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Diffstat (limited to 'lib/relocatable.c')
| -rw-r--r-- | lib/relocatable.c | 493 |
1 files changed, 493 insertions, 0 deletions
diff --git a/lib/relocatable.c b/lib/relocatable.c new file mode 100644 index 00000000..09ff8c9e --- /dev/null +++ b/lib/relocatable.c @@ -0,0 +1,493 @@ +/* Provide relocatable packages. + Copyright (C) 2003-2006, 2008 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 Library General Public License as published + by the Free Software Foundation; either version 2, 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, + USA. */ + + +/* 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 + +#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 + +#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__ + /* Win32, Cygwin, 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 + +/* 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) + +/* 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 filesystem 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__ + /* Win32, Cygwin, OS/2, DOS - case insignificant filesystem */ + 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 + +/* Full pathname of shared library, or NULL. */ +static char *shared_library_fullname; + +#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ + +/* 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; + + { +#if defined __CYGWIN__ + /* On Cygwin, we need to convert paths coming from Win32 system calls + to the Unix-like slashified notation. */ + static char location_as_posix_path[2 * MAX_PATH]; + /* There's no error return defined for cygwin_conv_to_posix_path. + See cygwin-api/func-cygwin-conv-to-posix-path.html. + Does it overflow the buffer of expected size MAX_PATH or does it + truncate the path? I don't know. Let's catch both. */ + cygwin_conv_to_posix_path (location, location_as_posix_path); + location_as_posix_path[MAX_PATH - 1] = '\0'; + if (strlen (location_as_posix_path) >= MAX_PATH - 1) + /* A sign of buffer overflow or path truncation. */ + return FALSE; + shared_library_fullname = strdup (location_as_posix_path); +#else + shared_library_fullname = strdup (location); +#endif + } + } + + return TRUE; +} + +#else /* Unix except Cygwin */ + +static void +find_shared_library_fullname () +{ +#if defined __linux__ && __GLIBC__ >= 2 + /* Linux has /proc/self/maps. glibc 2 has the getline() function. */ + 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 /* (WIN32 or Cygwin) / (Unix except Cygwin) */ + +/* Return the full pathname of the current shared library. + Return NULL if unknown. + Guaranteed to work only on Linux, Cygwin and Woe32. */ +static char * +get_shared_library_fullname () +{ +#if !(defined _WIN32 || defined __WIN32__ || defined __CYGWIN__) + 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 + 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 filesystems, 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; + } + } + } + /* Nothing to relocate. */ + return pathname; +} + +#endif |