[email protected], le dim. 28 sept. 2025 19:17:16 +0100, a ecrit:
> From: Diego Nieto Cid <[email protected]>
>
> ../../daemons/getty.c: In function 'main':
> ../../daemons/getty.c:184:3: warning: ignoring return value of 'asprintf'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 184 | asprintf (&ttyname, "%s/%s", _PATH_DEV, argv[2]);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../daemons/getty.c:186:3: warning: ignoring return value of 'chown'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 186 | chown (ttyname, 0, 0);
> | ^~~~~~~~~~~~~~~~~~~~~
> ../../daemons/getty.c:188:3: warning: ignoring return value of 'revoke'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 188 | revoke (ttyname);
> | ^~~~~~~~~~~~~~~~
> ../../daemons/getty.c:210:3: warning: ignoring return value of 'asprintf'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 210 | asprintf (&arg, "TERM=%s", tt ? tt->ty_type : "unknown");
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../daemons/getty.c: In function 'print_banner':
> ../../daemons/getty.c:120:3: warning: ignoring return value of 'write'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 120 | write (fd, "\r\n", 2);
> | ^~~~~~~~~~~~~~~~~~~~~
> ../../daemons/getty.c:125:7: warning: ignoring return value of 'write'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 125 | write (fd, s, t - s);
> | ^~~~~~~~~~~~~~~~~~~~
> ../../daemons/getty.c:149:7: warning: ignoring return value of 'write'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 149 | write (fd, expansion, strlen (expansion));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> =======================================================================
>
> ../../daemons/lmail.c: In function 'deliver':
> ../../daemons/lmail.c:344:3: warning: ignoring return value of 'asprintf'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 344 | asprintf (&mbox, "%s/%s", params->mail_dir, rcpt);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> =======================================================================
>
> ../../daemons/runttys.c: In function 'setup_terminal':
> ../../daemons/runttys.c:105:7: warning: ignoring return value of
> 'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
> 105 | asprintf (&line, "%s %s", tt->ty_getty, tt->ty_name);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../daemons/runttys.c: In function 'shutdown_terminal':
> ../../daemons/runttys.c:323:3: warning: ignoring return value of 'revoke'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 323 | revoke (t->name);
> | ^~~~~~~~~~~~~~~~
> ../../daemons/runttys.c: In function 'main':
> ../../daemons/runttys.c:474:7: warning: ignoring return value of 'write'
> declared with attribute 'warn_unused_result' [-Wunused-result]
> 474 | write (2, "", 0);
> | ^~~~~~~~~~~~~~~~
> ---
> daemons/getty.c | 52 +++++++++++++++++++++++++++++++++++++++--------
> daemons/lmail.c | 4 ++--
> daemons/runttys.c | 11 ++++++----
> 3 files changed, 53 insertions(+), 14 deletions(-)
>
> diff --git a/daemons/getty.c b/daemons/getty.c
> index b5b162d5..02ea414a 100644
> --- a/daemons/getty.c
> +++ b/daemons/getty.c
> @@ -35,6 +35,7 @@
> #include <utmp.h>
> #include <sys/ioctl.h>
> #include <termios.h>
> +#include <assert-backtrace.h>
>
> /* XXX: should include directly from libshouldbeinlibc */
> extern char *localhost (void);
> @@ -111,18 +112,21 @@ load_banner (void)
> static void
> print_banner (int fd, char *ttyname)
> {
> + ssize_t err;
> char *s, *t, *expansion;
> struct utsname u;
>
> if (uname (&u))
> u.sysname[0] = u.release[0] = '\0';
>
> - write (fd, "\r\n", 2);
> + err = write (fd, "\r\n", 2);
> + assert_backtrace (err != -1);
> for (s = load_banner (); *s; s++)
> {
> for (t = s; *t && *t != '\\'; t++) /* nomnomnom */;
>
> - write (fd, s, t - s);
> + err = write (fd, s, t - s);
> + assert_backtrace (err != -1);
You actually want to check that the return value is the number of bytes
that you have passed, otherwise we had a short-write. That'd be
surprising for a tty (normally it would just block), but better be safe
than risk losing characters.
> if (! *t)
> return;
>
> @@ -146,7 +150,8 @@ print_banner (int fd, char *ttyname)
> default:
> expansion = "?";
> }
> - write (fd, expansion, strlen (expansion));
> + err = write (fd, expansion, strlen (expansion));
> + assert_backtrace (err != -1);
>
> s = t + 1;
> }
> @@ -155,6 +160,7 @@ print_banner (int fd, char *ttyname)
> int
> main (int argc, char **argv)
> {
> + int err;
> char *linespec, *ttyname;
> int tty;
> struct ttyent *tt;
> @@ -174,11 +180,35 @@ main (int argc, char **argv)
> linespec = argv[1];
>
> tt = getttynam (argv[2]);
> - asprintf (&ttyname, "%s/%s", _PATH_DEV, argv[2]);
> + err = asprintf (&ttyname, "%s/%s", _PATH_DEV, argv[2]);
> + if (err == -1)
> + {
> + syslog (LOG_ERR, "asprintf failed %s: %m", argv[2]);
> + closelog ();
> + exit (1);
> + }
>
> - chown (ttyname, 0, 0);
> - chmod (ttyname, 0600);
> - revoke (ttyname);
> + err = chown (ttyname, 0, 0);
> + if (err == -1)
> + {
> + syslog (LOG_ERR, "chown failed %s: %m", ttyname);
> + closelog ();
> + exit (1);
> + }
> + err = chmod (ttyname, 0600);
> + if (err == -1)
> + {
> + syslog (LOG_ERR, "chmod failed %s: %m", ttyname);
> + closelog ();
> + exit (1);
> + }
> + err = revoke (ttyname);
> + if (err == -1)
> + {
> + syslog (LOG_ERR, "revoke failed %s; %m", ttyname);
> + closelog ();
> + exit (1);
> + }
> sleep (2); /* leave DTR down for a bit */
>
> do
> @@ -200,7 +230,13 @@ main (int argc, char **argv)
> if (login_tty (tty) == -1)
> syslog (LOG_ERR, "cannot set controlling terminal to %s: %m", ttyname);
>
> - asprintf (&arg, "TERM=%s", tt ? tt->ty_type : "unknown");
> + err = asprintf (&arg, "TERM=%s", tt ? tt->ty_type : "unknown");
> + if (err == -1)
> + {
> + syslog (LOG_ERR, "asprintf failed %s: %m", ttyname);
> + closelog ();
> + exit (1);
> + }
>
> if (tt && strcmp (tt->ty_type, "dialup") == 0)
> /* Dialup lines time out (which is login's default). */
> diff --git a/daemons/lmail.c b/daemons/lmail.c
> index ee6b6fdc..513d33f8 100644
> --- a/daemons/lmail.c
> +++ b/daemons/lmail.c
> @@ -341,8 +341,8 @@ deliver (int msg, char *msg_name, char *rcpt, int flags,
> struct params *params)
> if (! pw)
> return ERR ("%s: Unknown user", rcpt);
>
> - asprintf (&mbox, "%s/%s", params->mail_dir, rcpt);
> - if (! mbox)
> + int err = asprintf (&mbox, "%s/%s", params->mail_dir, rcpt);
> + if (err == -1)
> return SYSERRX (ENOMEM, "%s", rcpt);
>
> do
> diff --git a/daemons/runttys.c b/daemons/runttys.c
> index 1b4b3601..2eff7e7b 100644
> --- a/daemons/runttys.c
> +++ b/daemons/runttys.c
> @@ -102,8 +102,8 @@ setup_terminal (struct terminal *t, struct ttyent *tt)
> }
>
> char *line;
> - asprintf (&line, "%s %s", tt->ty_getty, tt->ty_name);
> - if (line == 0)
> + int err = asprintf (&line, "%s %s", tt->ty_getty, tt->ty_name);
> + if (err == -1)
> {
> error (0, ENOMEM,
> "cannot allocate arguments for %s", t->name);
> @@ -319,8 +319,10 @@ restart_terminal (pid_t pid)
> static void
> shutdown_terminal (struct terminal *t)
> {
> + int err;
> kill (t->pid, SIGHUP);
> - revoke (t->name);
> + err = revoke (t->name);
> + assert_backtrace (err != -1);
> }
>
> /* Re-read /etc/ttys. If a line has turned off, kill what's there.
> @@ -471,7 +473,8 @@ main (void)
> /* Elicit a SIGLOST now if the console (on our stderr, i.e. fd 2) has
> died. That way, the next error message emitted will actually make
> it out to the console if it can be made it work at all. */
> - write (2, "", 0);
> + int err = write (2, "", 0);
> + assert_backtrace (err != -1);
>
> /* If a SIGTERM or SIGHUP arrived recently, it set a flag
> and broke us out of being blocked in waitpid. */
> --
> 2.51.0
>
>
--
Samuel
La fonction memfrob() crypte les n premiers octets de la
zone de mémoire s en effectuant un OU-exclusif entre
chaque octet et le nombre 42.
(extrait de la page de man de memfrob -- Manuel du programmeur Linux)
