minix/commands/simple/newroot.c

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/*
newroot.c
Replace the current root with a new one
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
void usage(void) {
fprintf(stderr, "Usage: newroot [-i] <block-special>\n");
fprintf(stderr, "-i: copy mfs binary from boot image to memory\n");
exit(1);
}
int main(int argc, char *argv[])
{
int r;
char *dev;
int mountflags;
r = 0;
mountflags = 0; /* !read-only */
if (argc != 2 && argc != 3) usage();
if(argc == 2) {
dev = argv[1];
} else if(argc == 3) {
/* -i flag was supposedly entered. Verify.*/
if(strcmp(argv[1], "-i") != 0) usage();
mountflags |= MS_REUSE;
dev = argv[2];
}
r = mount(dev, "/", mountflags, NULL, NULL);
if (r != 0) {
fprintf(stderr, "newroot: mount failed: %s\n",strerror(errno));
exit(1);
}
return 0;
}