sway/sway/commands/exec_always.c
Daniel Eklöf 1dd6df6a5d sway: commands: exec: restore SIGPIPE before exec:ing
Sway ignores SIGPIPE (by installing a SIG_IGN handler), in order to
“prevent IPC from crashing Sway”.

SIG_IGN handlers are the *only* signal handlers inherited in
sub-processes. As such, we should be a good citizen and restore
the SIGPIPE handler to its default handler.

Original bug report:
https://www.mail-archive.com/debian-bugs-dist@lists.debian.org/msg1806907.html
2021-06-05 11:50:11 +02:00

106 lines
2.6 KiB
C

#define _POSIX_C_SOURCE 200809L
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
#include <signal.h>
#include "sway/commands.h"
#include "sway/config.h"
#include "sway/tree/container.h"
#include "sway/tree/root.h"
#include "sway/tree/workspace.h"
#include "log.h"
#include "stringop.h"
struct cmd_results *cmd_exec_validate(int argc, char **argv) {
struct cmd_results *error = NULL;
if ((error = checkarg(argc, argv[-1], EXPECTED_AT_LEAST, 1))) {
return error;
}
if (!config->active || config->validating) {
return cmd_results_new(CMD_DEFER, NULL);
}
return error;
}
struct cmd_results *cmd_exec_process(int argc, char **argv) {
struct cmd_results *error = NULL;
char *cmd = NULL;
if (strcmp(argv[0], "--no-startup-id") == 0) {
sway_log(SWAY_INFO, "exec switch '--no-startup-id' not supported, ignored.");
--argc; ++argv;
if ((error = checkarg(argc, argv[-1], EXPECTED_AT_LEAST, 1))) {
return error;
}
}
if (argc == 1 && (argv[0][0] == '\'' || argv[0][0] == '"')) {
cmd = strdup(argv[0]);
strip_quotes(cmd);
} else {
cmd = join_args(argv, argc);
}
sway_log(SWAY_DEBUG, "Executing %s", cmd);
int fd[2];
if (pipe(fd) != 0) {
sway_log(SWAY_ERROR, "Unable to create pipe for fork");
}
pid_t pid, child;
// Fork process
if ((pid = fork()) == 0) {
// Fork child process again
setsid();
sigset_t set;
sigemptyset(&set);
sigprocmask(SIG_SETMASK, &set, NULL);
signal(SIGPIPE, SIG_DFL);
close(fd[0]);
if ((child = fork()) == 0) {
close(fd[1]);
execlp("sh", "sh", "-c", cmd, (void *)NULL);
sway_log_errno(SWAY_ERROR, "execlp failed");
_exit(1);
}
ssize_t s = 0;
while ((size_t)s < sizeof(pid_t)) {
s += write(fd[1], ((uint8_t *)&child) + s, sizeof(pid_t) - s);
}
close(fd[1]);
_exit(0); // Close child process
} else if (pid < 0) {
free(cmd);
close(fd[0]);
close(fd[1]);
return cmd_results_new(CMD_FAILURE, "fork() failed");
}
free(cmd);
close(fd[1]); // close write
ssize_t s = 0;
while ((size_t)s < sizeof(pid_t)) {
s += read(fd[0], ((uint8_t *)&child) + s, sizeof(pid_t) - s);
}
close(fd[0]);
// cleanup child process
waitpid(pid, NULL, 0);
if (child > 0) {
sway_log(SWAY_DEBUG, "Child process created with pid %d", child);
root_record_workspace_pid(child);
} else {
return cmd_results_new(CMD_FAILURE, "Second fork() failed");
}
return cmd_results_new(CMD_SUCCESS, NULL);
}
struct cmd_results *cmd_exec_always(int argc, char **argv) {
struct cmd_results *error;
if ((error = cmd_exec_validate(argc, argv))) {
return error;
}
return cmd_exec_process(argc, argv);
}