Changeset 7892963

Timestamp:

Apr 27, 2010, 5:21:31 PM (14 years ago)

Author:

Anders Kaseorg <andersk@mit.edu>

Branches:

master, release-1.10, release-1.7, release-1.8, release-1.9

Children:

8479494

Parents:

72634c5

git-author:

Anders Kaseorg <andersk@mit.edu> (04/27/10 16:31:56)

git-committer:

Anders Kaseorg <andersk@mit.edu> (04/27/10 17:21:31)

Message:

Mark variables modified from signal handlers as volatile sig_atomic_t.

According to POSIX, this is the only type of variable (other than
errno) that may be accessed from a signal handler with defined
results.  In practice, at least the volatile is important to prevent
the compiler from reordering accesses.

err_signal_info is a bigger struct that cannot be assigned atomically,
but it’s only for debugging so we just do the best we can.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Nelson Elhage <nelhage@mit.edu>

Files:

• global.c (modified) (1 diff)
• owl.h (modified) (3 diffs)

global.c

@@ -937 +937 @@
     g->err_signal_info = *siginfo;
   } else {
-    memset(&(g->err_signal_info), 0, sizeof(siginfo_t));
+    siginfo_t si;
+    memset(&si, 0, sizeof(si));
+    g->err_signal_info = si;
   }
 }

owl.h

@@ -568 +568 @@
   int needrefresh;
   int rightshift;
-  int resizepending;
+  volatile sig_atomic_t resizepending;
   int recwinlines;
   char *thishost;
@@ -610 +610 @@
   int haveaim;
   int ignoreaimlogin;
-  int got_err_signal;       /* 1 if we got an unexpected signal */
-  siginfo_t err_signal_info;
+  volatile sig_atomic_t got_err_signal; /* 1 if we got an unexpected signal */
+  volatile siginfo_t err_signal_info;
   owl_zbuddylist zbuddies;
   owl_timer zephyr_buddycheck_timer;
@@ -623 +623 @@
   owl_timer *aim_nop_timer;
   int load_initial_subs;
-  int interrupted;
+  volatile sig_atomic_t interrupted;
 } owl_global;