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/*
gen_minfd.c
Author: David Mazieres <dm@lcs.mit.edu>
Contributed to be part of ssh.
Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
All rights reserved
Created: Tue Aug 22 17:22:57 1995 ylo
Last modified: Tue Aug 22 17:44:32 1995 ylo
*/
#include "includes.h"
#include <sys/resource.h>
#include "fdlim.h"
static char *self;
static void
child_test (char *fdstr)
{
int fd = atoi (fdstr);
if (fcntl (fd, F_GETFL, NULL) < 0) {
exit (1);
}
exit (0);
}
static int
run_child (char *shell, int fd)
{
char cmd[128];
int pid;
int status;
if (dup2 (0, fd) < 0) {
perror ("dup2");
return (-1);
}
sprintf (cmd, "%s -fd %d", self, fd);
fflush (stdout);
pid = fork ();
if (! pid) {
close (1); /* prevent any garbage from entering the output */
dup (2);
execlp (shell, shell, "-c", cmd, NULL);
exit (1);
}
close (fd);
if (wait (&status) != pid) {
fprintf (stderr, "wrong/no child??\n");
exit (1);
}
return (status ? -1 : 0);
}
static int
do_shell (char *shell)
{
int fd, min, max;
min = 3;
max = fdlim_get (0) - 1;
if (max < 0) {
printf ("fdlim_get: bad value\n");
exit (1);
}
if (run_child (shell, max)
&& run_child (shell, --max)) /* bizarre ultrix weirdness */
return (-1);
while (min + 1 < max) {
fd = (min + max) / 2;
if (run_child (shell, fd))
min = fd;
else
max = fd;
}
return (max);
}
int
main (int argc, char **argv)
{
int fd;
int i;
char *p;
if (argc == 3 && !strcmp (argv[1], "-fd"))
child_test (argv[2]);
self = argv[0];
fd = fdlim_get (1);
if (fd < 0) {
fprintf (stderr, "fdlim_get: bad value\n");
exit (1);
}
fdlim_set (fd);
printf ("/* maximum file descriptors = %d */\n\n", fd);
printf ("struct Min_Auth_Fd {\n"
" int fd;\n"
" char shell[32];\n"
"};\n\n"
"static struct Min_Auth_Fd mafd[] = {\n");
for (i = 1; i < argc; i++) {
fd = do_shell (argv[i]);
if ((p = strrchr (argv[i], '/')))
p++;
else
p = argv[i];
if (fd > 0)
printf (" { %d, \"%s\" },\n", fd, p);
}
printf (" { 0, \"\" },\n};\n\n"
"#define MAFD_MAX (sizeof (mafd) / sizeof (mafd[0]) - 1)\n");
return (0);
}
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