61 lines
1.7 KiB
C++
61 lines
1.7 KiB
C++
#include "common.hh"
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#include <charconv>
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#include <cstring>
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#include <format>
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#include <signal.h>
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#include <unistd.h>
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#if __APPLE__
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#include <sys/syscall.h>
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#endif
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LIBEXEC_HELPER(1)
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int helperMain(const char * name, std::span<char *> args) noexcept
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{
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std::string_view uidArg = args[0];
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uid_t uid;
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if (auto res = std::from_chars(uidArg.begin(), uidArg.end(), uid);
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res.ptr != uidArg.end() || res.ec != std::errc())
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{
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die("invalid uid argument");
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}
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/* The system call kill(-1, sig) sends the signal `sig' to all
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users to which the current process can send signals. So we
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switch to that uid and send a mass kill once we've done so. */
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if (setuid(uid) == -1) {
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die(std::format("setuid(): {}", strerror(errno)));
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}
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while (true) {
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#ifdef __APPLE__
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/* OSX's kill syscall takes a third parameter that, among
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other things, determines if kill(-1, signo) affects the
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calling process. In the OSX libc, it's set to true,
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which means "follow POSIX", which we don't want here */
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if (syscall(SYS_kill, -1, SIGKILL, false) == 0) {
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break;
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}
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#else
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if (kill(-1, SIGKILL) == 0) {
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break;
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}
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#endif
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if (errno == ESRCH || errno == EPERM) {
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break; /* no more processes */
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}
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if (errno != EINTR) {
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die(std::format("cannot kill processes for uid {}: {}", uid, strerror(errno)));
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}
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}
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/* !!! We should really do some check to make sure that there are
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no processes left running under `uid', but there is no portable
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way to do so (I think). The most reliable way may be `ps -eo
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uid | grep -q $uid'. */
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return 0;
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}
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