diff options
Diffstat (limited to 'login')
| -rw-r--r-- | login/pututline_r.c | 60 |
1 files changed, 35 insertions, 25 deletions
diff --git a/login/pututline_r.c b/login/pututline_r.c index 62fc83bd58..4fffbb7b38 100644 --- a/login/pututline_r.c +++ b/login/pututline_r.c @@ -60,7 +60,8 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) #if _HAVE_UT_TYPE - 0 /* Seek position to write. */ - if (utmp_data->ubuf.ut_type != id->ut_type) + if (utmp_data->loc_utmp >= sizeof (utmp) + && utmp_data->ubuf.ut_type != id->ut_type) { /* We must not overwrite the data in UTMP_DATA. */ struct utmp_data *data_tmp = alloca (sizeof (*data_tmp)); @@ -82,16 +83,6 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) } #endif - /* Find out how large the file is. */ - if (fstat (utmp_data->ut_fd, &st) < 0) - return -1; - - /* Position file correctly. */ - if (utmp_data->loc_utmp <= st.st_size - && lseek (utmp_data->ut_fd, utmp_data->loc_utmp - sizeof (struct utmp), - SEEK_SET) < 0) - return -1; - /* Try to lock the file. */ if (flock (utmp_data->ut_fd, LOCK_EX | LOCK_NB) < 0 && errno != ENOSYS) { @@ -102,20 +93,39 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) (void) flock (utmp_data->ut_fd, LOCK_EX | LOCK_NB); } - /* Write the new data. */ - if (write (utmp_data->ut_fd, id, sizeof (struct utmp)) - != sizeof (struct utmp)) - { - /* If we appended a new record this is only partially written. - Remove it. */ - if (utmp_data->loc_utmp > st.st_size) - { - (void) ftruncate (utmp_data->ut_fd, st.st_size); - utmp_data->loc_utmp = st.st_size; - } - - result = -1; - } + /* Find out how large the file is. */ + result = fstat (utmp_data->ut_fd, &st); + + if (result == 0) + /* Position file correctly. */ + if (utmp_data->loc_utmp < sizeof (struct utmp)) + /* Not located at any valid entry. Add at the end. */ + { + result = lseek (utmp_data->ut_fd, 0L, SEEK_END); + if (result == 0) + /* Where we'll be if the write succeeds. */ + utmp_data->loc_utmp = st.st_size + sizeof (struct utmp); + } + else if (utmp_data->loc_utmp <= st.st_size) + result = + lseek (utmp_data->ut_fd, utmp_data->loc_utmp - sizeof (struct utmp), + SEEK_SET); + + if (result == 0) + /* Write the new data. */ + if (write (utmp_data->ut_fd, id, sizeof (struct utmp)) + != sizeof (struct utmp)) + { + /* If we appended a new record this is only partially written. + Remove it. */ + if (utmp_data->loc_utmp > st.st_size) + { + (void) ftruncate (utmp_data->ut_fd, st.st_size); + utmp_data->loc_utmp = st.st_size; + } + + result = -1; + } /* And unlock the file. */ (void) flock (utmp_data->ut_fd, LOCK_UN); |