Edit File: relocatable.c
/* Provide relocatable packages. Copyright (C) 2003-2006, 2008-2016 Free Software Foundation, Inc. Written by Bruno Haible <bruno@clisp.org>, 2003. This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* Tell glibc's <stdio.h> to provide a prototype for getline(). This must come before <config.h> because <config.h> may include <features.h>, and once <features.h> has been included, it's too late. */ #ifndef _GNU_SOURCE # define _GNU_SOURCE 1 #endif #define _GL_USE_STDLIB_ALLOC 1 #include <config.h> /* Specification. */ #include "relocatable.h" #if ENABLE_RELOCATABLE #include <stddef.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #ifdef NO_XMALLOC # define xmalloc malloc #else # include "xalloc.h" #endif #if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__ # define WIN32_LEAN_AND_MEAN # include <windows.h> #endif #ifdef __EMX__ # define INCL_DOS # include <os2.h> # define strcmp stricmp # define strncmp strnicmp #endif #if DEPENDS_ON_LIBCHARSET # include <libcharset.h> #endif #if DEPENDS_ON_LIBICONV && HAVE_ICONV # include <iconv.h> #endif #if DEPENDS_ON_LIBINTL && ENABLE_NLS # include <libintl.h> #endif /* Faked cheap 'bool'. */ #undef bool #undef false #undef true #define bool int #define false 0 #define true 1 /* Pathname support. ISSLASH(C) tests whether C is a directory separator character. IS_PATH_WITH_DIR(P) tests whether P contains a directory specification. */ #if ((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__ /* Native Windows, OS/2, DOS */ # define ISSLASH(C) ((C) == '/' || (C) == '\\') # define HAS_DEVICE(P) \ ((((P)[0] >= 'A' && (P)[0] <= 'Z') || ((P)[0] >= 'a' && (P)[0] <= 'z')) \ && (P)[1] == ':') # define IS_PATH_WITH_DIR(P) \ (strchr (P, '/') != NULL || strchr (P, '\\') != NULL || HAS_DEVICE (P)) # define FILE_SYSTEM_PREFIX_LEN(P) (HAS_DEVICE (P) ? 2 : 0) #else /* Unix */ # define ISSLASH(C) ((C) == '/') # define IS_PATH_WITH_DIR(P) (strchr (P, '/') != NULL) # define FILE_SYSTEM_PREFIX_LEN(P) 0 #endif /* Whether to enable the more costly support for relocatable libraries. It allows libraries to be have been installed with a different original prefix than the program. But it is quite costly, especially on Cygwin platforms, see below. Therefore we enable it by default only on native Windows platforms. */ #ifndef ENABLE_COSTLY_RELOCATABLE # if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__ # define ENABLE_COSTLY_RELOCATABLE 1 # else # define ENABLE_COSTLY_RELOCATABLE 0 # endif #endif /* Original installation prefix. */ static char *orig_prefix; static size_t orig_prefix_len; /* Current installation prefix. */ static char *curr_prefix; static size_t curr_prefix_len; /* These prefixes do not end in a slash. Anything that will be concatenated to them must start with a slash. */ /* Sets the original and the current installation prefix of this module. Relocation simply replaces a pathname starting with the original prefix by the corresponding pathname with the current prefix instead. Both prefixes should be directory names without trailing slash (i.e. use "" instead of "/"). */ static void set_this_relocation_prefix (const char *orig_prefix_arg, const char *curr_prefix_arg) { if (orig_prefix_arg != NULL && curr_prefix_arg != NULL /* Optimization: if orig_prefix and curr_prefix are equal, the relocation is a nop. */ && strcmp (orig_prefix_arg, curr_prefix_arg) != 0) { /* Duplicate the argument strings. */ char *memory; orig_prefix_len = strlen (orig_prefix_arg); curr_prefix_len = strlen (curr_prefix_arg); memory = (char *) xmalloc (orig_prefix_len + 1 + curr_prefix_len + 1); #ifdef NO_XMALLOC if (memory != NULL) #endif { memcpy (memory, orig_prefix_arg, orig_prefix_len + 1); orig_prefix = memory; memory += orig_prefix_len + 1; memcpy (memory, curr_prefix_arg, curr_prefix_len + 1); curr_prefix = memory; return; } } orig_prefix = NULL; curr_prefix = NULL; /* Don't worry about wasted memory here - this function is usually only called once. */ } /* Sets the original and the current installation prefix of the package. Relocation simply replaces a pathname starting with the original prefix by the corresponding pathname with the current prefix instead. Both prefixes should be directory names without trailing slash (i.e. use "" instead of "/"). */ void set_relocation_prefix (const char *orig_prefix_arg, const char *curr_prefix_arg) { set_this_relocation_prefix (orig_prefix_arg, curr_prefix_arg); /* Now notify all dependent libraries. */ #if DEPENDS_ON_LIBCHARSET libcharset_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg); #endif #if DEPENDS_ON_LIBICONV && HAVE_ICONV && _LIBICONV_VERSION >= 0x0109 libiconv_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg); #endif #if DEPENDS_ON_LIBINTL && ENABLE_NLS && defined libintl_set_relocation_prefix libintl_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg); #endif } #if !defined IN_LIBRARY || (defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE) /* Convenience function: Computes the current installation prefix, based on the original installation prefix, the original installation directory of a particular file, and the current pathname of this file. Returns it, freshly allocated. Returns NULL upon failure. */ #ifdef IN_LIBRARY #define compute_curr_prefix local_compute_curr_prefix static #endif char * compute_curr_prefix (const char *orig_installprefix, const char *orig_installdir, const char *curr_pathname) { char *curr_installdir; const char *rel_installdir; if (curr_pathname == NULL) return NULL; /* Determine the relative installation directory, relative to the prefix. This is simply the difference between orig_installprefix and orig_installdir. */ if (strncmp (orig_installprefix, orig_installdir, strlen (orig_installprefix)) != 0) /* Shouldn't happen - nothing should be installed outside $(prefix). */ return NULL; rel_installdir = orig_installdir + strlen (orig_installprefix); /* Determine the current installation directory. */ { const char *p_base = curr_pathname + FILE_SYSTEM_PREFIX_LEN (curr_pathname); const char *p = curr_pathname + strlen (curr_pathname); char *q; while (p > p_base) { p--; if (ISSLASH (*p)) break; } q = (char *) xmalloc (p - curr_pathname + 1); #ifdef NO_XMALLOC if (q == NULL) return NULL; #endif memcpy (q, curr_pathname, p - curr_pathname); q[p - curr_pathname] = '\0'; curr_installdir = q; } /* Compute the current installation prefix by removing the trailing rel_installdir from it. */ { const char *rp = rel_installdir + strlen (rel_installdir); const char *cp = curr_installdir + strlen (curr_installdir); const char *cp_base = curr_installdir + FILE_SYSTEM_PREFIX_LEN (curr_installdir); while (rp > rel_installdir && cp > cp_base) { bool same = false; const char *rpi = rp; const char *cpi = cp; while (rpi > rel_installdir && cpi > cp_base) { rpi--; cpi--; if (ISSLASH (*rpi) || ISSLASH (*cpi)) { if (ISSLASH (*rpi) && ISSLASH (*cpi)) same = true; break; } /* Do case-insensitive comparison if the file system is always or often case-insensitive. It's better to accept the comparison if the difference is only in case, rather than to fail. */ #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__ /* Native Windows, Cygwin, OS/2, DOS - case insignificant file system */ if ((*rpi >= 'a' && *rpi <= 'z' ? *rpi - 'a' + 'A' : *rpi) != (*cpi >= 'a' && *cpi <= 'z' ? *cpi - 'a' + 'A' : *cpi)) break; #else if (*rpi != *cpi) break; #endif } if (!same) break; /* The last pathname component was the same. opi and cpi now point to the slash before it. */ rp = rpi; cp = cpi; } if (rp > rel_installdir) { /* Unexpected: The curr_installdir does not end with rel_installdir. */ free (curr_installdir); return NULL; } { size_t curr_prefix_len = cp - curr_installdir; char *curr_prefix; curr_prefix = (char *) xmalloc (curr_prefix_len + 1); #ifdef NO_XMALLOC if (curr_prefix == NULL) { free (curr_installdir); return NULL; } #endif memcpy (curr_prefix, curr_installdir, curr_prefix_len); curr_prefix[curr_prefix_len] = '\0'; free (curr_installdir); return curr_prefix; } } } #endif /* !IN_LIBRARY || PIC */ #if defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE /* Full pathname of shared library, or NULL. */ static char *shared_library_fullname; #if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__ /* Native Windows only. On Cygwin, it is better to use the Cygwin provided /proc interface, than to use native Windows API and cygwin_conv_to_posix_path, because it supports longer file names (see <http://cygwin.com/ml/cygwin/2011-01/msg00410.html>). */ /* Determine the full pathname of the shared library when it is loaded. */ BOOL WINAPI DllMain (HINSTANCE module_handle, DWORD event, LPVOID reserved) { (void) reserved; if (event == DLL_PROCESS_ATTACH) { /* The DLL is being loaded into an application's address range. */ static char location[MAX_PATH]; if (!GetModuleFileName (module_handle, location, sizeof (location))) /* Shouldn't happen. */ return FALSE; if (!IS_PATH_WITH_DIR (location)) /* Shouldn't happen. */ return FALSE; shared_library_fullname = strdup (location); } return TRUE; } #elif defined __EMX__ extern int _CRT_init (void); extern void _CRT_term (void); extern void __ctordtorInit (void); extern void __ctordtorTerm (void); unsigned long _System _DLL_InitTerm (unsigned long hModule, unsigned long ulFlag) { static char location[CCHMAXPATH]; switch (ulFlag) { case 0: if (_CRT_init () == -1) return 0; __ctordtorInit(); /* See http://cyberkinetica.homeunix.net/os2tk45/cp1/1247_L2H_DosQueryModuleNameSy.html for specification of DosQueryModuleName(). */ if (DosQueryModuleName (hModule, sizeof (location), location)) return 0; _fnslashify (location); shared_library_fullname = strdup (location); break; case 1: __ctordtorTerm(); _CRT_term (); break; } return 1; } #else /* Unix */ static void find_shared_library_fullname () { #if (defined __linux__ && (__GLIBC__ >= 2 || defined __UCLIBC__)) || defined __CYGWIN__ /* Linux has /proc/self/maps. glibc 2 and uClibc have the getline() function. Cygwin >= 1.5 has /proc/self/maps and the getline() function too. But it is costly: ca. 0.3 ms on Linux, 3 ms on Cygwin 1.5, and 5 ms on Cygwin 1.7. */ FILE *fp; /* Open the current process' maps file. It describes one VMA per line. */ fp = fopen ("/proc/self/maps", "r"); if (fp) { unsigned long address = (unsigned long) &find_shared_library_fullname; for (;;) { unsigned long start, end; int c; if (fscanf (fp, "%lx-%lx", &start, &end) != 2) break; if (address >= start && address <= end - 1) { /* Found it. Now see if this line contains a filename. */ while (c = getc (fp), c != EOF && c != '\n' && c != '/') continue; if (c == '/') { size_t size; int len; ungetc (c, fp); shared_library_fullname = NULL; size = 0; len = getline (&shared_library_fullname, &size, fp); if (len >= 0) { /* Success: filled shared_library_fullname. */ if (len > 0 && shared_library_fullname[len - 1] == '\n') shared_library_fullname[len - 1] = '\0'; } } break; } while (c = getc (fp), c != EOF && c != '\n') continue; } fclose (fp); } #endif } #endif /* Native Windows / EMX / Unix */ /* Return the full pathname of the current shared library. Return NULL if unknown. Guaranteed to work only on Linux, EMX, Cygwin, and native Windows. */ static char * get_shared_library_fullname () { #if (!((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__) \ && !defined __EMX__) static bool tried_find_shared_library_fullname; if (!tried_find_shared_library_fullname) { find_shared_library_fullname (); tried_find_shared_library_fullname = true; } #endif return shared_library_fullname; } #endif /* PIC */ /* Returns the pathname, relocated according to the current installation directory. The returned string is either PATHNAME unmodified or a freshly allocated string that you can free with free() after casting it to 'char *'. */ const char * relocate (const char *pathname) { #if defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE static int initialized; /* Initialization code for a shared library. */ if (!initialized) { /* At this point, orig_prefix and curr_prefix likely have already been set through the main program's set_program_name_and_installdir function. This is sufficient in the case that the library has initially been installed in the same orig_prefix. But we can do better, to also cover the cases that 1. it has been installed in a different prefix before being moved to orig_prefix and (later) to curr_prefix, 2. unlike the program, it has not moved away from orig_prefix. */ const char *orig_installprefix = INSTALLPREFIX; const char *orig_installdir = INSTALLDIR; char *curr_prefix_better; curr_prefix_better = compute_curr_prefix (orig_installprefix, orig_installdir, get_shared_library_fullname ()); set_relocation_prefix (orig_installprefix, curr_prefix_better != NULL ? curr_prefix_better : curr_prefix); if (curr_prefix_better != NULL) free (curr_prefix_better); initialized = 1; } #endif /* Note: It is not necessary to perform case insensitive comparison here, even for DOS-like file systems, because the pathname argument was typically created from the same Makefile variable as orig_prefix came from. */ if (orig_prefix != NULL && curr_prefix != NULL && strncmp (pathname, orig_prefix, orig_prefix_len) == 0) { if (pathname[orig_prefix_len] == '\0') { /* pathname equals orig_prefix. */ char *result = (char *) xmalloc (strlen (curr_prefix) + 1); #ifdef NO_XMALLOC if (result != NULL) #endif { strcpy (result, curr_prefix); return result; } } else if (ISSLASH (pathname[orig_prefix_len])) { /* pathname starts with orig_prefix. */ const char *pathname_tail = &pathname[orig_prefix_len]; char *result = (char *) xmalloc (curr_prefix_len + strlen (pathname_tail) + 1); #ifdef NO_XMALLOC if (result != NULL) #endif { memcpy (result, curr_prefix, curr_prefix_len); strcpy (result + curr_prefix_len, pathname_tail); return result; } } } #ifdef __EMX__ if (pathname && ISSLASH (pathname[0])) { const char *unixroot = getenv ("UNIXROOT"); if (unixroot && HAS_DEVICE (unixroot) && !unixroot[2]) { char *result = (char *) xmalloc (2 + strlen (pathname) + 1); #ifdef NO_XMALLOC if (result != NULL) #endif { strcpy (result, unixroot); strcpy (result + 2, pathname); return result; } } } #endif /* Nothing to relocate. */ return pathname; } #endif