[PATCH v7 1/5] PID namespace translation support
Ákos Uzonyi
uzonyi.akos at gmail.com
Sat Aug 8 21:14:33 UTC 2020
* defs.h (pidns_translation): New variable.
(tcb): Add pid_ns field.
(RVAL_MASK): Change value from 013 to 017.
(RVAL_TID, RVAL_SID, RVAL_TGID, RVAL_PGID): New definitions.
(pid_type): New enum.
(pidns_init, translate_pid, get_proc_pid, printpid, printpid_tgid_pgid):
New function declarations.
* largefile_wrappers.h (fstat_fd): New macro.
* pidns.c: New file.
* trie.c: New file.
* trie.h: New file.
* Makefile.am (libstrace_a_SOURCES): Add trie.c, trie.h, pidns.c.
* strace.c (pidns_translation): New variable.
(init): Add --pidns-translation option.
* syscall.c (syscall_exiting_trace): Handle RVAL_* return values.
* NEWS: Mention this.
* strace.1.in: Add description for new option.
Co-Authored-by: Eugene Syromyatnikov <evgsyr at gmail.com>
---
Makefile.am | 3 +
NEWS | 1 +
defs.h | 55 +++-
largefile_wrappers.h | 2 +
pidns.c | 604 +++++++++++++++++++++++++++++++++++++++++++
strace.1.in | 4 +
strace.c | 9 +
syscall.c | 15 ++
trie.c | 248 ++++++++++++++++++
trie.h | 89 +++++++
10 files changed, 1029 insertions(+), 1 deletion(-)
create mode 100644 pidns.c
create mode 100644 trie.c
create mode 100644 trie.h
diff --git a/Makefile.am b/Makefile.am
index f5447811..73c22035 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -233,6 +233,7 @@ libstrace_a_SOURCES = \
personality.c \
pidfd_getfd.c \
pidfd_open.c \
+ pidns.c \
pkeys.c \
poll.c \
prctl.c \
@@ -344,6 +345,8 @@ libstrace_a_SOURCES = \
time.c \
times.c \
trace_event.h \
+ trie.c \
+ trie.h \
truncate.c \
ubi.c \
ucopy.c \
diff --git a/NEWS b/NEWS
index 10039ceb..2ebe45c1 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,7 @@ Noteworthy changes in release 5.8 (2020-08-06)
KEYCTL_*, KVM_*, LOOP_*, NDA_*, RTC_*, TCA_*, STATX_*, and *_MAGIC
constants.
* Updated lists of ioctl commands from Linux 5.8.
+ * Added --pidns-translation option for PID namespace translation.
* Bug fixes
* Added statx syscall to %fstat trace class.
diff --git a/defs.h b/defs.h
index f7ac54f3..ea77f1ff 100644
--- a/defs.h
+++ b/defs.h
@@ -280,6 +280,13 @@ struct tcb {
struct timespec etime; /* Syscall entry time (CLOCK_MONOTONIC) */
struct timespec delay_expiration_time; /* When does the delay end */
+ /*
+ * The ID of the PID namespace of this process
+ * (inode number of /proc/<pid>/ns/pid)
+ * (0: not initialized)
+ */
+ unsigned int pid_ns;
+
struct mmap_cache_t *mmap_cache;
/*
@@ -413,7 +420,11 @@ extern const struct xlat whence_codes[];
# define RVAL_HEX 001 /* hex format */
# define RVAL_OCTAL 002 /* octal format */
# define RVAL_FD 010 /* file descriptor */
-# define RVAL_MASK 013 /* mask for these values */
+# define RVAL_TID 011 /* task ID */
+# define RVAL_SID 012 /* session ID */
+# define RVAL_TGID 013 /* thread group ID */
+# define RVAL_PGID 014 /* process group ID */
+# define RVAL_MASK 017 /* mask for these values */
# define RVAL_STR 020 /* Print `auxstr' field after return val */
# define RVAL_NONE 040 /* Print nothing */
@@ -428,6 +439,16 @@ extern const struct xlat whence_codes[];
# define indirect_ipccall(tcp) (tcp_sysent(tcp)->sys_flags & TRACE_INDIRECT_SUBCALL)
+enum pid_type {
+ PT_TID,
+ PT_TGID,
+ PT_PGID,
+ PT_SID,
+
+ PT_COUNT,
+ PT_NONE = -1
+};
+
enum sock_proto {
SOCK_PROTO_UNKNOWN,
SOCK_PROTO_UNIX,
@@ -469,6 +490,7 @@ extern int Tflag_scale;
extern int Tflag_width;
extern bool iflag;
extern bool count_wallclock;
+extern unsigned int pidns_translation;
/* are we filtering traces based on paths? */
extern struct path_set {
const char **paths_selected;
@@ -983,6 +1005,28 @@ print_local_array_ex(struct tcb *tcp,
extern kernel_ulong_t *
fetch_indirect_syscall_args(struct tcb *, kernel_ulong_t addr, unsigned int n_args);
+extern void pidns_init(void);
+
+/**
+ * Returns the pid of the tracee as present in /proc of the tracer (can be
+ * different from tcp->pid if /proc and the tracee process are in different PID
+ * namespaces).
+ */
+extern int get_proc_pid(struct tcb *);
+
+/**
+ * Translates a pid from tracee's namespace to our namepace.
+ *
+ * @param tcp The tcb of the tracee
+ * (NULL: from_id is in strace's namespace. Useful for
+ * getting the proc PID of from_id)
+ * @param from_id The id to be translated
+ * @param type The PID type of from_id
+ * @param proc_pid_ptr If not NULL, writes the proc PID to this location
+ */
+extern int translate_pid(struct tcb *, int dest_id, enum pid_type type,
+ int *proc_pid_ptr);
+
extern void
dumpiov_in_msghdr(struct tcb *, kernel_ulong_t addr, kernel_ulong_t data_size);
@@ -1058,6 +1102,15 @@ printfd(struct tcb *tcp, int fd)
* of the tracee the descriptor tcp). This is a stub.
*/
extern void printfd_pid_tracee_ns(struct tcb *tcp, pid_t pid, int fd);
+
+/** Prints a PID in the tracee's PID namespace */
+extern void printpid(struct tcb *, int pid, enum pid_type type);
+
+/**
+ * Prints pid as a TGID if positive, and PGID if negative
+ * (like the first argument of kill).
+ */
+extern void printpid_tgid_pgid(struct tcb *, int pid);
extern void print_sockaddr(struct tcb *, const void *sa, int len);
extern bool
print_inet_addr(int af, const void *addr, unsigned int len, const char *var_name);
diff --git a/largefile_wrappers.h b/largefile_wrappers.h
index 116e7048..9d8f5c92 100644
--- a/largefile_wrappers.h
+++ b/largefile_wrappers.h
@@ -29,6 +29,7 @@
# else
# define fcntl_fd fcntl
# endif
+# define fstat_fd fstat64
# define strace_stat_t struct stat64
# define stat_file stat64
# define struct_dirent struct dirent64
@@ -39,6 +40,7 @@
# define open_file open
# define fopen_stream fopen
# define fcntl_fd fcntl
+# define fstat_fd fstat
# define strace_stat_t struct stat
# define stat_file stat
# define struct_dirent struct dirent
diff --git a/pidns.c b/pidns.c
new file mode 100644
index 00000000..2f43838d
--- /dev/null
+++ b/pidns.c
@@ -0,0 +1,604 @@
+/*
+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos at gmail.com>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include "defs.h"
+
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <asm/unistd.h>
+
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "largefile_wrappers.h"
+#include "trie.h"
+#include "nsfs.h"
+#include "xmalloc.h"
+#include "xstring.h"
+
+/**
+ * Key: PID NS ID
+ * Value: a btree:
+ * Key: a process PID in NS
+ * Value: the process's PID as present in /proc
+ */
+static struct trie *ns_pid_to_proc_pid[PT_COUNT];
+
+/**
+ * Key: Proc PID
+ * Value: struct proc_data
+ */
+static struct trie *proc_data_cache;
+
+static bool ns_get_parent_enotty = false;
+
+static const char tid_str[] = "NSpid:\t";
+static const char tgid_str[] = "NStgid:\t";
+static const char pgid_str[] = "NSpgid:\t";
+static const char sid_str[] = "NSsid:\t";
+
+static const struct {
+ const char *str;
+ size_t size;
+} id_strs[PT_COUNT] = {
+ [PT_TID] = { tid_str, sizeof(tid_str) - 1 },
+ [PT_TGID] = { tgid_str, sizeof(tgid_str) - 1 },
+ [PT_PGID] = { pgid_str, sizeof(pgid_str) - 1 },
+ [PT_SID] = { sid_str, sizeof(sid_str) - 1 },
+};
+
+
+/**
+ * Limit on PID NS hierarchy depth, imposed since Linux 3.7. NS traversal
+ * is not possible before Linux 4.9, so we consider this limit pretty universal.
+ */
+#define MAX_NS_DEPTH 32
+
+static const size_t ns_id_size = sizeof(unsigned int);
+static const uint8_t ptr_sz_lg = (sizeof(void *) == 8 ? 6 : 5);
+
+static int pid_max;
+static uint8_t pid_max_size, pid_max_size_lg;
+
+struct proc_data {
+ int proc_pid;
+ int ns_count;
+ unsigned int ns_hierarchy[MAX_NS_DEPTH];
+ int id_count[PT_COUNT];
+ int id_hierarchy[PT_COUNT][MAX_NS_DEPTH];
+};
+
+/**
+ * Helper function for creating a trie.
+ *
+ * For node_key_bits and data_block_key_bits 4 is used (so trie height is 32 / 4
+ * = 8, and node sizes are 8 byte * 2^4 = 128 bytes), which seems to be a good
+ * tradeoff between memory usage and lookup time. It should not be too large,
+ * since there can be large holes between PIDs, and it would be just a waste of
+ * memory having large nodes with lot of NULL pointers in them.
+ */
+static struct trie *
+create_trie_4(uint8_t key_size, uint8_t item_size_lg, uint64_t empty_value)
+{
+ struct trie *t = trie_create(key_size, item_size_lg, 4, 4, empty_value);
+ if (!t)
+ error_msg_and_die("creating trie failed");
+
+ return t;
+}
+
+void
+pidns_init(void)
+{
+ if (proc_data_cache)
+ return;
+
+ pid_max = INT_MAX;
+ if (read_int_from_file("/proc/sys/kernel/pid_max", &pid_max) < 0)
+ debug_func_perror_msg("reading /proc/sys/kernel/pid_max");
+ pid_max_size = ilog2_32(pid_max - 1) + 1;
+ pid_max_size_lg = ilog2_32(pid_max_size - 1) + 1;
+
+ for (int i = 0; i < PT_COUNT; i++)
+ ns_pid_to_proc_pid[i] = create_trie_4(ns_id_size, ptr_sz_lg, 0);
+
+ proc_data_cache = create_trie_4(pid_max_size, ptr_sz_lg, 0);
+}
+
+static void
+put_proc_pid(unsigned int ns, int ns_pid, enum pid_type type, int proc_pid)
+{
+ struct trie *b = (struct trie *) (uintptr_t) trie_get(ns_pid_to_proc_pid[type], ns);
+ if (!b) {
+ b = create_trie_4(pid_max_size, pid_max_size_lg, 0);
+ trie_set(ns_pid_to_proc_pid[type], ns, (uint64_t) (uintptr_t) b);
+ }
+ trie_set(b, ns_pid, proc_pid);
+}
+
+static int
+get_cached_proc_pid(unsigned int ns, int ns_pid, enum pid_type type)
+{
+ struct trie *b = (struct trie *) (uintptr_t)
+ trie_get(ns_pid_to_proc_pid[type], ns);
+ if (!b)
+ return 0;
+
+ return trie_get(b, ns_pid);
+}
+
+/**
+ * Helper function, converts pid to string, or to "self" for pid == 0.
+ * Uses static buffer for operation.
+ */
+static const char *
+pid_to_str(pid_t pid)
+{
+ if (!pid)
+ return "self";
+
+ static char buf[sizeof("-2147483648")];
+ xsprintf(buf, "%d", pid);
+ return buf;
+}
+
+/**
+ * Returns a list of PID NS IDs for the specified PID.
+ *
+ * @param proc_pid PID (as present in /proc) to get information for.
+ * @param ns_buf Pointer to buffer that is able to contain at least
+ * ns_buf_size items.
+ * @return Amount of NS in list. 0 indicates error.
+ */
+static size_t
+get_ns_hierarchy(int proc_pid, unsigned int *ns_buf, size_t ns_buf_size)
+{
+ char path[PATH_MAX + 1];
+ xsprintf(path, "/proc/%s/ns/pid", pid_to_str(proc_pid));
+
+ int fd = open_file(path, O_RDONLY);
+ if (fd < 0)
+ return 0;
+
+ size_t n = 0;
+ while (n < ns_buf_size) {
+ strace_stat_t st;
+ if (fstat_fd(fd, &st))
+ break;
+
+ ns_buf[n++] = st.st_ino;
+ if (n >= ns_buf_size)
+ break;
+
+ if (ns_get_parent_enotty)
+ break;
+
+ int parent_fd = ioctl(fd, NS_GET_PARENT);
+ if (parent_fd < 0) {
+ switch (errno) {
+ case EPERM:
+ break;
+
+ case ENOTTY:
+ ns_get_parent_enotty = true;
+ error_msg("NS_* ioctl commands are not "
+ "supported by the kernel");
+ break;
+
+ default:
+ perror_func_msg("ioctl(NS_GET_PARENT)");
+ break;
+ }
+
+ break;
+ }
+
+ close(fd);
+ fd = parent_fd;
+ }
+
+ close(fd);
+
+ return n;
+}
+
+/**
+ * Get list of IDs present in NS* proc status record. IDs are placed as they are
+ * stored in /proc (from top to bottom of NS hierarchy).
+ *
+ * @param proc_pid PID (as present in /proc) to get information for.
+ * @param id_buf Pointer to buffer that is able to contain at least
+ * MAX_NS_DEPTH items. Can be NULL.
+ * @param type Type of ID requested.
+ * @return Number of items stored in id_list. 0 indicates error.
+ */
+static size_t
+get_id_list(int proc_pid, int *id_buf, enum pid_type type)
+{
+ const char *ns_str = id_strs[type].str;
+ size_t ns_str_size = id_strs[type].size;
+
+ size_t n = 0;
+
+ char status_path[PATH_MAX + 1];
+ xsprintf(status_path, "/proc/%s/status", pid_to_str(proc_pid));
+ FILE *f = fopen_stream(status_path, "r");
+ if (!f)
+ return 0;
+
+ char *line = NULL;
+ size_t linesize = 0;
+ char *p = NULL;
+
+ while (getline(&line, &linesize, f) > 0) {
+ if (strncmp(line, ns_str, ns_str_size) == 0) {
+ p = line + ns_str_size;
+ break;
+ }
+ }
+
+ while (p) {
+ errno = 0;
+ long id = strtol(p, NULL, 10);
+
+ if (errno || id < 1 || id > INT_MAX) {
+ perror_func_msg("converting pid (%ld) to int", id);
+ break;
+ }
+
+ if (id_buf)
+ id_buf[n] = (int) id;
+
+ n++;
+ strsep(&p, "\t");
+ }
+
+ free(line);
+ fclose(f);
+
+ return n;
+}
+
+/**
+ * Returns whether the /proc filesystem's PID namespace is the same as strace's.
+ */
+static bool
+is_proc_ours(void)
+{
+ static int cached_val = -1;
+
+ if (cached_val < 0)
+ cached_val = get_id_list(0, NULL, PT_TID) == 1;
+
+ return cached_val;
+}
+
+/**
+ * Returns the PID namespace of the tracee
+ */
+static unsigned int
+get_ns(struct tcb *tcp)
+{
+ if (!tcp->pid_ns) {
+ int proc_pid = 0;
+ translate_pid(NULL, tcp->pid, PT_TID, &proc_pid);
+
+ if (proc_pid)
+ get_ns_hierarchy(proc_pid, &tcp->pid_ns, 1);
+ }
+
+ return tcp->pid_ns;
+}
+
+/**
+ * Returns the PID namespace of strace
+ */
+static unsigned int
+get_our_ns(void)
+{
+ static unsigned int our_ns = 0;
+ static bool our_ns_initialised = false;
+
+ if (!our_ns_initialised) {
+ get_ns_hierarchy(0, &our_ns, 1);
+ our_ns_initialised = true;
+ }
+
+ return our_ns;
+}
+
+/**
+ * Returns the cached proc_data struct associated with proc_pid.
+ * If none found, allocates a new proc_data.
+ */
+static struct proc_data *
+get_or_create_proc_data(int proc_pid)
+{
+ struct proc_data *pd = (struct proc_data *) (uintptr_t)
+ trie_get(proc_data_cache, proc_pid);
+
+ if (!pd) {
+ pd = calloc(1, sizeof(*pd));
+ if (!pd)
+ return NULL;
+
+ pd->proc_pid = proc_pid;
+ trie_set(proc_data_cache, proc_pid, (uint64_t) (uintptr_t) pd);
+ }
+
+ return pd;
+}
+
+/**
+ * Updates the proc_data from /proc
+ * If the process does not exists, returns false, and frees the proc_data
+ */
+static bool
+update_proc_data(struct proc_data *pd, enum pid_type type)
+{
+ pd->ns_count = get_ns_hierarchy(pd->proc_pid,
+ pd->ns_hierarchy, MAX_NS_DEPTH);
+ if (!pd->ns_count)
+ goto fail;
+
+ pd->id_count[type] = get_id_list(pd->proc_pid,
+ pd->id_hierarchy[type], type);
+ if (!pd->id_count[type])
+ goto fail;
+
+ return true;
+
+fail:
+ trie_set(proc_data_cache, pd->proc_pid, (uint64_t) (uintptr_t) NULL);
+ free(pd);
+ return false;
+}
+
+/**
+ * Paramters for id translation
+ */
+struct translate_id_params {
+ /* The result (output) */
+ int result_id;
+ /* The proc data of the process (output) */
+ struct proc_data *pd;
+
+ /* The namespace to be translated from */
+ unsigned int from_ns;
+ /* The id to be translated */
+ int from_id;
+ /* The type of the id */
+ enum pid_type type;
+};
+
+/**
+ * Translates an id to our namespace, given the proc_pid of the process,
+ * by reading files in /proc.
+ *
+ * @param tip The parameters
+ * @param proc_pid The proc pid of the process.
+ * If 0, use the cached values in tip->pd.
+ */
+static void
+translate_id_proc_pid(struct translate_id_params *tip, int proc_pid)
+{
+ struct proc_data *pd = proc_pid ?
+ get_or_create_proc_data(proc_pid) :
+ tip->pd;
+
+ tip->result_id = 0;
+ tip->pd = NULL;
+
+ if (!pd)
+ return;
+
+ if (proc_pid && !update_proc_data(pd, tip->type))
+ return;
+
+ if (!pd->ns_count || pd->id_count[tip->type] < pd->ns_count)
+ return;
+
+ int our_ns_id_idx = pd->id_count[tip->type] - pd->ns_count;
+
+ for (int i = 0; i < pd->ns_count; i++) {
+ if (pd->ns_hierarchy[i] != tip->from_ns)
+ continue;
+
+ int id_idx = pd->id_count[tip->type] - i - 1;
+ if (pd->id_hierarchy[tip->type][id_idx] != tip->from_id)
+ return;
+
+ tip->result_id = pd->id_hierarchy[tip->type][our_ns_id_idx];
+ tip->pd = pd;
+ return;
+ }
+}
+
+/**
+ * Translates an id to our namespace, by reading all proc entries in dir.
+ *
+ * @param tip The parameters
+ * @param path The path of the dir to be read.
+ * @param read_task_dir Whether recurse to "task" subdirectory.
+ */
+static void
+translate_id_dir(struct translate_id_params *tip, const char *path,
+ bool read_task_dir)
+{
+ DIR *dir = opendir(path);
+ if (!dir) {
+ debug_func_perror_msg("opening dir: %s", path);
+ return;
+ }
+
+ while (!tip->result_id) {
+ errno = 0;
+ struct_dirent *entry = read_dir(dir);
+ if (!entry) {
+ if (errno)
+ perror_func_msg("readdir");
+
+ break;
+ }
+
+ if (entry->d_type != DT_DIR)
+ continue;
+
+ errno = 0;
+ long proc_pid = strtol(entry->d_name, NULL, 10);
+ if (errno)
+ continue;
+ if (proc_pid < 1 || proc_pid > INT_MAX)
+ continue;
+
+ if (read_task_dir) {
+ char task_dir_path[PATH_MAX + 1];
+ xsprintf(task_dir_path, "/proc/%ld/task", proc_pid);
+ translate_id_dir(tip, task_dir_path, false);
+ }
+
+ if (tip->result_id)
+ break;
+
+ translate_id_proc_pid(tip, proc_pid);
+ }
+
+ closedir(dir);
+}
+
+/**
+ * Iterator function of the proc_data_cache for id translation.
+ * If the cache contains the id we are looking for, reads the corresponding
+ * directory in /proc, and if cache is valid, saves the result.
+ */
+static void
+proc_data_cache_iterator_fn(void* fn_data, uint64_t key, uint64_t val)
+{
+ struct translate_id_params *tip = (struct translate_id_params *)fn_data;
+ struct proc_data *pd = (struct proc_data *) (uintptr_t) val;
+
+ if (!pd)
+ return;
+
+ /* Result already found in an earlier iteration */
+ if (tip->result_id)
+ return;
+
+ /* Translate from cache */
+ tip->pd = pd;
+ translate_id_proc_pid(tip, 0);
+ if (!tip->result_id)
+ return;
+
+ /* Now translate from actual data in /proc, to check cache validity */
+ translate_id_proc_pid(tip, pd->proc_pid);
+}
+
+int
+translate_pid(struct tcb *tcp, int from_id, enum pid_type type,
+ int *proc_pid_ptr)
+{
+ if (from_id <= 0 || type < 0 || type >= PT_COUNT)
+ return 0;
+
+ /* If translation is trivial */
+ if ((!tcp || get_ns(tcp) == get_our_ns()) &&
+ (is_proc_ours() || !proc_pid_ptr)) {
+ if (proc_pid_ptr)
+ *proc_pid_ptr = from_id;
+
+ return from_id;
+ }
+
+ struct translate_id_params tip = {
+ .result_id = 0,
+ .pd = NULL,
+ .from_ns = tcp ? get_ns(tcp) : get_our_ns(),
+ .from_id = from_id,
+ .type = type,
+ };
+
+ if (!tip.from_ns)
+ return 0;
+
+ if (ns_get_parent_enotty)
+ return 0;
+
+ /* Look for a cached proc_pid for this (from_ns, from_id) pair */
+ int cached_proc_pid = get_cached_proc_pid(tip.from_ns, tip.from_id,
+ tip.type);
+ if (cached_proc_pid) {
+ translate_id_proc_pid(&tip, cached_proc_pid);
+ if (tip.result_id)
+ goto exit;
+ }
+
+ /* Iterate through the cache, find potential proc_data */
+ trie_iterate_keys(proc_data_cache, 0, pid_max,
+ proc_data_cache_iterator_fn, &tip);
+ /* (proc_data_cache_iterator_fn takes care about updating proc_data) */
+ if (tip.result_id)
+ goto exit;
+
+ /* No cache helped, read all entries in /proc */
+ translate_id_dir(&tip, "/proc", true);
+
+exit:
+ if (tip.pd) {
+ if (tip.pd->proc_pid)
+ put_proc_pid(tip.from_ns, tip.from_id, tip.type,
+ tip.pd->proc_pid);
+
+ if (proc_pid_ptr)
+ *proc_pid_ptr = tip.pd->proc_pid;
+ }
+
+ return tip.result_id;
+}
+
+int
+get_proc_pid(struct tcb *tcp)
+{
+ int proc_pid = 0;
+ translate_pid(NULL, tcp->pid, PT_TID, &proc_pid);
+ return proc_pid;
+}
+
+static void
+printpid_translation(struct tcb *tcp, int pid, enum pid_type type)
+{
+ if (!pidns_translation)
+ return;
+
+ int strace_pid = translate_pid(tcp, pid, type, NULL);
+ if (strace_pid && strace_pid != pid)
+ tprintf_comment("%d in strace's PID NS", strace_pid);
+}
+
+void
+printpid(struct tcb *tcp, int pid, enum pid_type type)
+{
+ tprintf("%d", pid);
+ printpid_translation(tcp, pid, type);
+}
+
+void
+printpid_tgid_pgid(struct tcb *tcp, int pid)
+{
+ tprintf("%d", pid);
+ if (pid > 0)
+ printpid_translation(tcp, pid, PT_TGID);
+ else if (pid < -1)
+ printpid_translation(tcp, -pid, PT_PGID);
+}
diff --git a/strace.1.in b/strace.1.in
index 3b21caec..83776e88 100644
--- a/strace.1.in
+++ b/strace.1.in
@@ -1075,6 +1075,10 @@ Print all available information associated with file descritors:
protocol-specific information associated with socket file descriptors,
block/character device number associated with device file descriptors,
and PIDs asociated with pidfd file descriptors.
+.TP
+.B \-\-pidns\-translation
+If strace and tracee are in different PID namespaces, print PIDs in
+strace's namespace, too.
.SS Statistics
.TP 12
.B \-c
diff --git a/strace.c b/strace.c
index 4c96a98b..249533ea 100644
--- a/strace.c
+++ b/strace.c
@@ -133,6 +133,8 @@ static unsigned int daemonized_tracer;
static int post_attach_sigstop = TCB_IGNORE_ONE_SIGSTOP;
#define use_seize (post_attach_sigstop == 0)
+unsigned int pidns_translation;
+
static bool detach_on_execve;
static int exit_code;
@@ -1998,6 +2000,8 @@ init(int argc, char *argv[])
os_release = get_os_release();
+ pidns_init();
+
shared_log = stderr;
set_sortby(DEFAULT_SORTBY);
set_personality(DEFAULT_PERSONALITY);
@@ -2022,6 +2026,7 @@ init(int argc, char *argv[])
GETOPT_FOLLOWFORKS,
GETOPT_OUTPUT_SEPARATELY,
GETOPT_TS,
+ GETOPT_PIDNS_TRANSLATION,
GETOPT_QUAL_TRACE,
GETOPT_QUAL_ABBREV,
@@ -2072,6 +2077,7 @@ init(int argc, char *argv[])
{ "summary-wall-clock", no_argument, 0, 'w' },
{ "strings-in-hex", optional_argument, 0, GETOPT_HEX_STR },
{ "const-print-style", required_argument, 0, 'X' },
+ { "pidns-translation", no_argument , 0, GETOPT_PIDNS_TRANSLATION },
{ "successful-only", no_argument, 0, 'z' },
{ "failed-only", no_argument, 0, 'Z' },
{ "failing-only", no_argument, 0, 'Z' },
@@ -2285,6 +2291,9 @@ init(int argc, char *argv[])
case 'y':
yflag_short++;
break;
+ case GETOPT_PIDNS_TRANSLATION:
+ pidns_translation++;
+ break;
case 'z':
clear_number_set_array(status_set, 1);
add_number_to_set(STATUS_SUCCESSFUL, status_set);
diff --git a/syscall.c b/syscall.c
index bcc87025..0f4bab6d 100644
--- a/syscall.c
+++ b/syscall.c
@@ -937,6 +937,21 @@ syscall_exiting_trace(struct tcb *tcp, struct timespec *ts, int res)
tprintf("= %" PRI_kld, tcp->u_rval);
}
break;
+ case RVAL_TID:
+ case RVAL_SID:
+ case RVAL_TGID:
+ case RVAL_PGID: {
+ #define _(_t) [RVAL_##_t - RVAL_TID] = PT_##_t
+ static const enum pid_type types[] = {
+ _(TID), _(SID), _(TGID), _(PGID),
+ };
+ #undef _
+
+ tprints("= ");
+ printpid(tcp, tcp->u_rval,
+ types[(sys_res & RVAL_MASK) - RVAL_TID]);
+ break;
+ }
default:
error_msg("invalid rval format");
break;
diff --git a/trie.c b/trie.c
new file mode 100644
index 00000000..b7d56ed5
--- /dev/null
+++ b/trie.c
@@ -0,0 +1,248 @@
+/*
+ * Simple trie implementation for key-value mapping storage
+ *
+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos at gmail.com>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include "defs.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "trie.h"
+
+static const uint8_t ptr_sz_lg = (sizeof(void *) == 8 ? 6 : 5);
+
+/**
+ * Returns lg2 of node size in bits for the specific level of the trie.
+ */
+static uint8_t
+trie_get_node_size(struct trie *t, uint8_t depth)
+{
+ /* Last level contains data and we allow it having a different size */
+ if (depth == t->max_depth)
+ return t->data_block_key_bits + t->item_size_lg;
+ /* Last level of the tree can be smaller */
+ if (depth == t->max_depth - 1)
+ return (t->key_size - t->data_block_key_bits - 1) %
+ t->node_key_bits + 1 + ptr_sz_lg;
+
+ return t->node_key_bits + ptr_sz_lg;
+}
+
+/**
+ * Provides starting offset of bits in key corresponding to the node index
+ * at the specific level.
+ */
+static uint8_t
+trie_get_node_bit_offs(struct trie *t, uint8_t depth)
+{
+ uint8_t offs;
+
+ if (depth == t->max_depth)
+ return 0;
+
+ offs = t->data_block_key_bits;
+
+ if (depth == t->max_depth - 1)
+ return offs;
+
+ /* data_block_size + remainder */
+ offs += trie_get_node_size(t, t->max_depth - 1) - ptr_sz_lg;
+ offs += (t->max_depth - depth - 2) * t->node_key_bits;
+
+ return offs;
+}
+
+struct trie *
+trie_create(uint8_t key_size, uint8_t item_size_lg, uint8_t node_key_bits,
+ uint8_t data_block_key_bits, uint64_t empty_value)
+{
+ if (item_size_lg > 6)
+ return NULL;
+ if (key_size > 64)
+ return NULL;
+ if (node_key_bits < 1)
+ return NULL;
+ if (data_block_key_bits < 1 || data_block_key_bits > key_size)
+ return NULL;
+
+ struct trie *t = malloc(sizeof(*t));
+ if (!t)
+ return NULL;
+
+ t->empty_value = empty_value;
+ t->data = NULL;
+ t->item_size_lg = item_size_lg;
+ t->node_key_bits = node_key_bits;
+ t->data_block_key_bits = data_block_key_bits;
+ t->key_size = key_size;
+ t->max_depth = (key_size - data_block_key_bits + node_key_bits - 1)
+ / t->node_key_bits;
+
+ return t;
+}
+
+static uint64_t *
+trie_get_node(struct trie *t, uint64_t key, bool auto_create)
+{
+ void **cur_node = &(t->data);
+
+ if (t->key_size < 64 && key > (uint64_t) 1 << t->key_size)
+ return NULL;
+
+ for (uint8_t cur_depth = 0; cur_depth <= t->max_depth; cur_depth++) {
+ uint8_t offs = trie_get_node_bit_offs(t, cur_depth);
+ uint8_t sz = trie_get_node_size(t, cur_depth);
+
+ if (!*cur_node) {
+ if (!auto_create)
+ return NULL;
+
+ *cur_node = xcalloc(1 << sz, 1);
+ }
+
+ if (cur_depth >= t->max_depth)
+ break;
+
+ size_t pos = (key >> offs) & ((1 << (sz - ptr_sz_lg)) - 1);
+ cur_node = (((void **) (*cur_node)) + pos);
+ }
+
+ return (uint64_t *) (*cur_node);
+}
+
+static void
+trie_data_block_calc_pos(struct trie *t, uint64_t key,
+ uint64_t *pos, uint64_t *mask, uint64_t *offs)
+{
+ uint64_t key_mask;
+
+ key_mask = (1 << t->data_block_key_bits) - 1;
+ *pos = (key & key_mask) >> (6 - t->item_size_lg);
+
+ key_mask = (1 << (6 - t->item_size_lg)) - 1;
+ *offs = (key & key_mask) * (1 << t->item_size_lg);
+
+ *mask = (((uint64_t) 1 << (1 << t->item_size_lg)) - 1) << *offs;
+}
+
+bool
+trie_set(struct trie *t, uint64_t key, uint64_t val)
+{
+ uint64_t *data = trie_get_node(t, key, true);
+ if (!data)
+ return false;
+
+ uint64_t pos, mask, offs;
+ trie_data_block_calc_pos(t, key, &pos, &mask, &offs);
+
+ data[pos] &= ~mask;
+ data[pos] |= (val << offs) & mask;
+
+ return true;
+}
+
+static uint64_t
+trie_data_block_get(struct trie *t, uint64_t *data, uint64_t key)
+{
+ if (!data)
+ return t->empty_value;
+
+ uint64_t pos, mask, offs;
+ trie_data_block_calc_pos(t, key, &pos, &mask, &offs);
+
+ return (data[pos] & mask) >> offs;
+}
+
+uint64_t
+trie_get(struct trie *b, uint64_t key)
+{
+ return trie_data_block_get(b, trie_get_node(b, key, false), key);
+}
+
+static uint64_t
+trie_iterate_keys_node(struct trie *t,
+ trie_iterate_fn fn, void *fn_data,
+ void *node, uint64_t start, uint64_t end,
+ uint8_t depth)
+{
+ if (start > end || !node)
+ return 0;
+
+ if (depth == t->max_depth) {
+ for (uint64_t i = start; i <= end; i++)
+ fn(fn_data, i, trie_data_block_get(t,
+ (uint64_t *) node, i));
+
+ return end - start + 1;
+ }
+
+ uint8_t parent_node_bit_off = depth == 0 ?
+ t->key_size :
+ trie_get_node_bit_offs(t, depth - 1);
+
+ uint64_t first_key_in_node = start &
+ (uint64_t) -1 << parent_node_bit_off;
+
+ uint8_t node_bit_off = trie_get_node_bit_offs(t, depth);
+ uint8_t node_key_bits = parent_node_bit_off - node_bit_off;
+ uint64_t mask = ((uint64_t) 1 << (node_key_bits)) - 1;
+ uint64_t start_index = (start >> node_bit_off) & mask;
+ uint64_t end_index = (end >> node_bit_off) & mask;
+ uint64_t child_key_count = (uint64_t) 1 << node_bit_off;
+
+ uint64_t count = 0;
+
+ for (uint64_t i = start_index; i <= end_index; i++) {
+ uint64_t child_start = first_key_in_node + i * child_key_count;
+ uint64_t child_end = first_key_in_node +
+ (i + 1) * child_key_count - 1;
+
+ if (child_start < start)
+ child_start = start;
+ if (child_end > end)
+ child_end = end;
+
+ count += trie_iterate_keys_node(t, fn, fn_data,
+ ((void **) node)[i], child_start, child_end,
+ depth + 1);
+ }
+
+ return count;
+}
+
+uint64_t trie_iterate_keys(struct trie *t, uint64_t start, uint64_t end,
+ trie_iterate_fn fn, void *fn_data)
+{
+ return trie_iterate_keys_node(t, fn, fn_data, t->data,
+ start, end, 0);
+}
+
+static void
+trie_free_node(struct trie *t, void *node, uint8_t depth)
+{
+ if (!node)
+ return;
+
+ if (depth >= t->max_depth)
+ goto free_node;
+
+ size_t sz = 1 << (trie_get_node_size(t, depth) - ptr_sz_lg);
+ for (size_t i = 0; i < sz; i++)
+ trie_free_node(t, ((void **) node)[i], depth + 1);
+
+free_node:
+ free(node);
+}
+
+void
+trie_free(struct trie *t)
+{
+ trie_free_node(t, t->data, 0);
+ free(t);
+}
diff --git a/trie.h b/trie.h
new file mode 100644
index 00000000..1ff31397
--- /dev/null
+++ b/trie.h
@@ -0,0 +1,89 @@
+/*
+ * Simple trie interface
+ *
+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos at gmail.com>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#ifndef STRACE_TRIE_H
+#define STRACE_TRIE_H
+
+/**
+ * Trie control structure.
+ * Trie implemented here has the following properties:
+ * * It allows storing values of the same size, the size can vary from 1 bit to
+ * 64 bit values (only power of 2 sizes are allowed).
+ * * The key can be up to 64 bits in size.
+ * * It has separate configuration for node size and data block size.
+ *
+ * How bits of key are used for different node levels:
+ *
+ * highest bits lowest bits
+ * | node_key_bits | node_key_bits | ... | <remainder> | data_block_key_bits |
+ * \_________________________________________________________________________/
+ * key_size
+ *
+ * So, the remainder is used on the lowest non-data node level.
+ *
+ * As of now, it doesn't implement any mechanisms for resizing/changing key
+ * size. De-fragmentation is also unsupported currently.
+ */
+struct trie {
+ /** Return value of trie_get if key is not found */
+ uint64_t empty_value;
+
+ /** Pointer to root node */
+ void *data;
+
+ /** Key size in bits (0..64). */
+ uint8_t key_size;
+
+ /**
+ * Size of the stored values in log2 bits (0..6).
+ * (6: 64 bit values, 5: 32 bit values, ...)
+ */
+ uint8_t item_size_lg;
+
+ /**
+ * Number of bits in the key that make a symbol for a node.
+ * (equals to log2 of the child count of the node)
+ */
+ uint8_t node_key_bits;
+
+ /**
+ * Number of bits in the key that make a symbol for the data block (leaf).
+ * (equals to log2 of the value count stored in a data block)
+ */
+ uint8_t data_block_key_bits;
+
+ /** The depth of the data block. Calculated from the values above */
+ uint8_t max_depth;
+};
+
+struct trie* trie_create(uint8_t key_size, uint8_t item_size_lg,
+ uint8_t node_key_bits, uint8_t data_block_key_bits,
+ uint64_t empty_value);
+
+bool trie_set(struct trie *t, uint64_t key, uint64_t val);
+uint64_t trie_get(struct trie *t, uint64_t key);
+
+typedef void (*trie_iterate_fn)(void *data, uint64_t key, uint64_t val);
+
+/**
+ * Calls trie_iterate_fn for each key-value pair where
+ * key is inside the [start, end] interval (inclusive).
+ *
+ * @param t The trie.
+ * @param start The start of the key interval (inclusive).
+ * @param end The end of the key interval (inclusive).
+ * @param fn The function to be called.
+ * @param fn_data The value to be passed to fn.
+ */
+uint64_t trie_iterate_keys(struct trie *t, uint64_t start, uint64_t end,
+ trie_iterate_fn fn, void *fn_data);
+
+void trie_free(struct trie *t);
+
+#endif /* !STRACE_TRIE_H */
--
2.27.0
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