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Move linux_find_memory_regions_full & co.

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This should be just a move with no changes.

gdb/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	Move linux_find_memory_regions_full & co.
	* linux-tdep.c (nat/linux-maps.h): Include.
	(gdb_regex.h): Remove the include.
	(enum filterflags, struct smaps_vmflags, read_mapping, decode_vmflags)
	(mapping_is_anonymous_p, dump_mapping_p): Moved to nat/linux-maps.c.
	(linux_find_memory_region_ftype): Moved typedef to nat/linux-maps.h.
	(linux_find_memory_regions_full): Moved definition to nat/linux-maps.c.
	* nat/linux-maps.c: Include ctype.h, target/target-utils.h, gdb_regex.h
	and target/target.h.
	(struct smaps_vmflags, read_mapping, decode_vmflags)
	(mapping_is_anonymous_p, dump_mapping_p): Move from linux-tdep.c.
	(linux_find_memory_regions_full): Move from linux-tdep.c.
	* nat/linux-maps.h (read_mapping): New declaration.
	(linux_find_memory_region_ftype, enum filterflags): Moved from
	linux-tdep.c.
	(linux_find_memory_regions_full): New declaration.
	* target.c (target/target-utils.h): Include.
	(read_alloc_pread_ftype): Moved typedef to target/target-utils.h.
	(read_alloc, read_stralloc_func_ftype, read_stralloc): Moved
	definitions to target/target-utils.c.
	* target.h (target_fileio_read_stralloc): Move it to target/target.h.
	* target/target-utils.c (read_alloc, read_stralloc): Move definitions
	from target.c.
	* target/target-utils.h (read_alloc_pread_ftype): New typedef.
	(read_alloc): New declaration.
	(read_stralloc_func_ftype): New typedef.
	(read_stralloc): New declaration.
	* target/target.h (target_fileio_read_stralloc): Move it from target.h.

gdb/gdbserver/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* target.c: Include target/target-utils.h and fcntl.h.
	(target_fileio_read_stralloc_1_pread, target_fileio_read_stralloc_1)
	(target_fileio_read_stralloc): New functions.
This commit is contained in:
Jan Kratochvil 2015-07-15 17:37:27 +02:00
parent f7af1fcd75
commit 9904185cfd
11 changed files with 695 additions and 597 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
gdb/ChangeLog
View File

@ -1,3 +1,35 @@
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
Move linux_find_memory_regions_full & co.
* linux-tdep.c (nat/linux-maps.h): Include.
(gdb_regex.h): Remove the include.
(enum filterflags, struct smaps_vmflags, read_mapping, decode_vmflags)
(mapping_is_anonymous_p, dump_mapping_p): Moved to nat/linux-maps.c.
(linux_find_memory_region_ftype): Moved typedef to nat/linux-maps.h.
(linux_find_memory_regions_full): Moved definition to nat/linux-maps.c.
* nat/linux-maps.c: Include ctype.h, target/target-utils.h, gdb_regex.h
and target/target.h.
(struct smaps_vmflags, read_mapping, decode_vmflags)
(mapping_is_anonymous_p, dump_mapping_p): Move from linux-tdep.c.
(linux_find_memory_regions_full): Move from linux-tdep.c.
* nat/linux-maps.h (read_mapping): New declaration.
(linux_find_memory_region_ftype, enum filterflags): Moved from
linux-tdep.c.
(linux_find_memory_regions_full): New declaration.
* target.c (target/target-utils.h): Include.
(read_alloc_pread_ftype): Moved typedef to target/target-utils.h.
(read_alloc, read_stralloc_func_ftype, read_stralloc): Moved
definitions to target/target-utils.c.
* target.h (target_fileio_read_stralloc): Move it to target/target.h.
* target/target-utils.c (read_alloc, read_stralloc): Move definitions
from target.c.
* target/target-utils.h (read_alloc_pread_ftype): New typedef.
(read_alloc): New declaration.
(read_stralloc_func_ftype): New typedef.
(read_stralloc): New declaration.
* target/target.h (target_fileio_read_stralloc): Move it from target.h.
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>

7
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,10 @@
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
* target.c: Include target/target-utils.h and fcntl.h.
(target_fileio_read_stralloc_1_pread, target_fileio_read_stralloc_1)
(target_fileio_read_stralloc): New functions.
2015-07-15 Jan Kratochvil <jan.kratochvil@redhat.com>
* Makefile.in (OBS): Add gdb_regex.o.

36
gdb/gdbserver/target.c
View File

@ -20,6 +20,8 @@
#include "server.h"
#include "tracepoint.h"
#include "target/target-utils.h"
#include <fcntl.h>
struct target_ops *the_target;
@ -218,3 +220,37 @@ kill_inferior (int pid)
return (*the_target->kill) (pid);
}
static int
target_fileio_read_stralloc_1_pread (int handle, gdb_byte *read_buf, int len,
ULONGEST offset, int *target_errno)
{
int retval = pread (handle, read_buf, len, offset);
*target_errno = errno;
return retval;
}
static LONGEST
target_fileio_read_stralloc_1 (struct inferior *inf, const char *filename,
gdb_byte **buf_p, int padding)
{
int fd;
LONGEST retval;
fd = open (filename, O_RDONLY);
if (fd == -1)
return -1;
retval = read_alloc (buf_p, fd, target_fileio_read_stralloc_1_pread, padding);
close (fd);
return retval;
}
char *
target_fileio_read_stralloc (struct inferior *inf, const char *filename)
{
return read_stralloc (inf, filename, target_fileio_read_stralloc_1);
}

499
gdb/linux-tdep.c
View File

@ -35,56 +35,11 @@
#include "observer.h"
#include "objfiles.h"
#include "infcall.h"
#include "nat/linux-maps.h"
#include "gdbcmd.h"
#include "gdb_regex.h"
#include <ctype.h>
/* This enum represents the values that the user can choose when
informing the Linux kernel about which memory mappings will be
dumped in a corefile. They are described in the file
Documentation/filesystems/proc.txt, inside the Linux kernel
tree. */
enum filterflags
{
COREFILTER_ANON_PRIVATE = 1 << 0,
COREFILTER_ANON_SHARED = 1 << 1,
COREFILTER_MAPPED_PRIVATE = 1 << 2,
COREFILTER_MAPPED_SHARED = 1 << 3,
COREFILTER_ELF_HEADERS = 1 << 4,
COREFILTER_HUGETLB_PRIVATE = 1 << 5,
COREFILTER_HUGETLB_SHARED = 1 << 6,
};
/* This struct is used to map flags found in the "VmFlags:" field (in
the /proc/<PID>/smaps file). */
struct smaps_vmflags
{
/* Zero if this structure has not been initialized yet. It
probably means that the Linux kernel being used does not emit
the "VmFlags:" field on "/proc/PID/smaps". */
unsigned int initialized_p : 1;
/* Memory mapped I/O area (VM_IO, "io"). */
unsigned int io_page : 1;
/* Area uses huge TLB pages (VM_HUGETLB, "ht"). */
unsigned int uses_huge_tlb : 1;
/* Do not include this memory region on the coredump (VM_DONTDUMP, "dd"). */
unsigned int exclude_coredump : 1;
/* Is this a MAP_SHARED mapping (VM_SHARED, "sh"). */
unsigned int shared_mapping : 1;
};
/* Whether to take the /proc/PID/coredump_filter into account when
generating a corefile. */
@ -395,286 +350,6 @@ linux_core_pid_to_str (struct gdbarch *gdbarch, ptid_t ptid)
return normal_pid_to_str (ptid);
}
/* Service function for corefiles and info proc. */
static void
read_mapping (const char *line,
ULONGEST *addr, ULONGEST *endaddr,
const char **permissions, size_t *permissions_len,
ULONGEST *offset,
const char **device, size_t *device_len,
ULONGEST *inode,
const char **filename)
{
const char *p = line;
*addr = strtoulst (p, &p, 16);
if (*p == '-')
p++;
*endaddr = strtoulst (p, &p, 16);
p = skip_spaces_const (p);
*permissions = p;
while (*p && !isspace (*p))
p++;
*permissions_len = p - *permissions;
*offset = strtoulst (p, &p, 16);
p = skip_spaces_const (p);
*device = p;
while (*p && !isspace (*p))
p++;
*device_len = p - *device;
*inode = strtoulst (p, &p, 10);
p = skip_spaces_const (p);
*filename = p;
}
/* Helper function to decode the "VmFlags" field in /proc/PID/smaps.
This function was based on the documentation found on
<Documentation/filesystems/proc.txt>, on the Linux kernel.
Linux kernels before commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10) do not have this
field on smaps. */
static void
decode_vmflags (char *p, struct smaps_vmflags *v)
{
char *saveptr = NULL;
const char *s;
v->initialized_p = 1;
p = skip_to_space (p);
p = skip_spaces (p);
for (s = strtok_r (p, " ", &saveptr);
s != NULL;
s = strtok_r (NULL, " ", &saveptr))
{
if (strcmp (s, "io") == 0)
v->io_page = 1;
else if (strcmp (s, "ht") == 0)
v->uses_huge_tlb = 1;
else if (strcmp (s, "dd") == 0)
v->exclude_coredump = 1;
else if (strcmp (s, "sh") == 0)
v->shared_mapping = 1;
}
}
/* Return 1 if the memory mapping is anonymous, 0 otherwise.
FILENAME is the name of the file present in the first line of the
memory mapping, in the "/proc/PID/smaps" output. For example, if
the first line is:
7fd0ca877000-7fd0d0da0000 r--p 00000000 fd:02 2100770 /path/to/file
Then FILENAME will be "/path/to/file". */
static int
mapping_is_anonymous_p (const char *filename)
{
static regex_t dev_zero_regex, shmem_file_regex, file_deleted_regex;
static int init_regex_p = 0;
if (!init_regex_p)
{
struct cleanup *c = make_cleanup (null_cleanup, NULL);
/* Let's be pessimistic and assume there will be an error while
compiling the regex'es. */
init_regex_p = -1;
/* DEV_ZERO_REGEX matches "/dev/zero" filenames (with or
without the "(deleted)" string in the end). We know for
sure, based on the Linux kernel code, that memory mappings
whose associated filename is "/dev/zero" are guaranteed to be
MAP_ANONYMOUS. */
compile_rx_or_error (&dev_zero_regex, "^/dev/zero\\( (deleted)\\)\\?$",
_("Could not compile regex to match /dev/zero "
"filename"));
/* SHMEM_FILE_REGEX matches "/SYSV%08x" filenames (with or
without the "(deleted)" string in the end). These filenames
refer to shared memory (shmem), and memory mappings
associated with them are MAP_ANONYMOUS as well. */
compile_rx_or_error (&shmem_file_regex,
"^/\\?SYSV[0-9a-fA-F]\\{8\\}\\( (deleted)\\)\\?$",
_("Could not compile regex to match shmem "
"filenames"));
/* FILE_DELETED_REGEX is a heuristic we use to try to mimic the
Linux kernel's 'n_link == 0' code, which is responsible to
decide if it is dealing with a 'MAP_SHARED | MAP_ANONYMOUS'
mapping. In other words, if FILE_DELETED_REGEX matches, it
does not necessarily mean that we are dealing with an
anonymous shared mapping. However, there is no easy way to
detect this currently, so this is the best approximation we
have.
As a result, GDB will dump readonly pages of deleted
executables when using the default value of coredump_filter
(0x33), while the Linux kernel will not dump those pages.
But we can live with that. */
compile_rx_or_error (&file_deleted_regex, " (deleted)$",
_("Could not compile regex to match "
"'<file> (deleted)'"));
/* We will never release these regexes, so just discard the
cleanups. */
discard_cleanups (c);
/* If we reached this point, then everything succeeded. */
init_regex_p = 1;
}
if (init_regex_p == -1)
{
const char deleted[] = " (deleted)";
size_t del_len = sizeof (deleted) - 1;
size_t filename_len = strlen (filename);
/* There was an error while compiling the regex'es above. In
order to try to give some reliable information to the caller,
we just try to find the string " (deleted)" in the filename.
If we managed to find it, then we assume the mapping is
anonymous. */
return (filename_len >= del_len
&& strcmp (filename + filename_len - del_len, deleted) == 0);
}
if (*filename == '\0'
|| regexec (&dev_zero_regex, filename, 0, NULL, 0) == 0
|| regexec (&shmem_file_regex, filename, 0, NULL, 0) == 0
|| regexec (&file_deleted_regex, filename, 0, NULL, 0) == 0)
return 1;
return 0;
}
/* Return 0 if the memory mapping (which is related to FILTERFLAGS, V,
MAYBE_PRIVATE_P, and MAPPING_ANONYMOUS_P) should not be dumped, or
greater than 0 if it should.
In a nutshell, this is the logic that we follow in order to decide
if a mapping should be dumped or not.
- If the mapping is associated to a file whose name ends with
" (deleted)", or if the file is "/dev/zero", or if it is
"/SYSV%08x" (shared memory), or if there is no file associated
with it, or if the AnonHugePages: or the Anonymous: fields in the
/proc/PID/smaps have contents, then GDB considers this mapping to
be anonymous. Otherwise, GDB considers this mapping to be a
file-backed mapping (because there will be a file associated with
it).
It is worth mentioning that, from all those checks described
above, the most fragile is the one to see if the file name ends
with " (deleted)". This does not necessarily mean that the
mapping is anonymous, because the deleted file associated with
the mapping may have been a hard link to another file, for
example. The Linux kernel checks to see if "i_nlink == 0", but
GDB cannot easily (and normally) do this check (iff running as
root, it could find the mapping in /proc/PID/map_files/ and
determine whether there still are other hard links to the
inode/file). Therefore, we made a compromise here, and we assume
that if the file name ends with " (deleted)", then the mapping is
indeed anonymous. FWIW, this is something the Linux kernel could
do better: expose this information in a more direct way.
- If we see the flag "sh" in the "VmFlags:" field (in
/proc/PID/smaps), then certainly the memory mapping is shared
(VM_SHARED). If we have access to the VmFlags, and we don't see
the "sh" there, then certainly the mapping is private. However,
Linux kernels before commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10) do not have the
"VmFlags:" field; in that case, we use another heuristic: if we
see 'p' in the permission flags, then we assume that the mapping
is private, even though the presence of the 's' flag there would
mean VM_MAYSHARE, which means the mapping could still be private.
This should work OK enough, however. */
static int
dump_mapping_p (enum filterflags filterflags, const struct smaps_vmflags *v,
int maybe_private_p, int mapping_anon_p, int mapping_file_p,
const char *filename)
{
/* Initially, we trust in what we received from our caller. This
value may not be very precise (i.e., it was probably gathered
from the permission line in the /proc/PID/smaps list, which
actually refers to VM_MAYSHARE, and not VM_SHARED), but it is
what we have until we take a look at the "VmFlags:" field
(assuming that the version of the Linux kernel being used
supports it, of course). */
int private_p = maybe_private_p;
/* We always dump vDSO and vsyscall mappings, because it's likely that
there'll be no file to read the contents from at core load time.
The kernel does the same. */
if (strcmp ("[vdso]", filename) == 0
|| strcmp ("[vsyscall]", filename) == 0)
return 1;
if (v->initialized_p)
{
/* We never dump I/O mappings. */
if (v->io_page)
return 0;
/* Check if we should exclude this mapping. */
if (v->exclude_coredump)
return 0;
/* Update our notion of whether this mapping is shared or
private based on a trustworthy value. */
private_p = !v->shared_mapping;
/* HugeTLB checking. */
if (v->uses_huge_tlb)
{
if ((private_p && (filterflags & COREFILTER_HUGETLB_PRIVATE))
|| (!private_p && (filterflags & COREFILTER_HUGETLB_SHARED)))
return 1;
return 0;
}
}
if (private_p)
{
if (mapping_anon_p && mapping_file_p)
{
/* This is a special situation. It can happen when we see a
mapping that is file-backed, but that contains anonymous
pages. */
return ((filterflags & COREFILTER_ANON_PRIVATE) != 0
|| (filterflags & COREFILTER_MAPPED_PRIVATE) != 0);
}
else if (mapping_anon_p)
return (filterflags & COREFILTER_ANON_PRIVATE) != 0;
else
return (filterflags & COREFILTER_MAPPED_PRIVATE) != 0;
}
else
{
if (mapping_anon_p && mapping_file_p)
{
/* This is a special situation. It can happen when we see a
mapping that is file-backed, but that contains anonymous
pages. */
return ((filterflags & COREFILTER_ANON_SHARED) != 0
|| (filterflags & COREFILTER_MAPPED_SHARED) != 0);
}
else if (mapping_anon_p)
return (filterflags & COREFILTER_ANON_SHARED) != 0;
else
return (filterflags & COREFILTER_MAPPED_SHARED) != 0;
}
}
/* Implement the "info proc" command. */
static void
@ -1098,178 +773,6 @@ linux_core_info_proc (struct gdbarch *gdbarch, const char *args,
error (_("unable to handle request"));
}
/* Callback function for linux_find_memory_regions_full. If it returns
non-zero linux_find_memory_regions_full returns immediately with that
value. */
typedef int linux_find_memory_region_ftype (ULONGEST vaddr, ULONGEST size,
ULONGEST offset, ULONGEST inode,
int read, int write,
int exec, int modified,
const char *filename,
void *data);
/* List memory regions in the inferior PID matched to FILTERFLAGS for
a corefile. Call FUNC with FUNC_DATA for each such region. Return
immediately with the value returned by FUNC if it is non-zero.
*MEMORY_TO_FREE_PTR should be registered to be freed automatically if
called FUNC throws an exception. MEMORY_TO_FREE_PTR can be also
passed as NULL if it is not used. Return -1 if error occurs, 0 if
all memory regions have been processed or return the value from FUNC
if FUNC returns non-zero. */
static int
linux_find_memory_regions_full (pid_t pid, enum filterflags filterflags,
linux_find_memory_region_ftype *func,
void *func_data)
{
char mapsfilename[100];
char *data;
xsnprintf (mapsfilename, sizeof mapsfilename, "/proc/%d/smaps", pid);
data = target_fileio_read_stralloc (NULL, mapsfilename);
if (data == NULL)
{
/* Older Linux kernels did not support /proc/PID/smaps. */
xsnprintf (mapsfilename, sizeof mapsfilename, "/proc/%d/maps", pid);
data = target_fileio_read_stralloc (NULL, mapsfilename);
}
if (data != NULL)
{
struct cleanup *cleanup = make_cleanup (xfree, data);
char *line, *t;
int retval = 0;
line = strtok_r (data, "\n", &t);
while (line != NULL)
{
ULONGEST addr, endaddr, offset, inode;
const char *permissions, *device, *filename;
struct smaps_vmflags v;
size_t permissions_len, device_len;
int read, write, exec, priv;
int has_anonymous = 0;
int should_dump_p = 0;
int mapping_anon_p;
int mapping_file_p;
memset (&v, 0, sizeof (v));
read_mapping (line, &addr, &endaddr, &permissions, &permissions_len,
&offset, &device, &device_len, &inode, &filename);
mapping_anon_p = mapping_is_anonymous_p (filename);
/* If the mapping is not anonymous, then we can consider it
to be file-backed. These two states (anonymous or
file-backed) seem to be exclusive, but they can actually
coexist. For example, if a file-backed mapping has
"Anonymous:" pages (see more below), then the Linux
kernel will dump this mapping when the user specified
that she only wants anonymous mappings in the corefile
(*even* when she explicitly disabled the dumping of
file-backed mappings). */
mapping_file_p = !mapping_anon_p;
/* Decode permissions. */
read = (memchr (permissions, 'r', permissions_len) != 0);
write = (memchr (permissions, 'w', permissions_len) != 0);
exec = (memchr (permissions, 'x', permissions_len) != 0);
/* 'private' here actually means VM_MAYSHARE, and not
VM_SHARED. In order to know if a mapping is really
private or not, we must check the flag "sh" in the
VmFlags field. This is done by decode_vmflags. However,
if we are using a Linux kernel released before the commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10), we will
not have the VmFlags there. In this case, there is
really no way to know if we are dealing with VM_SHARED,
so we just assume that VM_MAYSHARE is enough. */
priv = memchr (permissions, 'p', permissions_len) != 0;
/* Try to detect if region should be dumped by parsing smaps
counters. */
for (line = strtok_r (NULL, "\n", &t);
line != NULL && line[0] >= 'A' && line[0] <= 'Z';
line = strtok_r (NULL, "\n", &t))
{
char keyword[64 + 1];
if (sscanf (line, "%64s", keyword) != 1)
{
warning (_("Error parsing {s,}maps file '%s'"), mapsfilename);
break;
}
if (strcmp (keyword, "Anonymous:") == 0)
{
/* Older Linux kernels did not support the
"Anonymous:" counter. Check it here. */
has_anonymous = 1;
}
else if (strcmp (keyword, "VmFlags:") == 0)
decode_vmflags (line, &v);
if (strcmp (keyword, "AnonHugePages:") == 0
|| strcmp (keyword, "Anonymous:") == 0)
{
unsigned long number;
if (sscanf (line, "%*s%lu", &number) != 1)
{
warning (_("Error parsing {s,}maps file '%s' number"),
mapsfilename);
break;
}
if (number > 0)
{
/* Even if we are dealing with a file-backed
mapping, if it contains anonymous pages we
consider it to be *also* an anonymous
mapping, because this is what the Linux
kernel does:
// Dump segments that have been written to.
if (vma->anon_vma && FILTER(ANON_PRIVATE))
goto whole;
Note that if the mapping is already marked as
file-backed (i.e., mapping_file_p is
non-zero), then this is a special case, and
this mapping will be dumped either when the
user wants to dump file-backed *or* anonymous
mappings. */
mapping_anon_p = 1;
}
}
}
if (has_anonymous)
should_dump_p = dump_mapping_p (filterflags, &v, priv,
mapping_anon_p, mapping_file_p,
filename);
else
{
/* Older Linux kernels did not support the "Anonymous:" counter.
If it is missing, we can't be sure - dump all the pages. */
should_dump_p = 1;
}
/* Invoke the callback function to create the corefile segment. */
if (should_dump_p)
retval = func (addr, endaddr - addr, offset, inode,
read, write, exec,
1, /* MODIFIED is true because we want to dump the
mapping. */
filename, func_data);
if (retval != 0)
break;
}
do_cleanups (cleanup);
return retval;
}
return -1;
}
/* A structure for passing information through
linux_find_memory_regions_full. */

473
gdb/nat/linux-maps.c
View File

@ -18,3 +18,476 @@
#include "common-defs.h"
#include "linux-maps.h"
#include <ctype.h>
#include "target/target-utils.h"
#include "gdb_regex.h"
#include "target/target.h"
/* This struct is used to map flags found in the "VmFlags:" field (in
the /proc/<PID>/smaps file). */
struct smaps_vmflags
{
/* Zero if this structure has not been initialized yet. It
probably means that the Linux kernel being used does not emit
the "VmFlags:" field on "/proc/PID/smaps". */
unsigned int initialized_p : 1;
/* Memory mapped I/O area (VM_IO, "io"). */
unsigned int io_page : 1;
/* Area uses huge TLB pages (VM_HUGETLB, "ht"). */
unsigned int uses_huge_tlb : 1;
/* Do not include this memory region on the coredump (VM_DONTDUMP, "dd"). */
unsigned int exclude_coredump : 1;
/* Is this a MAP_SHARED mapping (VM_SHARED, "sh"). */
unsigned int shared_mapping : 1;
};
/* Service function for corefiles and info proc. */
void
read_mapping (const char *line,
ULONGEST *addr, ULONGEST *endaddr,
const char **permissions, size_t *permissions_len,
ULONGEST *offset,
const char **device, size_t *device_len,
ULONGEST *inode,
const char **filename)
{
const char *p = line;
*addr = strtoulst (p, &p, 16);
if (*p == '-')
p++;
*endaddr = strtoulst (p, &p, 16);
p = skip_spaces_const (p);
*permissions = p;
while (*p && !isspace (*p))
p++;
*permissions_len = p - *permissions;
*offset = strtoulst (p, &p, 16);
p = skip_spaces_const (p);
*device = p;
while (*p && !isspace (*p))
p++;
*device_len = p - *device;
*inode = strtoulst (p, &p, 10);
p = skip_spaces_const (p);
*filename = p;
}
/* Helper function to decode the "VmFlags" field in /proc/PID/smaps.
This function was based on the documentation found on
<Documentation/filesystems/proc.txt>, on the Linux kernel.
Linux kernels before commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10) do not have this
field on smaps. */
static void
decode_vmflags (char *p, struct smaps_vmflags *v)
{
char *saveptr = NULL;
const char *s;
v->initialized_p = 1;
p = skip_to_space (p);
p = skip_spaces (p);
for (s = strtok_r (p, " ", &saveptr);
s != NULL;
s = strtok_r (NULL, " ", &saveptr))
{
if (strcmp (s, "io") == 0)
v->io_page = 1;
else if (strcmp (s, "ht") == 0)
v->uses_huge_tlb = 1;
else if (strcmp (s, "dd") == 0)
v->exclude_coredump = 1;
else if (strcmp (s, "sh") == 0)
v->shared_mapping = 1;
}
}
/* Return 1 if the memory mapping is anonymous, 0 otherwise.
FILENAME is the name of the file present in the first line of the
memory mapping, in the "/proc/PID/smaps" output. For example, if
the first line is:
7fd0ca877000-7fd0d0da0000 r--p 00000000 fd:02 2100770 /path/to/file
Then FILENAME will be "/path/to/file". */
static int
mapping_is_anonymous_p (const char *filename)
{
static regex_t dev_zero_regex, shmem_file_regex, file_deleted_regex;
static int init_regex_p = 0;
if (!init_regex_p)
{
struct cleanup *c = make_cleanup (null_cleanup, NULL);
/* Let's be pessimistic and assume there will be an error while
compiling the regex'es. */
init_regex_p = -1;
/* DEV_ZERO_REGEX matches "/dev/zero" filenames (with or
without the "(deleted)" string in the end). We know for
sure, based on the Linux kernel code, that memory mappings
whose associated filename is "/dev/zero" are guaranteed to be
MAP_ANONYMOUS. */
compile_rx_or_error (&dev_zero_regex, "^/dev/zero\\( (deleted)\\)\\?$",
_("Could not compile regex to match /dev/zero "
"filename"));
/* SHMEM_FILE_REGEX matches "/SYSV%08x" filenames (with or
without the "(deleted)" string in the end). These filenames
refer to shared memory (shmem), and memory mappings
associated with them are MAP_ANONYMOUS as well. */
compile_rx_or_error (&shmem_file_regex,
"^/\\?SYSV[0-9a-fA-F]\\{8\\}\\( (deleted)\\)\\?$",
_("Could not compile regex to match shmem "
"filenames"));
/* FILE_DELETED_REGEX is a heuristic we use to try to mimic the
Linux kernel's 'n_link == 0' code, which is responsible to
decide if it is dealing with a 'MAP_SHARED | MAP_ANONYMOUS'
mapping. In other words, if FILE_DELETED_REGEX matches, it
does not necessarily mean that we are dealing with an
anonymous shared mapping. However, there is no easy way to
detect this currently, so this is the best approximation we
have.
As a result, GDB will dump readonly pages of deleted
executables when using the default value of coredump_filter
(0x33), while the Linux kernel will not dump those pages.
But we can live with that. */
compile_rx_or_error (&file_deleted_regex, " (deleted)$",
_("Could not compile regex to match "
"'<file> (deleted)'"));
/* We will never release these regexes, so just discard the
cleanups. */
discard_cleanups (c);
/* If we reached this point, then everything succeeded. */
init_regex_p = 1;
}
if (init_regex_p == -1)
{
const char deleted[] = " (deleted)";
size_t del_len = sizeof (deleted) - 1;
size_t filename_len = strlen (filename);
/* There was an error while compiling the regex'es above. In
order to try to give some reliable information to the caller,
we just try to find the string " (deleted)" in the filename.
If we managed to find it, then we assume the mapping is
anonymous. */
return (filename_len >= del_len
&& strcmp (filename + filename_len - del_len, deleted) == 0);
}
if (*filename == '\0'
|| regexec (&dev_zero_regex, filename, 0, NULL, 0) == 0
|| regexec (&shmem_file_regex, filename, 0, NULL, 0) == 0
|| regexec (&file_deleted_regex, filename, 0, NULL, 0) == 0)
return 1;
return 0;
}
/* Return 0 if the memory mapping (which is related to FILTERFLAGS, V,
MAYBE_PRIVATE_P, and MAPPING_ANONYMOUS_P) should not be dumped, or
greater than 0 if it should.
In a nutshell, this is the logic that we follow in order to decide
if a mapping should be dumped or not.
- If the mapping is associated to a file whose name ends with
" (deleted)", or if the file is "/dev/zero", or if it is
"/SYSV%08x" (shared memory), or if there is no file associated
with it, or if the AnonHugePages: or the Anonymous: fields in the
/proc/PID/smaps have contents, then GDB considers this mapping to
be anonymous. Otherwise, GDB considers this mapping to be a
file-backed mapping (because there will be a file associated with
it).
It is worth mentioning that, from all those checks described
above, the most fragile is the one to see if the file name ends
with " (deleted)". This does not necessarily mean that the
mapping is anonymous, because the deleted file associated with
the mapping may have been a hard link to another file, for
example. The Linux kernel checks to see if "i_nlink == 0", but
GDB cannot easily (and normally) do this check (iff running as
root, it could find the mapping in /proc/PID/map_files/ and
determine whether there still are other hard links to the
inode/file). Therefore, we made a compromise here, and we assume
that if the file name ends with " (deleted)", then the mapping is
indeed anonymous. FWIW, this is something the Linux kernel could
do better: expose this information in a more direct way.
- If we see the flag "sh" in the "VmFlags:" field (in
/proc/PID/smaps), then certainly the memory mapping is shared
(VM_SHARED). If we have access to the VmFlags, and we don't see
the "sh" there, then certainly the mapping is private. However,
Linux kernels before commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10) do not have the
"VmFlags:" field; in that case, we use another heuristic: if we
see 'p' in the permission flags, then we assume that the mapping
is private, even though the presence of the 's' flag there would
mean VM_MAYSHARE, which means the mapping could still be private.
This should work OK enough, however. */
static int
dump_mapping_p (enum filterflags filterflags, const struct smaps_vmflags *v,
int maybe_private_p, int mapping_anon_p, int mapping_file_p,
const char *filename)
{
/* Initially, we trust in what we received from our caller. This
value may not be very precise (i.e., it was probably gathered
from the permission line in the /proc/PID/smaps list, which
actually refers to VM_MAYSHARE, and not VM_SHARED), but it is
what we have until we take a look at the "VmFlags:" field
(assuming that the version of the Linux kernel being used
supports it, of course). */
int private_p = maybe_private_p;
/* We always dump vDSO and vsyscall mappings, because it's likely that
there'll be no file to read the contents from at core load time.
The kernel does the same. */
if (strcmp ("[vdso]", filename) == 0
|| strcmp ("[vsyscall]", filename) == 0)
return 1;
if (v->initialized_p)
{
/* We never dump I/O mappings. */
if (v->io_page)
return 0;
/* Check if we should exclude this mapping. */
if (v->exclude_coredump)
return 0;
/* Update our notion of whether this mapping is shared or
private based on a trustworthy value. */
private_p = !v->shared_mapping;
/* HugeTLB checking. */
if (v->uses_huge_tlb)
{
if ((private_p && (filterflags & COREFILTER_HUGETLB_PRIVATE))
|| (!private_p && (filterflags & COREFILTER_HUGETLB_SHARED)))
return 1;
return 0;
}
}
if (private_p)
{
if (mapping_anon_p && mapping_file_p)
{
/* This is a special situation. It can happen when we see a
mapping that is file-backed, but that contains anonymous
pages. */
return ((filterflags & COREFILTER_ANON_PRIVATE) != 0
|| (filterflags & COREFILTER_MAPPED_PRIVATE) != 0);
}
else if (mapping_anon_p)
return (filterflags & COREFILTER_ANON_PRIVATE) != 0;
else
return (filterflags & COREFILTER_MAPPED_PRIVATE) != 0;
}
else
{
if (mapping_anon_p && mapping_file_p)
{
/* This is a special situation. It can happen when we see a
mapping that is file-backed, but that contains anonymous
pages. */
return ((filterflags & COREFILTER_ANON_SHARED) != 0
|| (filterflags & COREFILTER_MAPPED_SHARED) != 0);
}
else if (mapping_anon_p)
return (filterflags & COREFILTER_ANON_SHARED) != 0;
else
return (filterflags & COREFILTER_MAPPED_SHARED) != 0;
}
}
/* List memory regions in the inferior PID matched to FILTERFLAGS for
a corefile. Call FUNC with FUNC_DATA for each such region. Return
immediately with the value returned by FUNC if it is non-zero.
*MEMORY_TO_FREE_PTR should be registered to be freed automatically if
called FUNC throws an exception. MEMORY_TO_FREE_PTR can be also
passed as NULL if it is not used. Return -1 if error occurs, 0 if
all memory regions have been processed or return the value from FUNC
if FUNC returns non-zero. */
int
linux_find_memory_regions_full (pid_t pid, enum filterflags filterflags,
linux_find_memory_region_ftype *func,
void *func_data)
{
char mapsfilename[100];
char *data;
xsnprintf (mapsfilename, sizeof mapsfilename, "/proc/%d/smaps", pid);
data = target_fileio_read_stralloc (NULL, mapsfilename);
if (data == NULL)
{
/* Older Linux kernels did not support /proc/PID/smaps. */
xsnprintf (mapsfilename, sizeof mapsfilename, "/proc/%d/maps", pid);
data = target_fileio_read_stralloc (NULL, mapsfilename);
}
if (data != NULL)
{
struct cleanup *cleanup = make_cleanup (xfree, data);
char *line, *t;
int retval = 0;
line = strtok_r (data, "\n", &t);
while (line != NULL)
{
ULONGEST addr, endaddr, offset, inode;
const char *permissions, *device, *filename;
struct smaps_vmflags v;
size_t permissions_len, device_len;
int read, write, exec, priv;
int has_anonymous = 0;
int should_dump_p = 0;
int mapping_anon_p;
int mapping_file_p;
memset (&v, 0, sizeof (v));
read_mapping (line, &addr, &endaddr, &permissions, &permissions_len,
&offset, &device, &device_len, &inode, &filename);
mapping_anon_p = mapping_is_anonymous_p (filename);
/* If the mapping is not anonymous, then we can consider it
to be file-backed. These two states (anonymous or
file-backed) seem to be exclusive, but they can actually
coexist. For example, if a file-backed mapping has
"Anonymous:" pages (see more below), then the Linux
kernel will dump this mapping when the user specified
that she only wants anonymous mappings in the corefile
(*even* when she explicitly disabled the dumping of
file-backed mappings). */
mapping_file_p = !mapping_anon_p;
/* Decode permissions. */
read = (memchr (permissions, 'r', permissions_len) != 0);
write = (memchr (permissions, 'w', permissions_len) != 0);
exec = (memchr (permissions, 'x', permissions_len) != 0);
/* 'private' here actually means VM_MAYSHARE, and not
VM_SHARED. In order to know if a mapping is really
private or not, we must check the flag "sh" in the
VmFlags field. This is done by decode_vmflags. However,
if we are using a Linux kernel released before the commit
834f82e2aa9a8ede94b17b656329f850c1471514 (3.10), we will
not have the VmFlags there. In this case, there is
really no way to know if we are dealing with VM_SHARED,
so we just assume that VM_MAYSHARE is enough. */
priv = memchr (permissions, 'p', permissions_len) != 0;
/* Try to detect if region should be dumped by parsing smaps
counters. */
for (line = strtok_r (NULL, "\n", &t);
line != NULL && line[0] >= 'A' && line[0] <= 'Z';
line = strtok_r (NULL, "\n", &t))
{
char keyword[64 + 1];
if (sscanf (line, "%64s", keyword) != 1)
{
warning (_("Error parsing {s,}maps file '%s'"), mapsfilename);
break;
}
if (strcmp (keyword, "Anonymous:") == 0)
{
/* Older Linux kernels did not support the
"Anonymous:" counter. Check it here. */
has_anonymous = 1;
}
else if (strcmp (keyword, "VmFlags:") == 0)
decode_vmflags (line, &v);
if (strcmp (keyword, "AnonHugePages:") == 0
|| strcmp (keyword, "Anonymous:") == 0)
{
unsigned long number;
if (sscanf (line, "%*s%lu", &number) != 1)
{
warning (_("Error parsing {s,}maps file '%s' number"),
mapsfilename);
break;
}
if (number > 0)
{
/* Even if we are dealing with a file-backed
mapping, if it contains anonymous pages we
consider it to be *also* an anonymous
mapping, because this is what the Linux
kernel does:
// Dump segments that have been written to.
if (vma->anon_vma && FILTER(ANON_PRIVATE))
goto whole;
Note that if the mapping is already marked as
file-backed (i.e., mapping_file_p is
non-zero), then this is a special case, and
this mapping will be dumped either when the
user wants to dump file-backed *or* anonymous
mappings. */
mapping_anon_p = 1;
}
}
}
if (has_anonymous)
should_dump_p = dump_mapping_p (filterflags, &v, priv,
mapping_anon_p, mapping_file_p,
filename);
else
{
/* Older Linux kernels did not support the "Anonymous:" counter.
If it is missing, we can't be sure - dump all the pages. */
should_dump_p = 1;
}
/* Invoke the callback function to create the corefile segment. */
if (should_dump_p)
retval = func (addr, endaddr - addr, offset, inode,
read, write, exec,
1, /* MODIFIED is true because we want to dump the
mapping. */
filename, func_data);
if (retval != 0)
break;
}
do_cleanups (cleanup);
return retval;
}
return -1;
}

42
gdb/nat/linux-maps.h
View File

@ -19,4 +19,46 @@
#ifndef NAT_LINUX_MAPS_H
#define NAT_LINUX_MAPS_H
extern void
read_mapping (const char *line,
ULONGEST *addr, ULONGEST *endaddr,
const char **permissions, size_t *permissions_len,
ULONGEST *offset,
const char **device, size_t *device_len,
ULONGEST *inode,
const char **filename);
/* Callback function for linux_find_memory_regions_full. If it returns
non-zero linux_find_memory_regions_full returns immediately with that
value. */
typedef int linux_find_memory_region_ftype (ULONGEST vaddr, ULONGEST size,
ULONGEST offset, ULONGEST inode,
int read, int write,
int exec, int modified,
const char *filename,
void *data);
/* This enum represents the values that the user can choose when
informing the Linux kernel about which memory mappings will be
dumped in a corefile. They are described in the file
Documentation/filesystems/proc.txt, inside the Linux kernel
tree. */
enum filterflags
{
COREFILTER_ANON_PRIVATE = 1 << 0,
COREFILTER_ANON_SHARED = 1 << 1,
COREFILTER_MAPPED_PRIVATE = 1 << 2,
COREFILTER_MAPPED_SHARED = 1 << 3,
COREFILTER_ELF_HEADERS = 1 << 4,
COREFILTER_HUGETLB_PRIVATE = 1 << 5,
COREFILTER_HUGETLB_SHARED = 1 << 6,
};
extern int
linux_find_memory_regions_full (pid_t pid, enum filterflags filterflags,
linux_find_memory_region_ftype *func,
void *func_data);
#endif /* NAT_LINUX_MAPS_H */

91
gdb/target.c
View File

@ -43,6 +43,7 @@
#include "agent.h"
#include "auxv.h"
#include "target-debug.h"
#include "target/target-utils.h"
static void target_info (char *, int);
@ -2973,9 +2974,6 @@ target_fileio_close_cleanup (void *opaque)
target_fileio_close (fd, &target_errno);
}
typedef int (read_alloc_pread_ftype) (int handle, gdb_byte *read_buf, int len,
ULONGEST offset, int *target_errno);
/* Helper for target_fileio_read_alloc_1 to make it interruptible. */
static int
@ -2995,57 +2993,6 @@ target_fileio_read_alloc_1_pread (int handle, gdb_byte *read_buf, int len,
target_fileio_read_alloc; see the declaration of that function for
more information. */
static LONGEST
read_alloc (gdb_byte **buf_p, int handle, read_alloc_pread_ftype *pread_func,
int padding)
{
size_t buf_alloc, buf_pos;
gdb_byte *buf;
LONGEST n;
int target_errno;
/* Start by reading up to 4K at a time. The target will throttle
this number down if necessary. */
buf_alloc = 4096;
buf = xmalloc (buf_alloc);
buf_pos = 0;
while (1)
{
n = pread_func (handle, &buf[buf_pos], buf_alloc - buf_pos - padding,
buf_pos, &target_errno);
if (n <= 0)
{
if (n < 0 || (n == 0 && buf_pos == 0))
xfree (buf);
else
*buf_p = buf;
if (n < 0)
{
/* An error occurred. */
return -1;
}
else
{
/* Read all there was. */
return buf_pos;
}
}
buf_pos += n;
/* If the buffer is filling up, expand it. */
if (buf_alloc < buf_pos * 2)
{
buf_alloc *= 2;
buf = xrealloc (buf, buf_alloc);
}
}
}
typedef LONGEST (read_stralloc_func_ftype) (struct inferior *inf,
const char *filename,
gdb_byte **buf_p, int padding);
static LONGEST
target_fileio_read_alloc_1 (struct inferior *inf, const char *filename,
gdb_byte **buf_p, int padding)
@ -3073,41 +3020,7 @@ target_fileio_read_alloc (struct inferior *inf, const char *filename,
return target_fileio_read_alloc_1 (inf, filename, buf_p, 0);
}
/* Helper for target_fileio_read_stralloc. */
static char *
read_stralloc (struct inferior *inf, const char *filename,
read_stralloc_func_ftype *func)
{
gdb_byte *buffer;
char *bufstr;
LONGEST i, transferred;
transferred = func (inf, filename, &buffer, 1);
bufstr = (char *) buffer;
if (transferred < 0)
return NULL;
if (transferred == 0)
return xstrdup ("");
bufstr[transferred] = 0;
/* Check for embedded NUL bytes; but allow trailing NULs. */
for (i = strlen (bufstr); i < transferred; i++)
if (bufstr[i] != 0)
{
warning (_("target file %s "
"contained unexpected null characters"),
filename);
break;
}
return bufstr;
}
/* See target.h. */
/* See target/target.h. */
char *
target_fileio_read_stralloc (struct inferior *inf, const char *filename)

10
gdb/target.h
View File

@ -2033,16 +2033,6 @@ extern LONGEST target_fileio_read_alloc (struct inferior *inf,
const char *filename,
gdb_byte **buf_p);
/* Read target file FILENAME, in the filesystem as seen by INF. If
INF is NULL, use the filesystem seen by the debugger (GDB or, for
remote targets, the remote stub). The result is NUL-terminated and
returned as a string, allocated using xmalloc. If an error occurs
or the transfer is unsupported, NULL is returned. Empty objects
are returned as allocated but empty strings. A warning is issued
if the result contains any embedded NUL bytes. */
extern char *target_fileio_read_stralloc (struct inferior *inf,
const char *filename);
/* Tracepoint-related operations. */

79
gdb/target/target-utils.c
View File

@ -19,3 +19,82 @@
#include "common-defs.h"
#include "target/target-utils.h"
LONGEST
read_alloc (gdb_byte **buf_p, int handle, read_alloc_pread_ftype *pread_func,
int padding)
{
size_t buf_alloc, buf_pos;
gdb_byte *buf;
LONGEST n;
int target_errno;
/* Start by reading up to 4K at a time. The target will throttle
this number down if necessary. */
buf_alloc = 4096;
buf = xmalloc (buf_alloc);
buf_pos = 0;
while (1)
{
n = pread_func (handle, &buf[buf_pos], buf_alloc - buf_pos - padding,
buf_pos, &target_errno);
if (n <= 0)
{
if (n < 0 || (n == 0 && buf_pos == 0))
xfree (buf);
else
*buf_p = buf;
if (n < 0)
{
/* An error occurred. */
return -1;
}
else
{
/* Read all there was. */
return buf_pos;
}
}
buf_pos += n;
/* If the buffer is filling up, expand it. */
if (buf_alloc < buf_pos * 2)
{
buf_alloc *= 2;
buf = xrealloc (buf, buf_alloc);
}
}
}
char *
read_stralloc (struct inferior *inf, const char *filename,
read_stralloc_func_ftype *func)
{
gdb_byte *buffer;
char *bufstr;
LONGEST i, transferred;
transferred = func (inf, filename, &buffer, 1);
bufstr = (char *) buffer;
if (transferred < 0)
return NULL;
if (transferred == 0)
return xstrdup ("");
bufstr[transferred] = 0;
/* Check for embedded NUL bytes; but allow trailing NULs. */
for (i = strlen (bufstr); i < transferred; i++)
if (bufstr[i] != 0)
{
warning (_("target file %s "
"contained unexpected null characters"),
filename);
break;
}
return bufstr;
}

12
gdb/target/target-utils.h
View File

@ -20,4 +20,16 @@
#ifndef TARGET_TARGET_UTILS_H
#define TARGET_TARGET_UTILS_H
typedef int (read_alloc_pread_ftype) (int handle, gdb_byte *read_buf, int len,
ULONGEST offset, int *target_errno);
extern LONGEST read_alloc (gdb_byte **buf_p, int handle,
read_alloc_pread_ftype *pread_func, int padding);
struct inferior;
typedef LONGEST (read_stralloc_func_ftype) (struct inferior *inf,
const char *filename,
gdb_byte **buf_p, int padding);
extern char *read_stralloc (struct inferior *inf, const char *filename,
read_stralloc_func_ftype *func);
#endif /* TARGET_TARGET_UTILS_H */

11
gdb/target/target.h
View File

@ -70,4 +70,15 @@ extern void target_stop_and_wait (ptid_t ptid);
extern void target_continue_no_signal (ptid_t ptid);
/* Read target file FILENAME, in the filesystem as seen by INF. If
INF is NULL, use the filesystem seen by the debugger (GDB or, for
remote targets, the remote stub). The result is NUL-terminated and
returned as a string, allocated using xmalloc. If an error occurs
or the transfer is unsupported, NULL is returned. Empty objects
are returned as allocated but empty strings. A warning is issued
if the result contains any embedded NUL bytes. */
struct inferior;
extern char *target_fileio_read_stralloc (struct inferior *inf,
const char *filename);
#endif /* TARGET_COMMON_H */