From 2733d9d5d62c62023dc2d7a93fa5afa22f386ffd Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Tue, 15 Mar 2022 18:08:06 +0100 Subject: [PATCH] gdb, gdbserver: extend RSP to support namespaces Introduce a new qXfer:libraries-svr4:read annex key/value pair lmid= to be used together with start and prev to provide the namespace of start and prev to gdbserver. Unknown key/value pairs are ignored by gdbserver so no new supports check is needed. Introduce a new library-list-svr4 library attribute lmid to provide the namespace of a library entry to GDB. This implementation uses the address of a namespace's r_debug object as namespace identifier. This should have incremented the minor version but since unknown XML attributes are ignored, anyway, and since changing the version results in a warning from GDB, the version is left at 1.0. --- gdb/doc/gdb.texinfo | 16 +++++++++++-- gdb/features/library-list-svr4.dtd | 4 ++++ gdb/solib-svr4.c | 38 +++++++++++++++++++++++++++--- gdbserver/linux-low.cc | 26 +++++++++++++------- 4 files changed, 70 insertions(+), 14 deletions(-) diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 3de511a4844..ea66f4ee42d 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -43706,6 +43706,12 @@ specified by the @samp{start} argument. If unset or zero then the remote stub will expect that no @samp{struct link_map} exists prior to the starting point. +@item lmid=@var{lmid} +A hexadecimal number specifying a namespace identifier. This is +currently only used together with @samp{start} to provide the +namespace identifier back to @value{GDBN} in the response. +@value{GDBN} will only provide values that were previously reported to +it. If unset, the response will include @samp{lmid="0x0"}. @end table Arguments that are not understood by the remote stub will be silently @@ -46244,6 +46250,11 @@ memory address. It is a displacement of absolute memory address against address the file was prelinked to during the library load. @item @code{l_ld}, which is memory address of the @code{PT_DYNAMIC} segment +@item +@code{lmid}, which is an identifier for a linker namespace, such as +the memory address of the @code{r_debug} object that contains this +namespace's load map or the namespace identifier returned by +@code{dlinfo (3)}. @end itemize Additionally the single @code{main-lm} attribute specifies address of @@ -46259,9 +46270,9 @@ looks like this: @smallexample + l_ld="0xe4eefc" lmid="0xfffe0"/> + l_ld="0x152350" lmid="0xfffe0"/> @end smallexample @@ -46277,6 +46288,7 @@ The format of an SVR4 library list is described by this DTD: + @end smallexample @node Memory Map Format diff --git a/gdb/features/library-list-svr4.dtd b/gdb/features/library-list-svr4.dtd index 7d62354c34c..e869ff1349e 100644 --- a/gdb/features/library-list-svr4.dtd +++ b/gdb/features/library-list-svr4.dtd @@ -14,3 +14,7 @@ + + diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index a80e7e30561..295e9b8b69d 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -1067,8 +1067,37 @@ library_list_start_library (struct gdb_xml_parser *parser, new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0; strcpy (new_elem->so_original_name, new_elem->so_name); - *list->tailp = new_elem; - list->tailp = &new_elem->next; + /* Older versions did not supply lmid. Put the element into the flat + list of the special namespace zero in that case. */ + gdb_xml_value *at_lmid = xml_find_attribute (attributes, "lmid"); + if (at_lmid == nullptr) + { + *list->tailp = new_elem; + list->tailp = &new_elem->next; + } + else + { + ULONGEST lmid = *(ULONGEST *) at_lmid->value.get (); + + /* Ensure that the element is actually initialized. */ + if (list->solib_lists.find (lmid) == list->solib_lists.end ()) + list->solib_lists[lmid] = nullptr; + + so_list **psolist = &list->solib_lists[lmid]; + so_list **pnext = psolist; + + /* Walk to the end of the list if we have one. */ + so_list *solist = *psolist; + if (solist != nullptr) + { + for (; solist->next != nullptr; solist = solist->next) + /* Nothing. */; + + pnext = &solist->next; + } + + *pnext = new_elem; + } } /* Handle the start of a element. */ @@ -1108,6 +1137,7 @@ static const struct gdb_xml_attribute svr4_library_attributes[] = { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, + { "lmid", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, { NULL, GDB_XML_AF_NONE, NULL, NULL } }; @@ -1869,7 +1899,9 @@ solist_update_incremental (svr4_info *info, CORE_ADDR debug_base, struct svr4_library_list library_list; char annex[64]; - xsnprintf (annex, sizeof (annex), "start=%s;prev=%s", + /* Unknown key=value pairs are ignored by the gdbstub. */ + xsnprintf (annex, sizeof (annex), "lmid=%s;start=%s;prev=%s", + phex_nz (debug_base, sizeof (debug_base)), phex_nz (lm, sizeof (lm)), phex_nz (prev_lm, sizeof (prev_lm))); if (!svr4_current_sos_via_xfer_libraries (&library_list, annex)) diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc index e83ccceed83..4754366d443 100644 --- a/gdbserver/linux-low.cc +++ b/gdbserver/linux-low.cc @@ -6489,8 +6489,8 @@ static const link_map_offsets lmo_64bit_offsets = /* Get the loaded shared libraries from one namespace. */ static void -read_link_map (std::string &document, CORE_ADDR lm_addr, CORE_ADDR lm_prev, - int ptr_size, const link_map_offsets *lmo) +read_link_map (std::string &document, CORE_ADDR lmid, CORE_ADDR lm_addr, + CORE_ADDR lm_prev, int ptr_size, const link_map_offsets *lmo) { CORE_ADDR l_name, l_addr, l_ld, l_next, l_prev; @@ -6525,9 +6525,9 @@ read_link_map (std::string &document, CORE_ADDR lm_addr, CORE_ADDR lm_prev, string_appendf (document, "", + "l_ld=\"0x%s\" lmid=\"0x%s\"/>", paddress (lm_addr), paddress (l_addr), - paddress (l_ld)); + paddress (l_ld), paddress (lmid)); } lm_prev = lm_addr; @@ -6547,7 +6547,7 @@ linux_process_target::qxfer_libraries_svr4 (const char *annex, char filename[PATH_MAX]; int pid, is_elf64; unsigned int machine; - CORE_ADDR lm_addr = 0, lm_prev = 0; + CORE_ADDR lmid = 0, lm_addr = 0, lm_prev = 0; if (writebuf != NULL) return -2; @@ -6581,7 +6581,9 @@ linux_process_target::qxfer_libraries_svr4 (const char *annex, break; name_len = sep - annex; - if (name_len == 5 && startswith (annex, "start")) + if (name_len == 4 && startswith (annex, "lmid")) + addrp = &lmid; + else if (name_len == 5 && startswith (annex, "start")) addrp = &lm_addr; else if (name_len == 4 && startswith (annex, "prev")) addrp = &lm_prev; @@ -6600,19 +6602,25 @@ linux_process_target::qxfer_libraries_svr4 (const char *annex, std::string document = "r_debug; if (r_debug == 0) r_debug = priv->r_debug = get_r_debug (pid, is_elf64); @@ -6678,7 +6686,7 @@ linux_process_target::qxfer_libraries_svr4 (const char *annex, } } - read_link_map (document, lm_addr, lm_prev, ptr_size, lmo); + read_link_map (document, r_debug, lm_addr, lm_prev, ptr_size, lmo); if (r_version < 2) break; -- 2.30.2