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-rw-r--r--gdb/nat/linux-maps.c493
1 files changed, 0 insertions, 493 deletions
diff --git a/gdb/nat/linux-maps.c b/gdb/nat/linux-maps.c
deleted file mode 100644
index ef3da6a..0000000
--- a/gdb/nat/linux-maps.c
+++ /dev/null
@@ -1,493 +0,0 @@
-/* Linux-specific memory maps manipulation routines.
- Copyright (C) 2015 Free Software Foundation, Inc.
-
- This file is part of GDB.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-#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;
-}
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