basic: add make_mount_point_inode helper

Creates a file or a directory depending on the source path, useful
for creating mount points.
This commit is contained in:
Luca Boccassi 2020-12-19 21:40:47 +00:00 committed by Lennart Poettering
parent 9df1e11e31
commit 8bab802910
5 changed files with 91 additions and 28 deletions

View File

@ -8,14 +8,17 @@
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "label.h"
#include "missing_stat.h"
#include "missing_syscall.h"
#include "mkdir.h"
#include "mountpoint-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "stat-util.h"
#include "stdio-util.h"
#include "strv.h"
#include "user-util.h"
/* This is the original MAX_HANDLE_SZ definition from the kernel, when the API was introduced. We use that in place of
* any more currently defined value to future-proof things: if the size is increased in the API headers, and our code
@ -509,3 +512,25 @@ int mount_propagation_flags_from_string(const char *name, unsigned long *ret) {
return -EINVAL;
return 0;
}
int make_mount_point_inode_from_stat(const struct stat *st, const char *dest, mode_t mode) {
assert(st);
assert(dest);
if (S_ISDIR(st->st_mode))
return mkdir_label(dest, mode);
else
return mknod(dest, S_IFREG|(mode & ~0111), 0);
}
int make_mount_point_inode_from_path(const char *source, const char *dest, mode_t mode) {
struct stat st;
assert(source);
assert(dest);
if (stat(source, &st) < 0)
return -errno;
return make_mount_point_inode_from_stat(&st, dest, mode);
}

View File

@ -23,3 +23,7 @@ int dev_is_devtmpfs(void);
const char *mount_propagation_flags_to_string(unsigned long flags);
int mount_propagation_flags_from_string(const char *name, unsigned long *ret);
/* Creates a mount point (not parents) based on the source path or stat - ie, a file or a directory */
int make_mount_point_inode_from_stat(const struct stat *st, const char *dest, mode_t mode);
int make_mount_point_inode_from_path(const char *source, const char *dest, mode_t mode);

View File

@ -1184,29 +1184,19 @@ static int apply_mount(
bool try_again = false;
if (r == -ENOENT && make) {
struct stat st;
int q;
/* Hmm, either the source or the destination are missing. Let's see if we can create
the destination, then try again. */
if (stat(what, &st) < 0)
log_error_errno(errno, "Mount point source '%s' is not accessible: %m", what);
else {
int q;
(void) mkdir_parents(mount_entry_path(m), 0755);
(void) mkdir_parents(mount_entry_path(m), 0755);
if (S_ISDIR(st.st_mode))
q = mkdir(mount_entry_path(m), 0755) < 0 ? -errno : 0;
else
q = touch(mount_entry_path(m));
if (q < 0)
log_error_errno(q, "Failed to create destination mount point node '%s': %m",
mount_entry_path(m));
else
try_again = true;
}
q = make_mount_point_inode_from_path(what, mount_entry_path(m), 0755);
if (q < 0)
log_error_errno(q, "Failed to create destination mount point node '%s': %m",
mount_entry_path(m));
else
try_again = true;
}
if (try_again)

View File

@ -32,6 +32,7 @@
#include "missing_capability.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "namespace-util.h"
#include "os-util.h"
#include "path-util.h"
@ -908,10 +909,7 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
/* Second, we mount the source file or directory to a directory inside of our MS_SLAVE playground. */
mount_tmp = strjoina(mount_slave, "/mount");
if (S_ISDIR(st.st_mode))
r = mkdir_errno_wrapper(mount_tmp, 0700);
else
r = touch(mount_tmp);
r = make_mount_point_inode_from_stat(&st, mount_tmp, 0700);
if (r < 0) {
sd_bus_error_set_errnof(error, r, "Failed to create temporary mount point %s: %m", mount_tmp);
goto finish;
@ -1003,12 +1001,8 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
}
if (make_file_or_directory) {
if (S_ISDIR(st.st_mode))
(void) mkdir_p(dest, 0755);
else {
(void) mkdir_parents(dest, 0755);
(void) mknod(dest, S_IFREG|0600, 0);
}
(void) mkdir_parents(dest, 0755);
(void) make_mount_point_inode_from_stat(&st, dest, 0700);
}
mount_inside = strjoina("/run/host/incoming/", basename(mount_outside));

View File

@ -8,13 +8,16 @@
#include "def.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "hashmap.h"
#include "log.h"
#include "mkdir.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"
#include "tests.h"
#include "tmpfile-util.h"
static void test_mount_propagation_flags(const char *name, int ret, unsigned long expected) {
long unsigned flags;
@ -287,6 +290,52 @@ static void test_fd_is_mount_point(void) {
assert_se(IN_SET(fd_is_mount_point(fd, "root/", 0), -ENOENT, 0));
}
static void test_make_mount_point_inode(void) {
_cleanup_(rm_rf_physical_and_freep) char *d = NULL;
const char *src_file, *src_dir, *dst_file, *dst_dir;
struct stat st;
log_info("/* %s */", __func__);
assert_se(mkdtemp_malloc(NULL, &d) >= 0);
src_file = strjoina(d, "/src/file");
src_dir = strjoina(d, "/src/dir");
dst_file = strjoina(d, "/dst/file");
dst_dir = strjoina(d, "/dst/dir");
assert_se(mkdir_p(src_dir, 0755) >= 0);
assert_se(mkdir_parents(dst_file, 0755) >= 0);
assert_se(touch(src_file) >= 0);
assert_se(make_mount_point_inode_from_path(src_file, dst_file, 0755) >= 0);
assert_se(make_mount_point_inode_from_path(src_dir, dst_dir, 0755) >= 0);
assert_se(stat(dst_dir, &st) == 0);
assert_se(S_ISDIR(st.st_mode));
assert_se(stat(dst_file, &st) == 0);
assert_se(S_ISREG(st.st_mode));
assert_se(!(S_IXUSR & st.st_mode));
assert_se(!(S_IXGRP & st.st_mode));
assert_se(!(S_IXOTH & st.st_mode));
assert_se(unlink(dst_file) == 0);
assert_se(rmdir(dst_dir) == 0);
assert_se(stat(src_file, &st) == 0);
assert_se(make_mount_point_inode_from_stat(&st, dst_file, 0755) >= 0);
assert_se(stat(src_dir, &st) == 0);
assert_se(make_mount_point_inode_from_stat(&st, dst_dir, 0755) >= 0);
assert_se(stat(dst_dir, &st) == 0);
assert_se(S_ISDIR(st.st_mode));
assert_se(stat(dst_file, &st) == 0);
assert_se(S_ISREG(st.st_mode));
assert_se(!(S_IXUSR & st.st_mode));
assert_se(!(S_IXGRP & st.st_mode));
assert_se(!(S_IXOTH & st.st_mode));
}
int main(int argc, char *argv[]) {
test_setup_logging(LOG_DEBUG);
@ -311,6 +360,7 @@ int main(int argc, char *argv[]) {
test_mnt_id();
test_path_is_mount_point();
test_fd_is_mount_point();
test_make_mount_point_inode();
return 0;
}