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drgn/libdrgn/linux_kernel_helpers.c

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Update copyright headers to Meta Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-11-21 23:59:44 +00:00
// Copyright (c) Meta Platforms, Inc. and affiliates.
Use GPL-3.0-or-later license identifier instead of GPL-3.0+ Apparently the latter is deprecated and the former is preferred. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-04-03 09:10:35 +01:00
// SPDX-License-Identifier: GPL-3.0-or-later
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
Clean up #includes with include-what-you-use I recently hit a couple of CI failures caused by relying on transitive includes that weren't always present. include-what-you-use is a Clang-based tool that helps with this. It's a bit finicky and noisy, so this adds scripts/iwyu.py to make running it more convenient (but not reliable enough to automate it in Travis). This cleans up all reasonable include-what-you-use warnings and reorganizes a few header files. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-09-24 00:02:02 +01:00
#include <stdio.h>
#include <stdlib.h>
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
#include <inttypes.h>
Clean up #includes with include-what-you-use I recently hit a couple of CI failures caused by relying on transitive includes that weren't always present. include-what-you-use is a Clang-based tool that helps with this. It's a bit finicky and noisy, so this adds scripts/iwyu.py to make running it more convenient (but not reliable enough to automate it in Travis). This cleans up all reasonable include-what-you-use warnings and reorganizes a few header files. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-09-24 00:02:02 +01:00
#include "drgn.h"
libdrgn: add Linux kernel task iterator The thread API needs a way to iterate over all task_structs in the kernel. Previously, we translated the existing for_each_task helper, which supports iterating through specific PID namespaces by walking through the PID radix tree or PID hashtable. However, we don't need specific namespaces for the thread API, so we can instead use the much simpler linked lists of thread groups and threads. Signed-off-by: Kevin Svetlitski <svetlitski@fb.com>
2021-12-18 00:56:00 +00:00
#include "helpers.h"
libdrgn: add {min,max}_iconst() and rewrite min() and max() min() and max() from the Linux kernel go through the trouble of resulting in a constant expression if the arguments are constant expressions, but they can't be used outside of a function due to their use of ({ }). This means that they can't be used for, e.g., enumerators or global arrays. Let's simplify min() and max() and instead add explicit min_iconst() and max_iconst() macros that can be used everywhere that an integer constant expression is required. We can then use it in hash_table.h. While we're here, let's split these into their own header file and document them better. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-10-10 01:59:23 +01:00
#include "minmax.h"
Clean up #includes with include-what-you-use I recently hit a couple of CI failures caused by relying on transitive includes that weren't always present. include-what-you-use is a Clang-based tool that helps with this. It's a bit finicky and noisy, so this adds scripts/iwyu.py to make running it more convenient (but not reliable enough to automate it in Travis). This cleans up all reasonable include-what-you-use warnings and reorganizes a few header files. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-09-24 00:02:02 +01:00
#include "platform.h"
libdrgn: add task_state_to_char() helper Add a helper to get the state of a task (e.g., 'R', 'S', 'D'). This will be used to make sure that a task is not running when getting a stack trace, so implement it in libdrgn.
2019-10-28 09:38:51 +00:00
#include "program.h"
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
helpers: add access_process_vm() and access_remote_vm() Now that we can walk page tables, we can finally read memory from userspace tasks. Closes #53.
2020-05-06 02:21:36 +01:00
struct drgn_error *linux_helper_read_vm(struct drgn_program *prog,
uint64_t pgtable, uint64_t virt_addr,
void *buf, size_t count)
{
struct drgn_error *err;
struct pgtable_iterator *it;
pgtable_iterator_next_fn *next;
uint64_t read_addr = 0;
size_t read_size = 0;
if (!(prog->flags & DRGN_PROGRAM_IS_LINUX_KERNEL)) {
return drgn_error_create(DRGN_ERROR_INVALID_ARGUMENT,
"virtual address translation is only available for the Linux kernel");
}
if (!prog->has_platform) {
return drgn_error_create(DRGN_ERROR_INVALID_ARGUMENT,
"cannot do virtual address translation without platform");
}
if (!prog->platform.arch->linux_kernel_pgtable_iterator_next) {
return drgn_error_format(DRGN_ERROR_INVALID_ARGUMENT,
"virtual address translation is not implemented for %s architecture",
prog->platform.arch->name);
}
if (!count)
return NULL;
libdrgn: add page table walker kernel memory reader Now that we can walk page tables, we can use it in a memory reader that reads kernel memory via the kernel page table. This means that we don't need libkdumpfile for ELF vmcores anymore (although I'll keep the functionality around until this code has been validated more).
2020-05-06 08:35:29 +01:00
if (prog->pgtable_it_in_use) {
return drgn_error_create_fault("recursive address translation; "
"page table may be missing from core dump",
virt_addr);
}
helpers: add access_process_vm() and access_remote_vm() Now that we can walk page tables, we can finally read memory from userspace tasks. Closes #53.
2020-05-06 02:21:36 +01:00
if (prog->pgtable_it) {
it = prog->pgtable_it;
} else {
it = malloc(sizeof(*it) +
prog->platform.arch->pgtable_iterator_arch_size);
if (!it)
return &drgn_enomem;
prog->pgtable_it = it;
it->prog = prog;
}
it->pgtable = pgtable;
it->virt_addr = virt_addr;
libdrgn: add page table walker kernel memory reader Now that we can walk page tables, we can use it in a memory reader that reads kernel memory via the kernel page table. This means that we don't need libkdumpfile for ELF vmcores anymore (although I'll keep the functionality around until this code has been validated more).
2020-05-06 08:35:29 +01:00
prog->pgtable_it_in_use = true;
helpers: add access_process_vm() and access_remote_vm() Now that we can walk page tables, we can finally read memory from userspace tasks. Closes #53.
2020-05-06 02:21:36 +01:00
prog->platform.arch->pgtable_iterator_arch_init(it->arch);
next = prog->platform.arch->linux_kernel_pgtable_iterator_next;
do {
uint64_t virt_addr, start_virt_addr, end_virt_addr;
uint64_t start_phys_addr, end_phys_addr;
size_t n;
virt_addr = it->virt_addr;
err = next(it, &start_virt_addr, &start_phys_addr);
if (err)
break;
if (start_phys_addr == UINT64_MAX) {
err = drgn_error_create_fault("address is not mapped",
virt_addr);
break;
}
end_virt_addr = it->virt_addr;
end_phys_addr = start_phys_addr + (end_virt_addr - start_virt_addr);
n = min(end_virt_addr - virt_addr, (uint64_t)count);
if (read_size && end_phys_addr == read_addr + read_size) {
read_size += n;
} else {
if (read_size) {
err = drgn_program_read_memory(prog, buf,
read_addr,
read_size, true);
if (err)
break;
buf = (char *)buf + read_size;
}
read_addr = start_phys_addr + (virt_addr - start_virt_addr);
read_size = n;
}
count -= n;
} while (count);
if (!err) {
err = drgn_program_read_memory(prog, buf, read_addr, read_size,
true);
}
libdrgn: add page table walker kernel memory reader Now that we can walk page tables, we can use it in a memory reader that reads kernel memory via the kernel page table. This means that we don't need libkdumpfile for ELF vmcores anymore (although I'll keep the functionality around until this code has been validated more).
2020-05-06 08:35:29 +01:00
prog->pgtable_it_in_use = false;
helpers: add access_process_vm() and access_remote_vm() Now that we can walk page tables, we can finally read memory from userspace tasks. Closes #53.
2020-05-06 02:21:36 +01:00
return err;
}
libdrgn: linux: translate per_cpu_ptr() helper to C The next change will add a C helper that needs per_cpu_ptr(). Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:39:50 +00:00
struct drgn_error *linux_helper_per_cpu_ptr(struct drgn_object *res,
const struct drgn_object *ptr,
uint64_t cpu)
{
struct drgn_error *err;
struct drgn_program *prog = drgn_object_program(ptr);
struct drgn_object tmp;
drgn_object_init(&tmp, prog);
err = drgn_program_find_object(prog, "__per_cpu_offset", NULL,
DRGN_FIND_OBJECT_ANY, &tmp);
libdrgn: linux: make per_cpu_ptr() support !SMP kernels Kernels built without multiprocessing support don't have __per_cpu_offset; instead, per_cpu_ptr() is a no-op. Make the helper do the same and update the test case to work on !SMP as well. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:51:15 +00:00
if (!err) {
err = drgn_object_subscript(&tmp, &tmp, cpu);
if (err)
goto out;
union drgn_value per_cpu_offset;
err = drgn_object_read_integer(&tmp, &per_cpu_offset);
if (err)
goto out;
libdrgn: linux: translate per_cpu_ptr() helper to C The next change will add a C helper that needs per_cpu_ptr(). Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:39:50 +00:00
libdrgn: linux: make per_cpu_ptr() support !SMP kernels Kernels built without multiprocessing support don't have __per_cpu_offset; instead, per_cpu_ptr() is a no-op. Make the helper do the same and update the test case to work on !SMP as well. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:51:15 +00:00
uint64_t ptr_value;
err = drgn_object_read_unsigned(ptr, &ptr_value);
if (err)
goto out;
libdrgn: linux: translate per_cpu_ptr() helper to C The next change will add a C helper that needs per_cpu_ptr(). Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:39:50 +00:00
libdrgn: linux: make per_cpu_ptr() support !SMP kernels Kernels built without multiprocessing support don't have __per_cpu_offset; instead, per_cpu_ptr() is a no-op. Make the helper do the same and update the test case to work on !SMP as well. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:51:15 +00:00
err = drgn_object_set_unsigned(res,
drgn_object_qualified_type(ptr),
ptr_value + per_cpu_offset.uvalue,
0);
} else if (err->code == DRGN_ERROR_LOOKUP) {
drgn_error_destroy(err);
err = drgn_object_copy(res, ptr);
}
libdrgn: linux: translate per_cpu_ptr() helper to C The next change will add a C helper that needs per_cpu_ptr(). Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:39:50 +00:00
out:
drgn_object_deinit(&tmp);
return err;
}
libdrgn: linux: replace idle_thread() with idle_task() I missed that the kernel has an idle_task() function which uses cpu_rq()->idle instead of idle_threads; the latter is technically architecture-specific. So, replace idle_thread() with idle_task(), which is architecture-independent and more consistent with the kernel. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:03:25 +00:00
struct drgn_error *linux_helper_idle_task(struct drgn_object *res, uint64_t cpu)
libdrgn: linux: add idle_thread() helper PR #129 will need to get the idle thread for a CPU when the idle thread crashed. Add a helper for this. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:40:57 +00:00
{
struct drgn_error *err;
struct drgn_program *prog = drgn_object_program(res);
struct drgn_object tmp;
drgn_object_init(&tmp, prog);
libdrgn: linux: replace idle_thread() with idle_task() I missed that the kernel has an idle_task() function which uses cpu_rq()->idle instead of idle_threads; the latter is technically architecture-specific. So, replace idle_thread() with idle_task(), which is architecture-independent and more consistent with the kernel. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:03:25 +00:00
err = drgn_program_find_object(prog, "runqueues", NULL,
libdrgn: linux: add idle_thread() helper PR #129 will need to get the idle thread for a CPU when the idle thread crashed. Add a helper for this. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:40:57 +00:00
DRGN_FIND_OBJECT_ANY, &tmp);
libdrgn: linux: replace idle_thread() with idle_task() I missed that the kernel has an idle_task() function which uses cpu_rq()->idle instead of idle_threads; the latter is technically architecture-specific. So, replace idle_thread() with idle_task(), which is architecture-independent and more consistent with the kernel. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-22 00:03:25 +00:00
if (err)
goto out;
err = drgn_object_address_of(&tmp, &tmp);
if (err)
goto out;
err = linux_helper_per_cpu_ptr(&tmp, &tmp, cpu);
if (err)
goto out;
err = drgn_object_member_dereference(res, &tmp, "idle");
libdrgn: linux: add idle_thread() helper PR #129 will need to get the idle thread for a CPU when the idle thread crashed. Add a helper for this. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-21 22:40:57 +00:00
out:
drgn_object_deinit(&tmp);
return err;
}
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
struct drgn_error *
linux_helper_radix_tree_lookup(struct drgn_object *res,
const struct drgn_object *root, uint64_t index)
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
{
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
struct drgn_error *err;
static const uint64_t RADIX_TREE_ENTRY_MASK = 3;
uint64_t RADIX_TREE_INTERNAL_NODE;
uint64_t RADIX_TREE_MAP_MASK;
struct drgn_object node, tmp;
struct drgn_qualified_type node_type;
drgn_object_init(&node, drgn_object_program(res));
drgn_object_init(&tmp, drgn_object_program(res));
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
/* node = root->xa_head */
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
err = drgn_object_member_dereference(&node, root, "xa_head");
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (!err) {
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
err = drgn_program_find_type(drgn_object_program(res),
"struct xa_node *", NULL,
&node_type);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
RADIX_TREE_INTERNAL_NODE = 2;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
} else if (err->code == DRGN_ERROR_LOOKUP) {
drgn_error_destroy(err);
/* node = (void *)root.rnode */
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
err = drgn_object_member_dereference(&node, root, "rnode");
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
err = drgn_program_find_type(drgn_object_program(res), "void *",
NULL, &node_type);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
err = drgn_object_cast(&node, node_type, &node);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
err = drgn_program_find_type(drgn_object_program(res),
"struct radix_tree_node *", NULL,
&node_type);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
RADIX_TREE_INTERNAL_NODE = 1;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
} else {
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
}
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_type_member *member;
uint64_t member_bit_offset;
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
err = drgn_type_find_member(drgn_type_type(node_type.type).type,
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
"slots", &member, &member_bit_offset);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
goto out;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_qualified_type member_type;
libdrgn: get drgn_type_member.bit_field_size through drgn_member_type() Getting the bit field size of a member will soon require evaluating the lazy type, so return it from drgn_member_type() instead of accessing it directly. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-18 22:11:29 +00:00
err = drgn_member_type(member, &member_type, NULL);
Rewrite linux helper iterators in C In preparation for introducing an API to represent threads, the linux helper iterators, radix_tree_for_each, idr_for_each, for_each_pid, and for_each_task have been rewritten in C. This will allow them to be accessed from libdrgn, which will be necessary for the threads API. Signed-off-by: Kevin Svetlitski <svetlitski@fb.com>
2021-11-19 00:46:59 +00:00
if (err)
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
goto out;
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
if (drgn_type_kind(member_type.type) != DRGN_TYPE_ARRAY) {
err = drgn_error_create(DRGN_ERROR_TYPE,
"struct radix_tree_node slots member is not an array");
goto out;
}
RADIX_TREE_MAP_MASK = drgn_type_length(member_type.type) - 1;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
for (;;) {
uint64_t value;
union drgn_value shift;
uint64_t offset;
err = drgn_object_read(&node, &node);
if (err)
goto out;
err = drgn_object_read_unsigned(&node, &value);
if (err)
goto out;
if ((value & RADIX_TREE_ENTRY_MASK) != RADIX_TREE_INTERNAL_NODE)
break;
err = drgn_object_set_unsigned(&node, node_type,
value & ~RADIX_TREE_INTERNAL_NODE,
0);
if (err)
goto out;
err = drgn_object_member_dereference(&tmp, &node, "shift");
if (err)
goto out;
err = drgn_object_read_integer(&tmp, &shift);
if (err)
goto out;
if (shift.uvalue >= 64)
offset = 0;
else
offset = (index >> shift.uvalue) & RADIX_TREE_MAP_MASK;
err = drgn_object_member_dereference(&tmp, &node, "slots");
if (err)
goto out;
err = drgn_object_subscript(&node, &tmp, offset);
if (err)
goto out;
}
err = drgn_object_copy(res, &node);
out:
drgn_object_deinit(&tmp);
drgn_object_deinit(&node);
return err;
}
struct drgn_error *linux_helper_idr_find(struct drgn_object *res,
const struct drgn_object *idr,
uint64_t id)
{
struct drgn_error *err;
struct drgn_object tmp;
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
drgn_object_init(&tmp, drgn_object_program(res));
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
/* id -= idr->idr_base */
err = drgn_object_member_dereference(&tmp, idr, "idr_base");
if (!err) {
union drgn_value idr_base;
err = drgn_object_read_integer(&tmp, &idr_base);
if (err)
goto out;
id -= idr_base.uvalue;
} else if (err->code == DRGN_ERROR_LOOKUP) {
/* idr_base was added in v4.16. */
drgn_error_destroy(err);
} else {
goto out;
}
/* radix_tree_lookup(&idr->idr_rt, id) */
err = drgn_object_member_dereference(&tmp, idr, "idr_rt");
if (err)
goto out;
err = drgn_object_address_of(&tmp, &tmp);
if (err)
goto out;
err = linux_helper_radix_tree_lookup(res, &tmp, id);
out:
drgn_object_deinit(&tmp);
return err;
}
/*
* Before Linux kernel commit 95846ecf9dac ("pid: replace pid bitmap
* implementation with IDR API") (in v4.15), (struct pid_namespace).idr does not
* exist, so we have to search pid_hash. We could implement pid_hashfn() and
* only search that bucket, but it's different for 32-bit and 64-bit systems,
* and it has changed at least once, in v4.7. Searching the whole hash table is
* slower but foolproof.
*/
static struct drgn_error *
find_pid_in_pid_hash(struct drgn_object *res, const struct drgn_object *ns,
const struct drgn_object *pid_hash, uint64_t pid)
{
struct drgn_error *err;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_qualified_type pidp_type;
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
err = drgn_program_find_type(drgn_object_program(res), "struct pid *",
NULL, &pidp_type);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
return err;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
struct drgn_qualified_type upid_type;
err = drgn_program_find_type(drgn_object_program(res), "struct upid",
NULL, &upid_type);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
return err;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_type_member *pid_chain_member;
uint64_t pid_chain_bit_offset;
err = drgn_type_find_member(upid_type.type, "pid_chain",
&pid_chain_member, &pid_chain_bit_offset);
if (err)
return err;
struct drgn_type_member *nr_member;
uint64_t nr_bit_offset;
err = drgn_type_find_member(upid_type.type, "nr", &nr_member,
&nr_bit_offset);
if (err)
return err;
struct drgn_qualified_type nr_type;
libdrgn: get drgn_type_member.bit_field_size through drgn_member_type() Getting the bit field size of a member will soon require evaluating the lazy type, so return it from drgn_member_type() instead of accessing it directly. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-18 22:11:29 +00:00
err = drgn_member_type(nr_member, &nr_type, NULL);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
return err;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_type_member *ns_member;
uint64_t ns_bit_offset;
err = drgn_type_find_member(upid_type.type, "ns", &ns_member,
&ns_bit_offset);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
return err;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
struct drgn_qualified_type ns_type;
libdrgn: get drgn_type_member.bit_field_size through drgn_member_type() Getting the bit field size of a member will soon require evaluating the lazy type, so return it from drgn_member_type() instead of accessing it directly. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-18 22:11:29 +00:00
err = drgn_member_type(ns_member, &ns_type, NULL);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
return err;
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
struct drgn_object node, tmp;
drgn_object_init(&node, drgn_object_program(res));
drgn_object_init(&tmp, drgn_object_program(res));
err = drgn_object_read(&tmp, ns);
if (err)
goto out;
uint64_t ns_addr;
err = drgn_object_read_unsigned(&tmp, &ns_addr);
if (err)
goto out;
union drgn_value ns_level;
err = drgn_object_member_dereference(&tmp, &tmp, "level");
if (err)
goto out;
err = drgn_object_read_integer(&tmp, &ns_level);
if (err)
goto out;
/* i = 1 << pidhash_shift */
err = drgn_program_find_object(drgn_object_program(res),
"pidhash_shift", NULL,
DRGN_FIND_OBJECT_ANY, &tmp);
if (err)
goto out;
union drgn_value pidhash_shift;
err = drgn_object_read_integer(&tmp, &pidhash_shift);
if (err)
goto out;
uint64_t i;
if (pidhash_shift.uvalue >= 64)
i = 0;
else
i = UINT64_C(1) << pidhash_shift.uvalue;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
while (i--) {
/* for (node = pid_hash[i].first; node; node = node->next) */
err = drgn_object_subscript(&node, pid_hash, i);
if (err)
goto out;
err = drgn_object_member(&node, &node, "first");
if (err)
goto out;
for (;;) {
uint64_t addr, tmp_addr;
union drgn_value node_nr;
uint64_t node_ns;
char member[64];
err = drgn_object_read(&node, &node);
if (err)
goto out;
err = drgn_object_read_unsigned(&node, &addr);
if (err)
goto out;
if (!addr)
break;
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
addr -= pid_chain_bit_offset / 8;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
/* tmp = container_of(node, struct upid, pid_chain)->nr */
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
tmp_addr = addr + nr_bit_offset / 8;
err = drgn_object_set_reference(&tmp, nr_type, tmp_addr,
Track byte order in scalar types instead of objects Currently, reference objects and buffer value objects have a byte order. However, this doesn't always make sense for a couple of reasons: - Byte order is only meaningful for scalars. What does it mean for a struct to be big endian? A struct doesn't have a most or least significant byte; its scalar members do. - The DWARF specification allows either types or variables to have a byte order (DW_AT_endianity). The only producer I could find that uses this is GCC for the scalar_storage_order type attribute, and it only uses it for base types, not variables. GDB only seems to use to check it for base types, as well. So, remove the byte order from objects, and move it to integer, boolean, floating-point, and pointer types. This model makes more sense, and it means that we can get the binary representation of any object now. The only downside is that we can no longer support a bit offset for non-scalars, but as far as I can tell, nothing needs that. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-18 00:13:23 +00:00
0, 0);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
goto out;
err = drgn_object_read_integer(&tmp, &node_nr);
if (err)
goto out;
if (node_nr.uvalue != pid)
goto next;
/* tmp = container_of(node, struct upid, pid_chain)->ns */
libdrgn: replace drgn_program_member_info() with drgn_type_find_member() Now that types are associated with their program, we don't need to pass the program separately to drgn_program_member_info() and can replace it with a more natural drgn_type_find_member() API that takes only the type and member name. While we're at it, get rid of drgn_member_info and return the drgn_type_member and bit_offset directly. This also fixes a bug that drgn_error_member_not_found() ignores the member name length. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-15 01:58:44 +00:00
tmp_addr = addr + ns_bit_offset / 8;
err = drgn_object_set_reference(&tmp, ns_type, tmp_addr,
Track byte order in scalar types instead of objects Currently, reference objects and buffer value objects have a byte order. However, this doesn't always make sense for a couple of reasons: - Byte order is only meaningful for scalars. What does it mean for a struct to be big endian? A struct doesn't have a most or least significant byte; its scalar members do. - The DWARF specification allows either types or variables to have a byte order (DW_AT_endianity). The only producer I could find that uses this is GCC for the scalar_storage_order type attribute, and it only uses it for base types, not variables. GDB only seems to use to check it for base types, as well. So, remove the byte order from objects, and move it to integer, boolean, floating-point, and pointer types. This model makes more sense, and it means that we can get the binary representation of any object now. The only downside is that we can no longer support a bit offset for non-scalars, but as far as I can tell, nothing needs that. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-18 00:13:23 +00:00
0, 0);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (err)
goto out;
err = drgn_object_read_unsigned(&tmp, &node_ns);
if (err)
goto out;
if (node_ns != ns_addr)
goto next;
sprintf(member, "numbers[%" PRIu64 "].pid_chain",
Revert "Rewrite linux helper iterators in C" This reverts commit 2b47583c732a1ad63fe544a08feddd2ea96ef1a5. After Kevin had completed this, we realized that there is a simpler method for iterating through tasks from libdrgn, which the next commit will implement. Revert the translation, but keep the improved tests.helpers.linux.test_pid.TestPid.test_for_each_task. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2022-01-10 20:13:04 +00:00
ns_level.uvalue);
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
err = drgn_object_container_of(res, &node,
drgn_type_type(pidp_type.type),
member);
goto out;
next:
err = drgn_object_member_dereference(&node, &node, "next");
if (err)
goto out;
}
}
err = drgn_object_set_unsigned(res, pidp_type, 0, 0);
out:
drgn_object_deinit(&tmp);
drgn_object_deinit(&node);
return err;
}
struct drgn_error *linux_helper_find_pid(struct drgn_object *res,
const struct drgn_object *ns,
uint64_t pid)
{
struct drgn_error *err;
struct drgn_object tmp;
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
drgn_object_init(&tmp, drgn_object_program(res));
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
/* (struct pid *)idr_find(&ns->idr, pid) */
err = drgn_object_member_dereference(&tmp, ns, "idr");
if (!err) {
struct drgn_qualified_type qualified_type;
err = drgn_object_address_of(&tmp, &tmp);
if (err)
goto out;
err = linux_helper_idr_find(&tmp, &tmp, pid);
if (err)
goto out;
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
err = drgn_program_find_type(drgn_object_program(res),
"struct pid *", NULL,
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
&qualified_type);
if (err)
goto out;
err = drgn_object_cast(res, qualified_type, &tmp);
} else if (err->code == DRGN_ERROR_LOOKUP) {
drgn_error_destroy(err);
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
err = drgn_program_find_object(drgn_object_program(res),
"pid_hash", NULL,
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
DRGN_FIND_OBJECT_ANY, &tmp);
if (err)
goto out;
err = find_pid_in_pid_hash(res, ns, &tmp, pid);
}
out:
drgn_object_deinit(&tmp);
return err;
}
struct drgn_error *linux_helper_pid_task(struct drgn_object *res,
const struct drgn_object *pid,
uint64_t pid_type)
{
struct drgn_error *err;
struct drgn_qualified_type task_structp_type;
struct drgn_qualified_type task_struct_type;
bool truthy;
struct drgn_object first;
char member[64];
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
drgn_object_init(&first, drgn_object_program(res));
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
err = drgn_program_find_type(drgn_object_program(res),
"struct task_struct *", NULL,
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
&task_structp_type);
if (err)
goto out;
task_struct_type = drgn_type_type(task_structp_type.type);
err = drgn_object_bool(pid, &truthy);
libdrgn: helpers: add missing error check in linux_helper_pid_task() Found with clang-static-analyzer. Reported-by: Kevin Svetlitski <svetlitski@fb.com> Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-12-08 21:37:01 +00:00
if (err)
goto out;
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
if (!truthy)
goto null;
/* first = &pid->tasks[pid_type].first */
err = drgn_object_member_dereference(&first, pid, "tasks");
if (err)
goto out;
err = drgn_object_subscript(&first, &first, pid_type);
if (err)
goto out;
err = drgn_object_member(&first, &first, "first");
if (err)
goto out;
err = drgn_object_bool(&first, &truthy);
if (err)
goto out;
if (!truthy)
goto null;
/* container_of(first, struct task_struct, pid_links[pid_type]) */
sprintf(member, "pid_links[%" PRIu64 "]", pid_type);
err = drgn_object_container_of(res, &first, task_struct_type, member);
if (err && err->code == DRGN_ERROR_LOOKUP) {
drgn_error_destroy(err);
/* container_of(first, struct task_struct, pids[pid_type].node) */
sprintf(member, "pids[%" PRIu64 "].node", pid_type);
err = drgn_object_container_of(res, &first, task_struct_type,
member);
}
out:
drgn_object_deinit(&first);
return err;
null:
err = drgn_object_set_unsigned(res, task_structp_type, 0, 0);
goto out;
}
struct drgn_error *linux_helper_find_task(struct drgn_object *res,
const struct drgn_object *ns,
uint64_t pid)
{
struct drgn_error *err;
struct drgn_object pid_obj;
struct drgn_object pid_type_obj;
union drgn_value pid_type;
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
drgn_object_init(&pid_obj, drgn_object_program(res));
drgn_object_init(&pid_type_obj, drgn_object_program(res));
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
err = linux_helper_find_pid(&pid_obj, ns, pid);
if (err)
goto out;
libdrgn: remove struct drgn_object::prog We can get it via the type now. Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 19:26:39 +01:00
err = drgn_program_find_object(drgn_object_program(res), "PIDTYPE_PID",
NULL, DRGN_FIND_OBJECT_CONSTANT,
Translate find_task() helper (and dependencies) to C We'd like to be able to look up tasks by PID from libdrgn, but those helpers are written in Python. Translate them to C and add some thin bindings so we can use the same implementation from Python.
2019-10-25 23:23:02 +01:00
&pid_type_obj);
if (err)
goto out;
err = drgn_object_read_integer(&pid_type_obj, &pid_type);
if (err)
goto out;
err = linux_helper_pid_task(res, &pid_obj, pid_type.uvalue);
out:
drgn_object_deinit(&pid_type_obj);
drgn_object_deinit(&pid_obj);
return err;
}
libdrgn: add Linux kernel task iterator The thread API needs a way to iterate over all task_structs in the kernel. Previously, we translated the existing for_each_task helper, which supports iterating through specific PID namespaces by walking through the PID radix tree or PID hashtable. However, we don't need specific namespaces for the thread API, so we can instead use the much simpler linked lists of thread groups and threads. Signed-off-by: Kevin Svetlitski <svetlitski@fb.com>
2021-12-18 00:56:00 +00:00
struct drgn_error *
linux_helper_task_iterator_init(struct linux_helper_task_iterator *it,
struct drgn_program *prog)
{
struct drgn_error *err;
it->done = false;
drgn_object_init(&it->task, prog);
err = drgn_program_find_object(prog, "init_task", NULL,
DRGN_FIND_OBJECT_VARIABLE, &it->task);
if (err)
goto err;
it->task_struct_type = drgn_object_qualified_type(&it->task);
err = drgn_object_address_of(&it->task, &it->task);
if (err)
goto err;
err = drgn_object_read_unsigned(&it->task, &it->init_task_address);
if (err)
goto err;
it->thread_group_address = it->init_task_address;
return NULL;
err:
drgn_object_deinit(&it->task);
return err;
}
void linux_helper_task_iterator_deinit(struct linux_helper_task_iterator *it)
{
drgn_object_deinit(&it->task);
}
struct drgn_error *
linux_helper_task_iterator_next(struct linux_helper_task_iterator *it,
Implement a new API for representing threads Previously, drgn had no way to represent a thread – retrieving a stack trace (the only extant thread-specific operation) was achieved by requiring the user to directly provide a tid. This commit introduces the scaffolding for the design outlined in issue #92, and implements the corresponding methods for userspace core dumps, the live Linux kernel, and Linux kernel core dumps. Future work will build on top of this commit to support live userspace processes. Signed-off-by: Kevin Svetlitski <svetlitski@fb.com>
2021-11-19 00:46:59 +00:00
const struct drgn_object **ret)
libdrgn: add Linux kernel task iterator The thread API needs a way to iterate over all task_structs in the kernel. Previously, we translated the existing for_each_task helper, which supports iterating through specific PID namespaces by walking through the PID radix tree or PID hashtable. However, we don't need specific namespaces for the thread API, so we can instead use the much simpler linked lists of thread groups and threads. Signed-off-by: Kevin Svetlitski <svetlitski@fb.com>
2021-12-18 00:56:00 +00:00
{
if (it->done) {
*ret = NULL;
return NULL;
}
struct drgn_error *err;
struct drgn_object *task = &it->task;
err = drgn_object_member_dereference(task, task, "thread_group");
if (err)
return err;
err = drgn_object_member(task, task, "next");
if (err)
return err;
err = drgn_object_container_of(task, task, it->task_struct_type,
"thread_group");
if (err)
return err;
uint64_t task_address;
err = drgn_object_read_unsigned(task, &task_address);
if (err)
return err;
if (task_address == it->thread_group_address) {
err = drgn_object_member_dereference(task, task, "tasks");
if (err)
return err;
err = drgn_object_member(task, task, "next");
if (err)
return err;
err = drgn_object_container_of(task, task,
it->task_struct_type, "tasks");
if (err)
return err;
err = drgn_object_read_unsigned(task,
&it->thread_group_address);
if (err)
return err;
if (it->thread_group_address == it->init_task_address)
it->done = true;
}
*ret = task;
return NULL;
}
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