diff options
Diffstat (limited to 'src/basic/process-util.c')
-rw-r--r-- | src/basic/process-util.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/src/basic/process-util.c b/src/basic/process-util.c index 01c73cfa64..f91e2a49ce 100644 --- a/src/basic/process-util.c +++ b/src/basic/process-util.c @@ -1271,6 +1271,77 @@ int safe_fork_full( return 0; } +int fork_agent(const char *name, const int except[], unsigned n_except, pid_t *ret_pid, const char *path, ...) { + bool stdout_is_tty, stderr_is_tty; + unsigned n, i; + va_list ap; + char **l; + int r; + + assert(path); + + /* Spawns a temporary TTY agent, making sure it goes away when we go away */ + + r = safe_fork_full(name, except, n_except, FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, ret_pid); + if (r < 0) + return r; + if (r > 0) + return 0; + + /* In the child: */ + + stdout_is_tty = isatty(STDOUT_FILENO); + stderr_is_tty = isatty(STDERR_FILENO); + + if (!stdout_is_tty || !stderr_is_tty) { + int fd; + + /* Detach from stdout/stderr. and reopen + * /dev/tty for them. This is important to + * ensure that when systemctl is started via + * popen() or a similar call that expects to + * read EOF we actually do generate EOF and + * not delay this indefinitely by because we + * keep an unused copy of stdin around. */ + fd = open("/dev/tty", O_WRONLY); + if (fd < 0) { + log_error_errno(errno, "Failed to open /dev/tty: %m"); + _exit(EXIT_FAILURE); + } + + if (!stdout_is_tty && dup2(fd, STDOUT_FILENO) < 0) { + log_error_errno(errno, "Failed to dup2 /dev/tty: %m"); + _exit(EXIT_FAILURE); + } + + if (!stderr_is_tty && dup2(fd, STDERR_FILENO) < 0) { + log_error_errno(errno, "Failed to dup2 /dev/tty: %m"); + _exit(EXIT_FAILURE); + } + + if (fd > STDERR_FILENO) + close(fd); + } + + /* Count arguments */ + va_start(ap, path); + for (n = 0; va_arg(ap, char*); n++) + ; + va_end(ap); + + /* Allocate strv */ + l = alloca(sizeof(char *) * (n + 1)); + + /* Fill in arguments */ + va_start(ap, path); + for (i = 0; i <= n; i++) + l[i] = va_arg(ap, char*); + va_end(ap); + + execv(path, l); + _exit(EXIT_FAILURE); +} + static const char *const ioprio_class_table[] = { [IOPRIO_CLASS_NONE] = "none", [IOPRIO_CLASS_RT] = "realtime", |