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* BinReloc - a library for creating relocatable executables
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* Written by: Mike Hearn <mike@theoretic.com>
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* Hongli Lai <h.lai@chello.nl>
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* http://autopackage.org/
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* This source code is public domain. You can relicense this code
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* under whatever license you want.
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* NOTE: if you're using C++ and are getting "undefined reference
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* to br_*", try renaming prefix.c to prefix.cpp
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* enrico - all the code below is only compiled and used if ENABLE_BINRELOC is set in config.h,
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* this only happens if configure option --enable-binreloc was used
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#ifdef ENABLE_BINRELOC
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#define NULL ((void *) 0)
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#define br_return_val_if_fail(expr,val) if (!(expr)) {fprintf (stderr, "** BinReloc (%s): assertion %s failed\n", __PRETTY_FUNCTION__, #expr); return val;}
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#define br_return_val_if_fail(expr,val) if (!(expr)) return val
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#include <sys/types.h>
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#include <sys/param.h>
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static char *br_last_value = (char*)NULL;
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* br_thread_local_store:
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* str: A dynamically allocated string.
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* Returns: str. This return value must not be freed.
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* Store str in a thread-local variable and return str. The next
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* you run this function, that variable is freed too.
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* This function is created so you don't have to worry about freeing
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* foo = thread_local_store (strdup ("hello")); --> foo == "hello"
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* foo = thread_local_store (strdup ("world")); --> foo == "world"; "hello" is now freed.
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br_thread_local_store (char *str)
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static int initialized = 0;
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atexit (br_free_last_value);
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return (const char *) str;
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* symbol: A symbol that belongs to the app/library you want to locate.
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* Returns: A newly allocated string containing the full path of the
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* app/library that func belongs to, or NULL on error. This
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* string should be freed when not when no longer needed.
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* Finds out to which application or library symbol belongs, then locate
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* the full path of that application or library.
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* Note that symbol cannot be a pointer to a function. That will not work.
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* #include "prefix.h"
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* #include "libfoo.h"
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* int main (int argc, char *argv[]) {
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* printf ("Full path of this app: %s\n", br_locate (&argc));
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* --> libfoo.c starts here
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* #include "prefix.h"
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* void libfoo_start () {
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* --> "" is a symbol that belongs to libfoo (because it's called
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* --> from libfoo_start()); that's why this works.
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* printf ("libfoo is located in: %s\n", br_locate (""));
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br_locate (void *symbol)
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br_return_val_if_fail (symbol != NULL, NULL);
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f = fopen ("/proc/self/maps", "r");
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unsigned long start, end;
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if (!fgets (line, sizeof (line), f))
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if (!strstr (line, " r-xp ") || !strchr (line, '/'))
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sscanf (line, "%lx-%lx ", &start, &end);
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if (symbol >= (void *) start && symbol < (void *) end)
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/* Extract the filename; it is always an absolute path */
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path = strchr (line, '/');
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/* Get rid of the newline */
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tmp = strrchr (path, '\n');
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/* Get rid of "(deleted)" */
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if (len > 10 && strcmp (path + len - 10, " (deleted)") == 0)
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tmp = path + len - 10;
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return strdup (path);
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* path: The full path of an executable or library.
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* Returns: The prefix, or NULL on error. This string should be freed when no longer needed.
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* Extracts the prefix from path. This function assumes that your executable
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* or library is installed in an LSB-compatible directory structure.
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* br_extract_prefix ("/usr/bin/gnome-panel"); --> Returns "/usr"
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* br_extract_prefix ("/usr/local/lib/libfoo.so"); --> Returns "/usr/local"
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* br_extract_prefix ("/usr/local/libfoo.so"); --> Returns "/usr"
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br_extract_prefix (const char *path)
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char *end, *tmp, *result;
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br_return_val_if_fail (path != (char*)NULL, (char*)NULL);
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if (!*path) return strdup ("/");
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end = strrchr (path, '/');
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if (!end) return strdup (path);
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tmp = g_strndup ((char *) path, end - path);
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end = strrchr (tmp, '/');
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if (!end) return tmp;
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result = g_strndup (tmp, end - tmp);
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result = strdup ("/");
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* symbol: A symbol that belongs to the app/library you want to locate.
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* Returns: A prefix. This string should be freed when no longer needed.
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* Locates the full path of the app/library that symbol belongs to, and return
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* the prefix of that path, or NULL on error.
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* Note that symbol cannot be a pointer to a function. That will not work.
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* --> This application is located in /usr/bin/foo
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* br_locate_prefix (&argc); --> returns: "/usr"
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br_locate_prefix (void *symbol)
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br_return_val_if_fail (symbol != NULL, NULL);
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path = br_locate (symbol);
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if (!path) return NULL;
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prefix = br_extract_prefix (path);
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* symbol: A symbol that belongs to the app/library you want to locate.
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* path: The path that you want to prepend the prefix to.
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* Returns: The new path, or NULL on error. This string should be freed when no
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* Gets the prefix of the app/library that symbol belongs to. Prepend that prefix to path.
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* Note that symbol cannot be a pointer to a function. That will not work.
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* --> The application is /usr/bin/foo
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* br_prepend_prefix (&argc, "/share/foo/data.png"); --> Returns "/usr/share/foo/data.png"
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br_prepend_prefix (void *symbol, char *path)
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br_return_val_if_fail (symbol != NULL, NULL);
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br_return_val_if_fail (path != NULL, NULL);
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tmp = br_locate_prefix (symbol);
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if (!tmp) return NULL;
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if (strcmp (tmp, "/") == 0)
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newpath = strdup (path);
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newpath = g_strconcat (tmp, path, NULL);
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#else /* ENABLE_BINRELOC */
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typedef int iso_c_forbids_an_empty_source_file;
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#endif /* ENABLE_BINRELOC */
added
removed
src/prefix.c
