109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/* This file contains routines for creating and manipulating path strings.
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*
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* The entry points into this file are:
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* make_path construct a path string for an inode
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* push_path add a path component to the end of a path string
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* pop_path remove the last path component from a path string
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*
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* Created:
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* April 2009 (D.C. van Moolenbroek)
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*/
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#include "inc.h"
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/*===========================================================================*
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* make_path *
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*===========================================================================*/
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int make_path(char path[PATH_MAX], struct inode *ino)
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{
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/* Given an inode, construct the path identifying that inode.
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*/
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char buf[PATH_MAX], *p, *prefix;
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size_t len, plen, total;
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p = &buf[sizeof(buf) - 1];
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p[0] = 0;
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dprintf(("%s: make_path: constructing path for inode %d\n",
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sffs_name, ino->i_num));
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/* Get the length of the prefix, skipping any leading slashes. */
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for (prefix = sffs_params->p_prefix; prefix[0] == '/'; prefix++);
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plen = strlen(prefix);
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/* Construct the path right-to-left in a temporary buffer first. */
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for (total = plen; ino != NULL && !IS_ROOT(ino); ino = ino->i_parent) {
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len = strlen(ino->i_name);
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total += len + 1;
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p -= len + 1;
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if (total >= sizeof(buf))
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return ENAMETOOLONG;
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p[0] = '/';
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memcpy(p + 1, ino->i_name, len);
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}
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/* If any of the intermediate inodes has no parent, the final inode is no
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* longer addressable by name.
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*/
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if (ino == NULL)
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return ENOENT;
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/* Put the result in the actual buffer. We need the leading slash in the
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* temporary buffer only when the prefix is not empty.
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*/
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if (!prefix[0] && p[0] == '/') p++;
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strlcpy(path, prefix, PATH_MAX);
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strlcpy(&path[plen], p, PATH_MAX - plen);
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dprintf(("%s: make_path: resulting path is '%s'\n", sffs_name, path));
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return OK;
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}
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/*===========================================================================*
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* push_path *
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*===========================================================================*/
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int push_path(char path[PATH_MAX], char *name)
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{
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/* Add a component to the end of a path.
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*/
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size_t len, add;
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len = strlen(path);
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add = strlen(name);
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if (len > 0) add++;
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if (len + add >= PATH_MAX)
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return ENAMETOOLONG;
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if (len > 0) path[len++] = '/';
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strlcpy(&path[len], name, PATH_MAX - len);
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return OK;
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}
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/*===========================================================================*
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* pop_path *
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*===========================================================================*/
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void pop_path(char path[PATH_MAX])
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{
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/* Remove the last component from a path.
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*/
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char *p;
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p = strrchr(path, '/');
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if (p == NULL) {
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p = path;
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/* Can't pop the root component */
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assert(p[0] != 0);
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}
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p[0] = 0;
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}
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