]> granicus.if.org Git - strace/blobdiff - strace.c
x32: fix decoding of 3rd argument of preadv* and pwritev* syscalls
[strace] / strace.c
index 680456bf92052a6f54b85be10234ef0e600eea22..56fdfdee29aae98b2ce69bebc7903692b7334408 100644 (file)
--- a/strace.c
+++ b/strace.c
@@ -80,7 +80,8 @@ const unsigned int syscall_trap_sig = SIGTRAP | 0x80;
 
 cflag_t cflag = CFLAG_NONE;
 unsigned int followfork = 0;
-unsigned int ptrace_setoptions = PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEEXEC;
+unsigned int ptrace_setoptions = PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEEXEC
+                                | PTRACE_O_TRACEEXIT;
 unsigned int xflag = 0;
 bool debug_flag = 0;
 bool Tflag = 0;
@@ -133,10 +134,6 @@ bool not_failing_only = 0;
 unsigned int show_fd_path = 0;
 
 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 int exit_code;
 static int strace_child = 0;
@@ -229,7 +226,7 @@ Statistics:\n\
 \n\
 Filtering:\n\
   -e expr        a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
-     options:    trace, abbrev, verbose, raw, signal, read, write\n\
+     options:    trace, abbrev, verbose, raw, signal, read, write, fault\n\
   -P path        trace accesses to path\n\
 \n\
 Tracing:\n\
@@ -405,10 +402,8 @@ ptrace_restart(int op, struct tcb *tcp, int sig)
                msg = "CONT";
        if (op == PTRACE_DETACH)
                msg = "DETACH";
-#ifdef PTRACE_LISTEN
        if (op == PTRACE_LISTEN)
                msg = "LISTEN";
-#endif
        /*
         * Why curcol != 0? Otherwise sometimes we get this:
         *
@@ -787,6 +782,10 @@ droptcb(struct tcb *tcp)
        if (tcp->pid == 0)
                return;
 
+       int p;
+       for (p = 0; p < SUPPORTED_PERSONALITIES; ++p)
+               free(tcp->fault_vec[p]);
+
        free_tcb_priv_data(tcp);
 
 #ifdef USE_LIBUNWIND
@@ -836,10 +835,6 @@ detach(struct tcb *tcp)
         * 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;
@@ -1221,6 +1216,12 @@ exec_or_die(void)
        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)
 {
@@ -1229,9 +1230,56 @@ open_dummy_desc(void)
        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)
 {
@@ -1367,17 +1415,17 @@ startup_child(char **argv)
                                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, the tracee is our parent. */
                strace_child = strace_tracer_pid;
                strace_tracer_pid = getpid();
-               alloctcb(strace_child);
+               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! */
 
@@ -1409,18 +1457,11 @@ startup_child(char **argv)
         * 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 closing strace's stdin/out.
+        * 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").
         */
-       close(0);
-       open_dummy_desc(); /* opens to fd#0 */
-       dup2(0, 1);
-#if 0
-       /* A good idea too, but we sometimes need to print error messages */
-       if (shared_log != stderr)
-               dup2(0, 2);
-#endif
+       redirect_standard_fds();
 }
 
 #if USE_SEIZE
@@ -1598,7 +1639,7 @@ init(int argc, char *argv[])
                        break;
                case 'r':
                        rflag = 1;
-                       /* fall through to tflag++ */
+                       break;
                case 't':
                        tflag++;
                        break;
@@ -1669,8 +1710,8 @@ init(int argc, char *argv[])
                                die_out_of_memory();
                        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:
@@ -1721,9 +1762,21 @@ init(int argc, char *argv[])
                        error_msg("-%c has no effect with -c", 'y');
        }
 
+       if (rflag) {
+               if (tflag > 1)
+                       error_msg("-tt has no effect with -r");
+               tflag = 1;
+       }
+
 #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. */
@@ -1753,24 +1806,18 @@ init(int argc, char *argv[])
                error_msg("ptrace_setoptions = %#x", ptrace_setoptions);
        test_ptrace_seize();
 
-       if (fcntl(0, F_GETFD) == -1 || fcntl(1, F_GETFD) == -1) {
-               /*
-                * Something weird with our stdin and/or stdout -
-                * for example, may 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.
-                */
-               int fd = open_dummy_desc();
-               while (fd >= 0 && fd < 2)
-                       fd = dup(fd);
-               if (fd > 2)
-                       close(fd);
-       }
+       /*
+        * 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) {
@@ -1793,8 +1840,7 @@ init(int argc, char *argv[])
        }
 
        if (!outfname || outfname[0] == '|' || outfname[0] == '!') {
-               char *buf = xmalloc(BUFSIZ);
-               setvbuf(shared_log, buf, _IOLBF, BUFSIZ);
+               setvbuf(shared_log, NULL, _IOLBF, 0);
        }
        if (outfname && argv[0]) {
                if (!opt_intr)
@@ -1821,9 +1867,6 @@ init(int argc, char *argv[])
         * 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);
        }
 
@@ -2057,8 +2100,7 @@ print_signalled(struct tcb *tcp, const int pid, int status)
        }
 
        if (cflag != CFLAG_ONLY_STATS
-        && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)
-       ) {
+           && is_number_in_set(WTERMSIG(status), &signal_set)) {
                printleader(tcp);
 #ifdef WCOREDUMP
                tprintf("+++ killed by %s %s+++\n",
@@ -2092,9 +2134,8 @@ static void
 print_stopped(struct tcb *tcp, const siginfo_t *si, const unsigned int sig)
 {
        if (cflag != CFLAG_ONLY_STATS
-           && !hide_log_until_execve
-           && (qual_flags[sig] & QUAL_SIGNAL)
-          ) {
+           && !hide_log(tcp)
+           && is_number_in_set(sig, &signal_set)) {
                printleader(tcp);
                if (si) {
                        tprintf("--- %s ", signame(sig));
@@ -2127,6 +2168,43 @@ startup_tcb(struct tcb *tcp)
        }
 }
 
+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();
+}
+
 /* Returns true iff the main trace loop has to continue. */
 static bool
 trace(void)
@@ -2228,11 +2306,14 @@ trace(void)
                if (os_release >= KERNEL_VERSION(3,0,0))
                        tcp = maybe_switch_tcbs(tcp, pid);
 
-               if (detach_on_execve && !skip_one_b_execve) {
-                       detach(tcp); /* do "-b execve" thingy */
-                       return true;
+               if (detach_on_execve) {
+                       if (tcp->flags & TCB_SKIP_DETACH_ON_FIRST_EXEC) {
+                               tcp->flags &= ~TCB_SKIP_DETACH_ON_FIRST_EXEC;
+                       } else {
+                               detach(tcp); /* do "-b execve" thingy */
+                               return true;
+                       }
                }
-               skip_one_b_execve = 0;
        }
 
        /* Set current output file */
@@ -2274,10 +2355,14 @@ trace(void)
 
        sig = WSTOPSIG(status);
 
-       if (event != 0) {
-               /* Ptrace event */
+       switch (event) {
+               case 0:
+                       break;
+               case PTRACE_EVENT_EXIT:
+                       print_event_exit(tcp);
+                       goto restart_tracee_with_sig_0;
 #if USE_SEIZE
-               if (event == PTRACE_EVENT_STOP) {
+               case PTRACE_EVENT_STOP:
                        /*
                         * PTRACE_INTERRUPT-stop or group-stop.
                         * PTRACE_INTERRUPT-stop has sig == SIGTRAP here.
@@ -2290,9 +2375,10 @@ trace(void)
                                        stopped = true;
                                        goto show_stopsig;
                        }
-               }
+                       /* fall through */
 #endif
-               goto restart_tracee_with_sig_0;
+               default:
+                       goto restart_tracee_with_sig_0;
        }
 
        /*