/*
* switchroot.c - switch to new root directory and start init.
*
- * Copyright 2002-2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2002-2009 Red Hat, Inc. All rights reserved.
*
* 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
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authors:
- * Peter Jones <pjones@redhat.com>
+ * Peter Jones <pjones@redhat.com>
* Jeremy Katz <katzj@redhat.com>
*/
-
-#define _GNU_SOURCE 1
-
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <ctype.h>
#include <dirent.h>
+#include <err.h>
#ifndef MS_MOVE
#define MS_MOVE 8192
#endif
-#ifndef MNT_DETACH
-#define MNT_DETACH 0x2
-#endif
+/* remove all files/directories below dirName -- don't cross mountpoints */
+static int recursiveRemove(char *dirName)
+{
+ struct stat rb;
+ DIR *dir;
+ int rc = -1;
+ int dfd;
+
+ if (!(dir = opendir(dirName))) {
+ warn("failed to open %s", dirName);
+ goto done;
+ }
-enum {
- ok,
- err_no_directory,
- err_usage,
-};
+ dfd = dirfd(dir);
-/* remove all files/directories below dirName -- don't cross mountpoints */
-static int
-recursiveRemove(char * dirName)
- {
- struct stat sb,rb;
- DIR * dir;
- struct dirent * d;
- char * strBuf = alloca(strlen(dirName) + 1024);
-
- if (!(dir = opendir(dirName))) {
- printf("error opening %s: %m\n", dirName);
- return 0;
- }
-
- if (fstat(dirfd(dir),&rb)) {
- printf("unable to stat %s: %m\n", dirName);
- closedir(dir);
- return 0;
- }
-
- errno = 0;
- while ((d = readdir(dir))) {
- errno = 0;
-
- if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) {
- errno = 0;
- continue;
- }
-
- strcpy(strBuf, dirName);
- strcat(strBuf, "/");
- strcat(strBuf, d->d_name);
-
- if (lstat(strBuf, &sb)) {
- printf("failed to stat %s: %m\n", strBuf);
- errno = 0;
- continue;
- }
-
- /* only descend into subdirectories if device is same as dir */
- if (S_ISDIR(sb.st_mode)) {
- if (sb.st_dev == rb.st_dev) {
- recursiveRemove(strBuf);
- if (rmdir(strBuf))
- printf("failed to rmdir %s: %m\n", strBuf);
- }
- errno = 0;
- continue;
- }
- if (unlink(strBuf)) {
- printf("failed to remove %s: %m\n", strBuf);
- errno = 0;
- continue;
- }
- }
-
- if (errno) {
- closedir(dir);
- printf("error reading from %s: %m\n", dirName);
- return 1;
- }
-
- closedir(dir);
-
- return 0;
- }
+ if (fstat(dfd, &rb)) {
+ warn("failed to stat %s", dirName);
+ goto done;
+ }
+
+ while(1) {
+ struct dirent *d;
+
+ errno = 0;
+ if (!(d = readdir(dir))) {
+ if (errno) {
+ warn("failed to read %s", dirName);
+ goto done;
+ }
+ break; /* end of directory */
+ }
+
+ if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+ continue;
+
+ if (d->d_type == DT_DIR) {
+ struct stat sb;
+
+ if (fstatat(dfd, d->d_name, &sb, AT_SYMLINK_NOFOLLOW)) {
+ warn("failed to stat %s/%s", dirName, d->d_name);
+ continue;
+ }
+
+ /* remove subdirectories if device is same as dir */
+ if (sb.st_dev == rb.st_dev) {
+ char subdir[ strlen(dirName) +
+ strlen(d->d_name) + 2 ];
+
+ sprintf(subdir, "%s/%s", dirName, d->d_name);
+ recursiveRemove(subdir);
+ } else
+ continue;
+ }
+
+ if (unlinkat(dfd, d->d_name,
+ d->d_type == DT_DIR ? AT_REMOVEDIR : 0))
+ warn("failed to unlink %s/%s", dirName, d->d_name);
+ }
+
+ rc = 0; /* success */
+
+done:
+ if (dir)
+ closedir(dir);
+ return rc;
+}
static int switchroot(const char *newroot)
{
/* Don't try to unmount the old "/", there's no way to do it. */
const char *umounts[] = { "/dev", "/proc", "/sys", NULL };
- int errnum;
int i;
for (i = 0; umounts[i] != NULL; i++) {
char newmount[PATH_MAX];
- strcpy(newmount, newroot);
- strcat(newmount, umounts[i]);
+
+ snprintf(newmount, sizeof(newmount), "%s%s", newroot, umounts[i]);
+
if (mount(umounts[i], newmount, NULL, MS_MOVE, NULL) < 0) {
- fprintf(stderr, "Error mount moving old %s %s %m\n",
+ warn("failed to mount moving %s to %s",
umounts[i], newmount);
- fprintf(stderr, "Forcing unmount of %s\n", umounts[i]);
+ warnx("forcing unmount of %s", umounts[i]);
umount2(umounts[i], MNT_FORCE);
}
}
- if (chdir(newroot) < 0) {
- errnum=errno;
- fprintf(stderr, "switchroot: chdir failed: %m\n");
- errno=errnum;
- return -1;
+ if (chdir(newroot)) {
+ warn("failed to change directory to %s", newroot);
+ return -1;
}
+
recursiveRemove("/");
+
if (mount(newroot, "/", NULL, MS_MOVE, NULL) < 0) {
- errnum = errno;
- fprintf(stderr, "switchroot: mount failed: %m\n");
- errno = errnum;
+ warn("failed to mount moving %s to /", newroot);
return -1;
}
if (chroot(".")) {
- errnum = errno;
- fprintf(stderr, "switchroot: chroot failed: %m\n");
- errno = errnum;
- return -2;
+ warn("failed to change root");
+ return -1;
}
- return 1;
+ return 0;
}
static void usage(FILE *output)
{
- fprintf(output, "usage: switchroot <newrootdir> <init> <args to init>\n");
- if (output == stderr)
- exit(err_usage);
- exit(ok);
+ fprintf(output, "usage: %s <newrootdir> <init> <args to init>\n",
+ program_invocation_short_name);
+ exit(output == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+static void version(void)
+{
+ fprintf(stdout, "%s from %s\n", program_invocation_short_name,
+ PACKAGE_STRING);
+ exit(EXIT_SUCCESS);
}
int main(int argc, char *argv[])
{
- char *newroot = argv[1];
- char *init = argv[2];
- char **initargs = &argv[2];
+ char *newroot, *init, **initargs;
- if (newroot == NULL || newroot[0] == '\0' ||
- init == NULL || init[0] == '\0' ) {
+ if (argv[1] && (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")))
+ usage(stdout);
+ if (argv[1] && (!strcmp(argv[1], "--version") || !strcmp(argv[1], "-V")))
+ version();
+ if (argc < 3)
usage(stderr);
- }
- if (switchroot(newroot) < 0) {
- fprintf(stderr, "switchroot has failed. Sorry.\n");
- return 1;
- }
- if (access(initargs[0], X_OK))
- fprintf(stderr, "WARNING: can't access %s\n", initargs[0]);
+ newroot = argv[1];
+ init = argv[2];
+ initargs = &argv[2];
+
+ if (!*newroot || !*init)
+ usage(stderr);
+
+ if (switchroot(newroot))
+ errx(EXIT_FAILURE, "failed. Sorry.");
+
+ if (access(init, X_OK))
+ warn("cannot access %s", init);
/* get session leader */
setsid();
+
/* set controlling terminal */
- ioctl (0, TIOCSCTTY, 1);
+ if (ioctl (0, TIOCSCTTY, 1))
+ warn("failed to TIOCSCTTY");
- execv(initargs[0], initargs);
+ execv(init, initargs);
+ err(EXIT_FAILURE, "failed to execute %s", init);
}
-/*
- * vim:noet:ts=8:sw=8:sts=8
- */
projects / platform / upstream / dracut.git / commitdiff