/bin/kill in ubuntu22.04 has bug in killing process group

root@master:~/software/test# cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.1 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

procps 2:3.3.17-6ubuntu2

root@master:~/software/test# strace -f kill -15 -2345
execve("/usr/bin/kill", ["kill", "-15", "-2345"], 0x7ffc2eb1ba28 /* 34 vars */) = 0
brk(NULL) = 0x55ac1f787000
kill(0, SIGTERMstrace: Process 228286 detached
 <detached ...>
Terminated

when pid is not exist negative pid(-2345), then become 0

test code:
```c
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <pthread.h>

void parentProcess();
void childProcess();

static struct sigaction siga;

static void signal_handler(int sig, siginfo_t *siginfo, void *context) {
    // get pid of sender,
    pid_t sender_pid = siginfo->si_pid;

    if(sig == SIGTERM) {
        printf("TERM, from [%d]\n", (int)sender_pid);
        return;
    }

    return;
}

int main(int argc, const char *argv[])
{
 int status;
 // prepare sigaction
    siga.sa_sigaction = *signal_handler;
    siga.sa_flags |= SA_SIGINFO; // get detail info
 if(sigaction(SIGTERM, &siga, NULL) != 0) {
  printf("error sigaction()");
  return errno;
    }

 int pid = fork();

 if (pid != 0) {
  parentProcess();
  pid = wait(&status);
  printf("End of process %d: \n", pid);
  if (WIFEXITED(status)) {
   printf("The child process ended with exit(%d).\n", WEXITSTATUS(status));
  }
  if (WIFSIGNALED(status)) {
   printf("The child process ended with kill -%d.\n", WTERMSIG(status));
  }
 }
 else
  childProcess();

 return 0;
}

void parentProcess()
{
 pid_t pid = getpid();
 char prefix[] = "Parent: ";
 printf("%sPID：%d %s\n", prefix, pid, "");
}

void childProcess()
{
 pid_t pid = getpid();
 char prefix[] = "Child: ";
 printf("%sPID：%d %s\n", prefix, pid, "");
 char *args[4];

    args[0] = "kill"; // first arg is the full path to the executable
    args[1] = "-15";
 args[2] = "-2345";
 args[3] = NULL; // list of args must be NULL terminated
 execv( "/bin/kill", args );

 sleep(5);
}

```

pid equals 0, then sig is sent to every process in the process group of the calling process.

skill.c code:

```c
static void __attribute__ ((__noreturn__))
    kill_main(int argc, char **argv)
{
 int signo, i;
 long pid;
 int exitvalue = EXIT_SUCCESS;
 union sigval sigval;
 bool use_sigqueue = false;
 char *sig_option;

 static const struct option longopts[] = {
  {"list", optional_argument, NULL, 'l'},
  {"table", no_argument, NULL, 'L'},
  {"signal", required_argument, NULL, 's'},
  {"help", no_argument, NULL, 'h'},
  {"version", no_argument, NULL, 'V'},
  {"queue", required_argument, NULL, 'q'},
  {NULL, 0, NULL, 0}
 };

 setlocale (LC_ALL, "");
 bindtextdomain(PACKAGE, LOCALEDIR);
 textdomain(PACKAGE);
 atexit(close_stdout);

 if (argc < 2)
  kill_usage(stderr);

 signo = skill_sig_option(&argc, argv);
 if (signo < 0)
  signo = SIGTERM;

 opterr=0; /* suppress errors on -123 */
 while ((i = getopt_long(argc, argv, "l::Ls:hVq:", longopts, NULL)) != -1)
  switch (i) {

  case '?':
   if (!isdigit(optopt)) {
    xwarnx(_("invalid argument %c"), optopt);
    kill_usage(stderr);
   } else {
       /* Special case for signal digit negative
        * PIDs */
       pid = atoi(argv[optind-1]);
       if (kill((pid_t)pid, signo) != 0)
    exitvalue = EXIT_FAILURE;
       exit(exitvalue);
   }
   xerrx(EXIT_FAILURE, _("internal error"));
  default:
   kill_usage(stderr);
  }
}

```

maybe getopt_long parse negative pid(-2345) as opt,so pid = atoi(argv[optind-1]) become 0.