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Minor fixes to init/init.c
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  o Make sure we print errors and warnings to stderr.
  o Don't assume fork succeeds.
  o Use err(3) and warn(3), cuts some lines.
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haesbaert committed Jan 19, 2022
1 parent 587aa1f commit 63af27a
Showing 1 changed file with 29 additions and 44 deletions.
73 changes: 29 additions & 44 deletions init/init.c
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#include <limits.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
Expand Down Expand Up @@ -29,7 +30,7 @@ void set_rlimits(const char *rlimits)

lim_id = strtoull(item, &item, 10);
if (lim_id == ULLONG_MAX) {
printf("Invalid rlimit ID\n");
fprintf(stderr, "Invalid rlimit ID\n");
break;
}

Expand All @@ -41,7 +42,7 @@ void set_rlimits(const char *rlimits)
rlim.rlim_cur = lim_cur;
rlim.rlim_max = lim_max;
if (setrlimit(lim_id, &rlim) != 0) {
printf("Error setting rlimit for ID=%lld\n", lim_id);
fprintf(stderr, "Can't set rlimit for ID=%llu\n", lim_id);
}

if (*item != '\0') {
Expand Down Expand Up @@ -78,76 +79,60 @@ int main(int argc, char **argv)
pipe(pipefd);

pid = fork();
if (pid == 0) {
if (pid == -1)
err(-1, "fork");
else if (pid == 0) {
close(pipefd[1]);
dup2(pipefd[0], 0);
close(pipefd[0]);

if (execl("/sbin/cryptsetup", "cryptsetup", "open", "/dev/vda", "luksroot", "-", NULL) < 0) {
perror("execl");
exit(-1);
}
if (execl("/sbin/cryptsetup", "cryptsetup", "open", "/dev/vda",
"luksroot", "-", NULL) < 0)
err(-1, "execl");
} else {
write(pipefd[1], passp, strnlen(passp, 128));
if (write(pipefd[1], passp, strnlen(passp, 128) < 0))
warn(-1, "write"); // XXX - ignores short count
close(pipefd[1]);
waitpid(pid, &wstatus, 0);
}

printf("Mounting LUKS root filesystem\n");

if (mount("/dev/mapper/luksroot", "/luksroot", "ext4", 0, NULL) < 0) {
perror("mount(/luksroot)");
exit(-1);
}
if (mount("/dev/mapper/luksroot", "/luksroot", "ext4", 0, NULL) < 0)
err(-1, "mount(/luksroot)");

chdir("/luksroot");

if (mount(".", "/", NULL, MS_MOVE, NULL)) {
perror("remount root");
exit(-1);
}
if (mount(".", "/", NULL, MS_MOVE, NULL))
err(-1, "remount root");
chroot(".");
}

if (mount("proc", "/proc", "proc",
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0) {
perror("mount(/proc)");
exit(-1);
}
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0)
err(-1, "mount(/proc)");

if (mount("sysfs", "/sys", "sysfs",
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0) {
perror("mount(/sys)");
exit(-1);
}
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0)
err(-1, "mount(/sys)");

if (mount("cgroup2", "/sys/fs/cgroup", "cgroup2",
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0) {
perror("mount(/sys/fs/cgroup)");
exit(-1);
}
MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0)
err(-1, "mount(/sys/fs/cgroup)");

if (mkdir("/dev/pts", 0755) < 0 && errno != EEXIST) {
perror("mkdir(/dev/pts)");
exit(-1);
}
if (mkdir("/dev/pts", 0755) < 0 && errno != EEXIST)
err(-1, "mkdir(/dev/pts)");

if (mount("devpts", "/dev/pts", "devpts",
MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0) {
perror("mount(/dev/pts)");
exit(-1);
}
MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0)
err(-1, "mount(/dev/pts)");

if (mkdir("/dev/shm", 0755) < 0 && errno != EEXIST) {
perror("mkdir(/dev/shm)");
exit(-1);
}
if (mkdir("/dev/shm", 0755) < 0 && errno != EEXIST)
err(-1, "mkdir(/dev/shm)");

if (mount("tmpfs", "/dev/shm", "tmpfs",
MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0) {
perror("mount(/dev/shm)");
exit(-1);
}
MS_NOEXEC | MS_NOSUID | MS_RELATIME, NULL) < 0)
err(-1, "mount(/dev/shm)");

/* May fail if already exists and that's fine. */
symlink("/proc/self/fd", "/dev/fd");
Expand Down

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