Merge pull request #26465 from DaanDeMeyer/openat-helpers

Add more openat() helpers of utility functions

src/basic/env-file.c

@@ -578,14 +578,15 @@ static void write_env_var(FILE *f, const char *v) {
         fputc_unlocked('\n', f);
 }
 
-int write_env_file(const char *fname, char **l) {
+int write_env_file_at(int dir_fd, const char *fname, char **l) {
         _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *p = NULL;
         int r;
 
+        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
         assert(fname);
 
-        r = fopen_temporary(fname, &f, &p);
+        r = fopen_temporary_at(dir_fd, fname, &f, &p);
         if (r < 0)
                 return r;
 
@@ -596,12 +597,12 @@ int write_env_file(const char *fname, char **l) {
 
         r = fflush_and_check(f);
         if (r >= 0) {
-                if (rename(p, fname) >= 0)
+                if (renameat(dir_fd, p, dir_fd, fname) >= 0)
                         return 0;
 
                 r = -errno;
         }
 
-        (void) unlink(p);
+        (void) unlinkat(dir_fd, p, 0);
         return r;
 }

src/basic/env-file.h

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <fcntl.h>
 #include <stdarg.h>
 #include <stdio.h>
 
@@ -16,4 +17,7 @@ int load_env_file_pairs(FILE *f, const char *fname, char ***ret);
 
 int merge_env_file(char ***env, FILE *f, const char *fname);
 
-int write_env_file(const char *fname, char **l);
+int write_env_file_at(int dir_fd, const char *fname, char **l);
+static inline int write_env_file(const char *fname, char **l) {
+        return write_env_file_at(AT_FDCWD, fname, l);
+}

src/shared/copy.c

@@ -1329,8 +1329,10 @@ int copy_file_fd_full(
         return 0;
 }
 
-int copy_file_full(
+int copy_file_at_full(
+                int dir_fdf,
                 const char *from,
+                int dir_fdt,
                 const char *to,
                 int flags,
                 mode_t mode,
@@ -1344,10 +1346,12 @@ int copy_file_full(
         struct stat st;
         int r;
 
+        assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD);
+        assert(dir_fdt >= 0 || dir_fdt == AT_FDCWD);
         assert(from);
         assert(to);
 
-        fdf = open(from, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+        fdf = openat(dir_fdf, from, O_RDONLY|O_CLOEXEC|O_NOCTTY);
         if (fdf < 0)
                 return -errno;
 
@@ -1360,11 +1364,11 @@ int copy_file_full(
 
         WITH_UMASK(0000) {
                 if (copy_flags & COPY_MAC_CREATE) {
-                        r = mac_selinux_create_file_prepare(to, S_IFREG);
+                        r = mac_selinux_create_file_prepare_at(dir_fdt, to, S_IFREG);
                         if (r < 0)
                                 return r;
                 }
-                fdt = open(to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY,
+                fdt = openat(dir_fdt, to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY,
                            mode != MODE_INVALID ? mode : st.st_mode);
                 if (copy_flags & COPY_MAC_CREATE)
                         mac_selinux_create_file_clear();
@@ -1403,7 +1407,7 @@ int copy_file_full(
                 goto fail;
 
         if (copy_flags & COPY_FSYNC_FULL) {
-                r = fsync_parent_at(AT_FDCWD, to);
+                r = fsync_parent_at(dir_fdt, to);
                 if (r < 0)
                         goto fail;
         }
@@ -1413,7 +1417,7 @@ int copy_file_full(
 fail:
         /* Only unlink if we definitely are the ones who created the file */
         if (FLAGS_SET(flags, O_EXCL))
-                (void) unlink(to);
+                (void) unlinkat(dir_fdt, to, 0);
 
         return r;
 }

src/shared/copy.h

@@ -38,9 +38,15 @@ static inline int copy_file_fd(const char *from, int to, CopyFlags copy_flags) {
         return copy_file_fd_full(from, to, copy_flags, NULL, NULL);
 }
 
-int copy_file_full(const char *from, const char *to, int open_flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress, void *userdata);
+int copy_file_at_full(int dir_fdf, const char *from, int dir_fdt, const char *to, int open_flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress, void *userdata);
+static inline int copy_file_at(int dir_fdf, const char *from, int dir_fdt, const char *to, int open_flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags) {
+        return copy_file_at_full(dir_fdf, from, dir_fdt, to, open_flags, mode, chattr_flags, chattr_mask, copy_flags, NULL, NULL);
+}
+static inline int copy_file_full(const char *from, const char *to, int open_flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress, void *userdata) {
+        return copy_file_at_full(AT_FDCWD, from, AT_FDCWD, to, open_flags, mode, chattr_flags, chattr_mask, copy_flags, progress, userdata);
+}
 static inline int copy_file(const char *from, const char *to, int open_flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags) {
-        return copy_file_full(from, to, open_flags, mode, chattr_flags, chattr_mask, copy_flags, NULL, NULL);
+        return copy_file_at(AT_FDCWD, from, AT_FDCWD, to, open_flags, mode, chattr_flags, chattr_mask, copy_flags);
 }
 
 int copy_file_atomic_full(const char *from, const char *to, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress, void *userdata);

src/shared/smack-util.c

@@ -67,8 +67,8 @@ int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
         return fgetxattr_malloc(fd, smack_attr_to_string(attr), label);
 }
 
-int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
-        int r;
+int mac_smack_apply_at(int dir_fd, const char *path, SmackAttr attr, const char *label) {
+        _cleanup_close_ int fd = -EBADF;
 
         assert(path);
         assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
@@ -76,14 +76,11 @@ int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
         if (!mac_smack_use())
                 return 0;
 
-        if (label)
-                r = lsetxattr(path, smack_attr_to_string(attr), label, strlen(label), 0);
-        else
-                r = lremovexattr(path, smack_attr_to_string(attr));
-        if (r < 0)
+        fd = openat(dir_fd, path, O_PATH|O_CLOEXEC|O_NOFOLLOW);
+        if (fd < 0)
                 return -errno;
 
-        return 0;
+        return mac_smack_apply_fd(fd, attr, label);
 }
 
 int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
@@ -277,13 +274,16 @@ int mac_smack_copy(const char *dest, const char *src) {
 }
 #endif
 
-int rename_and_apply_smack_floor_label(const char *from, const char *to) {
+int renameat_and_apply_smack_floor_label(int fdf, const char *from, int fdt, const char *to) {
 
-        if (rename(from, to) < 0)
+        assert(fdf >= 0 || fdf == AT_FDCWD);
+        assert(fdt >= 0 || fdt == AT_FDCWD);
+
+        if (renameat(fdf, from, fdt, to) < 0)
                 return -errno;
 
 #if HAVE_SMACK_RUN_LABEL
-        return mac_smack_apply(to, SMACK_ATTR_ACCESS, SMACK_FLOOR_LABEL);
+        return mac_smack_apply_at(fdt, to, SMACK_ATTR_ACCESS, SMACK_FLOOR_LABEL);
 #else
         return 0;
 #endif

src/shared/smack-util.h

@@ -38,9 +38,15 @@ const char* smack_attr_to_string(SmackAttr i) _const_;
 SmackAttr smack_attr_from_string(const char *s) _pure_;
 int mac_smack_read(const char *path, SmackAttr attr, char **label);
 int mac_smack_read_fd(int fd, SmackAttr attr, char **label);
-int mac_smack_apply(const char *path, SmackAttr attr, const char *label);
+int mac_smack_apply_at(int dir_fd, const char *path, SmackAttr attr, const char *label);
+static inline int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
+        return mac_smack_apply_at(AT_FDCWD, path, attr, label);
+}
 int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label);
 int mac_smack_apply_pid(pid_t pid, const char *label);
 int mac_smack_copy(const char *dest, const char *src);
 
-int rename_and_apply_smack_floor_label(const char *temp_path, const char *dest_path);
+int renameat_and_apply_smack_floor_label(int fdf, const char *from, int fdt, const char *to);
+static inline int rename_and_apply_smack_floor_label(const char *from, const char *to) {
+        return renameat_and_apply_smack_floor_label(AT_FDCWD, from, AT_FDCWD, to);
+}

src/shared/tmpfile-util-label.c

@@ -6,7 +6,8 @@
 #include "tmpfile-util-label.h"
 #include "tmpfile-util.h"
 
-int fopen_temporary_label(
+int fopen_temporary_at_label(
+                int dir_fd,
                 const char *target,
                 const char *path,
                 FILE **f,
@@ -14,13 +15,14 @@ int fopen_temporary_label(
 
         int r;
 
+        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
         assert(path);
 
-        r = mac_selinux_create_file_prepare(target, S_IFREG);
+        r = mac_selinux_create_file_prepare_at(dir_fd, target, S_IFREG);
         if (r < 0)
                 return r;
 
-        r = fopen_temporary(path, f, temp_path);
+        r = fopen_temporary_at(dir_fd, path, f, temp_path);
 
         mac_selinux_create_file_clear();
 

src/shared/tmpfile-util-label.h

@@ -1,10 +1,14 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <fcntl.h>
 #include <stdio.h>
 
 /* These functions are split out of tmpfile-util.h (and not for example just flags to the functions they
  * wrap) in order to optimize linking: this way, -lselinux is needed only for the callers of these functions
  * that need selinux, but not for all. */
 
-int fopen_temporary_label(const char *target, const char *path, FILE **f, char **temp_path);
+int fopen_temporary_at_label(int dir_fd, const char *target, const char *path, FILE **f, char **temp_path);
+static inline int fopen_temporary_label(const char *target, const char *path, FILE **f, char **temp_path) {
+        return fopen_temporary_at_label(AT_FDCWD, target, path, f, temp_path);
+}