1 76193d7c 2003-09-30 devnull #include <fcntl.h>
  2 76193d7c 2003-09-30 devnull #include <unistd.h>
  3 76193d7c 2003-09-30 devnull #include "threadimpl.h"
  4 76193d7c 2003-09-30 devnull 
  5 5a8e63b2 2004-02-29 devnull static void efork(int[3], int[2], char*, char**);
  6 76193d7c 2003-09-30 devnull void
  7 5a8e63b2 2004-02-29 devnull threadexec(Channel *pidc, int fd[3], char *prog, char *args[])
  8 76193d7c 2003-09-30 devnull {
  9 5a8e63b2 2004-02-29 devnull 	int pfd[2];
 10 5a8e63b2 2004-02-29 devnull 	int n, pid;
 11 5a8e63b2 2004-02-29 devnull 	char exitstr[ERRMAX];
 12 76193d7c 2003-09-30 devnull 
 13 5a8e63b2 2004-02-29 devnull 	_threaddebug(DBGEXEC, "threadexec %s", prog);
 14 5a8e63b2 2004-02-29 devnull 	
 15 76193d7c 2003-09-30 devnull 	/*
 16 5a8e63b2 2004-02-29 devnull 	 * We want threadexec to behave like exec; if exec succeeds,
 17 76193d7c 2003-09-30 devnull 	 * never return, and if it fails, return with errstr set.
 18 76193d7c 2003-09-30 devnull 	 * Unfortunately, the exec happens in another proc since
 19 76193d7c 2003-09-30 devnull 	 * we have to wait for the exec'ed process to finish.
 20 76193d7c 2003-09-30 devnull 	 * To provide the semantics, we open a pipe with the 
 21 76193d7c 2003-09-30 devnull 	 * write end close-on-exec and hand it to the proc that
 22 76193d7c 2003-09-30 devnull 	 * is doing the exec.  If the exec succeeds, the pipe will
 23 76193d7c 2003-09-30 devnull 	 * close so that our read below fails.  If the exec fails,
 24 76193d7c 2003-09-30 devnull 	 * then the proc doing the exec sends the errstr down the
 25 76193d7c 2003-09-30 devnull 	 * pipe to us.
 26 76193d7c 2003-09-30 devnull 	 */
 27 5a8e63b2 2004-02-29 devnull 	if(pipe(pfd) < 0)
 28 76193d7c 2003-09-30 devnull 		goto Bad;
 29 5a8e63b2 2004-02-29 devnull 	if(fcntl(pfd[0], F_SETFD, 1) < 0)
 30 912fba95 2003-11-24 devnull 		goto Bad;
 31 5a8e63b2 2004-02-29 devnull 	if(fcntl(pfd[1], F_SETFD, 1) < 0)
 32 76193d7c 2003-09-30 devnull 		goto Bad;
 33 76193d7c 2003-09-30 devnull 
 34 5a8e63b2 2004-02-29 devnull 	switch(pid = fork()){
 35 5a8e63b2 2004-02-29 devnull 	case -1:
 36 5a8e63b2 2004-02-29 devnull 		close(pfd[0]);
 37 5a8e63b2 2004-02-29 devnull 		close(pfd[1]);
 38 5a8e63b2 2004-02-29 devnull 		goto Bad;
 39 5a8e63b2 2004-02-29 devnull 	case 0:
 40 5a8e63b2 2004-02-29 devnull 		efork(fd, pfd, prog, args);
 41 5a8e63b2 2004-02-29 devnull 		_exit(0);
 42 5a8e63b2 2004-02-29 devnull 	default:
 43 5a8e63b2 2004-02-29 devnull 		break;
 44 5a8e63b2 2004-02-29 devnull 	}
 45 76193d7c 2003-09-30 devnull 
 46 5a8e63b2 2004-02-29 devnull 	close(pfd[1]);
 47 5a8e63b2 2004-02-29 devnull 	if((n = read(pfd[0], exitstr, ERRMAX-1)) > 0){	/* exec failed */
 48 5a8e63b2 2004-02-29 devnull 		exitstr[n] = '\0';
 49 5a8e63b2 2004-02-29 devnull 		errstr(exitstr, ERRMAX);
 50 5a8e63b2 2004-02-29 devnull 		close(pfd[0]);
 51 76193d7c 2003-09-30 devnull 		goto Bad;
 52 76193d7c 2003-09-30 devnull 	}
 53 5a8e63b2 2004-02-29 devnull 	close(pfd[0]);
 54 32f69c36 2003-12-11 devnull 	close(fd[0]);
 55 32f69c36 2003-12-11 devnull 	if(fd[1] != fd[0])
 56 32f69c36 2003-12-11 devnull 		close(fd[1]);
 57 32f69c36 2003-12-11 devnull 	if(fd[2] != fd[1] && fd[2] != fd[0])
 58 32f69c36 2003-12-11 devnull 		close(fd[2]);
 59 76193d7c 2003-09-30 devnull 	if(pidc)
 60 5a8e63b2 2004-02-29 devnull 		sendul(pidc, pid);
 61 76193d7c 2003-09-30 devnull 
 62 5a8e63b2 2004-02-29 devnull 	_threaddebug(DBGEXEC, "threadexec schedexecwait");
 63 5a8e63b2 2004-02-29 devnull 	threadexits(0);
 64 76193d7c 2003-09-30 devnull 
 65 5a8e63b2 2004-02-29 devnull Bad:
 66 5a8e63b2 2004-02-29 devnull 	_threaddebug(DBGEXEC, "threadexec bad %r");
 67 5a8e63b2 2004-02-29 devnull 	if(pidc)
 68 5a8e63b2 2004-02-29 devnull 		sendul(pidc, ~0);
 69 76193d7c 2003-09-30 devnull }
 70 76193d7c 2003-09-30 devnull 
 71 76193d7c 2003-09-30 devnull void
 72 5a8e63b2 2004-02-29 devnull threadexecl(Channel *pidc, int fd[3], char *f, ...)
 73 76193d7c 2003-09-30 devnull {
 74 5a8e63b2 2004-02-29 devnull 	threadexec(pidc, fd, f, &f+1);
 75 76193d7c 2003-09-30 devnull }
 76 76193d7c 2003-09-30 devnull 
 77 76193d7c 2003-09-30 devnull static void
 78 5a8e63b2 2004-02-29 devnull efork(int stdfd[3], int fd[2], char *prog, char **args)
 79 76193d7c 2003-09-30 devnull {
 80 76193d7c 2003-09-30 devnull 	char buf[ERRMAX];
 81 32f69c36 2003-12-11 devnull 	int i;
 82 76193d7c 2003-09-30 devnull 
 83 5a8e63b2 2004-02-29 devnull 	_threaddebug(DBGEXEC, "_schedexec %s -- calling execv", prog);
 84 5a8e63b2 2004-02-29 devnull 	dup(stdfd[0], 0);
 85 5a8e63b2 2004-02-29 devnull 	dup(stdfd[1], 1);
 86 5a8e63b2 2004-02-29 devnull 	dup(stdfd[2], 2);
 87 32f69c36 2003-12-11 devnull 	for(i=3; i<40; i++)
 88 5a8e63b2 2004-02-29 devnull 		if(i != fd[1])
 89 32f69c36 2003-12-11 devnull 			close(i);
 90 49588d5d 2003-12-17 devnull 	rfork(RFNOTEG);
 91 5a8e63b2 2004-02-29 devnull 	execvp(prog, args);
 92 76193d7c 2003-09-30 devnull 	_threaddebug(DBGEXEC, "_schedexec failed: %r");
 93 76193d7c 2003-09-30 devnull 	rerrstr(buf, sizeof buf);
 94 76193d7c 2003-09-30 devnull 	if(buf[0]=='\0')
 95 76193d7c 2003-09-30 devnull 		strcpy(buf, "exec failed");
 96 5a8e63b2 2004-02-29 devnull 	write(fd[1], buf, strlen(buf));
 97 5a8e63b2 2004-02-29 devnull 	close(fd[1]);
 98 76193d7c 2003-09-30 devnull 	_exits(buf);
 99 76193d7c 2003-09-30 devnull }
100 76193d7c 2003-09-30 devnull