_entry; + + while (1) + { + if (read_old_entry (database, position, &old_entry) < 0) + break; + + if (read_entry (database, position, &entry) < 0 + || !compare_entry (&old_entry, &entry)) + { + if (write_entry (database, position, &old_entry) < 0) + return -1; + } + + position++; + } + + database->mtime = curtime; + } + + } + + return 0; +} + + +/* Close DATABASE. */ +void +close_database (utmp_database *database) +{ + assert (database); + + if (database->fd >= 0) + close (database->fd); + + if (database->old_fd >= 0) + close (database->old_fd); + + /* Free allocated memory. */ + if (database->file) + free (database->file); + if (database->old_file) + free (database->old_file); + free (database); +} + + +/* Read the entry at POSITION in DATABASE and store the result in + ENTRY. Returns 0 if successful, -1 if not. */ +int +read_entry (utmp_database *database, int position, struct utmp *entry) +{ + ssize_t nbytes; + off_t offset; + + offset = position * sizeof (struct utmp); + if (lseek (database->fd, offset, SEEK_SET) < 0) + return -1; + + nbytes = read (database->fd, entry, sizeof (struct utmp)); + if (nbytes != sizeof (struct utmp)) + return -1; + + return 0; +} + + +/* Write ENTRY at POSITION in DATABASE. Returns 0 if successful, -1 + on error. */ +int +write_entry (utmp_database *database, int position, + const struct utmp *entry) +{ + int result = -1; + struct flock fl; + ssize_t nbytes; + off_t offset; + + /* Try to lock the file. */ + memset (&fl, 0, sizeof (struct flock)); + fl.l_type = F_WRLCK; + fl.l_whence = SEEK_SET; + fcntl (database->fd, F_SETLKW, &fl); + + offset = position * sizeof (struct utmp); + if (lseek (database->fd, offset, SEEK_SET) < 0) + goto fail; + + nbytes = write (database->fd, entry, sizeof (struct utmp)); + if (nbytes != sizeof (struct utmp)) + { + ftruncate (database->fd, offset); + goto fail; + } + + result = 0; + +fail: + /* And unlock the file. */ + fl.l_type = F_UNLCK; + fcntl (database->fd, F_SETLKW, &fl); + + return result; +} + + +/* Append ENTRY to DATABASE. Returns the position of the appended + entry if successful, or -1 on error. */ +int +append_entry (utmp_database *database, const struct utmp *entry) +{ + int result = -1; + struct flock fl; + ssize_t nbytes; + off_t offset; + + /* Try to lock the file. */ + memset (&fl, 0, sizeof (struct flock)); + fl.l_type = F_WRLCK; + fl.l_whence = SEEK_SET; + fcntl (database->fd, F_SETLKW, &fl); + + offset = lseek (database->fd, 0, SEEK_END); + if (offset % sizeof (struct utmp) != 0) + { + offset -= offset % sizeof (struct utmp); + ftruncate (database->fd, offset); + + if (lseek (database->fd, 0, SEEK_END) < 0) + goto fail; + } + + nbytes = write (database->fd, entry, sizeof (struct utmp)); + if (nbytes != sizeof (struct utmp)) + { + ftruncate (database->fd, offset); + goto fail; + } + + result = offset / sizeof (struct utmp); + +fail: + /* And unlock the file. */ + fl.l_type = F_UNLCK; + fcntl (database->fd, F_SETLKW, &fl); + + return result; +} + + +int +read_old_entry (utmp_database *database, int position, + struct utmp *entry) +{ + struct xtmp old_entry; + ssize_t nbytes; + off_t offset; + + offset = position * sizeof (struct xtmp); + if (lseek (database->old_fd, offset, SEEK_SET) < 0) + return -1; + + nbytes = read (database->old_fd, &old_entry, sizeof (struct xtmp)); + if (nbytes != sizeof (struct xtmp)) + return -1; + + xtmp_to_utmp (&old_entry, entry); + return 0; +} + + +int +write_old_entry (utmp_database *database, int position, + const struct utmp *entry) +{ + struct xtmp old_entry; + ssize_t nbytes; + off_t offset; + + utmp_to_xtmp (entry, &old_entry); + + offset = position * sizeof (struct xtmp); + if (lseek (database->old_fd, offset, SEEK_SET) < 0) + return -1; + + nbytes = write (database->old_fd, &old_entry, sizeof (struct xtmp)); + if (nbytes != sizeof (struct xtmp)) + return -1; + + return 0; +} + + +/* Initialize DATABASE. */ +static int +initialize_database (utmp_database *database) +{ + struct utmp entry; + int position = 0; + + assert (database); + + /* Check if there is a file in the old format to read. */ + if (database->old_file) + { + while (1) + { + if (read_old_entry (database, position, &entry) < 0) + break; + +#if _HAVE_UT_TYPE - 0 + /* If the login type is one of RUN_LVL, BOOT_TIME, OLD_TIME or + NEW_TIME, search for an entry of the same type in the + database, and replace it if the entry in the file is newer. */ + if (entry.ut_type == RUN_LVL || entry.ut_type == BOOT_TIME + || entry.ut_type == OLD_TIME || entry.ut_type == NEW_TIME) + { + if (store_state_entry (database, position, &entry) < 0) + return -1; + } + else +#endif + { + if (store_process_entry (database, position, &entry) < 0) + return -1; + } + + /* Update position. */ + position++; + } + + while (1) + { + if (read_entry (database, position, &entry) < 0) + break; + + if (write_old_entry (database, position, &entry) < 0) + return -1; + + /* Update position. */ + position++; + } + } + + return 0; +} + + +static int +store_state_entry (utmp_database *database, int old_position, + const struct utmp *old_entry) +{ + struct utmp new_entry; + int new_position = 0; + int found = 0; + + assert (old_entry->ut_type == RUN_LVL + || old_entry->ut_type == BOOT_TIME + || old_entry->ut_type == OLD_TIME + || old_entry->ut_type == NEW_TIME); + + while (!found) + { + /* Read the next entry. */ + if (read_entry (database, new_position, &new_entry) < 0) + break; + + if (old_entry->ut_type == new_entry.ut_type) + { + found = 1; + continue; + } + + /* Update position. */ + new_position++; + } + + if (found) + { + const struct utmp *entry; + + if (old_entry->ut_time > new_entry.ut_time) + entry = old_entry; + else + entry = &new_entry; + + return replace_entry (database, old_position, new_position, entry); + } + + return store_entry (database, old_position, old_entry); +} + + +static int +store_process_entry (utmp_database *database, int old_position, + const struct utmp *old_entry) +{ + struct utmp new_entry; + int new_position = 0; + int found = 0; + + while (!found) + { + /* Read the next entry. */ + if (read_entry (database, new_position, &new_entry) < 0) + break; + + if (proc_utmp_eq (old_entry, &new_entry)) + { + found = 1; + continue; + } + + /* Update position. */ + new_position++; + } + + if (found) + { + const struct utmp *entry; + + if (old_entry->ut_time > new_entry.ut_time) + entry = old_entry; + else + entry = &new_entry; + + return replace_entry (database, old_position, new_position, entry); + } + + return store_entry (database, old_position, old_entry); +} + + +static int +replace_entry (utmp_database *database, int old_position, int new_position, + const struct utmp *entry) +{ + struct utmp tmp; + + if (read_entry (database, old_position, &tmp) < 0 + || write_entry (database, old_position, entry) < 0 + || write_entry (database, new_position, &tmp) < 0) + return -1; + + return 0; +} + + +static int +store_entry (utmp_database *database, int position, + const struct utmp *entry) +{ + struct utmp tmp; + + if (read_entry (database, position, &tmp) < 0) + return write_entry (database, position, entry); + + if (write_entry (database, position, entry) < 0 + || append_entry (database, &tmp) < 0) + return -1; + + return 0; +} + + +/* This function is identical to the one in login/utmp_file.c. */ +static int +proc_utmp_eq (const struct utmp *entry, const struct utmp *match) +{ + return + ( +#if _HAVE_UT_TYPE - 0 + (entry->ut_type == INIT_PROCESS + || entry->ut_type == LOGIN_PROCESS + || entry->ut_type == USER_PROCESS + || entry->ut_type == DEAD_PROCESS) + && + (match->ut_type == INIT_PROCESS + || match->ut_type == LOGIN_PROCESS + || match->ut_type == USER_PROCESS + || match->ut_type == DEAD_PROCESS) + && +#endif +#if _HAVE_UT_ID - 0 + strncmp (entry->ut_id, match->ut_id, sizeof match->ut_id) == 0 +#else + strncmp (entry->ut_line, match->ut_line, sizeof match->ut_line) == 0 +#endif + ); +} + + +/* Get modification time of FILE and put it in TIMER. returns 0 if + successful, -1 if not. */ +static int +get_mtime (const char *file, time_t *timer) +{ + struct stat st; + + if (stat (file, &st) < 0) + return -1; + + *timer = st.st_mtime; + + return 0; +} |