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/* febootstrap-supermin-helper reimplementation in C.
* Copyright (C) 2009-2010 Red Hat Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fnmatch.h>
#include <unistd.h>
#include <errno.h>
#include "error.h"
#include "xvasprintf.h"
#include "helper.h"
/* Directory containing candidate kernels. We could make this
* configurable at some point.
*/
#define KERNELDIR "/boot"
#define MODULESDIR "/lib/modules"
static char *
get_modpath (const char *kernel_name)
{
/* Ignore "vmlinuz-" at the beginning of the kernel name. */
const char *version = &kernel_name[8];
/* /lib/modules/<version> */
char *modpath = xasprintf (MODULESDIR "/%s", version);
if (!modpath) {
perror ("xasprintf");
exit (EXIT_FAILURE);
}
return modpath;
}
/* kernel_name is "vmlinuz-*". Check if there is a corresponding
* module path in /lib/modules.
*/
static int
has_modpath (const char *kernel_name)
{
char *modpath = get_modpath (kernel_name);
if (verbose)
fprintf (stderr, "checking modpath %s is a directory\n", modpath);
int r = isdir (modpath);
if (r) {
if (verbose)
fprintf (stderr, "picked %s because modpath %s exists\n",
kernel_name, modpath);
free (modpath);
return 1;
}
else {
free (modpath);
return 0;
}
}
static char *create_kernel_archlinux (const char *hostcpu, const char *kernel);
/* Create the kernel. This chooses an appropriate kernel and makes a
* symlink to it.
*
* Look for the most recent kernel named vmlinuz-*.<arch>* which has a
* corresponding directory in /lib/modules/. If the architecture is
* x86, look for any x86 kernel.
*
* RHEL 5 didn't append the arch to the kernel name, so look for
* kernels without arch second.
*
* If no suitable kernel can be found, exit with an error.
*
* This function returns the module path (ie. /lib/modules/<version>).
*/
const char *
create_kernel (const char *hostcpu, const char *kernel)
{
char **all_files = read_dir (KERNELDIR);
/* In ArchLinux, kernel is always named /boot/vmlinuz26. */
if (access ("/boot/vmlinuz26", F_OK) == 0)
return create_kernel_archlinux (hostcpu, kernel);
/* In original: ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen */
const char *patt;
if (hostcpu[0] == 'i' && hostcpu[2] == '8' && hostcpu[3] == '6' &&
hostcpu[4] == '\0')
patt = "vmlinuz-*.i?86*";
else
patt = xasprintf ("vmlinuz-*.%s*", hostcpu);
char **candidates;
candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE);
candidates = filter_notmatching_substring (candidates, "xen");
candidates = filter (candidates, has_modpath);
if (candidates[0] == NULL) {
/* In original: ls -1dvr /boot/vmlinuz-* 2>/dev/null | grep -v xen */
patt = "vmlinuz-*";
candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE);
candidates = filter_notmatching_substring (candidates, "xen");
candidates = filter (candidates, has_modpath);
if (candidates[0] == NULL)
goto no_kernels;
}
sort (candidates, reverse_filevercmp);
if (kernel) {
/* Choose the first candidate. */
char *tmp = xasprintf (KERNELDIR "/%s", candidates[0]);
if (verbose >= 2)
fprintf (stderr, "creating symlink %s -> %s\n", kernel, tmp);
if (symlink (tmp, kernel) == -1)
error (EXIT_FAILURE, errno, "symlink kernel");
free (tmp);
}
return get_modpath (candidates[0]);
/* Print more diagnostics here than the old script did. */
no_kernels:
fprintf (stderr,
"febootstrap-supermin-helper: failed to find a suitable kernel.\n"
"I looked for kernels in " KERNELDIR " and modules in " MODULESDIR
".\n"
"If this is a Xen guest, and you only have Xen domU kernels\n"
"installed, try installing a fullvirt kernel (only for\n"
"febootstrap use, you shouldn't boot the Xen guest with it).\n");
exit (EXIT_FAILURE);
}
/* In ArchLinux, kernel is always named /boot/vmlinuz26, and we have
* to use the 'file' command to work out what version it is.
*/
static char *
create_kernel_archlinux (const char *hostcpu, const char *kernel)
{
const char *file_cmd = "file /boot/vmlinuz26 | awk '{print $9}'";
FILE *pp;
char modversion[256];
char *modpath;
size_t len;
pp = popen (file_cmd, "r");
if (pp == NULL) {
error:
fprintf (stderr, "febootstrap-supermin-helper: %s: command failed\n",
file_cmd);
exit (EXIT_FAILURE);
}
if (fgets (modversion, sizeof modversion, pp) == NULL)
goto error;
if (pclose (pp) == -1)
goto error;
/* Chomp final \n */
len = strlen (modversion);
if (len > 0 && modversion[len-1] == '\n') {
modversion[len-1] = '\0';
len--;
}
/* Generate module path. */
modpath = xasprintf (MODULESDIR "/%s", modversion);
/* Check module path is a directory. */
if (!isdir (modpath)) {
fprintf (stderr, "febootstrap-supermin-helper: /boot/vmlinuz26 kernel exists but %s is not a valid module path\n",
modpath);
exit (EXIT_FAILURE);
}
if (kernel) {
/* Symlink from kernel to /boot/vmlinuz26. */
if (symlink ("/boot/vmlinuz26", kernel) == -1)
error (EXIT_FAILURE, errno, "symlink kernel");
}
/* Return module path. */
return modpath;
}
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