remove LFS64 symbol aliases; replace with dynamic linker remapping

originally the namespace-infringing "large file support" interfaces
were included as part of glibc-ABI-compat, with the intent that they
not be used for linking, since our off_t is and always has been
unconditionally 64-bit and since we usually do not aim to support
nonstandard interfaces when there is an equivalent standard interface.

unfortunately, having the symbols present and available for linking
caused configure scripts to detect them and attempt to use them
without declarations, producing all the expected ill effects that
entails.

as a result, commit 2dd8d5e was made
to prevent this, using macros to redirect the LFS64 names to the
standard names, conditional on _GNU_SOURCE or _LARGEFILE64_SOURCE.
however, this has turned out to be a source of further problems,
especially since g++ defines _GNU_SOURCE by default. in particular,
the presence of these names as macros breaks a lot of valid code.

this commit removes all the LFS64 symbols and replaces them with a
mechanism in the dynamic linker symbol lookup failure path to retry
with the spurious "64" removed from the symbol name. in the future,
if/when the rest of glibc-ABI-compat is moved out of libc, this can be
removed.

compat/time32/__xstat.c

@@ -3,22 +3,22 @@
 
 struct stat32;
 
-int __fxstat64(int ver, int fd, struct stat32 *buf)
+int __fxstat(int ver, int fd, struct stat32 *buf)
 {
 	return __fstat_time32(fd, buf);
 }
 
-int __fxstatat64(int ver, int fd, const char *path, struct stat32 *buf, int flag)
+int __fxstatat(int ver, int fd, const char *path, struct stat32 *buf, int flag)
 {
 	return __fstatat_time32(fd, path, buf, flag);
 }
 
-int __lxstat64(int ver, const char *path, struct stat32 *buf)
+int __lxstat(int ver, const char *path, struct stat32 *buf)
 {
 	return __lstat_time32(path, buf);
 }
 
-int __xstat64(int ver, const char *path, struct stat32 *buf)
+int __xstat(int ver, const char *path, struct stat32 *buf)
 {
 	return __stat_time32(path, buf);
 }

compat/time32/aio_suspend_time32.c

@@ -7,5 +7,3 @@ int __aio_suspend_time32(const struct aiocb *const cbs[], int cnt, const struct
 	return aio_suspend(cbs, cnt, ts32 ? (&(struct timespec){
 		.tv_sec = ts32->tv_sec, .tv_nsec = ts32->tv_nsec}) : 0);
 }
-
-weak_alias(aio_suspend, aio_suspend64);

compat/time32/fstat_time32.c

@@ -13,5 +13,3 @@ int __fstat_time32(int fd, struct stat32 *restrict st32)
 	if (!r) memcpy(st32, &st, offsetof(struct stat, st_atim));
 	return r;
 }
-
-weak_alias(fstat, fstat64);

compat/time32/fstatat_time32.c

@@ -13,5 +13,3 @@ int __fstatat_time32(int fd, const char *restrict path, struct stat32 *restrict
 	if (!r) memcpy(st32, &st, offsetof(struct stat, st_atim));
 	return r;
 }
-
-weak_alias(fstatat, fstatat64);

compat/time32/lstat_time32.c

@@ -13,5 +13,3 @@ int __lstat_time32(const char *restrict path, struct stat32 *restrict st32)
 	if (!r) memcpy(st32, &st, offsetof(struct stat, st_atim));
 	return r;
 }
-
-weak_alias(lstat, lstat64);

compat/time32/stat_time32.c

@@ -13,5 +13,3 @@ int __stat_time32(const char *restrict path, struct stat32 *restrict st32)
 	if (!r) memcpy(st32, &st, offsetof(struct stat, st_atim));
 	return r;
 }
-
-weak_alias(stat, stat64);

ldso/dynlink.c

@@ -337,6 +337,39 @@ static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 	return find_sym2(dso, s, need_def, 0);
 }
 
+static struct symdef get_lfs64(const char *name)
+{
+	static const char *p, lfs64_list[] =
+		"aio_cancel\0aio_error\0aio_fsync\0aio_read\0aio_return\0"
+		"aio_suspend\0aio_write\0alphasort\0creat\0fallocate\0"
+		"fgetpos\0fopen\0freopen\0fseeko\0fsetpos\0fstat\0"
+		"fstatat\0fstatfs\0fstatvfs\0ftello\0ftruncate\0ftw\0"
+		"getdents\0getrlimit\0glob\0globfree\0lio_listio\0"
+		"lockf\0lseek\0lstat\0mkostemp\0mkostemps\0mkstemp\0"
+		"mkstemps\0mmap\0nftw\0open\0openat\0posix_fadvise\0"
+		"posix_fallocate\0pread\0preadv\0prlimit\0pwrite\0"
+		"pwritev\0readdir\0scandir\0sendfile\0setrlimit\0"
+		"stat\0statfs\0statvfs\0tmpfile\0truncate\0versionsort\0"
+		"__fxstat\0__fxstatat\0__lxstat\0__xstat\0";
+	size_t l;
+	char buf[16];
+	for (l=0; name[l]; l++) {
+		if (l >= sizeof buf) goto nomatch;
+		buf[l] = name[l];
+	}
+	if (!strcmp(name, "readdir64_r"))
+		return find_sym(&ldso, "readdir_r", 1);
+	if (l<2 || name[l-2]!='6' || name[l-1]!='4')
+		goto nomatch;
+	buf[l-=2] = 0;
+	for (p=lfs64_list; *p; p++) {
+		if (!strcmp(buf, p)) return find_sym(&ldso, buf, 1);
+		while (*p) p++;
+	}
+nomatch:
+	return (struct symdef){ 0 };
+}
+
 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 {
 	unsigned char *base = dso->base;
@@ -390,6 +423,7 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
 			def = (sym->st_info>>4) == STB_LOCAL
 				? (struct symdef){ .dso = dso, .sym = sym }
 				: find_sym(ctx, name, type==REL_PLT);
+			if (!def.sym) def = get_lfs64(name);
 			if (!def.sym && (sym->st_shndx != SHN_UNDEF
 			    || sym->st_info>>4 != STB_WEAK)) {
 				if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {

src/aio/aio.c

@@ -409,10 +409,3 @@ void __aio_atfork(int who)
 					map[a][b][c][d] = 0;
 	pthread_rwlock_unlock(&maplock);
 }
-
-weak_alias(aio_cancel, aio_cancel64);
-weak_alias(aio_error, aio_error64);
-weak_alias(aio_fsync, aio_fsync64);
-weak_alias(aio_read, aio_read64);
-weak_alias(aio_write, aio_write64);
-weak_alias(aio_return, aio_return64);

src/aio/aio_suspend.c

@@ -73,7 +73,3 @@ int aio_suspend(const struct aiocb *const cbs[], int cnt, const struct timespec
 		}
 	}
 }
-
-#if !_REDIR_TIME64
-weak_alias(aio_suspend, aio_suspend64);
-#endif

src/aio/lio_listio.c

@@ -139,5 +139,3 @@ int lio_listio(int mode, struct aiocb *restrict const *restrict cbs, int cnt, st
 
 	return 0;
 }
-
-weak_alias(lio_listio, lio_listio64);

src/dirent/alphasort.c

@@ -5,5 +5,3 @@ int alphasort(const struct dirent **a, const struct dirent **b)
 {
 	return strcoll((*a)->d_name, (*b)->d_name);
 }
-
-weak_alias(alphasort, alphasort64);

src/dirent/readdir.c

@@ -25,5 +25,3 @@ struct dirent *readdir(DIR *dir)
 	dir->tell = de->d_off;
 	return de;
 }
-
-weak_alias(readdir, readdir64);

src/dirent/readdir_r.c

@@ -25,5 +25,3 @@ int readdir_r(DIR *restrict dir, struct dirent *restrict buf, struct dirent **re
 	*result = buf;
 	return 0;
 }
-
-weak_alias(readdir_r, readdir64_r);

src/dirent/scandir.c

@@ -43,5 +43,3 @@ int scandir(const char *path, struct dirent ***res,
 	*res = names;
 	return cnt;
 }
-
-weak_alias(scandir, scandir64);

src/dirent/versionsort.c

@@ -6,6 +6,3 @@ int versionsort(const struct dirent **a, const struct dirent **b)
 {
 	return strverscmp((*a)->d_name, (*b)->d_name);
 }
-
-#undef versionsort64
-weak_alias(versionsort, versionsort64);

src/fcntl/creat.c

@@ -4,5 +4,3 @@ int creat(const char *filename, mode_t mode)
 {
 	return open(filename, O_CREAT|O_WRONLY|O_TRUNC, mode);
 }
-
-weak_alias(creat, creat64);

src/fcntl/open.c

@@ -19,5 +19,3 @@ int open(const char *filename, int flags, ...)
 
 	return __syscall_ret(fd);
 }
-
-weak_alias(open, open64);

src/fcntl/openat.c

@@ -15,5 +15,3 @@ int openat(int fd, const char *filename, int flags, ...)
 
 	return syscall_cp(SYS_openat, fd, filename, flags|O_LARGEFILE, mode);
 }
-
-weak_alias(openat, openat64);

src/fcntl/posix_fadvise.c

@@ -14,5 +14,3 @@ int posix_fadvise(int fd, off_t base, off_t len, int advice)
 		__SYSCALL_LL_E(len), advice);
 #endif
 }
-
-weak_alias(posix_fadvise, posix_fadvise64);

src/fcntl/posix_fallocate.c

@@ -6,5 +6,3 @@ int posix_fallocate(int fd, off_t base, off_t len)
 	return -__syscall(SYS_fallocate, fd, 0, __SYSCALL_LL_E(base),
 		__SYSCALL_LL_E(len));
 }
-
-weak_alias(posix_fallocate, posix_fallocate64);

src/legacy/ftw.c

@@ -7,5 +7,3 @@ int ftw(const char *path, int (*fn)(const char *, const struct stat *, int), int
 	 * actually undefined, but works on all real-world machines. */
 	return nftw(path, (int (*)())fn, fd_limit, FTW_PHYS);
 }
-
-weak_alias(ftw, ftw64);

src/linux/fallocate.c

@@ -7,6 +7,3 @@ int fallocate(int fd, int mode, off_t base, off_t len)
 	return syscall(SYS_fallocate, fd, mode, __SYSCALL_LL_E(base),
 		__SYSCALL_LL_E(len));
 }
-
-#undef fallocate64
-weak_alias(fallocate, fallocate64);

src/linux/getdents.c

@@ -8,5 +8,3 @@ int getdents(int fd, struct dirent *buf, size_t len)
 	if (len>INT_MAX) len = INT_MAX;
 	return syscall(SYS_getdents, fd, buf, len);
 }
-
-weak_alias(getdents, getdents64);

src/linux/prlimit.c

@@ -21,6 +21,3 @@ int prlimit(pid_t pid, int resource, const struct rlimit *new_limit, struct rlim
 	}
 	return r;
 }
-
-#undef prlimit64
-weak_alias(prlimit, prlimit64);

src/linux/sendfile.c

@@ -5,5 +5,3 @@ ssize_t sendfile(int out_fd, int in_fd, off_t *ofs, size_t count)
 {
 	return syscall(SYS_sendfile, out_fd, in_fd, ofs, count);
 }
-
-weak_alias(sendfile, sendfile64);

src/misc/getrlimit.c

@@ -26,5 +26,3 @@ int getrlimit(int resource, struct rlimit *rlim)
 	return ret;
 #endif
 }
-
-weak_alias(getrlimit, getrlimit64);

src/misc/lockf.c

@@ -28,5 +28,3 @@ int lockf(int fd, int op, off_t size)
 	errno = EINVAL;
 	return -1;
 }
-
-weak_alias(lockf, lockf64);

src/misc/nftw.c

@@ -138,5 +138,3 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
 	pthread_setcancelstate(cs, 0);
 	return r;
 }
-
-weak_alias(nftw, nftw64);

src/misc/setrlimit.c

@@ -49,5 +49,3 @@ int setrlimit(int resource, const struct rlimit *rlim)
 	return __syscall_ret(ret);
 #endif
 }
-
-weak_alias(setrlimit, setrlimit64);

src/mman/mmap.c

@@ -37,5 +37,3 @@ void *__mmap(void *start, size_t len, int prot, int flags, int fd, off_t off)
 }
 
 weak_alias(__mmap, mmap);
-
-weak_alias(mmap, mmap64);

src/regex/glob.c

@@ -306,6 +306,3 @@ void globfree(glob_t *g)
 	g->gl_pathc = 0;
 	g->gl_pathv = NULL;
 }
-
-weak_alias(glob, glob64);
-weak_alias(globfree, globfree64);

src/stat/__xstat.c

@@ -22,11 +22,6 @@ int __xstat(int ver, const char *path, struct stat *buf)
 	return stat(path, buf);
 }
 
-weak_alias(__fxstat, __fxstat64);
-weak_alias(__fxstatat, __fxstatat64);
-weak_alias(__lxstat, __lxstat64);
-weak_alias(__xstat, __xstat64);
-
 #endif
 
 int __xmknod(int ver, const char *path, mode_t mode, dev_t *dev)

src/stat/fstat.c

@@ -11,7 +11,3 @@ int __fstat(int fd, struct stat *st)
 }
 
 weak_alias(__fstat, fstat);
-
-#if !_REDIR_TIME64
-weak_alias(fstat, fstat64);
-#endif

src/stat/fstatat.c

@@ -151,7 +151,3 @@ int __fstatat(int fd, const char *restrict path, struct stat *restrict st, int f
 }
 
 weak_alias(__fstatat, fstatat);
-
-#if !_REDIR_TIME64
-weak_alias(fstatat, fstatat64);
-#endif

src/stat/lstat.c

@@ -5,7 +5,3 @@ int lstat(const char *restrict path, struct stat *restrict buf)
 {
 	return fstatat(AT_FDCWD, path, buf, AT_SYMLINK_NOFOLLOW);
 }
-
-#if !_REDIR_TIME64
-weak_alias(lstat, lstat64);
-#endif

src/stat/stat.c

@@ -5,7 +5,3 @@ int stat(const char *restrict path, struct stat *restrict buf)
 {
 	return fstatat(AT_FDCWD, path, buf, 0);
 }
-
-#if !_REDIR_TIME64
-weak_alias(stat, stat64);
-#endif

src/stat/statvfs.c

@@ -56,8 +56,3 @@ int fstatvfs(int fd, struct statvfs *buf)
 	fixup(buf, &kbuf);
 	return 0;
 }
-
-weak_alias(statvfs, statvfs64);
-weak_alias(statfs, statfs64);
-weak_alias(fstatvfs, fstatvfs64);
-weak_alias(fstatfs, fstatfs64);

src/stdio/fgetpos.c

@@ -7,5 +7,3 @@ int fgetpos(FILE *restrict f, fpos_t *restrict pos)
 	*(long long *)pos = off;
 	return 0;
 }
-
-weak_alias(fgetpos, fgetpos64);

src/stdio/fopen.c

@@ -29,5 +29,3 @@ FILE *fopen(const char *restrict filename, const char *restrict mode)
 	__syscall(SYS_close, fd);
 	return 0;
 }
-
-weak_alias(fopen, fopen64);

src/stdio/freopen.c

@@ -51,5 +51,3 @@ FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *re
 	fclose(f);
 	return NULL;
 }
-
-weak_alias(freopen, freopen64);

src/stdio/fseek.c

@@ -46,5 +46,3 @@ int fseek(FILE *f, long off, int whence)
 }
 
 weak_alias(__fseeko, fseeko);
-
-weak_alias(fseeko, fseeko64);

src/stdio/fsetpos.c

@@ -4,5 +4,3 @@ int fsetpos(FILE *f, const fpos_t *pos)
 {
 	return __fseeko(f, *(const long long *)pos, SEEK_SET);
 }
-
-weak_alias(fsetpos, fsetpos64);

src/stdio/ftell.c

@@ -37,5 +37,3 @@ long ftell(FILE *f)
 }
 
 weak_alias(__ftello, ftello);
-
-weak_alias(ftello, ftello64);

src/stdio/tmpfile.c

@@ -27,5 +27,3 @@ FILE *tmpfile(void)
 	}
 	return 0;
 }
-
-weak_alias(tmpfile, tmpfile64);

src/temp/mkostemp.c

@@ -5,5 +5,3 @@ int mkostemp(char *template, int flags)
 {
 	return __mkostemps(template, 0, flags);
 }
-
-weak_alias(mkostemp, mkostemp64);

src/temp/mkostemps.c

@@ -26,4 +26,3 @@ int __mkostemps(char *template, int len, int flags)
 }
 
 weak_alias(__mkostemps, mkostemps);
-weak_alias(__mkostemps, mkostemps64);

src/temp/mkstemp.c

@@ -4,5 +4,3 @@ int mkstemp(char *template)
 {
 	return __mkostemps(template, 0, 0);
 }
-
-weak_alias(mkstemp, mkstemp64);

src/temp/mkstemps.c

@@ -5,5 +5,3 @@ int mkstemps(char *template, int len)
 {
 	return __mkostemps(template, len, 0);
 }
-
-weak_alias(mkstemps, mkstemps64);

src/unistd/ftruncate.c

@@ -5,5 +5,3 @@ int ftruncate(int fd, off_t length)
 {
 	return syscall(SYS_ftruncate, fd, __SYSCALL_LL_O(length));
 }
-
-weak_alias(ftruncate, ftruncate64);

src/unistd/lseek.c

@@ -12,4 +12,3 @@ off_t __lseek(int fd, off_t offset, int whence)
 }
 
 weak_alias(__lseek, lseek);
-weak_alias(__lseek, lseek64);

src/unistd/mipsn32/lseek.c

@@ -17,4 +17,3 @@ off_t __lseek(int fd, off_t offset, int whence)
 }
 
 weak_alias(__lseek, lseek);
-weak_alias(__lseek, lseek64);

src/unistd/pread.c

@@ -5,5 +5,3 @@ ssize_t pread(int fd, void *buf, size_t size, off_t ofs)
 {
 	return syscall_cp(SYS_pread, fd, buf, size, __SYSCALL_LL_PRW(ofs));
 }
-
-weak_alias(pread, pread64);