Fix unblocking of signals in interactive mode

In interactive mode (-I2), those signals that were blocked at startup
will remain blocked for the whole period of strace execution.

* strace.c (empty_set): Rename to start_set.  All users changed.
(init): Initialize start_set and blocked_set to the set of currently
blocked signals.
(startup_attach, trace): Use SIG_SETMASK instead of SIG_BLOCK.
* NEWS: Mention this change.

diff --git a/NEWS b/NEWS
index e6f2ccd0191ef38531035a1e0098dadc7a9d5da6..80479a15b7481f6585c8c80dd4e338f3d5359414 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,10 @@
 Noteworthy changes in release ?.?? (????-??-??)
 ===============================================
 
+* Bug fixes
+  * In interactive mode (-I2), those signals that were blocked at startup
+    will remain blocked for the whole period of strace execution.
+
 Noteworthy changes in release 4.17 (2017-05-24)
 ===============================================
 

diff --git a/strace.c b/strace.c
index e41c0da898ead351d3eff26cbde9a2cbd304e1da..59683d348d4d353c589c483a9db648c1ecc1395c 100644 (file)
--- a/strace.c
+++ b/strace.c
@@ -158,7 +158,7 @@ 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;
@@ -1128,7 +1128,7 @@ startup_attach(void)
         * 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();
@@ -1170,10 +1170,10 @@ startup_attach(void)
                attach_tcb(tcp);
 
                if (interactive) {
-                       sigprocmask(SIG_SETMASK, &empty_set, NULL);
+                       sigprocmask(SIG_SETMASK, &start_set, NULL);
                        if (interrupted)
                                goto ret;
-                       sigprocmask(SIG_BLOCK, &blocked_set, NULL);
+                       sigprocmask(SIG_SETMASK, &blocked_set, NULL);
                }
        } /* for each tcbtab[] */
 
@@ -1188,7 +1188,7 @@ startup_attach(void)
 
  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
@@ -1885,6 +1885,15 @@ init(int argc, char *argv[])
        if (!outfname || outfname[0] == '|' || outfname[0] == '!') {
                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;
@@ -1894,17 +1903,11 @@ init(int argc, char *argv[])
        if (!opt_intr)
                opt_intr = INTR_WHILE_WAIT;
 
-       /* 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
-        */
-
-       sigemptyset(&empty_set);
-       sigemptyset(&blocked_set);
+       sigprocmask(SIG_SETMASK, NULL, &start_set);
+       memcpy(&blocked_set, &start_set, sizeof(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.
@@ -2289,11 +2292,11 @@ trace(void)
        }
 
        if (interactive)
-               sigprocmask(SIG_SETMASK, &empty_set, NULL);
+               sigprocmask(SIG_SETMASK, &start_set, NULL);
        pid = wait4(-1, &status, __WALL, (cflag ? &ru : NULL));
        wait_errno = errno;
        if (interactive)
-               sigprocmask(SIG_BLOCK, &blocked_set, NULL);
+               sigprocmask(SIG_SETMASK, &blocked_set, NULL);
 
        if (pid < 0) {
                if (wait_errno == EINTR)