qemu

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/* 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 "qemu/osdep.h"
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#include <sys/param.h>
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#include <dirent.h>
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#include "qemu/cutils.h"
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#include "qemu/path.h"
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#include "qemu/thread.h"
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static const char *base;
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static GHashTable *hash;
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static QemuMutex lock;
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void init_paths(const char *prefix)
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{
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    if (prefix[0] == '\0' || !strcmp(prefix, "/")) {
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        return;
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    }
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    if (prefix[0] == '/') {
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        base = g_strdup(prefix);
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    } else {
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        char *cwd = g_get_current_dir();
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        base = g_build_filename(cwd, prefix, NULL);
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        g_free(cwd);
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    }
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    hash = g_hash_table_new(g_str_hash, g_str_equal);
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    qemu_mutex_init(&lock);
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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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    gpointer key, value;
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    const char *ret;
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    /* Only do absolute paths: quick and dirty, but should mostly be OK.  */
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    if (!base || !name || name[0] != '/') {
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        return name;
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    }
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    qemu_mutex_lock(&lock);
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    /* Have we looked up this file before?  */
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    if (g_hash_table_lookup_extended(hash, name, &key, &value)) {
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        ret = value ? value : name;
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    } else {
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        char *save = g_strdup(name);
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        char *full = g_build_filename(base, name, NULL);
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        /* Look for the path; record the result, pass or fail.  */
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        if (access(full, F_OK) == 0) {
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            /* Exists.  */
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            g_hash_table_insert(hash, save, full);
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            ret = full;
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        } else {
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            /* Does not exist.  */
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            g_free(full);
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            g_hash_table_insert(hash, save, NULL);
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            ret = name;
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        }
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    }
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    qemu_mutex_unlock(&lock);
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    return ret;
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}
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