From: Luca Boccassi Date: Sat, 19 Dec 2020 21:40:47 +0000 Subject: basic: add make_mount_point_inode helper Creates a file or a directory depending on the source path, useful for creating mount points. (cherry picked from commit 8bab8029105e44ce78c5e11bffa203a1135fe201) --- src/basic/mountpoint-util.c | 25 +++++++++++++++++++++ src/basic/mountpoint-util.h | 4 ++++ src/core/namespace.c | 26 +++++++-------------- src/machine/machine-dbus.c | 14 ++++-------- src/test/test-mountpoint-util.c | 50 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 91 insertions(+), 28 deletions(-) diff --git a/src/basic/mountpoint-util.c b/src/basic/mountpoint-util.c index a6602ad..ed7457f 100644 --- a/src/basic/mountpoint-util.c +++ b/src/basic/mountpoint-util.c @@ -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); +} diff --git a/src/basic/mountpoint-util.h b/src/basic/mountpoint-util.h index aadb212..cebcec5 100644 --- a/src/basic/mountpoint-util.h +++ b/src/basic/mountpoint-util.h @@ -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); diff --git a/src/core/namespace.c b/src/core/namespace.c index cdf427a..02381da 100644 --- a/src/core/namespace.c +++ b/src/core/namespace.c @@ -1176,29 +1176,19 @@ 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) diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c index bb67beb..1105008 100644 --- a/src/machine/machine-dbus.c +++ b/src/machine/machine-dbus.c @@ -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)); diff --git a/src/test/test-mountpoint-util.c b/src/test/test-mountpoint-util.c index 47fde5c..1ce3d5d 100644 --- a/src/test/test-mountpoint-util.c +++ b/src/test/test-mountpoint-util.c @@ -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; }