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Don't bother with ignoring SIGCHLD

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It added complexity, especially with the differences in behavior between
handled and ignored signals across an exec().
This commit is contained in:
Devin J. Pohly 2023-06-16 00:22:11 -05:00 committed by Leonardo Hernández
parent 9c592da01f
commit 68a17f962e
1 changed files with 32 additions and 41 deletions
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73
dwl.c
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@ -297,6 +297,7 @@ static void setmon(Client *c, Monitor *m, uint32_t newtags);
static void setpsel(struct wl_listener *listener, void *data);
static void setsel(struct wl_listener *listener, void *data);
static void setup(void);
static void sigchld(int unused);
static void spawn(const Arg *arg);
static void startdrag(struct wl_listener *listener, void *data);
static void tag(const Arg *arg);
@ -397,7 +398,6 @@ static void configurex11(struct wl_listener *listener, void *data);
static void createnotifyx11(struct wl_listener *listener, void *data);
static Atom getatom(xcb_connection_t *xc, const char *name);
static void sethints(struct wl_listener *listener, void *data);
static void sigchld(int unused);
static void xwaylandready(struct wl_listener *listener, void *data);
static struct wl_listener new_xwayland_surface = {.notify = createnotifyx11};
static struct wl_listener xwayland_ready = {.notify = xwaylandready};
@ -1963,8 +1963,6 @@ run(char *startup_cmd)
if ((child_pid = fork()) < 0)
die("startup: fork:");
if (child_pid == 0) {
sa.sa_handler = SIG_DFL;
sigaction(SIGCHLD, &sa, NULL);
dup2(piperw[0], STDIN_FILENO);
close(piperw[0]);
close(piperw[1]);
@ -2129,27 +2127,19 @@ setsel(struct wl_listener *listener, void *data)
void
setup(void)
{
struct sigaction sa_term = {.sa_flags = SA_RESTART, .sa_handler = quitsignal};
struct sigaction sa_sigchld = {
#ifdef XWAYLAND
.sa_flags = SA_RESTART,
.sa_handler = sigchld,
#else
.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT | SA_RESTART,
.sa_handler = SIG_IGN,
#endif
};
sigemptyset(&sa_term.sa_mask);
sigemptyset(&sa_sigchld.sa_mask);
/* Set up signal handlers */
struct sigaction sa = {.sa_flags = SA_RESTART, .sa_handler = sigchld};
sigemptyset(&sa.sa_mask);
sigaction(SIGCHLD, &sa, NULL);
sa.sa_handler = quitsignal;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
/* The Wayland display is managed by libwayland. It handles accepting
* clients from the Unix socket, manging Wayland globals, and so on. */
dpy = wl_display_create();
/* Set up signal handlers */
sigaction(SIGCHLD, &sa_sigchld, NULL);
sigaction(SIGINT, &sa_term, NULL);
sigaction(SIGTERM, &sa_term, NULL);
/* The backend is a wlroots feature which abstracts the underlying input and
* output hardware. The autocreate option will choose the most suitable
* backend based on the current environment, such as opening an X11 window
@ -2323,13 +2313,32 @@ setup(void)
#endif
}
void
sigchld(int unused)
{
#ifdef XWAYLAND
siginfo_t in;
/* We should be able to remove this function in favor of a simple
* struct sigaction sa = {.sa_handler = SIG_IGN};
* sigaction(SIGCHLD, &sa, NULL);
* but the Xwayland implementation in wlroots currently prevents us from
* setting our own disposition for SIGCHLD.
*/
/* WNOWAIT leaves the child in a waitable state, in case this is the
* XWayland process
*/
while (!waitid(P_ALL, 0, &in, WEXITED|WNOHANG|WNOWAIT) && in.si_pid
&& (!xwayland || in.si_pid != xwayland->server->pid))
waitpid(in.si_pid, NULL, 0);
#else
while (waitpid(-1, NULL, WNOHANG) > 0);
#endif
}
void
spawn(const Arg *arg)
{
if (fork() == 0) {
struct sigaction sa = {.sa_flags = SA_RESTART, .sa_handler = SIG_DFL};
sigemptyset(&sa.sa_mask);
sigaction(SIGCHLD, &sa, NULL);
dup2(STDERR_FILENO, STDOUT_FILENO);
setsid();
execvp(((char **)arg->v)[0], (char **)arg->v);
@ -2772,24 +2781,6 @@ sethints(struct wl_listener *listener, void *data)
}
}
void
sigchld(int unused)
{
siginfo_t in;
/* We should be able to remove this function in favor of a simple
* struct sigaction sa = {.sa_handler = SIG_IGN};
* sigaction(SIGCHLD, &sa, NULL);
* but the Xwayland implementation in wlroots currently prevents us from
* setting our own disposition for SIGCHLD.
*/
/* WNOWAIT leaves the child in a waitable state, in case this is the
* XWayland process
*/
while (!waitid(P_ALL, 0, &in, WEXITED|WNOHANG|WNOWAIT) && in.si_pid
&& (!xwayland || in.si_pid != xwayland->server->pid))
waitpid(in.si_pid, NULL, 0);
}
void
xwaylandready(struct wl_listener *listener, void *data)
{