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[Libunwind-devel] [PATCH 3/4] Change libunwind-ptrace to also look for .
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From: |
Ken Werner |
|
Subject: |
[Libunwind-devel] [PATCH 3/4] Change libunwind-ptrace to also look for .debug_frame if nothing found in .eh_frame. |
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Date: |
Mon, 15 Aug 2011 20:23:13 +0200 |
This changes the behavior of libunwind-ptrace to what we do for local
unwinding.
Signed-off-by: Ken Werner <address@hidden>
---
src/ptrace/_UPT_create.c | 5 +
src/ptrace/_UPT_find_proc_info.c | 300 ++++++++++++++++++++------------------
src/ptrace/_UPT_internal.h | 13 +-
3 files changed, 173 insertions(+), 145 deletions(-)
diff --git a/src/ptrace/_UPT_create.c b/src/ptrace/_UPT_create.c
index 2a4427b..44b0bbe 100644
--- a/src/ptrace/_UPT_create.c
+++ b/src/ptrace/_UPT_create.c
@@ -37,5 +37,10 @@ _UPT_create (pid_t pid)
memset (ui, 0, sizeof (*ui));
ui->pid = pid;
+ ui->di_cache.format = -1;
+ ui->di_debug.format = -1;
+#if UNW_TARGET_IA64
+ ui->ktab.format = -1;;
+#endif
return ui;
}
diff --git a/src/ptrace/_UPT_find_proc_info.c b/src/ptrace/_UPT_find_proc_info.c
index 0c00039..e98a344 100644
--- a/src/ptrace/_UPT_find_proc_info.c
+++ b/src/ptrace/_UPT_find_proc_info.c
@@ -164,7 +164,7 @@ dwarf_read_encoded_pointer (unw_addr_space_t as,
unw_accessors_t *a,
pi, valp, arg);
}
-HIDDEN unw_dyn_info_t *
+HIDDEN int
_UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
char *path, unw_word_t segbase, unw_word_t mapoff,
unw_word_t ip)
@@ -176,12 +176,12 @@ _UPTi_find_unwind_table (struct UPT_info *ui,
unw_addr_space_t as,
unw_proc_info_t pi;
unw_accessors_t *a;
Elf_W(Ehdr) *ehdr;
- int i, ret;
+ int i, ret, found = 0;
/* XXX: Much of this code is Linux/LSB-specific. */
if (!elf_w(valid_object) (&ui->ei))
- return NULL;
+ return -UNW_ENOINFO;
ehdr = ui->ei.image;
phdr = (Elf_W(Phdr) *) ((char *) ui->ei.image + ehdr->e_phoff);
@@ -209,10 +209,116 @@ _UPTi_find_unwind_table (struct UPT_info *ui,
unw_addr_space_t as,
break;
}
}
- if (!ptxt || !peh_hdr)
-#ifdef CONFIG_DEBUG_FRAME
+
+ if (!ptxt)
+ return 0;
+
+ if (peh_hdr)
{
- /* No .eh_frame found, try .debug_frame. */
+ if (pdyn)
+ {
+ /* For dynamicly linked executables and shared libraries,
+ DT_PLTGOT is the value that data-relative addresses are
+ relative to for that object. We call this the "gp". */
+ Elf_W(Dyn) *dyn = (Elf_W(Dyn) *)(pdyn->p_offset
+ + (char *) ui->ei.image);
+ for (; dyn->d_tag != DT_NULL; ++dyn)
+ if (dyn->d_tag == DT_PLTGOT)
+ {
+ /* Assume that _DYNAMIC is writable and GLIBC has
+ relocated it (true for x86 at least). */
+ ui->di_cache.gp = dyn->d_un.d_ptr;
+ break;
+ }
+ }
+ else
+ /* Otherwise this is a static executable with no _DYNAMIC. Assume
+ that data-relative addresses are relative to 0, i.e.,
+ absolute. */
+ ui->di_cache.gp = 0;
+
+ hdr = (struct dwarf_eh_frame_hdr *) (peh_hdr->p_offset
+ + (char *) ui->ei.image);
+ if (hdr->version != DW_EH_VERSION)
+ {
+ Debug (1, "table `%s' has unexpected version %d\n",
+ path, hdr->version);
+ return -UNW_ENOINFO;
+ }
+
+ a = unw_get_accessors (unw_local_addr_space);
+ addr = (unw_word_t) (hdr + 1);
+
+ /* Fill in a dummy proc_info structure. We just need to fill in
+ enough to ensure that dwarf_read_encoded_pointer() can do it's
+ job. Since we don't have a procedure-context at this point, all
+ we have to do is fill in the global-pointer. */
+ memset (&pi, 0, sizeof (pi));
+ pi.gp = ui->di_cache.gp;
+
+ /* (Optionally) read eh_frame_ptr: */
+ if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
+ &addr, hdr->eh_frame_ptr_enc, &pi,
+ &eh_frame_start, NULL)) < 0)
+ return -UNW_ENOINFO;
+
+ /* (Optionally) read fde_count: */
+ if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
+ &addr, hdr->fde_count_enc, &pi,
+ &fde_count, NULL)) < 0)
+ return -UNW_ENOINFO;
+
+ if (hdr->table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4))
+ {
+ #if 1
+ abort ();
+ #else
+ unw_word_t eh_frame_end;
+
+ /* If there is no search table or it has an unsupported
+ encoding, fall back on linear search. */
+ if (hdr->table_enc == DW_EH_PE_omit)
+ Debug (4, "EH lacks search table; doing linear search\n");
+ else
+ Debug (4, "EH table has encoding 0x%x; doing linear search\n",
+ hdr->table_enc);
+
+ eh_frame_end = max_load_addr; /* XXX can we do better? */
+
+ if (hdr->fde_count_enc == DW_EH_PE_omit)
+ fde_count = ~0UL;
+ if (hdr->eh_frame_ptr_enc == DW_EH_PE_omit)
+ abort ();
+
+ return linear_search (unw_local_addr_space, ip,
+ eh_frame_start, eh_frame_end, fde_count,
+ pi, need_unwind_info, NULL);
+ #endif
+ }
+
+ load_base = segbase - ptxt->p_vaddr;
+
+ ui->di_cache.start_ip = segbase;
+ ui->di_cache.end_ip = ui->di_cache.start_ip + ptxt->p_memsz;
+ ui->di_cache.format = UNW_INFO_FORMAT_REMOTE_TABLE;
+ ui->di_cache.u.rti.name_ptr = 0;
+ /* two 32-bit values (ip_offset/fde_offset) per table-entry: */
+ ui->di_cache.u.rti.table_len = (fde_count * 8) / sizeof (unw_word_t);
+ ui->di_cache.u.rti.table_data = ((load_base + peh_hdr->p_vaddr)
+ + (addr - (unw_word_t) ui->ei.image
+ - peh_hdr->p_offset));
+
+ /* For the binary-search table in the eh_frame_hdr, data-relative
+ means relative to the start of that section... */
+ ui->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr)
+ + ((unw_word_t) hdr - (unw_word_t)
ui->ei.image
+ - peh_hdr->p_offset));
+ found = 1;
+ }
+
+#ifdef CONFIG_DEBUG_FRAME
+ {
+ /* Try .debug_frame. */
struct dl_phdr_info info;
info.dlpi_name = path;
@@ -231,136 +337,34 @@ _UPTi_find_unwind_table (struct UPT_info *ui,
unw_addr_space_t as,
}
info.dlpi_addr = segbase;
- if (dwarf_find_debug_frame (0, &ui->di_cache, &info, ip))
- return &ui->di_cache;
- else
- return NULL;
- }
-#else
- return NULL;
+ found = dwarf_find_debug_frame (found, &ui->di_debug, &info, ip);
+ }
#endif
- if (pdyn)
- {
- /* For dynamicly linked executables and shared libraries,
- DT_PLTGOT is the value that data-relative addresses are
- relative to for that object. We call this the "gp". */
- Elf_W(Dyn) *dyn = (Elf_W(Dyn) *)(pdyn->p_offset
- + (char *) ui->ei.image);
- for (; dyn->d_tag != DT_NULL; ++dyn)
- if (dyn->d_tag == DT_PLTGOT)
- {
- /* Assume that _DYNAMIC is writable and GLIBC has
- relocated it (true for x86 at least). */
- ui->di_cache.gp = dyn->d_un.d_ptr;
- break;
- }
- }
- else
- /* Otherwise this is a static executable with no _DYNAMIC. Assume
- that data-relative addresses are relative to 0, i.e.,
- absolute. */
- ui->di_cache.gp = 0;
-
- hdr = (struct dwarf_eh_frame_hdr *) (peh_hdr->p_offset
- + (char *) ui->ei.image);
- if (hdr->version != DW_EH_VERSION)
- {
- Debug (1, "table `%s' has unexpected version %d\n",
- path, hdr->version);
- return 0;
- }
-
- a = unw_get_accessors (unw_local_addr_space);
- addr = (unw_word_t) (hdr + 1);
-
- /* Fill in a dummy proc_info structure. We just need to fill in
- enough to ensure that dwarf_read_encoded_pointer() can do it's
- job. Since we don't have a procedure-context at this point, all
- we have to do is fill in the global-pointer. */
- memset (&pi, 0, sizeof (pi));
- pi.gp = ui->di_cache.gp;
-
- /* (Optionally) read eh_frame_ptr: */
- if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
- &addr, hdr->eh_frame_ptr_enc, &pi,
- &eh_frame_start, NULL)) < 0)
- return NULL;
-
- /* (Optionally) read fde_count: */
- if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
- &addr, hdr->fde_count_enc, &pi,
- &fde_count, NULL)) < 0)
- return NULL;
-
- if (hdr->table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4))
- {
-#if 1
- abort ();
-#else
- unw_word_t eh_frame_end;
-
- /* If there is no search table or it has an unsupported
- encoding, fall back on linear search. */
- if (hdr->table_enc == DW_EH_PE_omit)
- Debug (4, "EH lacks search table; doing linear search\n");
- else
- Debug (4, "EH table has encoding 0x%x; doing linear search\n",
- hdr->table_enc);
-
- eh_frame_end = max_load_addr; /* XXX can we do better? */
-
- if (hdr->fde_count_enc == DW_EH_PE_omit)
- fde_count = ~0UL;
- if (hdr->eh_frame_ptr_enc == DW_EH_PE_omit)
- abort ();
-
- return linear_search (unw_local_addr_space, ip,
- eh_frame_start, eh_frame_end, fde_count,
- pi, need_unwind_info, NULL);
-#endif
- }
-
- load_base = segbase - ptxt->p_vaddr;
-
- ui->di_cache.start_ip = segbase;
- ui->di_cache.end_ip = ui->di_cache.start_ip + ptxt->p_memsz;
- ui->di_cache.format = UNW_INFO_FORMAT_REMOTE_TABLE;
- ui->di_cache.u.rti.name_ptr = 0;
- /* two 32-bit values (ip_offset/fde_offset) per table-entry: */
- ui->di_cache.u.rti.table_len = (fde_count * 8) / sizeof (unw_word_t);
- ui->di_cache.u.rti.table_data = ((load_base + peh_hdr->p_vaddr)
- + (addr - (unw_word_t) ui->ei.image
- - peh_hdr->p_offset));
-
- /* For the binary-search table in the eh_frame_hdr, data-relative
- means relative to the start of that section... */
- ui->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr)
- + ((unw_word_t) hdr - (unw_word_t) ui->ei.image
- - peh_hdr->p_offset));
-
- return &ui->di_cache;
+ return found;
}
#endif /* UNW_TARGET_X86 || UNW_TARGET_X86_64 || UNW_TARGET_HPPA*/
-static unw_dyn_info_t *
+static int
get_unwind_info (struct UPT_info *ui, unw_addr_space_t as, unw_word_t ip)
{
unsigned long segbase, mapoff;
char path[PATH_MAX];
- unw_dyn_info_t *di;
#if UNW_TARGET_IA64 && defined(__linux)
if (!ui->ktab.start_ip && _Uia64_get_kernel_table (&ui->ktab) < 0)
- return NULL;
+ return -UNW_ENOINFO;
- if (ip >= ui->ktab.start_ip && ip < ui->ktab.end_ip)
- return &ui->ktab;
+ if (ui->ktab.format != -1 && ip >= ui->ktab.start_ip && ip < ui->ktab.end_ip)
+ return 0;
#endif
- if (ip >= ui->di_cache.start_ip && ip < ui->di_cache.end_ip)
- return &ui->di_cache;
+ if ((ui->di_cache.format != -1
+ && ip >= ui->di_cache.start_ip && ip < ui->di_cache.end_ip)
+ || (ui->di_debug.format != -1
+ && ip >= ui->di_debug.start_ip && ip < ui->di_debug.end_ip))
+ return 0;
if (ui->ei.image)
{
@@ -370,24 +374,36 @@ get_unwind_info (struct UPT_info *ui, unw_addr_space_t
as, unw_word_t ip)
/* invalidate the cache: */
ui->di_cache.start_ip = ui->di_cache.end_ip = 0;
+ ui->di_debug.start_ip = ui->di_debug.end_ip = 0;
+ ui->di_cache.format = -1;
+ ui->di_debug.format = -1;
}
if (tdep_get_elf_image (&ui->ei, ui->pid, ip, &segbase, &mapoff, path,
sizeof(path)) < 0)
- return NULL;
+ return -UNW_ENOINFO;
/* Here, SEGBASE is the starting-address of the (mmap'ped) segment
which covers the IP we're looking for. */
- di = _UPTi_find_unwind_table (ui, as, path, segbase, mapoff, ip);
- if (!di
- /* This can happen in corner cases where dynamically generated
- code falls into the same page that contains the data-segment
- and the page-offset of the code is within the first page of
- the executable. */
- || ip < di->start_ip || ip >= di->end_ip)
- return NULL;
+ if (_UPTi_find_unwind_table (ui, as, path, segbase, mapoff, ip) < 0)
+ return -UNW_ENOINFO;
+
+ /* This can happen in corner cases where dynamically generated
+ code falls into the same page that contains the data-segment
+ and the page-offset of the code is within the first page of
+ the executable. */
+ if (ui->di_cache.format != -1
+ && (ip < ui->di_cache.start_ip || ip >= ui->di_cache.end_ip))
+ ui->di_cache.format = -1;
+
+ if (ui->di_debug.format != -1
+ && (ip < ui->di_debug.start_ip || ip >= ui->di_debug.end_ip))
+ ui->di_debug.format = -1;
+
+ if (ui->di_cache.format == -1 && ui->di_debug.format == -1)
+ return -UNW_ENOINFO;
- return di;
+ return 0;
}
int
@@ -395,14 +411,13 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip,
unw_proc_info_t *pi,
int need_unwind_info, void *arg)
{
struct UPT_info *ui = arg;
- unw_dyn_info_t *di;
+ int ret = -UNW_ENOINFO;
- di = get_unwind_info (ui, as, ip);
- if (!di)
+ if (get_unwind_info (ui, as, ip) < 0)
return -UNW_ENOINFO;
#if UNW_TARGET_IA64
- if (di == &ui->ktab)
+ if (ui->ktab.format != -1)
{
/* The kernel unwind table resides in local memory, so we have
to use the local address space to search it. Since
@@ -410,8 +425,8 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip,
unw_proc_info_t *pi,
case, we simply make a copy of the unwind-info, so
_UPT_put_unwind_info() can always free() the unwind-info
without ill effects. */
- int ret = tdep_search_unwind_table (unw_local_addr_space, ip, di, pi,
- need_unwind_info, arg);
+ ret = tdep_search_unwind_table (unw_local_addr_space, ip, &ui->ktab, pi,
+ need_unwind_info, arg);
if (ret >= 0)
{
if (!need_unwind_info)
@@ -426,9 +441,16 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip,
unw_proc_info_t *pi,
pi->unwind_info = mem;
}
}
- return ret;
}
- else
#endif
- return tdep_search_unwind_table (as, ip, di, pi, need_unwind_info, arg);
+
+ if (ret == -UNW_ENOINFO && ui->di_cache.format == -1)
+ ret = tdep_search_unwind_table (as, ip, &ui->di_cache,
+ pi, need_unwind_info, arg);
+
+ if (ret == -UNW_ENOINFO && ui->di_debug.format != -1)
+ ret = tdep_search_unwind_table (as, ip, &ui->di_debug, pi,
+ need_unwind_info, arg);
+
+ return ret;
}
diff --git a/src/ptrace/_UPT_internal.h b/src/ptrace/_UPT_internal.h
index bfc26b0..54d5fc9 100644
--- a/src/ptrace/_UPT_internal.h
+++ b/src/ptrace/_UPT_internal.h
@@ -53,6 +53,7 @@ struct UPT_info
pid_t pid; /* the process-id of the child we're unwinding */
struct elf_image ei;
unw_dyn_info_t di_cache;
+ unw_dyn_info_t di_debug; /* additional table info for .debug_frame */
#if UNW_TARGET_IA64
unw_dyn_info_t ktab;
#endif
@@ -60,11 +61,11 @@ struct UPT_info
extern int _UPT_reg_offset[UNW_REG_LAST + 1];
-extern unw_dyn_info_t *_UPTi_find_unwind_table (struct UPT_info *ui,
- unw_addr_space_t as,
- char *path,
- unw_word_t segbase,
- unw_word_t mapoff,
- unw_word_t ip);
+extern int _UPTi_find_unwind_table (struct UPT_info *ui,
+ unw_addr_space_t as,
+ char *path,
+ unw_word_t segbase,
+ unw_word_t mapoff,
+ unw_word_t ip);
#endif /* _UPT_internal_h */
--
1.7.4.1