The getutent() calls are not thread safe, and reference documentation is recommending to copy the context of the structures if information is wished to be stored. But excessive copying does not seem to be relevant for single threaded application. Reference: http://www.gnu.org/software/libc/manual/html_node/Manipulating-the-Database.html Signed-off-by: Sami Kerola <kerolasa@xxxxxx> --- term-utils/write.c | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/term-utils/write.c b/term-utils/write.c index 1ae3c82..403d4a7 100644 --- a/term-utils/write.c +++ b/term-utils/write.c @@ -126,17 +126,15 @@ static int check_tty(char *tty, int *mesg_allowed, time_t *tty_atime, int shower */ static int check_utmp(const struct write_control *ctl) { - struct utmp u; - struct utmp *uptr; + struct utmp *u; int res = 1; utmpname(_PATH_UTMP); setutent(); - while ((uptr = getutent())) { - memcpy(&u, uptr, sizeof(u)); - if (strncmp(ctl->dst_login, u.ut_user, sizeof(u.ut_user)) == 0 && - strncmp(ctl->dst_tty, u.ut_line, sizeof(u.ut_line)) == 0) { + while ((u = getutent())) { + if (strncmp(ctl->dst_login, u->ut_user, sizeof(u->ut_user)) == 0 && + strncmp(ctl->dst_tty, u->ut_line, sizeof(u->ut_line)) == 0) { res = 0; break; } @@ -159,38 +157,34 @@ static int check_utmp(const struct write_control *ctl) */ static void search_utmp(struct write_control *ctl) { - struct utmp u; - struct utmp *uptr; + struct utmp *u; time_t best_atime = 0, tty_atime; int num_ttys = 0, valid_ttys = 0, mesg_allowed = 0, user_is_me = 0; - char atty[sizeof(u.ut_line) + 1]; utmpname(_PATH_UTMP); setutent(); - while ((uptr = getutent())) { - memcpy(&u, uptr, sizeof(u)); - if (strncmp(ctl->dst_login, u.ut_user, sizeof(u.ut_user)) == 0) { + while ((u = getutent())) { + if (strncmp(ctl->dst_login, u->ut_user, sizeof(u->ut_user)) == 0) { num_ttys++; - xstrncpy(atty, u.ut_line, sizeof(atty)); - if (check_tty(atty, &mesg_allowed, &tty_atime, 0)) + if (check_tty(u->ut_line, &mesg_allowed, &tty_atime, 0)) /* bad term? skip */ continue; if (ctl->src_uid && !mesg_allowed) /* skip ttys with msgs off */ continue; - if (strcmp(atty, ctl->src_tty) == 0) { + if (strcmp(u->ut_line, ctl->src_tty) == 0) { user_is_me = 1; /* don't write to yourself */ continue; } - if (u.ut_type != USER_PROCESS) + if (u->ut_type != USER_PROCESS) /* it's not a valid entry */ continue; valid_ttys++; if (tty_atime > best_atime) { best_atime = tty_atime; - xstrncpy(ctl->dst_tty, atty, sizeof(ctl->dst_tty)); + xstrncpy(ctl->dst_tty, u->ut_line, sizeof(ctl->dst_tty)); } } } -- 2.8.2 -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
