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/*
* 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
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
/*
* enrico - all the code below is only compiled and used if ENABLE_BINRELOC is set in config.h,
* this only happens if configure option --enable-binreloc was used
*/
#ifdef ENABLE_BINRELOC
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <string.h>
#include <glib.h>
#include "prefix.h"
#undef NULL
#define NULL ((void *) 0)
#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__ */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <unistd.h>
static char *br_last_value = (char*)NULL;
static void
br_free_last_value ()
{
if (br_last_value)
free (br_last_value);
}
/**
* 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)
{
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;
return (const char *) str;
}
/**
* 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;
if (!strstr (line, " r-xp ") || !strchr (line, '/'))
continue;
sscanf (line, "%lx-%lx ", &start, &end);
if (symbol >= (void *) start && symbol < (void *) end)
{
char *tmp;
gsize len;
/* Extract the filename; it is always an absolute path */
path = strchr (line, '/');
/* 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_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)
{
char *end, *tmp, *result;
br_return_val_if_fail (path != (char*)NULL, (char*)NULL);
if (!*path) return strdup ("/");
end = strrchr (path, '/');
if (!end) return strdup (path);
tmp = g_strndup ((char *) path, end - path);
if (!*tmp)
{
g_free (tmp);
return strdup ("/");
}
end = strrchr (tmp, '/');
if (!end) return tmp;
result = g_strndup (tmp, end - tmp);
g_free (tmp);
if (!*result)
{
g_free (result);
result = strdup ("/");
}
return result;
}
/**
* 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 *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 = g_strconcat (tmp, path, NULL);
free (tmp);
return newpath;
}
#else /* ENABLE_BINRELOC */
typedef int iso_c_forbids_an_empty_source_file;
#endif /* ENABLE_BINRELOC */
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