thirdparty/util-linux
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last: should not use errx/warnx on signal handlers

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err/warn/et all are not async signal safe because they call
printf-like library functions that are never as-safe.

ctime_r is also not as-safe. you cannot use static storage
in the wrapper either, since access to it is not atomic.
This commit is contained in:
Cristian Rodríguez 2023-01-15 01:33:13 +00:00
parent 3649a3db01
commit 05bd23aade
1 changed files with 4 additions and 14 deletions
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18
login-utils/last.c
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@ -266,24 +266,14 @@ static int uread(FILE *fp, struct utmpx *u, int *quit, const char *filename)
}
#ifndef FUZZ_TARGET
/*
* Print a short date.
*/
static char *showdate(void)
{
static char s[CTIME_BUFSIZ];
ctime_r(&lastdate, s);
s[16] = 0;
return s;
}
/*
* SIGINT handler
*/
static void int_handler(int sig __attribute__((unused)))
{
errx(EXIT_FAILURE, _("Interrupted %s"), showdate());
/* can't use err on signal handler */
write(STDERR_FILENO, "Interrupted\n", sizeof("Interrupted\n")-1);
_exit(EXIT_FAILURE);
}
/*
@ -291,7 +281,7 @@ static void int_handler(int sig __attribute__((unused)))
*/
static void quit_handler(int sig __attribute__((unused)))
{
warnx(_("Interrupted %s"), showdate());
write(STDERR_FILENO, "Interrupted\n", sizeof("Interrupted\n")-1);
signal(SIGQUIT, quit_handler);
}
#endif