1 files changed, 430 insertions, 0 deletions
diff --git a/src/prefix.cpp b/src/prefix.cpp
new file mode 100644
index 0000000..1712841
--- /dev/null
+++ b/src/prefix.cpp
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+/*
+ * BinReloc - a library for creating relocatable executables
+ * Written by: Mike Hearn <mike@theoretic.com>
+ *             Hongli Lai <h.lai@chello.nl>
+ * http://autopackage.org/
+ *
+ * This source code is public domain. You can relicense this code
+ * under whatever license you want.
+ *
+ * NOTE: if you're using C++ and are getting "undefined reference
+ * to br_*", try renaming prefix.c to prefix.cpp
+ */
+
+/* WARNING, BEFORE YOU MODIFY PREFIX.C:
+ *
+ * If you make changes to any of the functions in prefix.c, you MUST
+ * change the BR_NAMESPACE macro (in prefix.h).
+ * This way you can avoid symbol table conflicts with other libraries
+ * that also happen to use BinReloc.
+ *
+ * Example:
+ * #define BR_NAMESPACE(funcName) foobar_ ## funcName
+ * --> expands br_locate to foobar_br_locate
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"  // only include where actually required!
+#endif
+
+#ifndef _PREFIX_C_
+#define _PREFIX_C_
+
+#include <glib.h>
+#include <cstdlib>
+#include <cstdio>
+#include <cstring>
+#include "prefix.h"
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+
+#ifdef __GNUC__
+    #define br_return_val_if_fail(expr,val) if (!(expr)) {fprintf (stderr, "** BinReloc (%s): assertion %s failed\n", __PRETTY_FUNCTION__, #expr); return val;}
+#else
+    #define br_return_val_if_fail(expr,val) if (!(expr)) return val
+#endif /* __GNUC__ */
+
+
+#ifdef ENABLE_BINRELOC
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <unistd.h>
+
+/**
+ * br_locate:
+ * symbol: A symbol that belongs to the app/library you want to locate.
+ * Returns: A newly allocated string containing the full path of the
+ *        app/library that func belongs to, or NULL on error. This
+ *        string should be freed when not when no longer needed.
+ *
+ * Finds out to which application or library symbol belongs, then locate
+ * the full path of that application or library.
+ * Note that symbol cannot be a pointer to a function. That will not work.
+ *
+ * Example:
+ * --> main.c
+ * #include "prefix.h"
+ * #include "libfoo.h"
+ *
+ * int main (int argc, char *argv[]) {
+ *    printf ("Full path of this app: %s\n", br_locate (&argc));
+ *    libfoo_start ();
+ *    return 0;
+ * }
+ *
+ * --> libfoo.c starts here
+ * #include "prefix.h"
+ *
+ * void libfoo_start () {
+ *    --> "" is a symbol that belongs to libfoo (because it's called
+ *    --> from libfoo_start()); that's why this works.
+ *    printf ("libfoo is located in: %s\n", br_locate (""));
+ * }
+ */
+char *
+br_locate (void *symbol)
+{
+    char line[5000];
+    FILE *f;
+    char *path;
+
+    br_return_val_if_fail (symbol != NULL, NULL);
+
+    f = fopen ("/proc/self/maps", "r");
+    if (!f)
+        return NULL;
+
+    while (!feof (f))
+    {
+        unsigned long start, end;
+
+        if (!fgets (line, sizeof (line), f))
+            continue;
+
+        int inode = 0;
+        if (sscanf(line, "%lx-%lx r%*s %*x %*s %d", &start, &end, &inode) != 3 || inode == 0)
+            continue;
+
+        if (symbol >= (void *) start && symbol < (void *) end)
+        {
+            char *tmp;
+            size_t len;
+
+            /* Extract the filename; it is always an absolute path */
+            path = strchr (line, '/');
+            if (!path)
+                continue;
+
+            /* Get rid of the newline */
+            tmp = strrchr (path, '\n');
+            if (tmp) *tmp = 0;
+
+            /* Get rid of "(deleted)" */
+            len = strlen (path);
+            if (len > 10 && strcmp (path + len - 10, " (deleted)") == 0)
+            {
+                tmp = path + len - 10;
+                *tmp = 0;
+            }
+
+            fclose(f);
+            return strdup (path);
+        }
+    }
+
+    fclose (f);
+    return NULL;
+}
+
+
+/**
+ * br_locate_prefix:
+ * symbol: A symbol that belongs to the app/library you want to locate.
+ * Returns: A prefix. This string should be freed when no longer needed.
+ *
+ * Locates the full path of the app/library that symbol belongs to, and return
+ * the prefix of that path, or NULL on error.
+ * Note that symbol cannot be a pointer to a function. That will not work.
+ *
+ * Example:
+ * --> This application is located in /usr/bin/foo
+ * br_locate_prefix (&argc);   --> returns: "/usr"
+ */
+char *
+br_locate_prefix (void *symbol)
+{
+    char *path, *prefix;
+
+    br_return_val_if_fail (symbol != NULL, NULL);
+
+    path = br_locate (symbol);
+    if (!path) return NULL;
+
+    prefix = br_extract_prefix (path);
+    free (path);
+    return prefix;
+}
+
+
+/**
+ * br_prepend_prefix:
+ * symbol: A symbol that belongs to the app/library you want to locate.
+ * path: The path that you want to prepend the prefix to.
+ * Returns: The new path, or NULL on error. This string should be freed when no
+ *        longer needed.
+ *
+ * Gets the prefix of the app/library that symbol belongs to. Prepend that prefix to path.
+ * Note that symbol cannot be a pointer to a function. That will not work.
+ *
+ * Example:
+ * --> The application is /usr/bin/foo
+ * br_prepend_prefix (&argc, "/share/foo/data.png");   --> Returns "/usr/share/foo/data.png"
+ */
+char *
+br_prepend_prefix (void *symbol, char const *path)
+{
+    char *tmp, *newpath;
+
+    br_return_val_if_fail (symbol != NULL, NULL);
+    br_return_val_if_fail (path != NULL, NULL);
+
+    tmp = br_locate_prefix (symbol);
+    if (!tmp) return NULL;
+
+    if (strcmp (tmp, "/") == 0)
+        newpath = strdup (path);
+    else
+        newpath = br_strcat (tmp, path);
+
+    /* Get rid of compiler warning ("br_prepend_prefix never used") */
+    if (0) br_prepend_prefix (NULL, NULL);
+
+    free (tmp);
+    return newpath;
+}
+
+#endif /* ENABLE_BINRELOC */
+
+
+/* Thread stuff for thread safetiness */
+#if BR_THREADS
+
+GPrivate* br_thread_key = (GPrivate *)NULL;
+
+/*
+   We do not need local store init() or fini(), because
+   g_private_new (g_free) will take care of all of that
+   for us.  Isn't GLib wonderful?
+*/
+
+#else /* !BR_THREADS */
+
+static char *br_last_value = (char*)nullptr;
+
+static void
+br_free_last_value ()
+{
+    if (br_last_value)
+        free (br_last_value);
+}
+
+#endif /* BR_THREADS */
+
+
+/**
+ * br_thread_local_store:
+ * str: A dynamically allocated string.
+ * Returns: str. This return value must not be freed.
+ *
+ * Store str in a thread-local variable and return str. The next
+ * you run this function, that variable is freed too.
+ * This function is created so you don't have to worry about freeing
+ * strings.
+ *
+ * Example:
+ * char *foo;
+ * foo = thread_local_store (strdup ("hello")); --> foo == "hello"
+ * foo = thread_local_store (strdup ("world")); --> foo == "world"; "hello" is now freed.
+ */
+const char *
+br_thread_local_store (char *str)
+{
+    #if BR_THREADS
+                if (!g_thread_supported ())
+                    {
+                    g_thread_init ((GThreadFunctions *)NULL);
+                    br_thread_key = g_private_new (g_free);
+                    }
+
+        char *specific = (char *) g_private_get (br_thread_key);
+        if (specific)
+                    free (specific);
+                g_private_set (br_thread_key, str);
+
+    #else /* !BR_THREADS */
+        static int initialized = 0;
+
+        if (!initialized)
+        {
+            atexit (br_free_last_value);
+            initialized = 1;
+        }
+
+        if (br_last_value)
+            free (br_last_value);
+        br_last_value = str;
+    #endif /* BR_THREADS */
+
+    return (const char *) str;
+}
+
+
+/**
+ * br_strcat:
+ * str1: A string.
+ * str2: Another string.
+ * Returns: A newly-allocated string. This string should be freed when no longer needed.
+ *
+ * Concatenate str1 and str2 to a newly allocated string.
+ */
+char *
+br_strcat (const char *str1, const char *str2)
+{
+    char *result;
+    size_t len1, len2;
+
+    if (!str1) str1 = "";
+    if (!str2) str2 = "";
+
+    len1 = strlen (str1);
+    len2 = strlen (str2);
+
+    result = (char *) malloc (len1 + len2 + 1);
+    memcpy (result, str1, len1);
+    memcpy (result + len1, str2, len2);
+    result[len1 + len2] = '\0';
+
+    return result;
+}
+
+
+/* Emulates glibc's strndup() */
+static char *
+br_strndup (char *str, size_t size)
+{
+    char *result = (char*)nullptr;
+    size_t len;
+
+    br_return_val_if_fail (str != (char*)nullptr, (char*)nullptr);
+
+    len = strlen (str);
+    if (!len) return strdup ("");
+    if (size > len) size = len;
+
+    result = (char *) calloc (sizeof (char), len + 1);
+    memcpy (result, str, size);
+    return result;
+}
+
+
+/**
+ * br_extract_dir:
+ * path: A path.
+ * Returns: A directory name. This string should be freed when no longer needed.
+ *
+ * Extracts the directory component of path. Similar to g_path_get_dirname()
+ * or the dirname commandline application.
+ *
+ * Example:
+ * br_extract_dir ("/usr/local/foobar");  --> Returns: "/usr/local"
+ */
+char *
+br_extract_dir (const char *path)
+{
+    const char *end;
+    char *result;
+
+    br_return_val_if_fail (path != (char*)nullptr, (char*)nullptr);
+
+    end = strrchr (path, '/');
+    if (!end) return strdup (".");
+
+    while (end > path && *end == '/')
+        end--;
+    result = br_strndup ((char *) path, end - path + 1);
+    if (!*result)
+    {
+        free (result);
+        return strdup ("/");
+    } else
+        return result;
+}
+
+
+/**
+ * br_extract_prefix:
+ * path: The full path of an executable or library.
+ * Returns: The prefix, or NULL on error. This string should be freed when no longer needed.
+ *
+ * Extracts the prefix from path. This function assumes that your executable
+ * or library is installed in an LSB-compatible directory structure.
+ *
+ * Example:
+ * br_extract_prefix ("/usr/bin/gnome-panel");       --> Returns "/usr"
+ * br_extract_prefix ("/usr/local/lib/libfoo.so");   --> Returns "/usr/local"
+ * br_extract_prefix ("/usr/local/libfoo.so");       --> Returns "/usr"
+ */
+char *
+br_extract_prefix (const char *path)
+{
+    const char *end;
+    char *tmp, *result;
+
+    br_return_val_if_fail (path != (char*)nullptr, (char*)nullptr);
+
+    if (!*path) return strdup ("/");
+    end = strrchr (path, '/');
+    if (!end) return strdup (path);
+
+    tmp = br_strndup ((char *) path, end - path);
+    if (!*tmp)
+    {
+        free (tmp);
+        return strdup ("/");
+    }
+    end = strrchr (tmp, '/');
+    if (!end) return tmp;
+
+    result = br_strndup (tmp, end - tmp);
+    free (tmp);
+
+    if (!*result)
+    {
+        free (result);
+        result = strdup ("/");
+    }
+
+    return result;
+}
+
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* _PREFIX_C */