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Addressed the issues raised by splint and flawfinder, with a TODO for a better cleanup for one issue.

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This commit is contained in:
Andrew Wood
2023-09-09 21:14:01 +01:00
parent e8dab7daf7
commit b0a67878bb
1 changed files with 131 additions and 53 deletions
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src/pv/signal.c
+131 -53
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@@ -22,7 +22,7 @@
void pv_crs_needreinit(pvstate_t);
#endif
static pvstate_t pv_sig_state = NULL;
/*@null@*/ static pvstate_t pv_sig_state = NULL;
/*
@@ -34,6 +34,9 @@ static void pv_sig_ensure_tty_tostop()
{
struct termios terminal_attributes;
if (NULL == pv_sig_state)
return;
if (0 != tcgetattr(STDERR_FILENO, &terminal_attributes)) {
debug("%s: %s", "failed to read terminal attributes", strerror(errno));
return;
@@ -66,20 +69,39 @@ static void pv_sig_ensure_tty_tostop()
* subsequent SIGCONT we can try writing to the terminal again, in case we
* get backgrounded and later get foregrounded again.
*/
static void pv_sig_ttou( __attribute__((unused))
static void pv_sig_ttou( /*@unused@ */ __attribute__((unused))
int s)
{
int fd;
fd = open("/dev/null", O_RDWR);
if (fd < 0)
if (NULL == pv_sig_state)
return;
fd = open("/dev/null", O_RDWR); /* flawfinder: ignore */
if (fd < 0) {
debug("%s: %s", "failed to open /dev/null", strerror(errno));
return;
}
/*
* flawfinder rationale: not checking for symlinks because this is
* explicitly a device file under /dev so we assume it is safe to
* open.
*
* TODO: look at just preventing stderr output instead of writing to
* stderr while backgrounded.
*/
if (-1 == pv_sig_state->pv_sig_old_stderr)
pv_sig_state->pv_sig_old_stderr = dup(STDERR_FILENO);
dup2(fd, STDERR_FILENO);
close(fd);
if (dup2(fd, STDERR_FILENO) < 0) {
debug("%s: %s", "failed to replace stderr", strerror(errno));
}
if (0 != close(fd)) {
debug("%s: %s", "failed to close /dev/null", strerror(errno));
}
}
@@ -87,11 +109,15 @@ static void pv_sig_ttou( __attribute__((unused))
* Handle SIGTSTP (stop typed at tty) by storing the time the signal
* happened for later use by pv_sig_cont(), and then stopping the process.
*/
static void pv_sig_tstp( __attribute__((unused))
static void pv_sig_tstp( /*@unused@ */ __attribute__((unused))
int s)
{
if (NULL == pv_sig_state)
return;
pv_elapsedtime_read(&(pv_sig_state->pv_sig_tstp_time));
raise(SIGSTOP);
if (0 != raise(SIGSTOP)) {
debug("%s: %s", "raise", strerror(errno));
}
}
@@ -100,12 +126,15 @@ static void pv_sig_tstp( __attribute__((unused))
* last SIGTSTP to the elapsed time offset, and by trying to write to the
* terminal again (by replacing the /dev/null stderr with the old stderr).
*/
static void pv_sig_cont( __attribute__((unused))
static void pv_sig_cont( /*@unused@ */ __attribute__((unused))
int s)
{
struct timespec current_time;
struct timespec time_spent_stopped;
if (NULL == pv_sig_state)
return;
pv_sig_state->pv_sig_newsize = 1;
/*
@@ -114,6 +143,9 @@ static void pv_sig_cont( __attribute__((unused))
*/
if (0 != pv_sig_state->pv_sig_tstp_time.tv_sec) {
memset(&current_time, 0, sizeof(current_time));
memset(&time_spent_stopped, 0, sizeof(time_spent_stopped));
pv_elapsedtime_read(&current_time);
/* time spent stopped = current time - time SIGTSTP received */
@@ -131,8 +163,12 @@ static void pv_sig_cont( __attribute__((unused))
* Restore the old stderr, if we had replaced it.
*/
if (pv_sig_state->pv_sig_old_stderr != -1) {
dup2(pv_sig_state->pv_sig_old_stderr, STDERR_FILENO);
close(pv_sig_state->pv_sig_old_stderr);
if (dup2(pv_sig_state->pv_sig_old_stderr, STDERR_FILENO) < 0) {
debug("%s: %s", "failed to restore old stderr", strerror(errno));
}
if (0 != close(pv_sig_state->pv_sig_old_stderr)) {
debug("%s: %s", "failed to close duplicate old stderr", strerror(errno));
}
pv_sig_state->pv_sig_old_stderr = -1;
}
@@ -144,22 +180,28 @@ static void pv_sig_cont( __attribute__((unused))
}
#ifdef SIGWINCH
/*
* Handle SIGWINCH (window size changed) by setting a flag.
*/
static void pv_sig_winch( __attribute__((unused))
static void pv_sig_winch( /*@unused@ */ __attribute__((unused))
int s)
{
if (NULL == pv_sig_state)
return;
pv_sig_state->pv_sig_newsize = 1;
}
#endif
/*
* Handle termination signals by setting the abort flag.
*/
static void pv_sig_term( __attribute__((unused))
static void pv_sig_term( /*@unused@ */ __attribute__((unused))
int s)
{
if (NULL == pv_sig_state)
return;
pv_sig_state->pv_sig_abort = 1;
}
@@ -169,7 +211,16 @@ static void pv_sig_term( __attribute__((unused))
*/
void pv_sig_init(pvstate_t state)
{
struct sigaction sa;
static struct sigaction sa;
memset(&sa, 0, sizeof(sa));
/*
* Note that wherever we use a "struct sigaction", we declare it
* static and explicitly zero it before use, because it may contain
* deeper structures (e.g. "sigset_t") which trigger splint
* warnings about potential memory leaks.
*/
pv_sig_state = state;
@@ -177,32 +228,38 @@ void pv_sig_init(pvstate_t state)
pv_elapsedtime_zero(&(pv_sig_state->pv_sig_tstp_time));
pv_elapsedtime_zero(&(pv_sig_state->pv_sig_toffset));
/*
* Note that we cast all sigemptyset() and sigaction() return values
* to void, because there's nothing we can reasonably do about any
* conceivable error they may return.
*/
/*
* Ignore SIGPIPE, so we don't die if stdout is a pipe and the other
* end closes unexpectedly.
*/
sa.sa_handler = SIG_IGN;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGPIPE, &sa, &(pv_sig_state->pv_sig_old_sigpipe));
(void) sigaction(SIGPIPE, &sa, &(pv_sig_state->pv_sig_old_sigpipe));
/*
* Handle SIGTTOU by continuing with output switched off, so that we
* can be stopped and backgrounded without messing up the terminal.
*/
sa.sa_handler = pv_sig_ttou;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGTTOU, &sa, &(pv_sig_state->pv_sig_old_sigttou));
(void) sigaction(SIGTTOU, &sa, &(pv_sig_state->pv_sig_old_sigttou));
/*
* Handle SIGTSTP by storing the time the signal happened for later
* use by pv_sig_cont(), and then stopping the process.
*/
sa.sa_handler = pv_sig_tstp;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGTSTP, &sa, &(pv_sig_state->pv_sig_old_sigtstp));
(void) sigaction(SIGTSTP, &sa, &(pv_sig_state->pv_sig_old_sigtstp));
/*
* Handle SIGCONT by adding the elapsed time since the last SIGTSTP
@@ -210,37 +267,39 @@ void pv_sig_init(pvstate_t state)
* terminal again.
*/
sa.sa_handler = pv_sig_cont;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGCONT, &sa, &(pv_sig_state->pv_sig_old_sigcont));
(void) sigaction(SIGCONT, &sa, &(pv_sig_state->pv_sig_old_sigcont));
/*
* Handle SIGWINCH by setting a flag to let the main loop know it
* has to reread the terminal size.
*/
#ifdef SIGWINCH
sa.sa_handler = pv_sig_winch;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGWINCH, &sa, &(pv_sig_state->pv_sig_old_sigwinch));
(void) sigaction(SIGWINCH, &sa, &(pv_sig_state->pv_sig_old_sigwinch));
#endif
/*
* Handle SIGINT, SIGHUP, SIGTERM by setting a flag to let the
* main loop know it should quit now.
*/
sa.sa_handler = pv_sig_term;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGINT, &sa, &(pv_sig_state->pv_sig_old_sigint));
(void) sigaction(SIGINT, &sa, &(pv_sig_state->pv_sig_old_sigint));
sa.sa_handler = pv_sig_term;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGHUP, &sa, &(pv_sig_state->pv_sig_old_sighup));
(void) sigaction(SIGHUP, &sa, &(pv_sig_state->pv_sig_old_sighup));
sa.sa_handler = pv_sig_term;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGTERM, &sa, &(pv_sig_state->pv_sig_old_sigterm));
(void) sigaction(SIGTERM, &sa, &(pv_sig_state->pv_sig_old_sigterm));
/*
* Ensure that the TOSTOP terminal attribute is set, so that a
@@ -257,18 +316,23 @@ void pv_sig_init(pvstate_t state)
* cursor "-c" mode, only do that if we're the last PV instance, otherwise
* leave the terminal alone).
*/
void pv_sig_fini( __attribute__((unused)) pvstate_t state)
void pv_sig_fini( /*@unused@ */ __attribute__((unused)) pvstate_t state)
{
bool need_to_clear_tostop = false;
sigaction(SIGPIPE, &(pv_sig_state->pv_sig_old_sigpipe), NULL);
sigaction(SIGTTOU, &(pv_sig_state->pv_sig_old_sigttou), NULL);
sigaction(SIGTSTP, &(pv_sig_state->pv_sig_old_sigtstp), NULL);
sigaction(SIGCONT, &(pv_sig_state->pv_sig_old_sigcont), NULL);
sigaction(SIGWINCH, &(pv_sig_state->pv_sig_old_sigwinch), NULL);
sigaction(SIGINT, &(pv_sig_state->pv_sig_old_sigint), NULL);
sigaction(SIGHUP, &(pv_sig_state->pv_sig_old_sighup), NULL);
sigaction(SIGTERM, &(pv_sig_state->pv_sig_old_sigterm), NULL);
if (NULL == pv_sig_state)
return;
(void) sigaction(SIGPIPE, &(pv_sig_state->pv_sig_old_sigpipe), NULL);
(void) sigaction(SIGTTOU, &(pv_sig_state->pv_sig_old_sigttou), NULL);
(void) sigaction(SIGTSTP, &(pv_sig_state->pv_sig_old_sigtstp), NULL);
(void) sigaction(SIGCONT, &(pv_sig_state->pv_sig_old_sigcont), NULL);
#ifdef SIGWINCH
(void) sigaction(SIGWINCH, &(pv_sig_state->pv_sig_old_sigwinch), NULL);
#endif
(void) sigaction(SIGINT, &(pv_sig_state->pv_sig_old_sigint), NULL);
(void) sigaction(SIGHUP, &(pv_sig_state->pv_sig_old_sighup), NULL);
(void) sigaction(SIGTERM, &(pv_sig_state->pv_sig_old_sigterm), NULL);
need_to_clear_tostop = pv_sig_state->pv_tty_tostop_added;
@@ -300,8 +364,9 @@ void pv_sig_fini( __attribute__((unused)) pvstate_t state)
debug("%s", "about to to clear TOSTOP terminal attribute if it is set");
tcgetattr(STDERR_FILENO, &terminal_attributes);
if (0 != (terminal_attributes.c_lflag & TOSTOP)) {
if (0 != tcgetattr(STDERR_FILENO, &terminal_attributes)) {
debug("%s: %s", "tcgetattr", strerror(errno));
} else if (0 != (terminal_attributes.c_lflag & TOSTOP)) {
terminal_attributes.c_lflag -= TOSTOP;
if (0 == tcsetattr(STDERR_FILENO, TCSANOW, &terminal_attributes)) {
debug("%s", "cleared TOSTOP terminal attribute");
@@ -320,17 +385,19 @@ void pv_sig_fini( __attribute__((unused)) pvstate_t state)
*/
void pv_sig_nopause(void)
{
struct sigaction sa;
static struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_IGN;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGTSTP, &sa, NULL);
(void) sigaction(SIGTSTP, &sa, NULL);
sa.sa_handler = SIG_DFL;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGCONT, &sa, NULL);
(void) sigaction(SIGCONT, &sa, NULL);
}
@@ -339,17 +406,19 @@ void pv_sig_nopause(void)
*/
void pv_sig_allowpause(void)
{
struct sigaction sa;
static struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = pv_sig_tstp;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGTSTP, &sa, NULL);
(void) sigaction(SIGTSTP, &sa, NULL);
sa.sa_handler = pv_sig_cont;
sigemptyset(&(sa.sa_mask));
(void) sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGCONT, &sa, NULL);
(void) sigaction(SIGCONT, &sa, NULL);
}
@@ -363,6 +432,9 @@ void pv_sig_checkbg(void)
{
static time_t next_check = 0;
if (NULL == pv_sig_state)
return;
if (time(NULL) < next_check)
return;
@@ -371,8 +443,14 @@ void pv_sig_checkbg(void)
if (-1 == pv_sig_state->pv_sig_old_stderr)
return;
dup2(pv_sig_state->pv_sig_old_stderr, STDERR_FILENO);
close(pv_sig_state->pv_sig_old_stderr);
if (dup2(pv_sig_state->pv_sig_old_stderr, STDERR_FILENO) < 0) {
debug("%s: %s", "failed to restore old stderr", strerror(errno));
}
if (0 != close(pv_sig_state->pv_sig_old_stderr)) {
debug("%s: %s", "failed to close duplicate old stderr", strerror(errno));
}
pv_sig_state->pv_sig_old_stderr = -1;
pv_sig_ensure_tty_tostop();