coreutils/nohup.c

   1 /* @nohup.c */
   2 #include <errno.h>
   3 #include <fcntl.h>
   4 #include <signal.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11
  12 int main(int argc, char **argv) {
  13  int outfd,tty_1,tty_2;
  14
  15  if(argc<2) {
  16   fprintf(stderr,"usage: %s utility [args...]\n",argv[0]);
  17   return 127;
  18  }
  19  tty_1=isatty(1);
  20  tty_2=isatty(2);
  21  if(tty_1 || tty_2) {
  22   outfd=open("nohup.out",O_APPEND|O_CREAT|O_WRONLY,S_IRUSR|S_IWUSR);
  23   if(outfd==-1) {
  24    char *filepath;
  25    char *homedir=getenv("HOME");
  26    if(!homedir) {
  27     fprintf(stderr,"%s: cannot get value of $HOME\n",argv[0]);
  28     return 127;
  29    }
  30    if(!(filepath=malloc(strlen(homedir)+11))) {
  31     fprintf(stderr,"%s: out of memory\n",argv[0]);
  32     return 127;
  33    }
  34    strcpy(filepath,homedir);
  35    strcat(filepath,"/nohup.out");
  36    outfd=open(filepath,O_APPEND|O_CREAT|O_WRONLY,S_IRUSR|S_IWUSR);
  37    free(filepath);
  38    if(outfd==-1) {
  39     fprintf(stderr,"%s: cannot create %s/nohup.out\n",argv[0],homedir);
  40     return 127;
  41    }
  42   }
  43   if(tty_2 && dup2(outfd,2)==-1) {
  44    fprintf(stderr,"%s: cannot redirect stderr: %s\n",argv[0],strerror(errno));
  45    return 127;
  46   }
  47   if(tty_1 && dup2(outfd,1)==-1) {
  48    fprintf(stderr,"%s: cannot redirect stdout: %s\n",argv[0],strerror(errno));
  49    return 127;
  50   }
  51  }
  52  signal(SIGHUP, SIG_IGN);
  53  execvp(argv[1], argv + 1);
  54  fprintf(stderr, "%s: cannot exec `%s': %s\n",argv[0],argv[1],strerror(errno));
  55  if(errno==ENOENT)
  56   return 127;
  57  return 126;
  58 }