From: Karel Zak <kzak@redhat.com>
Date: Thu, 24 Apr 2025 16:16:07 +0000 (+0200)
Subject: libmount: clean up statmount syscall-related functions
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b3bb829106e18c01c1fd984b3f68f22eba2c0c19;p=thirdparty%2Futil-linux.git

libmount: clean up statmount syscall-related functions

* Rename the raw version of the syscall from ul_statmount() to
  ul_statmount_syscall().

* Rename `sys_statmount()` to `ul_statmount()`. The goal is to use the
  same naming convention as `ul_listmount()` for a function that is
  expected to be called from code.

* Move ul_statmount() to be in the same #ifdef block as the rest of
  the statmount code in the header file.

* Add has_statmount() to make it easy to verify the usability of the
  statmount syscall.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/mount-api-utils.h b/include/mount-api-utils.h
index 02bb326c6..ea9aeb816 100644
--- a/include/mount-api-utils.h
+++ b/include/mount-api-utils.h
@@ -348,8 +348,9 @@ struct ul_statmount {
 # define LISTMOUNT_REVERSE      BIT(0)               /* List later mounts first */
 #endif
 
+/* Don't use this "raw" version. See ul_statmount() below. */
 #if defined(SYS_statmount)
-static inline int ul_statmount(uint64_t mnt_id,
+static inline int ul_statmount_syscall(uint64_t mnt_id,
 			uint64_t ns_id,
 			uint64_t mask,
 			struct ul_statmount *buf,
@@ -364,31 +365,21 @@ static inline int ul_statmount(uint64_t mnt_id,
 
        return syscall(SYS_statmount, &req, buf, bufsize, flags);
 }
-#endif
 
-#if defined(SYS_listmount)
-static inline ssize_t ul_listmount(uint64_t mnt_id,
-			uint64_t ns_id,
-			uint64_t last_mnt_id,
-			uint64_t list[], size_t num,
-			unsigned int flags)
+static inline int has_statmount(void)
 {
-       struct ul_mnt_id_req req = {
-		.size = MNT_ID_REQ_SIZE_VER1,
-		.mnt_id = mnt_id,
-		.param = last_mnt_id,
-		.mnt_ns_id = ns_id
-       };
+	errno = 0;
 
-       return syscall(SYS_listmount, &req, list, num, flags);
+	if (ul_statmount_syscall(0, 0, 0, NULL, 0, 0) < 0 && errno == ENOSYS)
+		return 0;
+	return 1;
 }
-#endif
 
 /* This is a version of statmount() that reallocates @buf to be large enough to
  * store data for the requested @id. This function never deallocates; it is the
  * caller's responsibility.
  */
-static inline int sys_statmount(uint64_t id,
+static inline int ul_statmount(uint64_t id,
 			uint64_t ns_id,
 			uint64_t mask,
 			struct ul_statmount **buf,
@@ -415,7 +406,7 @@ static inline int sys_statmount(uint64_t id,
 		}
 
 		errno = 0;
-		rc = ul_statmount(id, ns_id, mask, *buf, *bufsiz, flags);
+		rc = ul_statmount_syscall(id, ns_id, mask, *buf, *bufsiz, flags);
 		if (!rc)
 			break;
 		if (errno != EOVERFLOW)
@@ -427,6 +418,26 @@ static inline int sys_statmount(uint64_t id,
 
 	return rc;
 }
+#endif /* SYS_statmount */
+
+
+#if defined(SYS_listmount)
+static inline ssize_t ul_listmount(uint64_t mnt_id,
+			uint64_t ns_id,
+			uint64_t last_mnt_id,
+			uint64_t list[], size_t num,
+			unsigned int flags)
+{
+       struct ul_mnt_id_req req = {
+		.size = MNT_ID_REQ_SIZE_VER1,
+		.mnt_id = mnt_id,
+		.param = last_mnt_id,
+		.mnt_ns_id = ns_id
+       };
+
+       return syscall(SYS_listmount, &req, list, num, flags);
+}
+#endif
 
 #endif /* HAVE_STATMOUNT_API */
 
diff --git a/libmount/src/fs_statmount.c b/libmount/src/fs_statmount.c
index a998ee23c..3993c7b69 100644
--- a/libmount/src/fs_statmount.c
+++ b/libmount/src/fs_statmount.c
@@ -33,7 +33,7 @@ struct libmnt_statmnt *mnt_new_statmnt(void)
 	struct libmnt_statmnt *sm;
 
 	errno = 0;
-	if (ul_statmount(0, 0, 0, NULL, 0, 0) < 0 && errno == ENOSYS) {
+	if (!has_statmount()) {
 		DBG(FS, ul_debug("statmount: unsuppported"));
 		return NULL;
 	}
@@ -361,13 +361,14 @@ int mnt_fs_fetch_statmount(struct libmnt_fs *fs, uint64_t mask)
 	if (fs->stmnt) {
 		DBG(FS, ul_debugobj(fs, " reuse libmnt_stmnt"));
 		memset(fs->stmnt->buf, 0, fs->stmnt->bufsiz);
-		rc = sys_statmount(fs->uniq_id, 0, mask,
+
+		rc = ul_statmount(fs->uniq_id, 0, mask,
 				   &fs->stmnt->buf, &fs->stmnt->bufsiz, 0);
 		buf = fs->stmnt->buf;
 		bufsiz = fs->stmnt->bufsiz;
 	} else {
 		DBG(FS, ul_debugobj(fs, " use private buffer"));
-		rc = sys_statmount(fs->uniq_id, 0, mask, &buf, &bufsiz, 0);
+		rc = ul_statmount(fs->uniq_id, 0, mask, &buf, &bufsiz, 0);
 	}
 	DBG(FS, ul_debugobj(fs, " statmount [rc=%d bufsiz=%zu ns=%" PRIu64 " mask: %s%s%s%s%s%s%s]",
 				rc, bufsiz, ns,
@@ -378,11 +379,9 @@ int mnt_fs_fetch_statmount(struct libmnt_fs *fs, uint64_t mask)
 				mask & STATMOUNT_FS_TYPE ? "fs-type " : "",
 				mask & STATMOUNT_MNT_OPTS ? "mnt-opts " : "",
 				mask & STATMOUNT_SB_SOURCE ? "sb-source " : ""));
-
 	if (!rc)
 		rc = apply_statmount(fs, buf);
 done:
-
 	if (fs->stmnt)
 		mnt_statmnt_disable_fetching(fs->stmnt, status);
 	else
diff --git a/tests/helpers/test_sysinfo.c b/tests/helpers/test_sysinfo.c
index 95f50f3f6..00bf12727 100644
--- a/tests/helpers/test_sysinfo.c
+++ b/tests/helpers/test_sysinfo.c
@@ -145,13 +145,13 @@ static int hlp_fsopen_ok(void)
 
 static int hlp_statmount_ok(void)
 {
+	printf("%d\n",
 #ifdef HAVE_STATMOUNT_API
-	errno = 0;
-	ul_statmount(0, 0, 0, NULL, 0, 0);
+		has_statmount()
 #else
-	errno = ENOSYS;
+		0
 #endif
-	printf("%d\n", errno != ENOSYS);
+	);
 	return 0;
 }