32ce63371a
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@96 c046a42c-6fe2-441c-8c8c-71466251a162
143 lines
3.5 KiB
C
143 lines
3.5 KiB
C
/* Code to mangle pathnames into those matching a given prefix.
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eg. open("/lib/foo.so") => open("/usr/gnemul/i386-linux/lib/foo.so");
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The assumption is that this area does not change.
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*/
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#include <sys/types.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <stdio.h>
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#include "qemu.h"
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struct pathelem
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{
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/* Name of this, eg. lib */
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char *name;
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/* Full path name, eg. /usr/gnemul/x86-linux/lib. */
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char *pathname;
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struct pathelem *parent;
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/* Children */
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unsigned int num_entries;
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struct pathelem *entries[0];
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};
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static struct pathelem *base;
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/* First N chars of S1 match S2, and S2 is N chars long. */
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static int strneq(const char *s1, unsigned int n, const char *s2)
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{
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unsigned int i;
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for (i = 0; i < n; i++)
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if (s1[i] != s2[i])
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return 0;
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return s2[i] == 0;
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}
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static struct pathelem *add_entry(struct pathelem *root, const char *name);
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static struct pathelem *new_entry(const char *root,
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struct pathelem *parent,
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const char *name)
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{
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struct pathelem *new = malloc(sizeof(*new));
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new->name = strdup(name);
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asprintf(&new->pathname, "%s/%s", root, name);
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new->num_entries = 0;
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return new;
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}
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#define streq(a,b) (strcmp((a), (b)) == 0)
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static struct pathelem *add_dir_maybe(struct pathelem *path)
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{
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DIR *dir;
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if ((dir = opendir(path->pathname)) != NULL) {
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struct dirent *dirent;
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while ((dirent = readdir(dir)) != NULL) {
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if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
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path = add_entry(path, dirent->d_name);
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}
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}
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closedir(dir);
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}
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return path;
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}
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static struct pathelem *add_entry(struct pathelem *root, const char *name)
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{
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root->num_entries++;
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root = realloc(root, sizeof(*root)
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+ sizeof(root->entries[0])*root->num_entries);
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root->entries[root->num_entries-1] = new_entry(root->pathname, root, name);
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root->entries[root->num_entries-1]
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= add_dir_maybe(root->entries[root->num_entries-1]);
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return root;
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}
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/* This needs to be done after tree is stabalized (ie. no more reallocs!). */
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static void set_parents(struct pathelem *child, struct pathelem *parent)
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{
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unsigned int i;
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child->parent = parent;
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for (i = 0; i < child->num_entries; i++)
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set_parents(child->entries[i], child);
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}
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void init_paths(const char *prefix)
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{
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if (prefix[0] != '/' ||
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prefix[0] == '\0' ||
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!strcmp(prefix, "/"))
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return;
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base = new_entry("", NULL, prefix+1);
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base = add_dir_maybe(base);
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set_parents(base, base);
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}
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/* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */
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static const char *
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follow_path(const struct pathelem *cursor, const char *name)
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{
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unsigned int i, namelen;
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name += strspn(name, "/");
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namelen = strcspn(name, "/");
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if (namelen == 0)
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return cursor->pathname;
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if (strneq(name, namelen, ".."))
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return follow_path(cursor->parent, name + namelen);
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if (strneq(name, namelen, "."))
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return follow_path(cursor, name + namelen);
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for (i = 0; i < cursor->num_entries; i++)
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if (strneq(name, namelen, cursor->entries[i]->name))
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return follow_path(cursor->entries[i], name + namelen);
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/* Not found */
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return NULL;
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}
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/* Look for path in emulation dir, otherwise return name. */
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const char *path(const char *name)
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{
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/* Only do absolute paths: quick and dirty, but should mostly be OK.
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Could do relative by tracking cwd. */
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if (!base || name[0] != '/')
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return name;
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return follow_path(base, name) ?: name;
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}
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