cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

path.c (1809B)

      1/* Code to mangle pathnames into those matching a given prefix.
      2   eg. open("/lib/foo.so") => open("/usr/gnemul/i386-linux/lib/foo.so");
      3
      4   The assumption is that this area does not change.
      5*/
      6#include "qemu/osdep.h"
      7#include <sys/param.h>
      8#include <dirent.h>
      9#include "qemu/cutils.h"
     10#include "qemu/path.h"
     11#include "qemu/thread.h"
     12
     13static const char *base;
     14static GHashTable *hash;
     15static QemuMutex lock;
     16
     17void init_paths(const char *prefix)
     18{
     19    if (prefix[0] == '\0' || !strcmp(prefix, "/")) {
     20        return;
     21    }
     22
     23    if (prefix[0] == '/') {
     24        base = g_strdup(prefix);
     25    } else {
     26        char *cwd = g_get_current_dir();
     27        base = g_build_filename(cwd, prefix, NULL);
     28        g_free(cwd);
     29    }
     30
     31    hash = g_hash_table_new(g_str_hash, g_str_equal);
     32    qemu_mutex_init(&lock);
     33}
     34
     35/* Look for path in emulation dir, otherwise return name. */
     36const char *path(const char *name)
     37{
     38    gpointer key, value;
     39    const char *ret;
     40
     41    /* Only do absolute paths: quick and dirty, but should mostly be OK.  */
     42    if (!base || !name || name[0] != '/') {
     43        return name;
     44    }
     45
     46    qemu_mutex_lock(&lock);
     47
     48    /* Have we looked up this file before?  */
     49    if (g_hash_table_lookup_extended(hash, name, &key, &value)) {
     50        ret = value ? value : name;
     51    } else {
     52        char *save = g_strdup(name);
     53        char *full = g_build_filename(base, name, NULL);
     54
     55        /* Look for the path; record the result, pass or fail.  */
     56        if (access(full, F_OK) == 0) {
     57            /* Exists.  */
     58            g_hash_table_insert(hash, save, full);
     59            ret = full;
     60        } else {
     61            /* Does not exist.  */
     62            g_free(full);
     63            g_hash_table_insert(hash, save, NULL);
     64            ret = name;
     65        }
     66    }
     67
     68    qemu_mutex_unlock(&lock);
     69    return ret;
     70}