diff options
Diffstat (limited to 'login/pututline_r.c')
| -rw-r--r-- | login/pututline_r.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/login/pututline_r.c b/login/pututline_r.c index 4c9a91fdec..42994e899f 100644 --- a/login/pututline_r.c +++ b/login/pututline_r.c @@ -58,12 +58,15 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) return -1; } -#if _HAVE_UT_TYPE - 0 - /* Seek position to write. */ - if (utmp_data->loc_utmp >= sizeof (struct utmp) - && utmp_data->ubuf.ut_type != id->ut_type) +#if _HAVE_UT_ID - 0 + /* Check whether we need to reposition. Repositioning is necessary + either if the data in UTMP_DATA is not valid or if the ids don't + match: */ + if (utmp_data->loc_utmp < (off_t) sizeof (struct utmp) + || strncmp(utmp_data->ubuf.ut_id, id->ut_id, sizeof (id->ut_id)) != 0) { - /* We must not overwrite the data in UTMP_DATA. */ + /* We must not overwrite the data in UTMP_DATA since ID may be + aliasing it. */ struct utmp_data *data_tmp = alloca (sizeof (*data_tmp)); struct utmp *dummy; @@ -77,7 +80,7 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) pointer now is at the end of the file. */ return -1; - /* Set position pointer to position after adding of the record. */ + /* Set position pointer to position behind the record. */ utmp_data->loc_utmp += sizeof (struct utmp); } } @@ -98,7 +101,7 @@ pututline_r (const struct utmp *id, struct utmp_data *utmp_data) if (result >= 0) /* Position file correctly. */ - if (utmp_data->loc_utmp < sizeof (struct utmp)) + if (utmp_data->loc_utmp < (off_t) sizeof (struct utmp)) /* Not located at any valid entry. Add at the end. */ { result = lseek (utmp_data->ut_fd, 0L, SEEK_END); |