From e7776fefa76a5815493b463049fd7ced67cb31a2 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Fri, 2 Nov 2012 13:49:42 -0400 Subject: [PATCH] tile: improve simulator notification for relative paths in dlopen Normally, the simulator is notified of absolute pathnames by the _dl_load_hook hook. However, when a relative pathname is used, the simulator may not know that the relative path matches a path that it could figure out in the file system that it has access to. Instead we provide a simplified version of the realpath function so we can pass a plausible absolute pathname to the simulator. Since we're now doing more work at object load time, we also add a guard so we do no work at all if we're not running on the simulator. --- ports/ChangeLog.tile | 3 ++ ports/sysdeps/tile/dl-runtime.c | 103 ++++++++++++++++++++++++++++++++++------ 2 files changed, 92 insertions(+), 14 deletions(-) diff --git a/ports/ChangeLog.tile b/ports/ChangeLog.tile index bc3946c..71aaf56 100644 --- a/ports/ChangeLog.tile +++ b/ports/ChangeLog.tile @@ -1,5 +1,8 @@ 2012-11-02 Chris Metcalf + * sysdeps/tile/dl-runtime.c (_dl_after_load): Handle simulator + notification better for dlopen() of relative paths. + * sysdeps/tile/tilegx/memcpy.c (__memcpy): Optimize. * sysdeps/tile/memcopy.h: New file. * sysdeps/tile/wordcopy.c: New file. diff --git a/ports/sysdeps/tile/dl-runtime.c b/ports/sysdeps/tile/dl-runtime.c index 6864c3a..e965828 100644 --- a/ports/sysdeps/tile/dl-runtime.c +++ b/ports/sysdeps/tile/dl-runtime.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2011 Free Software Foundation, Inc. +/* Copyright (C) 2011-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Chris Metcalf , 2011. @@ -28,44 +28,119 @@ #include #include -/* Support notifying the simulator about new objects. */ +/* Like realpath(), but simplified: no dynamic memory use, no lstat(), + no set_errno(), no valid "rpath" on error, etc. This handles some + simple cases where the simulator might not have a valid entry for + a loaded Elf object, in particular dlopen() with a relative path. + For this relatively rare case, one could also imagine using + link_map.l_origin to avoid the getcwd() here, but the simpler code + here seems like a better solution. */ +static char * +dl_realpath (const char *name, char *rpath) +{ + char *dest; + const char *start, *end; + + if (name[0] != '/') + { + if (!__getcwd (rpath, PATH_MAX)) + return NULL; + dest = __rawmemchr (rpath, '\0'); + } + else + { + rpath[0] = '/'; + dest = rpath + 1; + } + + for (start = end = name; *start; start = end) + { + /* Skip sequence of multiple path-separators. */ + while (*start == '/') + ++start; + + /* Find end of path component. */ + for (end = start; *end && *end != '/'; ++end) + /* Nothing. */; + + if (end - start == 0) + break; + else if (end - start == 1 && start[0] == '.') + /* nothing */; + else if (end - start == 2 && start[0] == '.' && start[1] == '.') + { + /* Back up to previous component, ignore if at root already. */ + if (dest > rpath + 1) + while ((--dest)[-1] != '/'); + } + else + { + if (dest[-1] != '/') + *dest++ = '/'; + + if (dest + (end - start) >= rpath + PATH_MAX) + return NULL; + + dest = __mempcpy (dest, start, end - start); + *dest = '\0'; + } + } + if (dest > rpath + 1 && dest[-1] == '/') + --dest; + *dest = '\0'; + + return rpath; +} + +/* Support notifying the simulator about new objects. */ void internal_function _dl_after_load (struct link_map *l) { int shift; + char pathbuf[PATH_MAX]; + char *path; -#define DLPUTC(c) __insn_mtspr(SPR_SIM_CONTROL, \ - (SIM_CONTROL_DLOPEN \ - | ((c) << _SIM_CONTROL_OPERATOR_BITS))) + /* Don't bother if not in the simulator. */ + if (__insn_mfspr (SPR_SIM_CONTROL) == 0) + return; - /* Write the library address in hex. */ +#define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL, \ + (SIM_CONTROL_DLOPEN \ + | ((c) << _SIM_CONTROL_OPERATOR_BITS))) + + /* Write the library address in hex. */ DLPUTC ('0'); DLPUTC ('x'); for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4) DLPUTC ("0123456789abcdef"[(l->l_map_start >> shift) & 0xF]); DLPUTC (':'); - /* Write the library path, including the terminating '\0'. */ + /* Write the library path, including the terminating '\0'. */ + path = dl_realpath (l->l_name, pathbuf) ?: l->l_name; for (size_t i = 0;; i++) { - DLPUTC (l->l_name[i]); - if (l->l_name[i] == '\0') + DLPUTC (path[i]); + if (path[i] == '\0') break; } #undef DLPUTC } -/* Support notifying the simulator about removed objects prior to munmap(). */ +/* Support notifying the simulator about removed objects prior to munmap(). */ void internal_function _dl_unmap (struct link_map *l) { int shift; -#define DLPUTC(c) __insn_mtspr(SPR_SIM_CONTROL, \ - (SIM_CONTROL_DLCLOSE \ - | ((c) << _SIM_CONTROL_OPERATOR_BITS))) + /* Don't bother if not in the simulator. */ + if (__insn_mfspr (SPR_SIM_CONTROL) == 0) + return; + +#define DLPUTC(c) __insn_mtspr (SPR_SIM_CONTROL, \ + (SIM_CONTROL_DLCLOSE \ + | ((c) << _SIM_CONTROL_OPERATOR_BITS))) - /* Write the library address in hex. */ + /* Write the library address in hex. */ DLPUTC ('0'); DLPUTC ('x'); for (shift = (int) sizeof (unsigned long) * 8 - 4; shift >= 0; shift -= 4) -- 2.7.4