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xbps-uchroot: overlayfs fixes v2.

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- Do not use nftw(3), this won't clean up the tree properly.
  Rather use scandir(3) with alphasort, like xbps-create(1).

- Don't drop privs in the parent to make sure that the
  temp overlayfs tree can be removed properly.

This fixes the issues while building go modules and others
with xbps-src.
This commit is contained in:
Juan RP 2020-02-13 08:49:58 +01:00
parent fbba38b006
commit 6ccee8fd5e
1 changed files with 69 additions and 29 deletions
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98
bin/xbps-uchroot/main.c
View File

@ -52,6 +52,7 @@
#include <ftw.h>
#include <signal.h>
#include <getopt.h>
#include <dirent.h>
#include <xbps.h>
#include "queue.h"
@ -109,19 +110,16 @@ die(const char *fmt, ...)
}
static int
ftw_cb(const char *fpath, const struct stat *sb UNUSED, int type,
struct FTW *ftwbuf UNUSED)
ftw_cb(const char *fpath, const struct stat *sb)
{
int sverrno = 0;
if (type == FTW_F || type == FTW_SL || type == FTW_SLN) {
if (unlink(fpath) == -1)
sverrno = errno;
} else if (type == FTW_D || type == FTW_DNR || type == FTW_DP) {
if (S_ISDIR(sb->st_mode)) {
if (rmdir(fpath) == -1)
sverrno = errno;
} else {
return 0;
if (unlink(fpath) == -1)
sverrno = errno;
}
if (sverrno != 0) {
fprintf(stderr, "Failed to remove %s: %s\n", fpath, strerror(sverrno));
@ -129,20 +127,69 @@ ftw_cb(const char *fpath, const struct stat *sb UNUSED, int type,
return 0;
}
static int
walk_dir(const char *path,
int (*fn)(const char *fpath, const struct stat *sb))
{
struct dirent **list;
struct stat sb;
const char *p;
char tmp_path[PATH_MAX] = {0};
int rv, i;
i = scandir(path, &list, NULL, alphasort);
if (i == -1) {
rv = -1;
goto out;
}
while (i--) {
p = list[i]->d_name;
if (strcmp(p, ".") == 0 || strcmp(p, "..") == 0)
continue;
if (strlen(path) + strlen(p) + 1 >= (PATH_MAX - 1)) {
errno = ENAMETOOLONG;
rv = -1;
break;
}
strncpy(tmp_path, path, PATH_MAX - 1);
strncat(tmp_path, "/", PATH_MAX - 1 - strlen(tmp_path));
strncat(tmp_path, p, PATH_MAX - 1 - strlen(tmp_path));
if (lstat(tmp_path, &sb) < 0) {
break;
}
if (S_ISDIR(sb.st_mode)) {
if (walk_dir(tmp_path, fn) < 0) {
rv = -1;
break;
}
}
rv = fn(tmp_path, &sb);
if (rv != 0) {
break;
}
}
out:
free(list);
return rv;
}
static void
cleanup_overlayfs(void)
{
if (tmpdir == NULL)
return;
if (!overlayfs_on_tmpfs) {
/* recursively remove the temporary dir */
if (nftw(tmpdir, ftw_cb, 20, FTW_MOUNT|FTW_PHYS|FTW_DEPTH) != 0) {
fprintf(stderr, "Failed to remove directory tree %s: %s\n",
tmpdir, strerror(errno));
exit(EXIT_FAILURE);
}
if (overlayfs_on_tmpfs)
goto out;
/* recursively remove the temporary dir */
if (walk_dir(tmpdir, ftw_cb) != 0) {
fprintf(stderr, "Failed to remove directory tree %s: %s\n",
tmpdir, strerror(errno));
exit(EXIT_FAILURE);
}
out:
rmdir(tmpdir);
}
@ -342,17 +389,16 @@ main(int argc, char **argv)
die("failed to create tmpdir directory");
if (chown(tmpdir, ruid, rgid) == -1)
die("chown tmpdir %s", tmpdir);
/*
* Register a signal handler to clean up temporary masterdir.
*/
memset(&sa, 0, sizeof(sa));
sa.sa_handler = sighandler_cleanup;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGQUIT, &sa, NULL);
}
/*
* Register a signal handler to clean up temporary masterdir.
*/
memset(&sa, 0, sizeof(sa));
sa.sa_handler = sighandler_cleanup;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGQUIT, &sa, NULL);
clone_flags = (SIGCHLD|CLONE_NEWNS|CLONE_NEWIPC|CLONE_NEWUTS|CLONE_NEWPID);
container_flags = clone_flags & ~(CLONE_NEWNS|CLONE_NEWIPC|CLONE_NEWUTS|CLONE_NEWPID);
@ -420,12 +466,6 @@ main(int argc, char **argv)
if (execvp(cmd, cmdargs) == -1)
die("Failed to execute command %s", cmd);
}
/* Switch back to the gid/uid of invoking process also in the parent */
if (setgid(rgid) == -1)
die("setgid child");
if (setuid(ruid) == -1)
die("setuid child");
/* Wait until the child terminates */
while (waitpid(child, &child_status, 0) < 0) {
if (errno != EINTR)