diff options
| author | rsc <devnull@localhost> | 2005-01-14 03:45:44 +0000 |
|---|---|---|
| committer | rsc <devnull@localhost> | 2005-01-14 03:45:44 +0000 |
| commit | 78e51a8c6678b6e3dff3d619aa786669f531f4bc (patch) | |
| tree | 015e00fde4fc837fd31b705e18d17dc913829388 /man/man3/9p-file.html | |
| parent | 2634795b5f0053bc0ff08e5d7bbc0eda8efea061 (diff) | |
| download | plan9port-78e51a8c6678b6e3dff3d619aa786669f531f4bc.tar.gz plan9port-78e51a8c6678b6e3dff3d619aa786669f531f4bc.tar.bz2 plan9port-78e51a8c6678b6e3dff3d619aa786669f531f4bc.zip | |
checkpoint
Diffstat (limited to 'man/man3/9p-file.html')
| -rw-r--r-- | man/man3/9p-file.html | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/man/man3/9p-file.html b/man/man3/9p-file.html new file mode 100644 index 00000000..63ae5042 --- /dev/null +++ b/man/man3/9p-file.html @@ -0,0 +1,258 @@ +<head> +<title>9p-file(3) - Plan 9 from User Space</title> +<meta content="text/html; charset=utf-8" http-equiv=Content-Type> +</head> +<body bgcolor=#ffffff> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=10><td> +<tr><td width=20><td> +<tr><td width=20><td><b>9P-FILE(3)</b><td align=right><b>9P-FILE(3)</b> +<tr><td width=20><td colspan=2> + <br> +<p><font size=+1><b>NAME </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Tree, alloctree, freetree, File, createfile, closefile, removefile, + walkfile, opendirfile, readdirfile, closedirfile, hasperm – in-memory + file hierarchy<br> + +</table> +<p><font size=+1><b>SYNOPSIS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>#include <u.h><br> + #include <libc.h><br> + #include <fcall.h><br> + #include <thread.h><br> + #include <9p.h><br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + typedef struct File<br> + {<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Ref;<br> + Dir;<br> + void*aux;<br> + + </table> + + </table> + </font></tt> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>...<br> + </i> + </table> + + </table> + <tt><font size=+1>} File;<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + typedef struct Tree<br> + {<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + File *root;<br> + + </table> + + </table> + </font></tt> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>...<br> + </i> + </table> + + </table> + <tt><font size=+1>} Tree;<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Tree* alloctree(char *uid, char *gid, ulong mode,<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + void (*destroy)(File*))<br> + + </table> + + </table> + void freetree(Tree *tree)<br> + File* createfile(File *dir, char *name, char *uid,<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + ulong mode, void *aux)<br> + + </table> + + </table> + int removefile(File *file)<br> + void closefile(File *file)<br> + File* walkfile(File *dir, char *path)<br> + Readdir* opendirfile(File *dir)<br> + long readdirfile(Readdir *rdir, char *buf, long n)<br> + void closedirfile(Readdir *rdir)<br> + int hasperm(File *file, char *uid, int p)<br> + </font></tt> +</table> +<p><font size=+1><b>DESCRIPTION </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>File</font></tt>s and <tt><font size=+1>Tree</font></tt>s provide an in-memory file hierarchy intended for + use in 9P file servers. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <i>Alloctree</i> creates a new tree of files, and <i>freetree</i> destroys it. + The root of the tree (also the <tt><font size=+1>root</font></tt> element in the structure) + will have mode <i>mode</i> and be owned by user <i>uid</i> and group <i>gid</i>. <i>Destroy</i> + is used when freeing <tt><font size=+1>File</font></tt> structures and is described later. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <tt><font size=+1>File</font></tt>s (including directories) other than the root are created + using <i>createfile</i>, which attempts to create a file named <i>name</i> in + the directory <i>dir</i>. If created, the file will have owner <i>uid</i> and + have a group inherited from the directory. <i>Mode</i> and the permissions + of <i>dir</i> are used to calculate the permission bits for the file + as + described in <i>open</i>(9p). It is permissible for <i>name</i> to be a slash-separated + path rather than a single element. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <i>Removefile</i> removes a file from the file tree. The file will not + be freed until the last reference to it has been removed. Directories + may only be removed when empty. <i>Removefile</i> returns zero on success, + –1 on error. It is correct to consider <i>removefile</i> to be <i>closefile</i> + with the side effect of removing the file when possible. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <i>Walkfile</i> evaluates <i>path</i> relative to the directory <i>dir</i>, returning + the resulting file, or zero if the named file or any intermediate + element does not exist. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + The <tt><font size=+1>File</font></tt> structure’s <tt><font size=+1>aux</font></tt> pointer may be used by the client for + per-<tt><font size=+1>File</font></tt> storage. <tt><font size=+1>File</font></tt>s are reference-counted: if not zero, <i>destroy</i> + (specified in the call to <i>alloctree</i>) will be called for each file + when its last reference is removed or when the tree is freed. + <i>Destroy</i> should take care of any necessary cleanup related to + <tt><font size=+1>aux</font></tt>. When creating new file references by copying pointers, call + <i>incref</i> (see <a href="../man3/lock.html"><i>lock</i>(3)</a>) to update the reference count. To note the + removal of a reference to a file, call <i>closefile</i>. <i>Createfile</i> and + <i>walkfile</i> return new references. <i>Removefile</i>, <i>closefile</i>, and <i>walkfile</i> + (but not <i>createfile</i>) consume the passed reference. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Directories may be read, yielding a directory entry structure + (see <i>stat</i>(9p)) for each file in the directory. In order to allow + concurrent reading of directories, clients must obtain a <tt><font size=+1>Readdir</font></tt> + structure by calling <i>opendirfile</i> on a directory. Subsequent calls + to <i>readdirfile</i> will each yield an integral number of machine- + independent stat buffers, until end of directory. When finished, + call <i>closedirfile</i> to free the <tt><font size=+1>Readdir</font></tt>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <i>Hasperm</i> does simplistic permission checking; it assumes only one-user + groups named by uid and returns non-zero if <i>uid</i> has permission + <i>p</i> (a bitwise-or of <tt><font size=+1>AREAD</font></tt>, <tt><font size=+1>AWRITE</font></tt> and <tt><font size=+1>AEXEC</font></tt>) according to <i>file</i><tt><font size=+1>−>mode</font></tt>. + 9P servers written using <tt><font size=+1>File</font></tt> trees will do standard permission + checks automatically; <i>hasperm</i> may be + called explicitly to do additional checks. A 9P server may link + against a different <i>hasperm</i> implementation to provide more complex + groups.<br> + +</table> +<p><font size=+1><b>EXAMPLE </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The following code correctly handles references when elementwise + walking a path and creating a file.<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>f = tree−>root;<br> + incref(f);<br> + for(i=0; i<n && f!=nil; i++)<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + f = walkfile(f, elem[i]);<br> + + </table> + if(f == nil)<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + return nil;<br> + + </table> + nf = createfile(f, "foo", "nls", 0666, nil);<br> + closefile(f);<br> + return nf;<br> + </font></tt> + </table> + +</table> +<p><font size=+1><b>SOURCE </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>/usr/local/plan9/src/lib9p/file.c<br> + </font></tt> +</table> +<p><font size=+1><b>SEE ALSO </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <a href="../man3/9p.html"><i>9p</i>(3)</a><br> + +</table> +<p><font size=+1><b>BUGS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The reference counting is cumbersome.<br> + +</table> + +<td width=20> +<tr height=20><td> +</table> +<!-- TRAILER --> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=15><td width=10><td><td width=10> +<tr><td><td> +<center> +<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> +</center> +</table> +<!-- TRAILER --> +</body></html> |