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authorDavid Howells <dhowells@redhat.com>2018-11-01 23:36:09 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2019-03-20 18:49:06 -0400
commitecdab150fddb42fe6a739335257949220033b782 (patch)
treedf036d4821bb48fe0f369cc91087fcf442d72339 /arch/x86/entry
parent007ec26cdc9fefacbed85b592afc69413194499c (diff)
vfs: syscall: Add fsconfig() for configuring and managing a context
Add a syscall for configuring a filesystem creation context and triggering actions upon it, to be used in conjunction with fsopen, fspick and fsmount. long fsconfig(int fs_fd, unsigned int cmd, const char *key, const void *value, int aux); Where fs_fd indicates the context, cmd indicates the action to take, key indicates the parameter name for parameter-setting actions and, if needed, value points to a buffer containing the value and aux can give more information for the value. The following command IDs are proposed: (*) FSCONFIG_SET_FLAG: No value is specified. The parameter must be boolean in nature. The key may be prefixed with "no" to invert the setting. value must be NULL and aux must be 0. (*) FSCONFIG_SET_STRING: A string value is specified. The parameter can be expecting boolean, integer, string or take a path. A conversion to an appropriate type will be attempted (which may include looking up as a path). value points to a NUL-terminated string and aux must be 0. (*) FSCONFIG_SET_BINARY: A binary blob is specified. value points to the blob and aux indicates its size. The parameter must be expecting a blob. (*) FSCONFIG_SET_PATH: A non-empty path is specified. The parameter must be expecting a path object. value points to a NUL-terminated string that is the path and aux is a file descriptor at which to start a relative lookup or AT_FDCWD. (*) FSCONFIG_SET_PATH_EMPTY: As fsconfig_set_path, but with AT_EMPTY_PATH implied. (*) FSCONFIG_SET_FD: An open file descriptor is specified. value must be NULL and aux indicates the file descriptor. (*) FSCONFIG_CMD_CREATE: Trigger superblock creation. (*) FSCONFIG_CMD_RECONFIGURE: Trigger superblock reconfiguration. For the "set" command IDs, the idea is that the file_system_type will point to a list of parameters and the types of value that those parameters expect to take. The core code can then do the parse and argument conversion and then give the LSM and FS a cooked option or array of options to use. Source specification is also done the same way same way, using special keys "source", "source1", "source2", etc.. [!] Note that, for the moment, the key and value are just glued back together and handed to the filesystem. Every filesystem that uses options uses match_token() and co. to do this, and this will need to be changed - but not all at once. Example usage: fd = fsopen("ext4", FSOPEN_CLOEXEC); fsconfig(fd, fsconfig_set_path, "source", "/dev/sda1", AT_FDCWD); fsconfig(fd, fsconfig_set_path_empty, "journal_path", "", journal_fd); fsconfig(fd, fsconfig_set_fd, "journal_fd", "", journal_fd); fsconfig(fd, fsconfig_set_flag, "user_xattr", NULL, 0); fsconfig(fd, fsconfig_set_flag, "noacl", NULL, 0); fsconfig(fd, fsconfig_set_string, "sb", "1", 0); fsconfig(fd, fsconfig_set_string, "errors", "continue", 0); fsconfig(fd, fsconfig_set_string, "data", "journal", 0); fsconfig(fd, fsconfig_set_string, "context", "unconfined_u:...", 0); fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0); mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC); or: fd = fsopen("ext4", FSOPEN_CLOEXEC); fsconfig(fd, fsconfig_set_string, "source", "/dev/sda1", 0); fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0); mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC); or: fd = fsopen("afs", FSOPEN_CLOEXEC); fsconfig(fd, fsconfig_set_string, "source", "#grand.central.org:root.cell", 0); fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0); mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC); or: fd = fsopen("jffs2", FSOPEN_CLOEXEC); fsconfig(fd, fsconfig_set_string, "source", "mtd0", 0); fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0); mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC); Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-api@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/x86/entry')
-rw-r--r--arch/x86/entry/syscalls/syscall_32.tbl3
-rw-r--r--arch/x86/entry/syscalls/syscall_64.tbl1
2 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 37fd1fc5396e..786728143205 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -401,7 +401,8 @@
387 i386 open_tree sys_open_tree __ia32_sys_open_tree
388 i386 move_mount sys_move_mount __ia32_sys_move_mount
389 i386 fsopen sys_fsopen __ia32_sys_fsopen
-# don't use numbers 390 through 392, add new calls at the end
+390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
+# don't use numbers 391 through 392, add new calls at the end
393 i386 semget sys_semget __ia32_sys_semget
394 i386 semctl sys_semctl __ia32_compat_sys_semctl
395 i386 shmget sys_shmget __ia32_sys_shmget
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 511608a21611..7039a809d37d 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -346,6 +346,7 @@
335 common open_tree __x64_sys_open_tree
336 common move_mount __x64_sys_move_mount
337 common fsopen __x64_sys_fsopen
+338 common fsconfig __x64_sys_fsconfig
# don't use numbers 387 through 423, add new calls after the last
# 'common' entry
424 common pidfd_send_signal __x64_sys_pidfd_send_signal