envuidgid.c

#include <sys/types.h>
#include <pwd.h>
#include "fmt.h"
#include "strerr.h"
#include "pathexec.h"

#define FATAL "envuidgid: fatal: "

void nomem(void)
{
  strerr_die2x(111,FATAL,"out of memory");
}

char strnum[FMT_ULONG];
const char *account;
struct passwd *pw;

int main(int argc,const char *const *argv)
{
  account = *++argv;
  if (!account || !*++argv)
    strerr_die1x(100,"envuidgid: usage: envuidgid account child");

  pw = getpwnam(account);
  if (!pw)
    strerr_die3x(111,FATAL,"unknown account ",account);

  strnum[fmt_ulong(strnum,pw->pw_gid)] = 0;
  if (!pathexec_env("GID",strnum)) nomem();
  strnum[fmt_ulong(strnum,pw->pw_uid)] = 0;
  if (!pathexec_env("UID",strnum)) nomem();

  pathexec(argv);
  strerr_die3sys(111,FATAL,"unable to run ",*argv);
}