* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
+ * Copyright (c) 1999-2017 The strace developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
#include <stdarg.h>
#include <sys/param.h>
#include <fcntl.h>
+#include <signal.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <sys/stat.h>
#ifdef HAVE_PRCTL
# include <sys/prctl.h>
#endif
-#if defined(IA64)
-# include <asm/ptrace_offsets.h>
-#endif
+#include <asm/unistd.h>
+
+#include "scno.h"
+#include "ptrace.h"
+#include "printsiginfo.h"
+
/* In some libc, these aren't declared. Do it ourself: */
extern char **environ;
extern int optind;
#ifdef USE_LIBUNWIND
/* if this is true do the stack trace for every system call */
-bool stack_trace_enabled = false;
+bool stack_trace_enabled;
#endif
-#if defined __NR_tkill
-# define my_tkill(tid, sig) syscall(__NR_tkill, (tid), (sig))
-#else
- /* kill() may choose arbitrarily the target task of the process group
- while we later wait on a that specific TID. PID process waits become
- TID task specific waits for a process under ptrace(2). */
-# warning "tkill(2) not available, risk of strace hangs!"
-# define my_tkill(tid, sig) kill((tid), (sig))
-#endif
+#define my_tkill(tid, sig) syscall(__NR_tkill, (tid), (sig))
/* Glue for systems without a MMU that cannot provide fork() */
#if !defined(HAVE_FORK)
# define fork() vfork()
#endif
+const unsigned int syscall_trap_sig = SIGTRAP | 0x80;
+
cflag_t cflag = CFLAG_NONE;
-unsigned int followfork = 0;
-unsigned int ptrace_setoptions = 0;
-unsigned int xflag = 0;
-bool need_fork_exec_workarounds = 0;
-bool debug_flag = 0;
-bool Tflag = 0;
-bool iflag = 0;
-bool count_wallclock = 0;
-unsigned int qflag = 0;
-/* Which WSTOPSIG(status) value marks syscall traps? */
-static unsigned int syscall_trap_sig = SIGTRAP;
-static unsigned int tflag = 0;
-static bool rflag = 0;
-static bool print_pid_pfx = 0;
+unsigned int followfork;
+unsigned int ptrace_setoptions = PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEEXEC
+ | PTRACE_O_TRACEEXIT;
+unsigned int xflag;
+bool debug_flag;
+bool Tflag;
+bool iflag;
+bool count_wallclock;
+unsigned int qflag;
+static unsigned int tflag;
+static bool rflag;
+static bool print_pid_pfx;
/* -I n */
enum {
- INTR_NOT_SET = 0,
- INTR_ANYWHERE = 1, /* don't block/ignore any signals */
- INTR_WHILE_WAIT = 2, /* block fatal signals while decoding syscall. default */
- INTR_NEVER = 3, /* block fatal signals. default if '-o FILE PROG' */
- INTR_BLOCK_TSTP_TOO = 4, /* block fatal signals and SIGTSTP (^Z) */
- NUM_INTR_OPTS
+ INTR_NOT_SET = 0,
+ INTR_ANYWHERE = 1, /* don't block/ignore any signals */
+ INTR_WHILE_WAIT = 2, /* block fatal signals while decoding syscall. default */
+ INTR_NEVER = 3, /* block fatal signals. default if '-o FILE PROG' */
+ INTR_BLOCK_TSTP_TOO = 4, /* block fatal signals and SIGTSTP (^Z) */
+ NUM_INTR_OPTS
};
static int opt_intr;
/* We play with signal mask only if this mode is active: */
* wait() etc. Without -D, strace process gets lodged in between,
* disrupting parent<->child link.
*/
-static bool daemonized_tracer = 0;
+static bool daemonized_tracer;
#if USE_SEIZE
static int post_attach_sigstop = TCB_IGNORE_ONE_SIGSTOP;
#endif
/* Sometimes we want to print only succeeding syscalls. */
-bool not_failing_only = 0;
+bool not_failing_only;
/* Show path associated with fd arguments */
-unsigned int show_fd_path = 0;
+unsigned int show_fd_path;
-static bool detach_on_execve = 0;
-/* Are we "strace PROG" and need to skip detach on first execve? */
-static bool skip_one_b_execve = 0;
-/* Are we "strace PROG" and need to hide everything until execve? */
-bool hide_log_until_execve = 0;
+static bool detach_on_execve;
-static int exit_code = 0;
-static int strace_child = 0;
-static int strace_tracer_pid = 0;
+static int exit_code;
+static int strace_child;
+static int strace_tracer_pid;
-static char *username = NULL;
+static char *username;
static uid_t run_uid;
static gid_t run_gid;
static int acolumn = DEFAULT_ACOLUMN;
static char *acolumn_spaces;
-static char *outfname = NULL;
+static char *outfname;
/* If -ff, points to stderr. Else, it's our common output log */
static FILE *shared_log;
-struct tcb *printing_tcp = NULL;
+struct tcb *printing_tcp;
static struct tcb *current_tcp;
static struct tcb **tcbtab;
static unsigned int nprocs, tcbtabsize;
-static const char *progname;
+
+#ifndef HAVE_PROGRAM_INVOCATION_NAME
+char *program_invocation_name;
+#endif
unsigned os_release; /* generated from uname()'s u.release */
static void detach(struct tcb *tcp);
static void cleanup(void);
static void interrupt(int sig);
-static sigset_t empty_set, blocked_set;
+static sigset_t start_set, blocked_set;
#ifdef HAVE_SIG_ATOMIC_T
static volatile sig_atomic_t interrupted;
#endif /* HAVE_STERRROR */
static void
-usage(FILE *ofp, int exitval)
+print_version(void)
{
- fprintf(ofp, "\
-usage: strace [-CdffhiqrtttTvVxxy] [-I n] [-e expr]...\n\
+ printf("%s -- version %s\n"
+ "Copyright (c) 1991-%s The strace developers <%s>.\n"
+ "This is free software; see the source for copying conditions. There is NO\n"
+ "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
+ PACKAGE_NAME, PACKAGE_VERSION, COPYRIGHT_YEAR, PACKAGE_URL);
+}
+
+static void
+usage(void)
+{
+ printf("\
+usage: strace [-CdffhiqrtttTvVwxxy] [-I n] [-e expr]...\n\
[-a column] [-o file] [-s strsize] [-P path]...\n\
-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
- or: strace -c[df] [-I n] [-e expr]... [-O overhead] [-S sortby]\n\
+ or: strace -c[dfw] [-I n] [-e expr]... [-O overhead] [-S sortby]\n\
-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
--c -- count time, calls, and errors for each syscall and report summary\n\
--C -- like -c but also print regular output\n\
--w -- summarise syscall latency (default is system time)\n\
--d -- enable debug output to stderr\n\
--D -- run tracer process as a detached grandchild, not as parent\n\
--f -- follow forks, -ff -- with output into separate files\n\
--i -- print instruction pointer at time of syscall\n\
--q -- suppress messages about attaching, detaching, etc.\n\
--r -- print relative timestamp, -t -- absolute timestamp, -tt -- with usecs\n\
--T -- print time spent in each syscall\n\
--v -- verbose mode: print unabbreviated argv, stat, termios, etc. args\n\
--x -- print non-ascii strings in hex, -xx -- print all strings in hex\n\
--y -- print paths associated with file descriptor arguments\n\
--yy -- print ip:port pairs associated with socket file descriptors\n\
--h -- print help message, -V -- print version\n\
--a column -- alignment COLUMN for printing syscall results (default %d)\n\
--b execve -- detach on this syscall\n\
--e expr -- a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
- options: trace, abbrev, verbose, raw, signal, read, write\n\
--I interruptible --\n\
- 1: no signals are blocked\n\
- 2: fatal signals are blocked while decoding syscall (default)\n\
- 3: fatal signals are always blocked (default if '-o FILE PROG')\n\
- 4: fatal signals and SIGTSTP (^Z) are always blocked\n\
- (useful to make 'strace -o FILE PROG' not stop on ^Z)\n\
--o file -- send trace output to FILE instead of stderr\n\
--O overhead -- set overhead for tracing syscalls to OVERHEAD usecs\n\
--p pid -- trace process with process id PID, may be repeated\n\
--s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
--S sortby -- sort syscall counts by: time, calls, name, nothing (default %s)\n\
--u username -- run command as username handling setuid and/or setgid\n\
--E var=val -- put var=val in the environment for command\n\
--E var -- remove var from the environment for command\n\
--P path -- trace accesses to path\n\
+\n\
+Output format:\n\
+ -a column alignment COLUMN for printing syscall results (default %d)\n\
+ -i print instruction pointer at time of syscall\n\
"
#ifdef USE_LIBUNWIND
-"-k obtain stack trace between each syscall (experimental)\n\
+"\
+ -k obtain stack trace between each syscall (experimental)\n\
"
#endif
+"\
+ -o file send trace output to FILE instead of stderr\n\
+ -q suppress messages about attaching, detaching, etc.\n\
+ -r print relative timestamp\n\
+ -s strsize limit length of print strings to STRSIZE chars (default %d)\n\
+ -t print absolute timestamp\n\
+ -tt print absolute timestamp with usecs\n\
+ -T print time spent in each syscall\n\
+ -x print non-ascii strings in hex\n\
+ -xx print all strings in hex\n\
+ -y print paths associated with file descriptor arguments\n\
+ -yy print protocol specific information associated with socket file descriptors\n\
+\n\
+Statistics:\n\
+ -c count time, calls, and errors for each syscall and report summary\n\
+ -C like -c but also print regular output\n\
+ -O overhead set overhead for tracing syscalls to OVERHEAD usecs\n\
+ -S sortby sort syscall counts by: time, calls, name, nothing (default %s)\n\
+ -w summarise syscall latency (default is system time)\n\
+\n\
+Filtering:\n\
+ -e expr a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
+ options: trace, abbrev, verbose, raw, signal, read, write, fault\n\
+ -P path trace accesses to path\n\
+\n\
+Tracing:\n\
+ -b execve detach on execve syscall\n\
+ -D run tracer process as a detached grandchild, not as parent\n\
+ -f follow forks\n\
+ -ff follow forks with output into separate files\n\
+ -I interruptible\n\
+ 1: no signals are blocked\n\
+ 2: fatal signals are blocked while decoding syscall (default)\n\
+ 3: fatal signals are always blocked (default if '-o FILE PROG')\n\
+ 4: fatal signals and SIGTSTP (^Z) are always blocked\n\
+ (useful to make 'strace -o FILE PROG' not stop on ^Z)\n\
+\n\
+Startup:\n\
+ -E var remove var from the environment for command\n\
+ -E var=val put var=val in the environment for command\n\
+ -p pid trace process with process id PID, may be repeated\n\
+ -u username run command as username handling setuid and/or setgid\n\
+\n\
+Miscellaneous:\n\
+ -d enable debug output to stderr\n\
+ -v verbose mode: print unabbreviated argv, stat, termios, etc. args\n\
+ -h print help message\n\
+ -V print version\n\
+"
/* ancient, no one should use it
-F -- attempt to follow vforks (deprecated, use -f)\n\
*/
-z -- print only succeeding syscalls\n\
*/
, DEFAULT_ACOLUMN, DEFAULT_STRLEN, DEFAULT_SORTBY);
- exit(exitval);
+ exit(0);
}
-static void die(void) __attribute__ ((noreturn));
-static void die(void)
+static void ATTRIBUTE_NORETURN
+die(void)
{
if (strace_tracer_pid == getpid()) {
cflag = 0;
msg = NULL;
if (vasprintf(&msg, fmt, p) >= 0) {
if (err_no)
- fprintf(stderr, "%s: %s: %s\n", progname, msg, strerror(err_no));
+ fprintf(stderr, "%s: %s: %s\n",
+ program_invocation_name, msg, strerror(err_no));
else
- fprintf(stderr, "%s: %s\n", progname, msg);
+ fprintf(stderr, "%s: %s\n",
+ program_invocation_name, msg);
free(msg);
} else {
/* malloc in vasprintf failed, try it without malloc */
- fprintf(stderr, "%s: ", progname);
+ fprintf(stderr, "%s: ", program_invocation_name);
vfprintf(stderr, fmt, p);
if (err_no)
fprintf(stderr, ": %s\n", strerror(err_no));
die();
}
+void error_msg_and_help(const char *fmt, ...)
+{
+ if (fmt != NULL) {
+ va_list p;
+ va_start(p, fmt);
+ verror_msg(0, fmt, p);
+ }
+ fprintf(stderr, "Try '%s -h' for more information.\n",
+ program_invocation_name);
+ die();
+}
+
void perror_msg(const char *fmt, ...)
{
va_list p;
die();
}
-void die_out_of_memory(void)
-{
- static bool recursed = 0;
- if (recursed)
- exit(1);
- recursed = 1;
- error_msg_and_die("Out of memory");
-}
-
static void
error_opt_arg(int opt, const char *arg)
{
- error_msg_and_die("Invalid -%c argument: '%s'", opt, arg);
+ error_msg_and_help("invalid -%c argument: '%s'", opt, arg);
}
-#if USE_SEIZE
+static const char *ptrace_attach_cmd;
+
static int
ptrace_attach_or_seize(int pid)
{
+#if USE_SEIZE
int r;
if (!use_seize)
- return ptrace(PTRACE_ATTACH, pid, 0L, 0L);
- r = ptrace(PTRACE_SEIZE, pid, 0L, (unsigned long)ptrace_setoptions);
+ return ptrace_attach_cmd = "PTRACE_ATTACH",
+ ptrace(PTRACE_ATTACH, pid, 0L, 0L);
+ r = ptrace(PTRACE_SEIZE, pid, 0L, (unsigned long) ptrace_setoptions);
if (r)
- return r;
+ return ptrace_attach_cmd = "PTRACE_SEIZE", r;
r = ptrace(PTRACE_INTERRUPT, pid, 0L, 0L);
- return r;
-}
+ return ptrace_attach_cmd = "PTRACE_INTERRUPT", r;
#else
-# define ptrace_attach_or_seize(pid) ptrace(PTRACE_ATTACH, (pid), 0, 0)
+ return ptrace_attach_cmd = "PTRACE_ATTACH",
+ ptrace(PTRACE_ATTACH, pid, 0L, 0L);
#endif
+}
/*
* Used when we want to unblock stopped traced process.
* Otherwise prints error message and returns -1.
*/
static int
-ptrace_restart(int op, struct tcb *tcp, int sig)
+ptrace_restart(const unsigned int op, struct tcb *const tcp, unsigned int sig)
{
int err;
const char *msg;
errno = 0;
- ptrace(op, tcp->pid, (void *) 0, (long) sig);
+ ptrace(op, tcp->pid, 0L, (unsigned long) sig);
err = errno;
if (!err)
return 0;
- msg = "SYSCALL";
- if (op == PTRACE_CONT)
- msg = "CONT";
- if (op == PTRACE_DETACH)
- msg = "DETACH";
-#ifdef PTRACE_LISTEN
- if (op == PTRACE_LISTEN)
- msg = "LISTEN";
-#endif
+ switch (op) {
+ case PTRACE_CONT:
+ msg = "CONT";
+ break;
+ case PTRACE_DETACH:
+ msg = "DETACH";
+ break;
+ case PTRACE_LISTEN:
+ msg = "LISTEN";
+ break;
+ default:
+ msg = "SYSCALL";
+ }
+
/*
* Why curcol != 0? Otherwise sometimes we get this:
*
if (err == ESRCH)
return 0;
errno = err;
- perror_msg("ptrace(PTRACE_%s,pid:%d,sig:%d)", msg, tcp->pid, sig);
+ perror_msg("ptrace(PTRACE_%s,pid:%d,sig:%u)", msg, tcp->pid, sig);
return -1;
}
fcntl(fd, F_SETFD, newflags); /* never fails */
}
-static void kill_save_errno(pid_t pid, int sig)
+static void
+kill_save_errno(pid_t pid, int sig)
{
int saved_errno = errno;
return fp;
}
-static int popen_pid = 0;
+static int popen_pid;
#ifndef _PATH_BSHELL
# define _PATH_BSHELL "/bin/sh"
swap_uid();
fp = fdopen(fds[1], "w");
if (!fp)
- die_out_of_memory();
+ perror_msg_and_die("fdopen");
return fp;
}
-void
-tprintf(const char *fmt, ...)
+ATTRIBUTE_FORMAT((printf, 1, 0))
+static void
+tvprintf(const char *const fmt, va_list args)
{
- va_list args;
-
- va_start(args, fmt);
if (current_tcp) {
- int n = strace_vfprintf(current_tcp->outf, fmt, args);
+ int n = vfprintf(current_tcp->outf, fmt, args);
if (n < 0) {
if (current_tcp->outf != stderr)
perror_msg("%s", outfname);
} else
current_tcp->curcol += n;
}
+}
+
+void
+tprintf(const char *fmt, ...)
+{
+ va_list args;
+ va_start(args, fmt);
+ tvprintf(fmt, args);
va_end(args);
}
}
}
+void
+tprints_comment(const char *const str)
+{
+ if (str && *str)
+ tprintf(" /* %s */", str);
+}
+
+void
+tprintf_comment(const char *fmt, ...)
+{
+ if (!fmt || !*fmt)
+ return;
+
+ va_list args;
+ va_start(args, fmt);
+ tprints(" /* ");
+ tvprintf(fmt, args);
+ tprints(" */");
+ va_end(args);
+}
+
void
line_ended(void)
{
tprintf("%6ld.%06ld ",
(long) dtv.tv_sec, (long) dtv.tv_usec);
otv = tv;
- }
- else if (tflag > 2) {
+ } else if (tflag > 2) {
tprintf("%ld.%06ld ",
(long) tv.tv_sec, (long) tv.tv_usec);
- }
- else {
+ } else {
time_t local = tv.tv_sec;
strftime(str, sizeof(str), "%T", localtime(&local));
if (tflag > 1)
static void
expand_tcbtab(void)
{
- /* Allocate some more TCBs and expand the table.
+ /* Allocate some (more) TCBs (and expand the table).
We don't want to relocate the TCBs because our
callers have pointers and it would be a pain.
So tcbtab is a table of pointers. Since we never
free the TCBs, we allocate a single chunk of many. */
- unsigned int i = tcbtabsize;
- struct tcb *newtcbs = calloc(tcbtabsize, sizeof(newtcbs[0]));
- struct tcb **newtab = realloc(tcbtab, tcbtabsize * 2 * sizeof(tcbtab[0]));
- if (!newtab || !newtcbs)
- die_out_of_memory();
- tcbtabsize *= 2;
- tcbtab = newtab;
- while (i < tcbtabsize)
- tcbtab[i++] = newtcbs++;
+ unsigned int new_tcbtabsize, alloc_tcbtabsize;
+ struct tcb *newtcbs;
+
+ if (tcbtabsize) {
+ alloc_tcbtabsize = tcbtabsize;
+ new_tcbtabsize = tcbtabsize * 2;
+ } else {
+ new_tcbtabsize = alloc_tcbtabsize = 1;
+ }
+
+ newtcbs = xcalloc(alloc_tcbtabsize, sizeof(newtcbs[0]));
+ tcbtab = xreallocarray(tcbtab, new_tcbtabsize, sizeof(tcbtab[0]));
+ while (tcbtabsize < new_tcbtabsize)
+ tcbtab[tcbtabsize++] = newtcbs++;
}
static struct tcb *
nprocs++;
if (debug_flag)
- fprintf(stderr, "new tcb for pid %d, active tcbs:%d\n", tcp->pid, nprocs);
+ error_msg("new tcb for pid %d, active tcbs:%d",
+ tcp->pid, nprocs);
return tcp;
}
}
error_msg_and_die("bug in alloctcb");
}
+void *
+get_tcb_priv_data(const struct tcb *tcp)
+{
+ return tcp->_priv_data;
+}
+
+int
+set_tcb_priv_data(struct tcb *tcp, void *const priv_data,
+ void (*const free_priv_data)(void *))
+{
+ if (tcp->_priv_data)
+ return -1;
+
+ tcp->_free_priv_data = free_priv_data;
+ tcp->_priv_data = priv_data;
+
+ return 0;
+}
+
+void
+free_tcb_priv_data(struct tcb *tcp)
+{
+ if (tcp->_priv_data) {
+ if (tcp->_free_priv_data) {
+ tcp->_free_priv_data(tcp->_priv_data);
+ tcp->_free_priv_data = NULL;
+ }
+ tcp->_priv_data = NULL;
+ }
+}
+
static void
droptcb(struct tcb *tcp)
{
if (tcp->pid == 0)
return;
+ int p;
+ for (p = 0; p < SUPPORTED_PERSONALITIES; ++p)
+ free(tcp->inject_vec[p]);
+
+ free_tcb_priv_data(tcp);
+
#ifdef USE_LIBUNWIND
if (stack_trace_enabled) {
unwind_tcb_fin(tcp);
nprocs--;
if (debug_flag)
- fprintf(stderr, "dropped tcb for pid %d, %d remain\n", tcp->pid, nprocs);
+ error_msg("dropped tcb for pid %d, %d remain",
+ tcp->pid, nprocs);
if (tcp->outf) {
if (followfork >= 2) {
int error;
int status;
- if (tcp->flags & TCB_BPTSET)
- clearbpt(tcp);
-
/*
* Linux wrongly insists the child be stopped
* before detaching. Arghh. We go through hoops
* to make a clean break of things.
*/
-#if defined(SPARC)
-# undef PTRACE_DETACH
-# define PTRACE_DETACH PTRACE_SUNDETACH
-#endif
if (!(tcp->flags & TCB_ATTACHED))
goto drop;
goto wait_loop;
if (errno != ESRCH)
perror_msg("detach: ptrace(PTRACE_INTERRUPT,%u)", tcp->pid);
- }
- else {
+ } else {
error = my_tkill(tcp->pid, SIGSTOP);
if (!error)
goto wait_loop;
}
sig = WSTOPSIG(status);
if (debug_flag)
- fprintf(stderr, "detach wait: event:%d sig:%d\n",
- (unsigned)status >> 16, sig);
+ error_msg("detach wait: event:%d sig:%d",
+ (unsigned)status >> 16, sig);
if (use_seize) {
unsigned event = (unsigned)status >> 16;
if (event == PTRACE_EVENT_STOP /*&& sig == SIGTRAP*/) {
drop:
if (!qflag && (tcp->flags & TCB_ATTACHED))
- fprintf(stderr, "Process %u detached\n", tcp->pid);
+ error_msg("Process %u detached", tcp->pid);
droptcb(tcp);
}
* pidof uses space as delim, pgrep uses newline. :(
*/
int pid;
- char *delim = opt + strcspn(opt, ", \n\t");
+ char *delim = opt + strcspn(opt, "\n\t ,");
char c = *delim;
*delim = '\0';
}
}
+static void
+attach_tcb(struct tcb *const tcp)
+{
+ if (ptrace_attach_or_seize(tcp->pid) < 0) {
+ perror_msg("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, tcp->pid);
+ droptcb(tcp);
+ return;
+ }
+
+ tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
+ newoutf(tcp);
+ if (debug_flag)
+ error_msg("attach to pid %d (main) succeeded", tcp->pid);
+
+ char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
+ DIR *dir;
+ unsigned int ntid = 0, nerr = 0;
+
+ if (followfork && tcp->pid != strace_child &&
+ sprintf(procdir, "/proc/%d/task", tcp->pid) > 0 &&
+ (dir = opendir(procdir)) != NULL) {
+ struct_dirent *de;
+
+ while ((de = read_dir(dir)) != NULL) {
+ if (de->d_fileno == 0)
+ continue;
+
+ int tid = string_to_uint(de->d_name);
+ if (tid <= 0 || tid == tcp->pid)
+ continue;
+
+ ++ntid;
+ if (ptrace_attach_or_seize(tid) < 0) {
+ ++nerr;
+ if (debug_flag)
+ perror_msg("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, tid);
+ continue;
+ }
+ if (debug_flag)
+ error_msg("attach to pid %d succeeded", tid);
+
+ struct tcb *tid_tcp = alloctcb(tid);
+ tid_tcp->flags |= TCB_ATTACHED | TCB_STARTUP |
+ post_attach_sigstop;
+ newoutf(tid_tcp);
+ }
+
+ closedir(dir);
+ }
+
+ if (!qflag) {
+ if (ntid > nerr)
+ error_msg("Process %u attached"
+ " with %u threads",
+ tcp->pid, ntid - nerr + 1);
+ else
+ error_msg("Process %u attached",
+ tcp->pid);
+ }
+}
+
static void
startup_attach(void)
{
+ pid_t parent_pid = strace_tracer_pid;
unsigned int tcbi;
struct tcb *tcp;
* We rely on cleanup() from this point on.
*/
if (interactive)
- sigprocmask(SIG_BLOCK, &blocked_set, NULL);
+ sigprocmask(SIG_SETMASK, &blocked_set, NULL);
if (daemonized_tracer) {
pid_t pid = fork();
if (tcp->flags & TCB_ATTACHED)
continue; /* no, we already attached it */
- if (followfork && !daemonized_tracer) {
- char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
- DIR *dir;
-
- sprintf(procdir, "/proc/%d/task", tcp->pid);
- dir = opendir(procdir);
- if (dir != NULL) {
- unsigned int ntid = 0, nerr = 0;
- struct_dirent *de;
-
- while ((de = read_dir(dir)) != NULL) {
- struct tcb *cur_tcp;
- int tid;
-
- if (de->d_fileno == 0)
- continue;
- /* we trust /proc filesystem */
- tid = atoi(de->d_name);
- if (tid <= 0)
- continue;
- ++ntid;
- if (ptrace_attach_or_seize(tid) < 0) {
- ++nerr;
- if (debug_flag)
- fprintf(stderr, "attach to pid %d failed\n", tid);
- continue;
- }
- if (debug_flag)
- fprintf(stderr, "attach to pid %d succeeded\n", tid);
- cur_tcp = tcp;
- if (tid != tcp->pid)
- cur_tcp = alloctcb(tid);
- cur_tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
- newoutf(cur_tcp);
- }
- closedir(dir);
- if (interactive) {
- sigprocmask(SIG_SETMASK, &empty_set, NULL);
- if (interrupted)
- goto ret;
- sigprocmask(SIG_BLOCK, &blocked_set, NULL);
- }
- ntid -= nerr;
- if (ntid == 0) {
- perror_msg("attach: ptrace(PTRACE_ATTACH, ...)");
- droptcb(tcp);
- continue;
- }
- if (!qflag) {
- fprintf(stderr, ntid > 1
-? "Process %u attached with %u threads\n"
-: "Process %u attached\n",
- tcp->pid, ntid);
- }
- if (!(tcp->flags & TCB_ATTACHED)) {
- /* -p PID, we failed to attach to PID itself
- * but did attach to some of its sibling threads.
- * Drop PID's tcp.
- */
- droptcb(tcp);
- }
- continue;
- } /* if (opendir worked) */
- } /* if (-f) */
- if (ptrace_attach_or_seize(tcp->pid) < 0) {
- perror_msg("attach: ptrace(PTRACE_ATTACH, ...)");
+ if (tcp->pid == parent_pid || tcp->pid == strace_tracer_pid) {
+ errno = EPERM;
+ perror_msg("attach: pid %d", tcp->pid);
droptcb(tcp);
continue;
}
- tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
- newoutf(tcp);
- if (debug_flag)
- fprintf(stderr, "attach to pid %d (main) succeeded\n", tcp->pid);
- if (daemonized_tracer) {
- /*
- * Make parent go away.
- * Also makes grandparent's wait() unblock.
- */
- kill(getppid(), SIGKILL);
- }
+ attach_tcb(tcp);
- if (!qflag)
- fprintf(stderr,
- "Process %u attached\n",
- tcp->pid);
+ if (interactive) {
+ sigprocmask(SIG_SETMASK, &start_set, NULL);
+ if (interrupted)
+ goto ret;
+ sigprocmask(SIG_SETMASK, &blocked_set, NULL);
+ }
} /* for each tcbtab[] */
+ if (daemonized_tracer) {
+ /*
+ * Make parent go away.
+ * Also makes grandparent's wait() unblock.
+ */
+ kill(parent_pid, SIGKILL);
+ strace_child = 0;
+ }
+
ret:
if (interactive)
- sigprocmask(SIG_SETMASK, &empty_set, NULL);
+ sigprocmask(SIG_SETMASK, &start_set, NULL);
}
/* Stack-o-phobic exec helper, in the hope to work around
gid_t run_egid;
char **argv;
char *pathname;
+ struct sigaction child_sa;
};
static struct exec_params params_for_tracee;
-static void __attribute__ ((noinline, noreturn))
+
+static void ATTRIBUTE_NOINLINE ATTRIBUTE_NORETURN
exec_or_die(void)
{
struct exec_params *params = ¶ms_for_tracee;
if (setreuid(run_uid, params->run_euid) < 0) {
perror_msg_and_die("setreuid");
}
- }
- else if (geteuid() != 0)
+ } else if (geteuid() != 0)
if (setreuid(run_uid, run_uid) < 0) {
perror_msg_and_die("setreuid");
}
alarm(0);
}
+ if (params_for_tracee.child_sa.sa_handler != SIG_DFL)
+ sigaction(SIGCHLD, ¶ms_for_tracee.child_sa, NULL);
+
execv(params->pathname, params->argv);
perror_msg_and_die("exec");
}
+/*
+ * Open a dummy descriptor for use as a placeholder.
+ * The descriptor is O_RDONLY with FD_CLOEXEC flag set.
+ * A read attempt from such descriptor ends with EOF,
+ * a write attempt is rejected with EBADF.
+ */
+static int
+open_dummy_desc(void)
+{
+ int fds[2];
+
+ if (pipe(fds))
+ perror_msg_and_die("pipe");
+ close(fds[1]);
+ set_cloexec_flag(fds[0]);
+ return fds[0];
+}
+
+/* placeholder fds status for stdin and stdout */
+static bool fd_is_placeholder[2];
+
+/*
+ * Ensure that all standard file descriptors are open by opening placeholder
+ * file descriptors for those standard file descriptors that are not open.
+ *
+ * The information which descriptors have been made open is saved
+ * in fd_is_placeholder for later use.
+ */
+static void
+ensure_standard_fds_opened(void)
+{
+ int fd;
+
+ while ((fd = open_dummy_desc()) <= 2) {
+ if (fd == 2)
+ break;
+ fd_is_placeholder[fd] = true;
+ }
+
+ if (fd > 2)
+ close(fd);
+}
+
+/*
+ * Redirect stdin and stdout unless they have been opened earlier
+ * by ensure_standard_fds_opened as placeholders.
+ */
+static void
+redirect_standard_fds(void)
+{
+ int i;
+
+ /*
+ * It might be a good idea to redirect stderr as well,
+ * but we sometimes need to print error messages.
+ */
+ for (i = 0; i <= 1; ++i) {
+ if (!fd_is_placeholder[i]) {
+ close(i);
+ open_dummy_desc();
+ }
+ }
+}
+
static void
startup_child(char **argv)
{
struct_stat statbuf;
const char *filename;
+ size_t filename_len;
char pathname[PATH_MAX];
int pid;
struct tcb *tcp;
filename = argv[0];
+ filename_len = strlen(filename);
+
+ if (filename_len > sizeof(pathname) - 1) {
+ errno = ENAMETOOLONG;
+ perror_msg_and_die("exec");
+ }
if (strchr(filename, '/')) {
- if (strlen(filename) > sizeof pathname - 1) {
- errno = ENAMETOOLONG;
- perror_msg_and_die("exec");
- }
strcpy(pathname, filename);
}
#ifdef USE_DEBUGGING_EXEC
if (colon) {
n = colon - path;
m = n + 1;
- }
- else
+ } else
m = n = strlen(path);
if (n == 0) {
if (!getcwd(pathname, PATH_MAX))
continue;
len = strlen(pathname);
- }
- else if (n > sizeof pathname - 1)
+ } else if (n > sizeof(pathname) - 1)
continue;
else {
strncpy(pathname, path, n);
}
if (len && pathname[len - 1] != '/')
pathname[len++] = '/';
+ if (filename_len + len > sizeof(pathname) - 1)
+ continue;
strcpy(pathname + len, filename);
if (stat_file(pathname, &statbuf) == 0 &&
/* Accept only regular files
(statbuf.st_mode & 0111))
break;
}
+ if (!path || !*path)
+ pathname[0] = '\0';
}
if (stat_file(pathname, &statbuf) < 0) {
perror_msg_and_die("Can't stat '%s'", filename);
* On NOMMU, can be safely freed only after execve in tracee.
* It's hard to know when that happens, so we just leak it.
*/
- params_for_tracee.pathname = NOMMU_SYSTEM ? strdup(pathname) : pathname;
+ params_for_tracee.pathname = NOMMU_SYSTEM ? xstrdup(pathname) : pathname;
#if defined HAVE_PRCTL && defined PR_SET_PTRACER && defined PR_SET_PTRACER_ANY
if (daemonized_tracer)
}
if (!WIFSTOPPED(status) || WSTOPSIG(status) != SIGSTOP) {
kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("Unexpected wait status %x", status);
+ perror_msg_and_die("Unexpected wait status %#x",
+ status);
}
}
/* Else: NOMMU case, we have no way to sync.
if (ptrace_attach_or_seize(pid)) {
kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("Can't attach to %d", pid);
+ perror_msg_and_die("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, pid);
}
if (!NOMMU_SYSTEM)
kill(pid, SIGCONT);
}
tcp = alloctcb(pid);
- if (!NOMMU_SYSTEM)
- tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
- else
- tcp->flags |= TCB_ATTACHED | TCB_STARTUP;
+ tcp->flags |= TCB_ATTACHED | TCB_STARTUP
+ | TCB_SKIP_DETACH_ON_FIRST_EXEC
+ | (NOMMU_SYSTEM ? 0 : (TCB_HIDE_LOG | post_attach_sigstop));
newoutf(tcp);
- }
- else {
- /* With -D, we are *child* here, IOW: different pid. Fetch it: */
+ } else {
+ /* With -D, we are *child* here, the tracee is our parent. */
+ strace_child = strace_tracer_pid;
strace_tracer_pid = getpid();
- /* The tracee is our parent: */
- pid = getppid();
- alloctcb(pid);
+ tcp = alloctcb(strace_child);
+ tcp->flags |= TCB_SKIP_DETACH_ON_FIRST_EXEC | TCB_HIDE_LOG;
/* attaching will be done later, by startup_attach */
/* note: we don't do newoutf(tcp) here either! */
* to create a genuine separate stack and execute on it.
*/
}
+ /*
+ * A case where straced process is part of a pipe:
+ * { sleep 1; yes | head -n99999; } | strace -o/dev/null sh -c 'exec <&-; sleep 9'
+ * If strace won't close its fd#0, closing it in tracee is not enough:
+ * the pipe is still open, it has a reader. Thus, "head" will not get its
+ * SIGPIPE at once, on the first write.
+ *
+ * Preventing it by redirecting strace's stdin/out.
+ * (Don't leave fds 0 and 1 closed, this is bad practice: future opens
+ * will reuse them, unexpectedly making a newly opened object "stdin").
+ */
+ redirect_standard_fds();
}
-/*
- * Test whether the kernel support PTRACE_O_TRACECLONE et al options.
- * First fork a new child, call ptrace with PTRACE_SETOPTIONS on it,
- * and then see which options are supported by the kernel.
- */
-static int
-test_ptrace_setoptions_followfork(void)
+#if USE_SEIZE
+static void
+test_ptrace_seize(void)
{
- int pid, expected_grandchild = 0, found_grandchild = 0;
- const unsigned int test_options = PTRACE_O_TRACECLONE |
- PTRACE_O_TRACEFORK |
- PTRACE_O_TRACEVFORK;
+ int pid;
/* Need fork for test. NOMMU has no forks */
- if (NOMMU_SYSTEM)
- goto worked; /* be bold, and pretend that test succeeded */
+ if (NOMMU_SYSTEM) {
+ post_attach_sigstop = 0; /* this sets use_seize to 1 */
+ return;
+ }
pid = fork();
if (pid < 0)
perror_msg_and_die("fork");
+
if (pid == 0) {
- pid = getpid();
- if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) < 0)
- perror_msg_and_die("%s: PTRACE_TRACEME doesn't work",
- __func__);
- kill_save_errno(pid, SIGSTOP);
- if (fork() < 0)
- perror_msg_and_die("fork");
+ pause();
_exit(0);
}
+ /* PTRACE_SEIZE, unlike ATTACH, doesn't force tracee to trap. After
+ * attaching tracee continues to run unless a trap condition occurs.
+ * PTRACE_SEIZE doesn't affect signal or group stop state.
+ */
+ if (ptrace(PTRACE_SEIZE, pid, 0, 0) == 0) {
+ post_attach_sigstop = 0; /* this sets use_seize to 1 */
+ } else if (debug_flag) {
+ error_msg("PTRACE_SEIZE doesn't work");
+ }
+
+ kill(pid, SIGKILL);
+
while (1) {
int status, tracee_pid;
errno = 0;
- tracee_pid = wait(&status);
+ tracee_pid = waitpid(pid, &status, 0);
if (tracee_pid <= 0) {
if (errno == EINTR)
continue;
- if (errno == ECHILD)
- break;
- kill_save_errno(pid, SIGKILL);
perror_msg_and_die("%s: unexpected wait result %d",
- __func__, tracee_pid);
- }
- if (WIFEXITED(status)) {
- if (WEXITSTATUS(status)) {
- if (tracee_pid != pid)
- kill_save_errno(pid, SIGKILL);
- error_msg_and_die("%s: unexpected exit status %u",
- __func__, WEXITSTATUS(status));
- }
- continue;
+ __func__, tracee_pid);
}
if (WIFSIGNALED(status)) {
- if (tracee_pid != pid)
- kill_save_errno(pid, SIGKILL);
- error_msg_and_die("%s: unexpected signal %u",
- __func__, WTERMSIG(status));
- }
- if (!WIFSTOPPED(status)) {
- if (tracee_pid != pid)
- kill_save_errno(tracee_pid, SIGKILL);
- kill_save_errno(pid, SIGKILL);
- error_msg_and_die("%s: unexpected wait status %x",
- __func__, status);
- }
- if (tracee_pid != pid) {
- found_grandchild = tracee_pid;
- if (ptrace(PTRACE_CONT, tracee_pid, 0, 0) < 0) {
- kill_save_errno(tracee_pid, SIGKILL);
- kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("PTRACE_CONT doesn't work");
- }
- continue;
- }
- switch (WSTOPSIG(status)) {
- case SIGSTOP:
- if (ptrace(PTRACE_SETOPTIONS, pid, 0, test_options) < 0
- && errno != EINVAL && errno != EIO)
- perror_msg("PTRACE_SETOPTIONS");
- break;
- case SIGTRAP:
- if (status >> 16 == PTRACE_EVENT_FORK) {
- long msg = 0;
-
- if (ptrace(PTRACE_GETEVENTMSG, pid,
- NULL, (long) &msg) == 0)
- expected_grandchild = msg;
- }
- break;
- }
- if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) {
- kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("PTRACE_SYSCALL doesn't work");
+ return;
}
+ error_msg_and_die("%s: unexpected wait status %#x",
+ __func__, status);
}
- if (expected_grandchild && expected_grandchild == found_grandchild) {
- worked:
- ptrace_setoptions |= test_options;
- if (debug_flag)
- fprintf(stderr, "ptrace_setoptions = %#x\n",
- ptrace_setoptions);
- return 0;
- }
- error_msg("Test for PTRACE_O_TRACECLONE failed, "
- "giving up using this feature.");
- return 1;
}
+#else /* !USE_SEIZE */
+# define test_ptrace_seize() ((void)0)
+#endif
-/*
- * Test whether the kernel support PTRACE_O_TRACESYSGOOD.
- * First fork a new child, call ptrace(PTRACE_SETOPTIONS) on it,
- * and then see whether it will stop with (SIGTRAP | 0x80).
- *
- * Use of this option enables correct handling of user-generated SIGTRAPs,
- * and SIGTRAPs generated by special instructions such as int3 on x86:
-
-# compile with: gcc -nostartfiles -nostdlib -o int3 int3.S
-_start: .globl _start
- int3
- movl $42, %ebx
- movl $1, %eax
- int $0x80
- */
-static int
-test_ptrace_setoptions_for_all(void)
-{
- const unsigned int test_options = PTRACE_O_TRACESYSGOOD |
- PTRACE_O_TRACEEXEC;
- int pid;
- int it_worked = 0;
-
- /* Need fork for test. NOMMU has no forks */
- if (NOMMU_SYSTEM)
- goto worked; /* be bold, and pretend that test succeeded */
-
- pid = fork();
- if (pid < 0)
- perror_msg_and_die("fork");
-
- if (pid == 0) {
- pid = getpid();
- if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) < 0)
- /* Note: exits with exitcode 1 */
- perror_msg_and_die("%s: PTRACE_TRACEME doesn't work",
- __func__);
- kill(pid, SIGSTOP);
- _exit(0); /* parent should see entry into this syscall */
- }
-
- while (1) {
- int status, tracee_pid;
-
- errno = 0;
- tracee_pid = wait(&status);
- if (tracee_pid <= 0) {
- if (errno == EINTR)
- continue;
- kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("%s: unexpected wait result %d",
- __func__, tracee_pid);
- }
- if (WIFEXITED(status)) {
- if (WEXITSTATUS(status) == 0)
- break;
- error_msg_and_die("%s: unexpected exit status %u",
- __func__, WEXITSTATUS(status));
- }
- if (WIFSIGNALED(status)) {
- error_msg_and_die("%s: unexpected signal %u",
- __func__, WTERMSIG(status));
- }
- if (!WIFSTOPPED(status)) {
- kill(pid, SIGKILL);
- error_msg_and_die("%s: unexpected wait status %x",
- __func__, status);
- }
- if (WSTOPSIG(status) == SIGSTOP) {
- /*
- * We don't check "options aren't accepted" error.
- * If it happens, we'll never get (SIGTRAP | 0x80),
- * and thus will decide to not use the option.
- * IOW: the outcome of the test will be correct.
- */
- if (ptrace(PTRACE_SETOPTIONS, pid, 0L, test_options) < 0
- && errno != EINVAL && errno != EIO)
- perror_msg("PTRACE_SETOPTIONS");
- }
- if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
- it_worked = 1;
- }
- if (ptrace(PTRACE_SYSCALL, pid, 0L, 0L) < 0) {
- kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("PTRACE_SYSCALL doesn't work");
- }
- }
-
- if (it_worked) {
- worked:
- syscall_trap_sig = (SIGTRAP | 0x80);
- ptrace_setoptions |= test_options;
- if (debug_flag)
- fprintf(stderr, "ptrace_setoptions = %#x\n",
- ptrace_setoptions);
- return 0;
- }
-
- error_msg("Test for PTRACE_O_TRACESYSGOOD failed, "
- "giving up using this feature.");
- return 1;
-}
-
-#if USE_SEIZE
-static void
-test_ptrace_seize(void)
-{
- int pid;
-
- /* Need fork for test. NOMMU has no forks */
- if (NOMMU_SYSTEM) {
- post_attach_sigstop = 0; /* this sets use_seize to 1 */
- return;
- }
-
- pid = fork();
- if (pid < 0)
- perror_msg_and_die("fork");
-
- if (pid == 0) {
- pause();
- _exit(0);
- }
-
- /* PTRACE_SEIZE, unlike ATTACH, doesn't force tracee to trap. After
- * attaching tracee continues to run unless a trap condition occurs.
- * PTRACE_SEIZE doesn't affect signal or group stop state.
- */
- if (ptrace(PTRACE_SEIZE, pid, 0, 0) == 0) {
- post_attach_sigstop = 0; /* this sets use_seize to 1 */
- } else if (debug_flag) {
- fprintf(stderr, "PTRACE_SEIZE doesn't work\n");
- }
-
- kill(pid, SIGKILL);
-
- while (1) {
- int status, tracee_pid;
-
- errno = 0;
- tracee_pid = waitpid(pid, &status, 0);
- if (tracee_pid <= 0) {
- if (errno == EINTR)
- continue;
- perror_msg_and_die("%s: unexpected wait result %d",
- __func__, tracee_pid);
- }
- if (WIFSIGNALED(status)) {
- return;
- }
- error_msg_and_die("%s: unexpected wait status %x",
- __func__, status);
- }
-}
-#else /* !USE_SEIZE */
-# define test_ptrace_seize() ((void)0)
-#endif
-
-static unsigned
-get_os_release(void)
+static unsigned
+get_os_release(void)
{
unsigned rel;
const char *p;
error_msg_and_die("Bad OS release string: '%s'", u.release);
/* Note: this open-codes KERNEL_VERSION(): */
rel = (rel << 8) | atoi(p);
- if (rel >= KERNEL_VERSION(1,0,0))
+ if (rel >= KERNEL_VERSION(1, 0, 0))
break;
while (*p >= '0' && *p <= '9')
p++;
if (*p != '.') {
- if (rel >= KERNEL_VERSION(0,1,0)) {
+ if (rel >= KERNEL_VERSION(0, 1, 0)) {
/* "X.Y-something" means "X.Y.0" */
rel <<= 8;
break;
return rel;
}
+static void
+set_sigaction(int signo, void (*sighandler)(int), struct sigaction *oldact)
+{
+ /* if signal handler is a function, add the signal to blocked_set */
+ if (sighandler != SIG_IGN && sighandler != SIG_DFL)
+ sigaddset(&blocked_set, signo);
+
+ const struct sigaction sa = { .sa_handler = sighandler };
+ sigaction(signo, &sa, oldact);
+}
+
/*
* Initialization part of main() was eating much stack (~0.5k),
* which was unused after init.
* Don't want main() to inline us and defeat the reason
* we have a separate function.
*/
-static void __attribute__ ((noinline))
+static void ATTRIBUTE_NOINLINE
init(int argc, char *argv[])
{
- struct tcb *tcp;
int c, i;
int optF = 0;
- unsigned int tcbi;
- struct sigaction sa;
- progname = argv[0] ? argv[0] : "strace";
-
- /* Make sure SIGCHLD has the default action so that waitpid
- definitely works without losing track of children. The user
- should not have given us a bogus state to inherit, but he might
- have. Arguably we should detect SIG_IGN here and pass it on
- to children, but probably noone really needs that. */
- signal(SIGCHLD, SIG_DFL);
+ if (!program_invocation_name || !*program_invocation_name) {
+ static char name[] = "strace";
+ program_invocation_name =
+ (argv[0] && *argv[0]) ? argv[0] : name;
+ }
strace_tracer_pid = getpid();
os_release = get_os_release();
- /* Allocate the initial tcbtab. */
- tcbtabsize = argc; /* Surely enough for all -p args. */
- tcbtab = calloc(tcbtabsize, sizeof(tcbtab[0]));
- if (!tcbtab)
- die_out_of_memory();
- tcp = calloc(tcbtabsize, sizeof(*tcp));
- if (!tcp)
- die_out_of_memory();
- for (tcbi = 0; tcbi < tcbtabsize; tcbi++)
- tcbtab[tcbi] = tcp++;
-
shared_log = stderr;
set_sortby(DEFAULT_SORTBY);
set_personality(DEFAULT_PERSONALITY);
break;
case 'c':
if (cflag == CFLAG_BOTH) {
- error_msg_and_die("-c and -C are mutually exclusive");
+ error_msg_and_help("-c and -C are mutually exclusive");
}
cflag = CFLAG_ONLY_STATS;
break;
case 'C':
if (cflag == CFLAG_ONLY_STATS) {
- error_msg_and_die("-c and -C are mutually exclusive");
+ error_msg_and_help("-c and -C are mutually exclusive");
}
cflag = CFLAG_BOTH;
break;
followfork++;
break;
case 'h':
- usage(stdout, 0);
+ usage();
break;
case 'i':
iflag = 1;
break;
case 'r':
rflag = 1;
- /* fall through to tflag++ */
+ break;
case 't':
tflag++;
break;
qualify("abbrev=none");
break;
case 'V':
- printf("%s -- version %s\n", PACKAGE_NAME, VERSION);
+ print_version();
exit(0);
break;
case 'z':
qualify(optarg);
break;
case 'o':
- outfname = strdup(optarg);
+ outfname = xstrdup(optarg);
break;
case 'O':
i = string_to_uint(optarg);
break;
case 's':
i = string_to_uint(optarg);
- if (i < 0)
+ if (i < 0 || (unsigned int) i > -1U / 4)
error_opt_arg(c, optarg);
max_strlen = i;
break;
set_sortby(optarg);
break;
case 'u':
- username = strdup(optarg);
+ username = xstrdup(optarg);
break;
#ifdef USE_LIBUNWIND
case 'k':
#endif
case 'E':
if (putenv(optarg) < 0)
- die_out_of_memory();
+ perror_msg_and_die("putenv");
break;
case 'I':
- opt_intr = string_to_uint(optarg);
- if (opt_intr <= 0 || opt_intr >= NUM_INTR_OPTS)
+ opt_intr = string_to_uint_upto(optarg, NUM_INTR_OPTS - 1);
+ if (opt_intr <= 0)
error_opt_arg(c, optarg);
break;
default:
- usage(stderr, 1);
+ error_msg_and_help(NULL);
break;
}
}
- argv += optind;
- /* argc -= optind; - no need, argc is not used below */
- acolumn_spaces = malloc(acolumn + 1);
- if (!acolumn_spaces)
- die_out_of_memory();
- memset(acolumn_spaces, ' ', acolumn);
- acolumn_spaces[acolumn] = '\0';
+ argv += optind;
+ argc -= optind;
- /* Must have PROG [ARGS], or -p PID. Not both. */
- if (!argv[0] == !nprocs)
- usage(stderr, 1);
+ if (argc < 0 || (!argv[0] && !nprocs)) {
+ error_msg_and_help("must have PROG [ARGS] or -p PID");
+ }
- if (nprocs != 0 && daemonized_tracer) {
- error_msg_and_die("-D and -p are mutually exclusive");
+ if (!argv[0] && daemonized_tracer) {
+ error_msg_and_help("PROG [ARGS] must be specified with -D");
}
if (!followfork)
followfork = optF;
if (followfork >= 2 && cflag) {
- error_msg_and_die("(-c or -C) and -ff are mutually exclusive");
+ error_msg_and_help("(-c or -C) and -ff are mutually exclusive");
}
if (count_wallclock && !cflag) {
- error_msg_and_die("-w must be given with (-c or -C)");
+ error_msg_and_help("-w must be given with (-c or -C)");
}
if (cflag == CFLAG_ONLY_STATS) {
error_msg("-%c has no effect with -c", 'y');
}
+ if (rflag) {
+ if (tflag > 1)
+ error_msg("-tt has no effect with -r");
+ tflag = 1;
+ }
+
+ acolumn_spaces = xmalloc(acolumn + 1);
+ memset(acolumn_spaces, ' ', acolumn);
+ acolumn_spaces[acolumn] = '\0';
+
+ sigprocmask(SIG_SETMASK, NULL, &start_set);
+ memcpy(&blocked_set, &start_set, sizeof(blocked_set));
+
+ set_sigaction(SIGCHLD, SIG_DFL, ¶ms_for_tracee.child_sa);
+
#ifdef USE_LIBUNWIND
- if (stack_trace_enabled)
+ if (stack_trace_enabled) {
+ unsigned int tcbi;
+
unwind_init();
+ for (tcbi = 0; tcbi < tcbtabsize; ++tcbi) {
+ unwind_tcb_init(tcbtab[tcbi]);
+ }
+ }
#endif
/* See if they want to run as another user. */
}
run_uid = pent->pw_uid;
run_gid = pent->pw_gid;
- }
- else {
+ } else {
run_uid = getuid();
run_gid = getgid();
}
- /*
- * On any reasonably recent Linux kernel (circa about 2.5.46)
- * need_fork_exec_workarounds should stay 0 after these tests:
- */
- /*need_fork_exec_workarounds = 0; - already is */
if (followfork)
- need_fork_exec_workarounds = test_ptrace_setoptions_followfork();
- need_fork_exec_workarounds |= test_ptrace_setoptions_for_all();
+ ptrace_setoptions |= PTRACE_O_TRACECLONE |
+ PTRACE_O_TRACEFORK |
+ PTRACE_O_TRACEVFORK;
+ if (debug_flag)
+ error_msg("ptrace_setoptions = %#x", ptrace_setoptions);
test_ptrace_seize();
+ /*
+ * Is something weird with our stdin and/or stdout -
+ * for example, may they be not open? In this case,
+ * ensure that none of the future opens uses them.
+ *
+ * This was seen in the wild when /proc/sys/kernel/core_pattern
+ * was set to "|/bin/strace -o/tmp/LOG PROG":
+ * kernel runs coredump helper with fd#0 open but fd#1 closed (!),
+ * therefore LOG gets opened to fd#1, and fd#1 is closed by
+ * "don't hold up stdin/out open" code soon after.
+ */
+ ensure_standard_fds_opened();
+
/* Check if they want to redirect the output. */
if (outfname) {
/* See if they want to pipe the output. */
* when using popen, so prohibit it.
*/
if (followfork >= 2)
- error_msg_and_die("Piping the output and -ff are mutually exclusive");
+ error_msg_and_help("piping the output and -ff are mutually exclusive");
shared_log = strace_popen(outfname + 1);
- }
- else if (followfork < 2)
+ } else if (followfork < 2)
shared_log = strace_fopen(outfname);
} else {
/* -ff without -o FILE is the same as single -f */
}
if (!outfname || outfname[0] == '|' || outfname[0] == '!') {
- char *buf = malloc(BUFSIZ);
- if (!buf)
- die_out_of_memory();
- setvbuf(shared_log, buf, _IOLBF, BUFSIZ);
+ setvbuf(shared_log, NULL, _IOLBF, 0);
}
+
+ /*
+ * argv[0] -pPID -oFILE Default interactive setting
+ * yes * 0 INTR_WHILE_WAIT
+ * no 1 0 INTR_WHILE_WAIT
+ * yes * 1 INTR_NEVER
+ * no 1 1 INTR_WHILE_WAIT
+ */
+
if (outfname && argv[0]) {
if (!opt_intr)
opt_intr = INTR_NEVER;
- qflag = 1;
+ if (!qflag)
+ qflag = 1;
}
if (!opt_intr)
opt_intr = INTR_WHILE_WAIT;
- /* argv[0] -pPID -oFILE Default interactive setting
- * yes 0 0 INTR_WHILE_WAIT
- * no 1 0 INTR_WHILE_WAIT
- * yes 0 1 INTR_NEVER
- * no 1 1 INTR_WHILE_WAIT
- */
-
- sigemptyset(&empty_set);
- sigemptyset(&blocked_set);
-
- /* startup_child() must be called before the signal handlers get
+ /*
+ * startup_child() must be called before the signal handlers get
* installed below as they are inherited into the spawned process.
* Also we do not need to be protected by them as during interruption
* in the startup_child() mode we kill the spawned process anyway.
*/
if (argv[0]) {
- if (!NOMMU_SYSTEM || daemonized_tracer)
- hide_log_until_execve = 1;
- skip_one_b_execve = 1;
startup_child(argv);
}
- sa.sa_handler = SIG_IGN;
- sigemptyset(&sa.sa_mask);
- sa.sa_flags = 0;
- sigaction(SIGTTOU, &sa, NULL); /* SIG_IGN */
- sigaction(SIGTTIN, &sa, NULL); /* SIG_IGN */
+ set_sigaction(SIGTTOU, SIG_IGN, NULL);
+ set_sigaction(SIGTTIN, SIG_IGN, NULL);
if (opt_intr != INTR_ANYWHERE) {
if (opt_intr == INTR_BLOCK_TSTP_TOO)
- sigaction(SIGTSTP, &sa, NULL); /* SIG_IGN */
+ set_sigaction(SIGTSTP, SIG_IGN, NULL);
/*
* In interactive mode (if no -o OUTFILE, or -p PID is used),
* fatal signals are blocked while syscall stop is processed,
* and acted on in between, when waiting for new syscall stops.
* In non-interactive mode, signals are ignored.
*/
- if (opt_intr == INTR_WHILE_WAIT) {
- sigaddset(&blocked_set, SIGHUP);
- sigaddset(&blocked_set, SIGINT);
- sigaddset(&blocked_set, SIGQUIT);
- sigaddset(&blocked_set, SIGPIPE);
- sigaddset(&blocked_set, SIGTERM);
- sa.sa_handler = interrupt;
- }
- /* SIG_IGN, or set handler for these */
- sigaction(SIGHUP, &sa, NULL);
- sigaction(SIGINT, &sa, NULL);
- sigaction(SIGQUIT, &sa, NULL);
- sigaction(SIGPIPE, &sa, NULL);
- sigaction(SIGTERM, &sa, NULL);
+ set_sigaction(SIGHUP, interactive ? interrupt : SIG_IGN, NULL);
+ set_sigaction(SIGINT, interactive ? interrupt : SIG_IGN, NULL);
+ set_sigaction(SIGQUIT, interactive ? interrupt : SIG_IGN, NULL);
+ set_sigaction(SIGPIPE, interactive ? interrupt : SIG_IGN, NULL);
+ set_sigaction(SIGTERM, interactive ? interrupt : SIG_IGN, NULL);
}
+
if (nprocs != 0 || daemonized_tracer)
startup_attach();
if (!tcp->pid)
continue;
if (debug_flag)
- fprintf(stderr,
- "cleanup: looking at pid %u\n", tcp->pid);
+ error_msg("cleanup: looking at pid %u", tcp->pid);
if (tcp->pid == strace_child) {
kill(tcp->pid, SIGCONT);
kill(tcp->pid, fatal_sig);
}
static void
-trace(void)
+print_debug_info(const int pid, int status)
+{
+ const unsigned int event = (unsigned int) status >> 16;
+ char buf[sizeof("WIFEXITED,exitcode=%u") + sizeof(int)*3 /*paranoia:*/ + 16];
+ char evbuf[sizeof(",EVENT_VFORK_DONE (%u)") + sizeof(int)*3 /*paranoia:*/ + 16];
+
+ strcpy(buf, "???");
+ if (WIFSIGNALED(status))
+#ifdef WCOREDUMP
+ sprintf(buf, "WIFSIGNALED,%ssig=%s",
+ WCOREDUMP(status) ? "core," : "",
+ signame(WTERMSIG(status)));
+#else
+ sprintf(buf, "WIFSIGNALED,sig=%s",
+ signame(WTERMSIG(status)));
+#endif
+ if (WIFEXITED(status))
+ sprintf(buf, "WIFEXITED,exitcode=%u", WEXITSTATUS(status));
+ if (WIFSTOPPED(status))
+ sprintf(buf, "WIFSTOPPED,sig=%s", signame(WSTOPSIG(status)));
+ evbuf[0] = '\0';
+ if (event != 0) {
+ static const char *const event_names[] = {
+ [PTRACE_EVENT_CLONE] = "CLONE",
+ [PTRACE_EVENT_FORK] = "FORK",
+ [PTRACE_EVENT_VFORK] = "VFORK",
+ [PTRACE_EVENT_VFORK_DONE] = "VFORK_DONE",
+ [PTRACE_EVENT_EXEC] = "EXEC",
+ [PTRACE_EVENT_EXIT] = "EXIT",
+ /* [PTRACE_EVENT_STOP (=128)] would make biggish array */
+ };
+ const char *e = "??";
+ if (event < ARRAY_SIZE(event_names))
+ e = event_names[event];
+ else if (event == PTRACE_EVENT_STOP)
+ e = "STOP";
+ sprintf(evbuf, ",EVENT_%s (%u)", e, event);
+ }
+ error_msg("[wait(0x%06x) = %u] %s%s", status, pid, buf, evbuf);
+}
+
+static struct tcb *
+maybe_allocate_tcb(const int pid, int status)
+{
+ if (!WIFSTOPPED(status)) {
+ if (detach_on_execve && pid == strace_child) {
+ /* example: strace -bexecve sh -c 'exec true' */
+ strace_child = 0;
+ return NULL;
+ }
+ /*
+ * This can happen if we inherited an unknown child.
+ * Example: (sleep 1 & exec strace true)
+ */
+ error_msg("Exit of unknown pid %u ignored", pid);
+ return NULL;
+ }
+ if (followfork) {
+ /* We assume it's a fork/vfork/clone child */
+ struct tcb *tcp = alloctcb(pid);
+ tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
+ newoutf(tcp);
+ if (!qflag)
+ error_msg("Process %d attached", pid);
+ return tcp;
+ } else {
+ /* This can happen if a clone call used
+ * CLONE_PTRACE itself.
+ */
+ ptrace(PTRACE_CONT, pid, NULL, 0);
+ error_msg("Stop of unknown pid %u seen, PTRACE_CONTed it", pid);
+ return NULL;
+ }
+}
+
+static struct tcb *
+maybe_switch_tcbs(struct tcb *tcp, const int pid)
+{
+ FILE *fp;
+ struct tcb *execve_thread;
+ long old_pid = 0;
+
+ if (ptrace(PTRACE_GETEVENTMSG, pid, NULL, &old_pid) < 0)
+ return tcp;
+ /* Avoid truncation in pid2tcb() param passing */
+ if (old_pid <= 0 || old_pid == pid)
+ return tcp;
+ if ((unsigned long) old_pid > UINT_MAX)
+ return tcp;
+ execve_thread = pid2tcb(old_pid);
+ /* It should be !NULL, but I feel paranoid */
+ if (!execve_thread)
+ return tcp;
+
+ if (execve_thread->curcol != 0) {
+ /*
+ * One case we are here is -ff:
+ * try "strace -oLOG -ff test/threaded_execve"
+ */
+ fprintf(execve_thread->outf, " <pid changed to %d ...>\n", pid);
+ /*execve_thread->curcol = 0; - no need, see code below */
+ }
+ /* Swap output FILEs (needed for -ff) */
+ fp = execve_thread->outf;
+ execve_thread->outf = tcp->outf;
+ tcp->outf = fp;
+ /* And their column positions */
+ execve_thread->curcol = tcp->curcol;
+ tcp->curcol = 0;
+ /* Drop leader, but close execve'd thread outfile (if -ff) */
+ droptcb(tcp);
+ /* Switch to the thread, reusing leader's outfile and pid */
+ tcp = execve_thread;
+ tcp->pid = pid;
+ if (cflag != CFLAG_ONLY_STATS) {
+ printleader(tcp);
+ tprintf("+++ superseded by execve in pid %lu +++\n", old_pid);
+ line_ended();
+ tcp->flags |= TCB_REPRINT;
+ }
+
+ return tcp;
+}
+
+static void
+print_signalled(struct tcb *tcp, const int pid, int status)
+{
+ if (pid == strace_child) {
+ exit_code = 0x100 | WTERMSIG(status);
+ strace_child = 0;
+ }
+
+ if (cflag != CFLAG_ONLY_STATS
+ && is_number_in_set(WTERMSIG(status), &signal_set)) {
+ printleader(tcp);
+#ifdef WCOREDUMP
+ tprintf("+++ killed by %s %s+++\n",
+ signame(WTERMSIG(status)),
+ WCOREDUMP(status) ? "(core dumped) " : "");
+#else
+ tprintf("+++ killed by %s +++\n",
+ signame(WTERMSIG(status)));
+#endif
+ line_ended();
+ }
+}
+
+static void
+print_exited(struct tcb *tcp, const int pid, int status)
+{
+ if (pid == strace_child) {
+ exit_code = WEXITSTATUS(status);
+ strace_child = 0;
+ }
+
+ if (cflag != CFLAG_ONLY_STATS &&
+ qflag < 2) {
+ printleader(tcp);
+ tprintf("+++ exited with %d +++\n", WEXITSTATUS(status));
+ line_ended();
+ }
+}
+
+static void
+print_stopped(struct tcb *tcp, const siginfo_t *si, const unsigned int sig)
+{
+ if (cflag != CFLAG_ONLY_STATS
+ && !hide_log(tcp)
+ && is_number_in_set(sig, &signal_set)) {
+ printleader(tcp);
+ if (si) {
+ tprintf("--- %s ", signame(sig));
+ printsiginfo(si);
+ tprints(" ---\n");
+ } else
+ tprintf("--- stopped by %s ---\n", signame(sig));
+ line_ended();
+ }
+}
+
+static void
+startup_tcb(struct tcb *tcp)
+{
+ if (debug_flag)
+ error_msg("pid %d has TCB_STARTUP, initializing it", tcp->pid);
+
+ tcp->flags &= ~TCB_STARTUP;
+
+ if (!use_seize) {
+ if (debug_flag)
+ error_msg("setting opts 0x%x on pid %d",
+ ptrace_setoptions, tcp->pid);
+ if (ptrace(PTRACE_SETOPTIONS, tcp->pid, NULL, ptrace_setoptions) < 0) {
+ if (errno != ESRCH) {
+ /* Should never happen, really */
+ perror_msg_and_die("PTRACE_SETOPTIONS");
+ }
+ }
+ }
+
+ if (get_scno(tcp) == 1)
+ tcp->s_prev_ent = tcp->s_ent;
+}
+
+static void
+print_event_exit(struct tcb *tcp)
{
+ if (entering(tcp) || filtered(tcp) || hide_log(tcp)
+ || cflag == CFLAG_ONLY_STATS) {
+ return;
+ }
+
+ if (followfork < 2 && printing_tcp && printing_tcp != tcp
+ && printing_tcp->curcol != 0) {
+ current_tcp = printing_tcp;
+ tprints(" <unfinished ...>\n");
+ fflush(printing_tcp->outf);
+ printing_tcp->curcol = 0;
+ current_tcp = tcp;
+ }
+
+ if ((followfork < 2 && printing_tcp != tcp)
+ || (tcp->flags & TCB_REPRINT)) {
+ tcp->flags &= ~TCB_REPRINT;
+ printleader(tcp);
+ tprintf("<... %s resumed>", tcp->s_ent->sys_name);
+ }
+
+ if (!(tcp->sys_func_rval & RVAL_DECODED)) {
+ /*
+ * The decoder has probably decided to print something
+ * on exiting syscall which is not going to happen.
+ */
+ tprints(" <unfinished ...>");
+ }
+ tprints(") ");
+ tabto();
+ tprints("= ?\n");
+ line_ended();
+}
+
+enum trace_event {
+ /* Break the main loop. */
+ TE_BREAK,
+
+ /* Call next_event() again. */
+ TE_NEXT,
+
+ /* Restart the tracee with signal 0 and call next_event() again. */
+ TE_RESTART,
+
+ /*
+ * For all the events below, current_tcp is set to current tracee's
+ * tcb. All the suggested actions imply that you want to continue
+ * tracing of the current tracee; alternatively, you can detach it.
+ */
+
+ /*
+ * Syscall entry or exit.
+ * Restart the tracee with signal 0, or with an injected signal number.
+ */
+ TE_SYSCALL_STOP,
+
+ /*
+ * Tracee received signal with number WSTOPSIG(*pstatus); signal info
+ * is written to *si. Restart the tracee (with that signal number
+ * if you want to deliver it).
+ */
+ TE_SIGNAL_DELIVERY_STOP,
+
+ /*
+ * Tracee was killed by a signal with number WTERMSIG(*pstatus).
+ */
+ TE_SIGNALLED,
+
+ /*
+ * Tracee was stopped by a signal with number WSTOPSIG(*pstatus).
+ * Restart the tracee with that signal number.
+ */
+ TE_GROUP_STOP,
+
+ /*
+ * Tracee exited with status WEXITSTATUS(*pstatus).
+ */
+ TE_EXITED,
+
+ /*
+ * Tracee is going to perform execve().
+ * Restart the tracee with signal 0.
+ */
+ TE_STOP_BEFORE_EXECVE,
+
+ /*
+ * Tracee is going to terminate.
+ * Restart the tracee with signal 0.
+ */
+ TE_STOP_BEFORE_EXIT,
+};
+
+static enum trace_event
+next_event(int *pstatus, siginfo_t *si)
+{
+ int pid;
+ int wait_errno;
+ int status;
+ struct tcb *tcp;
struct rusage ru;
- /* Used to be "while (nprocs != 0)", but in this testcase:
- * int main() { _exit(!!fork()); }
+ if (interrupted)
+ return TE_BREAK;
+
+ /*
+ * Used to exit simply when nprocs hits zero, but in this testcase:
+ * int main(void) { _exit(!!fork()); }
* under strace -f, parent sometimes (rarely) manages
* to exit before we see the first stop of the child,
* and we are losing track of it:
* 19923 clone(...) = 19924
* 19923 exit_group(1) = ?
* 19923 +++ exited with 1 +++
- * Waiting for ECHILD works better.
- * (However, if -o|logger is in use, we can't do that.
- * Can work around that by double-forking the logger,
- * but that loses the ability to wait for its completion on exit.
- * Oh well...)
+ * Exiting only when wait() returns ECHILD works better.
*/
- while (1) {
- int pid;
- int wait_errno;
- int status;
- int stopped;
- unsigned int sig;
- unsigned event;
- struct tcb *tcp;
-
- if (interrupted)
- return;
-
- if (popen_pid != 0 && nprocs == 0)
- return;
+ if (popen_pid != 0) {
+ /* However, if -o|logger is in use, we can't do that.
+ * Can work around that by double-forking the logger,
+ * but that loses the ability to wait for its completion
+ * on exit. Oh well...
+ */
+ if (nprocs == 0)
+ return TE_BREAK;
+ }
- if (interactive)
- sigprocmask(SIG_SETMASK, &empty_set, NULL);
- pid = wait4(-1, &status, __WALL, (cflag ? &ru : NULL));
- wait_errno = errno;
- if (interactive)
- sigprocmask(SIG_BLOCK, &blocked_set, NULL);
+ if (interactive)
+ sigprocmask(SIG_SETMASK, &start_set, NULL);
+ pid = wait4(-1, pstatus, __WALL, (cflag ? &ru : NULL));
+ wait_errno = errno;
+ if (interactive)
+ sigprocmask(SIG_SETMASK, &blocked_set, NULL);
- if (pid < 0) {
- if (wait_errno == EINTR)
- continue;
- if (nprocs == 0 && wait_errno == ECHILD)
- return;
- /* If nprocs > 0, ECHILD is not expected,
- * treat it as any other error here:
- */
- errno = wait_errno;
- perror_msg_and_die("wait4(__WALL)");
- }
+ if (pid < 0) {
+ if (wait_errno == EINTR)
+ return TE_NEXT;
+ if (nprocs == 0 && wait_errno == ECHILD)
+ return TE_BREAK;
+ /*
+ * If nprocs > 0, ECHILD is not expected,
+ * treat it as any other error here:
+ */
+ errno = wait_errno;
+ perror_msg_and_die("wait4(__WALL)");
+ }
- if (pid == popen_pid) {
- if (!WIFSTOPPED(status))
- popen_pid = 0;
- continue;
- }
+ status = *pstatus;
- event = ((unsigned)status >> 16);
- if (debug_flag) {
- char buf[sizeof("WIFEXITED,exitcode=%u") + sizeof(int)*3 /*paranoia:*/ + 16];
- char evbuf[sizeof(",EVENT_VFORK_DONE (%u)") + sizeof(int)*3 /*paranoia:*/ + 16];
- strcpy(buf, "???");
- if (WIFSIGNALED(status))
-#ifdef WCOREDUMP
- sprintf(buf, "WIFSIGNALED,%ssig=%s",
- WCOREDUMP(status) ? "core," : "",
- signame(WTERMSIG(status)));
-#else
- sprintf(buf, "WIFSIGNALED,sig=%s",
- signame(WTERMSIG(status)));
-#endif
- if (WIFEXITED(status))
- sprintf(buf, "WIFEXITED,exitcode=%u", WEXITSTATUS(status));
- if (WIFSTOPPED(status))
- sprintf(buf, "WIFSTOPPED,sig=%s", signame(WSTOPSIG(status)));
-#ifdef WIFCONTINUED
- /* Should never be seen */
- if (WIFCONTINUED(status))
- strcpy(buf, "WIFCONTINUED");
-#endif
- evbuf[0] = '\0';
- if (event != 0) {
- static const char *const event_names[] = {
- [PTRACE_EVENT_CLONE] = "CLONE",
- [PTRACE_EVENT_FORK] = "FORK",
- [PTRACE_EVENT_VFORK] = "VFORK",
- [PTRACE_EVENT_VFORK_DONE] = "VFORK_DONE",
- [PTRACE_EVENT_EXEC] = "EXEC",
- [PTRACE_EVENT_EXIT] = "EXIT",
- /* [PTRACE_EVENT_STOP (=128)] would make biggish array */
- };
- const char *e = "??";
- if (event < ARRAY_SIZE(event_names))
- e = event_names[event];
- else if (event == PTRACE_EVENT_STOP)
- e = "STOP";
- sprintf(evbuf, ",EVENT_%s (%u)", e, event);
- }
- fprintf(stderr, " [wait(0x%06x) = %u] %s%s\n", status, pid, buf, evbuf);
- }
+ if (pid == popen_pid) {
+ if (!WIFSTOPPED(status))
+ popen_pid = 0;
+ return TE_NEXT;
+ }
- /* Look up 'pid' in our table. */
- tcp = pid2tcb(pid);
+ if (debug_flag)
+ print_debug_info(pid, status);
- if (!tcp) {
- if (!WIFSTOPPED(status)) {
- /* This can happen if we inherited
- * an unknown child. Example:
- * (sleep 1 & exec strace sleep 2)
- */
- error_msg("Exit of unknown pid %u seen", pid);
- continue;
- }
- if (followfork) {
- /* We assume it's a fork/vfork/clone child */
- tcp = alloctcb(pid);
- tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
- newoutf(tcp);
- if (!qflag)
- fprintf(stderr, "Process %d attached\n",
- pid);
- } else {
- /* This can happen if a clone call used
- * CLONE_PTRACE itself.
- */
- ptrace(PTRACE_CONT, pid, (char *) 0, 0);
- error_msg("Stop of unknown pid %u seen, PTRACE_CONTed it", pid);
- continue;
- }
- }
+ /* Look up 'pid' in our table. */
+ tcp = pid2tcb(pid);
- clear_regs();
- if (WIFSTOPPED(status))
- get_regs(pid);
+ if (!tcp) {
+ tcp = maybe_allocate_tcb(pid, status);
+ if (!tcp)
+ return TE_NEXT;
+ }
- /* Under Linux, execve changes pid to thread leader's pid,
- * and we see this changed pid on EVENT_EXEC and later,
- * execve sysexit. Leader "disappears" without exit
- * notification. Let user know that, drop leader's tcb,
- * and fix up pid in execve thread's tcb.
- * Effectively, execve thread's tcb replaces leader's tcb.
- *
- * BTW, leader is 'stuck undead' (doesn't report WIFEXITED
- * on exit syscall) in multithreaded programs exactly
- * in order to handle this case.
- *
- * PTRACE_GETEVENTMSG returns old pid starting from Linux 3.0.
- * On 2.6 and earlier, it can return garbage.
- */
- if (event == PTRACE_EVENT_EXEC && os_release >= KERNEL_VERSION(3,0,0)) {
- FILE *fp;
- struct tcb *execve_thread;
- long old_pid = 0;
-
- if (ptrace(PTRACE_GETEVENTMSG, pid, NULL, (long) &old_pid) < 0)
- goto dont_switch_tcbs;
- /* Avoid truncation in pid2tcb() param passing */
- if (old_pid <= 0 || old_pid == pid)
- goto dont_switch_tcbs;
- if ((unsigned long) old_pid > UINT_MAX)
- goto dont_switch_tcbs;
- execve_thread = pid2tcb(old_pid);
- /* It should be !NULL, but I feel paranoid */
- if (!execve_thread)
- goto dont_switch_tcbs;
-
- if (execve_thread->curcol != 0) {
- /*
- * One case we are here is -ff:
- * try "strace -oLOG -ff test/threaded_execve"
- */
- fprintf(execve_thread->outf, " <pid changed to %d ...>\n", pid);
- /*execve_thread->curcol = 0; - no need, see code below */
- }
- /* Swap output FILEs (needed for -ff) */
- fp = execve_thread->outf;
- execve_thread->outf = tcp->outf;
- tcp->outf = fp;
- /* And their column positions */
- execve_thread->curcol = tcp->curcol;
- tcp->curcol = 0;
- /* Drop leader, but close execve'd thread outfile (if -ff) */
- droptcb(tcp);
- /* Switch to the thread, reusing leader's outfile and pid */
- tcp = execve_thread;
- tcp->pid = pid;
- if (cflag != CFLAG_ONLY_STATS) {
- printleader(tcp);
- tprintf("+++ superseded by execve in pid %lu +++\n", old_pid);
- line_ended();
- tcp->flags |= TCB_REPRINT;
- }
- }
- dont_switch_tcbs:
+ clear_regs();
- if (event == PTRACE_EVENT_EXEC) {
- if (detach_on_execve && !skip_one_b_execve)
- detach(tcp); /* do "-b execve" thingy */
- skip_one_b_execve = 0;
- }
+ /* Set current output file */
+ current_tcp = tcp;
- /* Set current output file */
- current_tcp = tcp;
+ if (cflag) {
+ tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
+ tcp->stime = ru.ru_stime;
+ }
- if (cflag) {
- tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
- tcp->stime = ru.ru_stime;
- }
+ if (WIFSIGNALED(status))
+ return TE_SIGNALLED;
- if (WIFSIGNALED(status)) {
- if (pid == strace_child)
- exit_code = 0x100 | WTERMSIG(status);
- if (cflag != CFLAG_ONLY_STATS
- && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)
- ) {
- printleader(tcp);
-#ifdef WCOREDUMP
- tprintf("+++ killed by %s %s+++\n",
- signame(WTERMSIG(status)),
- WCOREDUMP(status) ? "(core dumped) " : "");
-#else
- tprintf("+++ killed by %s +++\n",
- signame(WTERMSIG(status)));
-#endif
- line_ended();
- }
- droptcb(tcp);
- continue;
- }
- if (WIFEXITED(status)) {
- if (pid == strace_child)
- exit_code = WEXITSTATUS(status);
- if (cflag != CFLAG_ONLY_STATS &&
- qflag < 2) {
- printleader(tcp);
- tprintf("+++ exited with %d +++\n", WEXITSTATUS(status));
- line_ended();
- }
- droptcb(tcp);
- continue;
- }
- if (!WIFSTOPPED(status)) {
- fprintf(stderr, "PANIC: pid %u not stopped\n", pid);
- droptcb(tcp);
- continue;
- }
+ if (WIFEXITED(status))
+ return TE_EXITED;
- /* Is this the very first time we see this tracee stopped? */
- if (tcp->flags & TCB_STARTUP) {
- if (debug_flag)
- fprintf(stderr, "pid %d has TCB_STARTUP, initializing it\n", tcp->pid);
- tcp->flags &= ~TCB_STARTUP;
- if (tcp->flags & TCB_BPTSET) {
- /*
- * One example is a breakpoint inherited from
- * parent through fork().
- */
- if (clearbpt(tcp) < 0) {
- /* Pretty fatal */
- droptcb(tcp);
- exit_code = 1;
- return;
- }
- }
- if (!use_seize && ptrace_setoptions) {
- if (debug_flag)
- fprintf(stderr, "setting opts 0x%x on pid %d\n", ptrace_setoptions, tcp->pid);
- if (ptrace(PTRACE_SETOPTIONS, tcp->pid, NULL, ptrace_setoptions) < 0) {
- if (errno != ESRCH) {
- /* Should never happen, really */
- perror_msg_and_die("PTRACE_SETOPTIONS");
- }
- }
- }
- }
+ /*
+ * As WCONTINUED flag has not been specified to wait4,
+ * it cannot be WIFCONTINUED(status), so the only case
+ * that remains is WIFSTOPPED(status).
+ */
- sig = WSTOPSIG(status);
+ /* Is this the very first time we see this tracee stopped? */
+ if (tcp->flags & TCB_STARTUP)
+ startup_tcb(tcp);
- if (event != 0) {
- /* Ptrace event */
-#if USE_SEIZE
- if (event == PTRACE_EVENT_STOP) {
- /*
- * PTRACE_INTERRUPT-stop or group-stop.
- * PTRACE_INTERRUPT-stop has sig == SIGTRAP here.
- */
- if (sig == SIGSTOP
- || sig == SIGTSTP
- || sig == SIGTTIN
- || sig == SIGTTOU
- ) {
- stopped = 1;
- goto show_stopsig;
- }
- }
-#endif
- goto restart_tracee_with_sig_0;
- }
+ const unsigned int sig = WSTOPSIG(status);
+ const unsigned int event = (unsigned int) status >> 16;
- /* Is this post-attach SIGSTOP?
+ switch (event) {
+ case 0:
+ /*
+ * Is this post-attach SIGSTOP?
* Interestingly, the process may stop
* with STOPSIG equal to some other signal
- * than SIGSTOP if we happend to attach
+ * than SIGSTOP if we happened to attach
* just before the process takes a signal.
*/
if (sig == SIGSTOP && (tcp->flags & TCB_IGNORE_ONE_SIGSTOP)) {
if (debug_flag)
- fprintf(stderr, "ignored SIGSTOP on pid %d\n", tcp->pid);
+ error_msg("ignored SIGSTOP on pid %d", tcp->pid);
tcp->flags &= ~TCB_IGNORE_ONE_SIGSTOP;
- goto restart_tracee_with_sig_0;
- }
-
- if (sig != syscall_trap_sig) {
- siginfo_t si;
-
- /* Nonzero (true) if tracee is stopped by signal
+ return TE_RESTART;
+ } else if (sig == syscall_trap_sig) {
+ return TE_SYSCALL_STOP;
+ } else {
+ *si = (siginfo_t) {};
+ /*
+ * True if tracee is stopped by signal
* (as opposed to "tracee received signal").
* TODO: shouldn't we check for errno == EINVAL too?
* We can get ESRCH instead, you know...
*/
- stopped = (ptrace(PTRACE_GETSIGINFO, pid, 0, (long) &si) < 0);
+ bool stopped = ptrace(PTRACE_GETSIGINFO, pid, 0, si) < 0;
+ return stopped ? TE_GROUP_STOP : TE_SIGNAL_DELIVERY_STOP;
+ }
+ break;
#if USE_SEIZE
- show_stopsig:
+ case PTRACE_EVENT_STOP:
+ /*
+ * PTRACE_INTERRUPT-stop or group-stop.
+ * PTRACE_INTERRUPT-stop has sig == SIGTRAP here.
+ */
+ switch (sig) {
+ case SIGSTOP:
+ case SIGTSTP:
+ case SIGTTIN:
+ case SIGTTOU:
+ return TE_GROUP_STOP;
+ }
+ return TE_RESTART;
#endif
- if (cflag != CFLAG_ONLY_STATS
- && !hide_log_until_execve
- && (qual_flags[sig] & QUAL_SIGNAL)
- ) {
- printleader(tcp);
- if (!stopped) {
- tprintf("--- %s ", signame(sig));
- printsiginfo(&si, verbose(tcp));
- tprints(" ---\n");
- } else
- tprintf("--- stopped by %s ---\n",
- signame(sig));
- line_ended();
- }
-
- if (!stopped)
- /* It's signal-delivery-stop. Inject the signal */
- goto restart_tracee;
+ case PTRACE_EVENT_EXEC:
+ return TE_STOP_BEFORE_EXECVE;
+ case PTRACE_EVENT_EXIT:
+ return TE_STOP_BEFORE_EXIT;
+ default:
+ return TE_RESTART;
+ }
+}
- /* It's group-stop */
- if (use_seize) {
- /*
- * This ends ptrace-stop, but does *not* end group-stop.
- * This makes stopping signals work properly on straced process
- * (that is, process really stops. It used to continue to run).
- */
- if (ptrace_restart(PTRACE_LISTEN, tcp, 0) < 0) {
- /* Note: ptrace_restart emitted error message */
- exit_code = 1;
- return;
- }
- continue;
- }
- /* We don't have PTRACE_LISTEN support... */
- goto restart_tracee;
+static int
+trace_syscall(struct tcb *tcp, unsigned int *sig)
+{
+ if (entering(tcp)) {
+ int res = syscall_entering_decode(tcp);
+ switch (res) {
+ case 0:
+ return 0;
+ case 1:
+ res = syscall_entering_trace(tcp, sig);
+ }
+ syscall_entering_finish(tcp, res);
+ return res;
+ } else {
+ struct timeval tv = {};
+ int res = syscall_exiting_decode(tcp, &tv);
+ if (res != 0) {
+ res = syscall_exiting_trace(tcp, tv, res);
}
+ syscall_exiting_finish(tcp);
+ return res;
+ }
+}
- /* We handled quick cases, we are permitted to interrupt now. */
- if (interrupted)
- return;
+/* Returns true iff the main trace loop has to continue. */
+static bool
+dispatch_event(enum trace_event ret, int *pstatus, siginfo_t *si)
+{
+ unsigned int restart_op = PTRACE_SYSCALL;
+ unsigned int restart_sig = 0;
- /* This should be syscall entry or exit.
- * (Or it still can be that pesky post-execve SIGTRAP!)
- * Handle it.
- */
- if (trace_syscall(tcp) < 0) {
- /* ptrace() failed in trace_syscall().
+ switch (ret) {
+ case TE_BREAK:
+ return false;
+
+ case TE_NEXT:
+ return true;
+
+ case TE_RESTART:
+ break;
+
+ case TE_SYSCALL_STOP:
+ if (trace_syscall(current_tcp, &restart_sig) < 0) {
+ /*
+ * ptrace() failed in trace_syscall().
* Likely a result of process disappearing mid-flight.
* Observed case: exit_group() or SIGKILL terminating
* all processes in thread group.
* We assume that ptrace error was caused by process death.
- * We used to detach(tcp) here, but since we no longer
- * implement "detach before death" policy/hack,
+ * We used to detach(current_tcp) here, but since we no
+ * longer implement "detach before death" policy/hack,
* we can let this process to report its death to us
* normally, via WIFEXITED or WIFSIGNALED wait status.
*/
- continue;
+ return true;
}
- restart_tracee_with_sig_0:
- sig = 0;
- restart_tracee:
- if (ptrace_restart(PTRACE_SYSCALL, tcp, sig) < 0) {
- /* Note: ptrace_restart emitted error message */
- exit_code = 1;
- return;
+ break;
+
+ case TE_SIGNAL_DELIVERY_STOP:
+ restart_sig = WSTOPSIG(*pstatus);
+ print_stopped(current_tcp, si, restart_sig);
+ break;
+
+ case TE_SIGNALLED:
+ print_signalled(current_tcp, current_tcp->pid, *pstatus);
+ droptcb(current_tcp);
+ return true;
+
+ case TE_GROUP_STOP:
+ restart_sig = WSTOPSIG(*pstatus);
+ print_stopped(current_tcp, NULL, restart_sig);
+ if (use_seize) {
+ /*
+ * This ends ptrace-stop, but does *not* end group-stop.
+ * This makes stopping signals work properly on straced
+ * process (that is, process really stops. It used to
+ * continue to run).
+ */
+ restart_op = PTRACE_LISTEN;
+ restart_sig = 0;
}
- } /* while (1) */
-}
+ break;
-int
-main(int argc, char *argv[])
-{
- init(argc, argv);
+ case TE_EXITED:
+ print_exited(current_tcp, current_tcp->pid, *pstatus);
+ droptcb(current_tcp);
+ return true;
+
+ case TE_STOP_BEFORE_EXECVE:
+ /*
+ * Under Linux, execve changes pid to thread leader's pid,
+ * and we see this changed pid on EVENT_EXEC and later,
+ * execve sysexit. Leader "disappears" without exit
+ * notification. Let user know that, drop leader's tcb,
+ * and fix up pid in execve thread's tcb.
+ * Effectively, execve thread's tcb replaces leader's tcb.
+ *
+ * BTW, leader is 'stuck undead' (doesn't report WIFEXITED
+ * on exit syscall) in multithreaded programs exactly
+ * in order to handle this case.
+ *
+ * PTRACE_GETEVENTMSG returns old pid starting from Linux 3.0.
+ * On 2.6 and earlier, it can return garbage.
+ */
+ if (os_release >= KERNEL_VERSION(3, 0, 0))
+ current_tcp = maybe_switch_tcbs(current_tcp, current_tcp->pid);
+
+ if (detach_on_execve) {
+ if (current_tcp->flags & TCB_SKIP_DETACH_ON_FIRST_EXEC) {
+ current_tcp->flags &= ~TCB_SKIP_DETACH_ON_FIRST_EXEC;
+ } else {
+ detach(current_tcp); /* do "-b execve" thingy */
+ return true;
+ }
+ }
+ break;
+
+ case TE_STOP_BEFORE_EXIT:
+ print_event_exit(current_tcp);
+ break;
+ }
+
+ /* We handled quick cases, we are permitted to interrupt now. */
+ if (interrupted)
+ return false;
+
+ if (ptrace_restart(restart_op, current_tcp, restart_sig) < 0) {
+ /* Note: ptrace_restart emitted error message */
+ exit_code = 1;
+ return false;
+ }
+ return true;
+}
- /* Run main tracing loop */
- trace();
+#ifdef ENABLE_COVERAGE_GCOV
+extern void __gcov_flush(void);
+#endif
+static void ATTRIBUTE_NORETURN
+terminate(void)
+{
cleanup();
fflush(NULL);
if (shared_log != stderr)
/* Child was killed by a signal, mimic that. */
exit_code &= 0xff;
signal(exit_code, SIG_DFL);
+#ifdef ENABLE_COVERAGE_GCOV
+ __gcov_flush();
+#endif
raise(exit_code);
+
+ /* Unblock the signal. */
+ sigset_t mask;
+ sigemptyset(&mask);
+ sigaddset(&mask, exit_code);
+#ifdef ENABLE_COVERAGE_GCOV
+ __gcov_flush();
+#endif
+ sigprocmask(SIG_UNBLOCK, &mask, NULL);
+
/* Paranoia - what if this signal is not fatal?
Exit with 128 + signo then. */
exit_code += 128;
}
+ exit(exit_code);
+}
- return exit_code;
+int
+main(int argc, char *argv[])
+{
+ init(argc, argv);
+
+ exit_code = !nprocs;
+
+ int status;
+ siginfo_t si;
+ while (dispatch_event(next_event(&status, &si), &status, &si))
+ ;
+ terminate();
}