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Some more stylistic changes to switch_root

This commit is contained in:
sin 2014-04-14 11:20:09 +01:00
parent fb45d91ccc
commit fc4dc81535
1 changed files with 19 additions and 28 deletions
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47
switch_root.c
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@ -20,9 +20,8 @@ delete_content(const char *dir, dev_t curdevice)
struct dirent *dent;
/* don't dive into other filesystems */
if (lstat(dir, &st) || st.st_dev != curdevice){
if (lstat(dir, &st) || st.st_dev != curdevice)
return;
}
/* delete contents recursively */
if (S_ISDIR(st.st_mode)) {
d = opendir(dir);
@ -32,9 +31,7 @@ delete_content(const char *dir, dev_t curdevice)
if (dent->d_name[0] == '.'
&& ((dent->d_name[1] == '.' && dent->d_name[2] == 0)
|| (dent->d_name[1] == 0)))
{
continue;
}
/* build path and dive deeper */
strlcat(path, dir, sizeof(path));
@ -77,45 +74,39 @@ main(int argc, char **argv)
} ARGEND;
/* check number of args and if we are PID 1 */
if (argc != 2 || getpid() != 1){
if (argc != 2 || getpid() != 1)
usage();
}
/* chdir to newroot and make sure it's a different fs */
if (chdir(argv[0])) {
if (chdir(argv[0]))
eprintf("chdir %s:", argv[0]);
}
if (stat("/", &st)) {
eprintf("stat %s:", "/");
}
curdev = st.st_dev;
if (stat(".", &st)) {
eprintf("stat %s:", ".");
}
if (st.st_dev == curdev) {
usage();
}
/* further checks */
if (stat("/init", &st) || !S_ISREG(st.st_mode)) {
/* avoids trouble with real filesystems */
if (stat("/", &st))
eprintf("stat %s:", "/");
curdev = st.st_dev;
if (stat(".", &st))
eprintf("stat %s:", ".");
if (st.st_dev == curdev)
usage();
/* avoids trouble with real filesystems */
if (stat("/init", &st) || !S_ISREG(st.st_mode))
eprintf("/init is not a regular file\n");
}
statfs("/", &stfs);
if ((unsigned)stfs.f_type != RAMFS_MAGIC && (unsigned)stfs.f_type != TMPFS_MAGIC){
if ((unsigned)stfs.f_type != RAMFS_MAGIC && (unsigned)stfs.f_type != TMPFS_MAGIC)
eprintf("current filesystem is not a RAMFS or TMPFS\n");
}
/* wipe / */
delete_content("/", curdev);
/* overmount / with newroot and chroot into it */
if (mount(".", "/", NULL, MS_MOVE, NULL)) {
if (mount(".", "/", NULL, MS_MOVE, NULL))
eprintf("mount %s:", ".");
}
if (chroot(".")) {
if (chroot("."))
eprintf("chroot failed\n");
}
/* if -c is set, redirect stdin/stdout/stderr to console */
if (console) {