UNIX

strindex(s, t) /* return index of t in s, -1 if none */

 char *s, *t;

{

 int i, n;

 n = strlen(t);

 for (i = 0; s[i] != '\0'; i++)

  if (strncmp(s+i, t, n) == 0)

   return i;

 return -1;

}

3.8.51 sv.c

/* sv: save new files */

#include

#include

#include

#include

char *progname;

main(argc, argv)

 int argc;

 char *argv[];

{

 int i;

 struct stat stbuf;

 char *dir = argv[argc-1];

 progname = argv[0];

 if (argc <= 2)

  error ("Usage: %s files... dir", progname);

 if (stat(dir, festbuf) == -1)

  error("can't access directory %s", dir);

 if ((stbuf.st_mode & S_IFMT) != S_IFDIR)

  error("%s is not a directory", dir);

 for (i = 1; i < argc-1; i++)

  sv(argv[i], dir);

 exit(0);

}

sv(file, dir) /* save file in dir */

 char *file, *dir;

{

 struct stat sti, sto;

 int fin, fout, n;

 char target[BUFSIZ], buf[BUFSIZ], *index();

 sprintf(target, "%s/%s", dir, file);

 if (index(file, '/') != NULL) /* strchr() in some systems */

  error("won't handle '/'s in %s", file);

 if (stat(file, &sti) == -1)

  error("can't stat %s", file);

 if (stat(target, &sto) == -1) /* target not present */

  sto.st_mtime = 0; /* so make it look old */

 if (sti.st_mtime < sto.st_mtime) /* target is newer */

  fprintf(stderr, "%s: %s not copied\n", progname, file);

 else if ((fin = open(file, 0)) == -1)

  error("can't open file %s", file);

 else if ((fout = creat(target, sti.st_mode)) == -1)

  error("can't create %s", target);

 while ((n = read(fin, buf, sizeof buf)) > 0)

  if (write(fout, buf, n) != n)

   error("error writing %s", target);

 close(fin);

 close(fout);

}

#include "error.c"

3.8.52 system1.c

#include

system(s) /* run command line s */

 char *s;

{

 int status, pid, w, tty;

 int (*istat)(), (*qstat)();

 ...

 if ((pid = fork()) == 0) {

  ...

  execlp("sh", "sh", "-c", s, (char*)0);

  exit(127);

 }

 ...

 istat = signal(SIGINT, SIG_IGN);

 qstat = signal(SIGQUIT, SIG_IGN);

 while ((w = wait(&status)) != pid && w != -1)

  ;

 if (w == -1)

  status = -1;

 signal(SIGINT, istat);

 signal(SIGQUIT, qstat);

 return status;

}

3.8.53 system.c

/*

 * Safer version of system for interactive programs

 */

#include

#include

system(s) /* run command line s */

 char *s;

{

 int status, pid, w, tty;

 int (*istat)(), (*qstat)();

 extern char *progname;

 fflush(stdout);

 tty = open("/dev/tty", 2);

 if (tty == -1) {

  fprintf (stderr, "%s: can't open /dev/tty\n", progname);

  return -1;

 }

 if ((pid = fork()) == 0) {

  close(0);

  dup(tty);

  close(1);

  dup(tty);

  close(2);

  dup(tty);

  close(tty);

  execlp("sh", "sh", "-c", s, (char*)0);

  exit(127);

 }

 close(tty);

 istat = signal(SIGINT, SIG_IGN);

 qstat = signal(SIGQUIT, SIG_IGN);

 while ((w = wait(&status)) != pid && w != -1)

  ;

 if (w == -1)

  status = -1;

 signal(SIGINT, istat);

 signal(SIGQUIT, qstat);