stat(3) - Plan 9 from User Space

From adc93f6097615f16d57e8a24a256302f2144ec4e Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 17:37:50 +0000 Subject: cut out the html - they're going to cause diffing problems. --- man/man3/stat.html | 244 ----------------------------------------------------- 1 file changed, 244 deletions(-) delete mode 100644 man/man3/stat.html (limited to 'man/man3/stat.html') diff --git a/man/man3/stat.html b/man/man3/stat.html deleted file mode 100644 index fb79a647..00000000 --- a/man/man3/stat.html +++ /dev/null @@ -1,244 +0,0 @@ - -stat(3) - Plan 9 from User Space - - - - -

STAT(3) STAT(3) -

-
-

NAME
- -
- - stat, fstat, wstat, fwstat, dirstat, dirfstat, dirwstat, dirfwstat, - nulldir – get and put file status
- -
-

SYNOPSIS
- -
- - #include <u.h> - #include <libc.h> - - - int stat(char *name, uchar *edir, int nedir) - - - int fstat(int fd, uchar *edir, int nedir) - - - int wstat(char *name, uchar *edir, int nedir) - - - int fwstat(int fd, uchar *edir, int nedir) - - - Dir* dirstat(char *name) - - - Dir* dirfstat(int fd) - - - int dirwstat(char *name, Dir *dir) - - - int dirfwstat(int fd, Dir *dir) - - - void nulldir(Dir *d) - -
-

DESCRIPTION
- -
- - Given a file’s name, or an open file descriptor fd, these routines - retrieve or modify file status information. Stat, fstat, wstat, - and fwstat are the system calls; they deal with machine-independent - directory entries. Their format is defined by stat(9p). Stat and - fstat retrieve information about name or fd into edir, a buffer - of length nedir, defined in <libc.h>. Wstat and fwstat write information - back, thus changing file attributes according to the contents - of edir. The data returned from the kernel includes its leading - 16-bit length field as described in intro(9p). For symmetry, this - field must also be present when passing data to the - kernel in a call to wstat and fwstat, but its value is ignored. - -
- - Dirstat, dirfstat, dirwstat, and dirfwstat are similar to their - counterparts, except that they operate on Dir structures:
- -
- - typedef - struct Dir { - - - - /* system−modified data */ - uint    type;      /* server type */ - uint    dev;       /* server subtype */ - /* file data */ - Qid     qid;       /* unique id from server */ - ulong mode;      /* permissions */ - ulong atime;     /* last read time */ - ulong mtime;     /* last write time */ - vlong length;    /* file length: see <u.h> */ - char    *name;     /* last element of path */ - char    *uid;      /* owner name */ - char    *gid;      /* group name */ - char    *muid;     /* last modifier name */ - - - } Dir; - - - - -
- The returned structure is allocated by malloc(3); freeing it also - frees the associated strings. -
- - This structure and the Qid structure are defined in <libc.h>. If - the file resides on permanent storage and is not a directory, - the length returned by stat is the number of bytes in the file. - For directories, the length returned is zero. For files that are - streams (e.g., pipes and network connections), the length is the - number of bytes that can be read without blocking. -
- - Each file is the responsibility of some server: it could be a - file server, a kernel device, or a user process. Type identifies - the server type, and dev says which of a group of servers of the - same type is the one responsible for this file. Qid is a structure - containing path and vers fields: path is guaranteed to be - unique among all path names currently on the file server, and - vers changes each time the file is modified. The path is a long - long (64 bits, vlong) and the vers is an unsigned long (32 bits, - ulong). Thus, if two files have the same type, dev, and qid they - are the same file. -
- - The bits in mode are defined by -
- - -
- - 0x80000000     directory
- 0x40000000     append only
- 0x20000000     exclusive use (locked)
- -
- - 0400     read permission by owner
- 0200     write permission by owner
- 0100     execute permission (search on directory) by owner
- 0070     read, write, execute (search) by group
- 0007     read, write, execute (search) by others
- -
- - -
- -
- There are constants defined in <libc.h> for these bits: DMDIR, DMAPPEND, - and DMEXCL for the first three; and DMREAD, DMWRITE, and DMEXEC - for the read, write, and execute bits for others. -
- - The two time fields are measured in seconds since the epoch (Jan - 1 00:00 1970 GMT). Mtime is the time of the last change of content. - Similarly, atime is set whenever the contents are accessed; also, - it is set whenever mtime is set. -
- - Uid and gid are the names of the owner and group of the file; - muid is the name of the user that last modified the file (setting - mtime). Groups are also users, but each server is free to associate - a list of users with any user name g, and that list is the set - of users in the group g. When an initial attachment is made to - a - server, the user string in the process group is communicated to - the server. Thus, the server knows, for any given file access, - whether the accessing process is the owner of, or in the group - of, the file. This selects which sets of three bits in mode is - used to check permissions. -
- - Only some of the fields may be changed with the wstat calls. The - name can be changed by anyone with write permission in the parent - directory. The mode and mtime can be changed by the owner or the - group leader of the file’s current group. The gid can be changed: - by the owner if also a member of the new - group; or by the group leader of the file’s current group if also - leader of the new group (see intro(9p) for more information about - permissions, users, and groups). The length can be changed by - anyone with write permission, provided the operation is implemented - by the server. (See intro(9p) for permission, user, - and group information). -
- - Special values in the fields of the Dir passed to wstat indicate - that the field is not intended to be changed by the call. The - values are the maximum unsigned integer of appropriate size for - integral values (usually ~0, but beware of conversions and size - mismatches when comparing values) and the empty or nil string - for string values. The routine nulldir initializes all the elements - of d to these “don’t care” values. Thus one may change the mode, - for example, by using nulldir to initialize a Dir, then setting - the mode, and then doing wstat; it is not necessary to use stat - to retrieve the initial values first. - -
-

SOURCE
- -
- - /usr/local/plan9/src/lib9/dirstat.c - -
-

SEE ALSO
- -
- - intro(3), fcall(3), dirread(3), stat(9p)
- -
-

DIAGNOSTICS
- -
- - The dir functions return a pointer to the data for a successful - call, or nil on error. The others return the number of bytes copied - on success, or –1 on error. All set errstr. -
- - If the buffer for stat or fstat is too short for the returned - data, the return value will be BIT16SZ (see fcall(3)) and the - two bytes returned will contain the initial count field of the - returned data; retrying with nedir equal to that value plus BIT16SZ - (for the count itself) should succeed.
- -
- -

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