BSD syscalls: Filesystem namespace
Dispatch and catalog guide · Every number and configuration alternative
This page is generated from syscalls.master and authored descriptions.json. The signature is the master declaration, not the internal handler's (proc, args, retval) ABI. Descriptions identify selected local mechanisms; they do not claim every branch was audited.
9: link
int link(user_addr_t path, user_addr_t link);
Declaration: syscalls.master · Condition: always · Audit event: AUE_LINK.
Create a hard link, with the *at form accepting directory descriptors and lookup flags.
Implementation: link. linkat_internal resolves source/destination, checks authorization and same-filesystem constraints, then performs the vnode link operation and releases lookup references.
10: unlink
int unlink(user_addr_t path) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_UNLINK.
Remove a pathname through the shared unlink implementation.
Implementation: unlink. unlinkat_internal selects the operation's compatibility flags, resolves parent/target state and performs authorized vnode removal; name removal is distinct from final vnode/open-file destruction.
12: sys_chdir
int sys_chdir(user_addr_t path);
Declaration: syscalls.master · Condition: always · Audit event: AUE_CHDIR.
Set the current-directory context for the process or current pthread, respectively.
Implementation: sys_chdir. common_chdir resolves/checks a directory and selects process-wide or per-thread state according to the entry's mode; it replaces references rather than just storing the user pathname.
13: sys_fchdir
int sys_fchdir(int fd);
Declaration: syscalls.master · Condition: always · Audit event: AUE_FCHDIR.
Set process or per-thread current-directory context from an open descriptor.
Implementation: sys_fchdir. The shared fchdir helper obtains and checks the descriptor's directory vnode and updates the selected directory context with reference ownership.
14: mknod
int mknod(user_addr_t path, int mode, int dev);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKNOD.
Create a filesystem node, including eligible special-device nodes.
Implementation: mknod. Builds vnode attributes from mode/device inputs and calls mknodat_internal using current-directory or directory-fd lookup semantics.
56: revoke
int revoke(char *path);
Declaration: syscalls.master · Condition: always · Audit event: AUE_REVOKE.
Invalidate access through eligible character/block-device vnodes and aliases.
Implementation: revoke. Resolves the vnode, checks type/mount/ownership/MAC restrictions, and invokes VNOP_REVOKE; it does not implement generic regular-file descriptor revocation.
57: symlink
int symlink(char *path, char *link);
Declaration: syscalls.master · Condition: always · Audit event: AUE_SYMLINK.
Create a symbolic link containing the supplied target string.
Implementation: symlink. symlinkat_internal imports the link content and resolves/creates the destination under the selected directory context, then dispatches the vnode creation operation.
58: readlink
int readlink(char *path, char *buf, int count);
Declaration: syscalls.master · Condition: always · Audit event: AUE_READLINK.
Read a symlink's stored target bytes without following its final component.
Implementation: readlink. readlinkat_internal uses the requested lookup base and a user buffer/uio, then calls the vnode readlink operation; returned bytes need not include a terminating NUL.
61: chroot
int chroot(user_addr_t path);
Declaration: syscalls.master · Condition: always · Audit event: AUE_CHROOT.
Change the process's root-directory lookup context.
Implementation: chroot. Requires the local privilege/entitlement checks, resolves the directory through change_dir, applies MAC policy and replaces root/cwd-related vnode state; it is not a separate filesystem namespace implementation.
128: rename
int rename(char *from, char *to) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_RENAME.
Rename filesystem names; *at variants supply directory descriptors and the extended variant supplies operation flags.
Implementation: rename. renameat_internal coordinates both lookups, compound-operation/retry paths, authorization and the filesystem rename operation. Extended swap/exclusive semantics are flag-selected branches, not separate syscalls.
132: mkfifo
int mkfifo(user_addr_t path, int mode);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKFIFO.
Create a named pipe node, with optional directory-fd or extended security attributes.
Implementation: mkfifo. Builds vnode creation attributes and uses mkfifo1; the extended form first imports/frees filesec storage. Opening the resulting FIFO later constructs its data-transfer state.
136: mkdir
int mkdir(user_addr_t path, int mode);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKDIR.
Create a directory, with optional directory-relative lookup or extended security attributes.
Implementation: mkdir. Builds creation attributes and calls mkdir1at; the extended form imports/frees filesec data. Namespace publication occurs in the filesystem operation, not at argument copyin.
137: rmdir
int rmdir(char *path) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_RMDIR.
Remove an empty directory by pathname.
Implementation: rmdir. rmdirat_internal coordinates directory lookup/authorization and vnode removal, including the normal lookup cleanup.
205: undelete
int undelete(user_addr_t path);
Declaration: syscalls.master · Condition: always · Audit event: AUE_UNDELETE.
Retain a historical undelete syscall number without an implementation.
Implementation: undelete. The local handler immediately returns ENOTSUP; no name restoration or filesystem operation occurs.
223: exchangedata
int exchangedata(const char *path1, const char *path2, u_long options);
Declaration: syscalls.master · Condition: always · Audit event: AUE_EXCHANGEDATA.
Exchange data between eligible regular files.
Implementation: exchangedata. Resolves both vnodes, authorizes the exchange, handles lease/event bookkeeping and dispatches the filesystem exchange operation; its storage implementation is external for absent filesystems.
226: delete
int delete(user_addr_t path) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_DELETE.
Remove a pathname through the shared unlink implementation.
Implementation: delete. unlinkat_internal selects the operation's compatibility flags, resolves parent/target state and performs authorized vnode removal; name removal is distinct from final vnode/open-file destruction.
227: copyfile
int copyfile(char *from, char *to, int mode, int flags) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_COPYFILE.
Request the filesystem-level copyfile operation between names.
Implementation: copyfile. Resolves source/destination, checks MAC/authorization and leases, and invokes VNOP_COPYFILE; this syscall is not the entire userspace copyfile library's fallback implementation.
291: mkfifo_extended
int mkfifo_extended(user_addr_t path, uid_t uid, gid_t gid, int mode, user_addr_t xsecurity) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKFIFO_EXTENDED.
Create a named pipe node, with optional directory-fd or extended security attributes.
Implementation: mkfifo_extended. Builds vnode creation attributes and uses mkfifo1; the extended form first imports/frees filesec storage. Opening the resulting FIFO later constructs its data-transfer state.
292: mkdir_extended
int mkdir_extended(user_addr_t path, uid_t uid, gid_t gid, int mode, user_addr_t xsecurity) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKDIR_EXTENDED.
Create a directory, with optional directory-relative lookup or extended security attributes.
Implementation: mkdir_extended. Builds creation attributes and calls mkdir1at; the extended form imports/frees filesec data. Namespace publication occurs in the filesystem operation, not at argument copyin.
348: __pthread_chdir
int __pthread_chdir(user_addr_t path);
Declaration: syscalls.master · Condition: always · Audit event: AUE_NULL.
Set the current-directory context for the process or current pthread, respectively.
Implementation: __pthread_chdir. common_chdir resolves/checks a directory and selects process-wide or per-thread state according to the entry's mode; it replaces references rather than just storing the user pathname.
349: __pthread_fchdir
int __pthread_fchdir(int fd);
Declaration: syscalls.master · Condition: always · Audit event: AUE_NULL.
Set process or per-thread current-directory context from an open descriptor.
Implementation: __pthread_fchdir. The shared fchdir helper obtains and checks the descriptor's directory vnode and updates the selected directory context with reference ownership.
462: clonefileat
int clonefileat(int src_dirfd, user_addr_t src, int dst_dirfd, user_addr_t dst, uint32_t flags);
Declaration: syscalls.master · Condition: always · Audit event: AUE_CLONEFILEAT.
Clone a source pathname into a destination directory/name.
Implementation: clonefileat. Resolves source identity, then clonefile_internal validates and dispatches cloning to the filesystem. Copy-on-write extent behavior depends on that filesystem implementation.
465: renameat
int renameat(int fromfd, char *from, int tofd, char *to) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_RENAMEAT.
Rename filesystem names; *at variants supply directory descriptors and the extended variant supplies operation flags.
Implementation: renameat. renameat_internal coordinates both lookups, compound-operation/retry paths, authorization and the filesystem rename operation. Extended swap/exclusive semantics are flag-selected branches, not separate syscalls.
471: linkat
int linkat(int fd1, user_addr_t path, int fd2, user_addr_t link, int flag);
Declaration: syscalls.master · Condition: always · Audit event: AUE_LINKAT.
Create a hard link, with the *at form accepting directory descriptors and lookup flags.
Implementation: linkat. linkat_internal resolves source/destination, checks authorization and same-filesystem constraints, then performs the vnode link operation and releases lookup references.
472: unlinkat
int unlinkat(int fd, user_addr_t path, int flag) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_UNLINKAT.
Remove a directory-relative name or, with the directory flag, a directory.
Implementation: unlinkat. Selects rmdirat_internal for directory removal or unlinkat_internal otherwise, retaining the caller's directory-fd/flag semantics.
473: readlinkat
int readlinkat(int fd, user_addr_t path, user_addr_t buf, size_t bufsize);
Declaration: syscalls.master · Condition: always · Audit event: AUE_READLINKAT.
Read a symlink's stored target bytes without following its final component.
Implementation: readlinkat. readlinkat_internal uses the requested lookup base and a user buffer/uio, then calls the vnode readlink operation; returned bytes need not include a terminating NUL.
474: symlinkat
int symlinkat(user_addr_t *path1, int fd, user_addr_t path2);
Declaration: syscalls.master · Condition: always · Audit event: AUE_SYMLINKAT.
Create a symbolic link containing the supplied target string.
Implementation: symlinkat. symlinkat_internal imports the link content and resolves/creates the destination under the selected directory context, then dispatches the vnode creation operation.
475: mkdirat
int mkdirat(int fd, user_addr_t path, int mode);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKDIRAT.
Create a directory, with optional directory-relative lookup or extended security attributes.
Implementation: mkdirat. Builds creation attributes and calls mkdir1at; the extended form imports/frees filesec data. Namespace publication occurs in the filesystem operation, not at argument copyin.
488: renameatx_np
int renameatx_np(int fromfd, char *from, int tofd, char *to, u_int flags) NO_SYSCALL_STUB;
Declaration: syscalls.master · Condition: always · Audit event: AUE_RENAMEAT.
Rename filesystem names; *at variants supply directory descriptors and the extended variant supplies operation flags.
Implementation: renameatx_np. renameat_internal coordinates both lookups, compound-operation/retry paths, authorization and the filesystem rename operation. Extended swap/exclusive semantics are flag-selected branches, not separate syscalls.
517: fclonefileat
int fclonefileat(int src_fd, int dst_dirfd, user_addr_t dst, uint32_t flags);
Declaration: syscalls.master · Condition: always · Audit event: AUE_FCLONEFILEAT.
Clone an open source file into a destination directory/name.
Implementation: fclonefileat. Pins the source fileproc/vnode, calls clonefile_internal, and drops both references on completion; filesystem cloning remains behind the VNOP boundary.
551: freadlink
int freadlink(int fd, user_addr_t buf, user_size_t bufsize);
Declaration: syscalls.master · Condition: always · Audit event: AUE_FREADLINK.
Read symlink content through an existing descriptor.
Implementation: freadlink. Takes a vnode reference from the descriptor, passes that vnode to readlinkat_internal, and drops it after the read.
553: mkfifoat
int mkfifoat(int fd, user_addr_t path, int mode);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKFIFOAT.
Create a named pipe node, with optional directory-fd or extended security attributes.
Implementation: mkfifoat. Builds vnode creation attributes and uses mkfifo1; the extended form first imports/frees filesec storage. Opening the resulting FIFO later constructs its data-transfer state.
554: mknodat
int mknodat(int fd, user_addr_t path, int mode, int dev);
Declaration: syscalls.master · Condition: always · Audit event: AUE_MKNODAT.
Create a filesystem node, including eligible special-device nodes.
Implementation: mknodat. Builds vnode attributes from mode/device inputs and calls mknodat_internal using current-directory or directory-fd lookup semantics.