sigs.py: print signals for a process

Print pending, blocked, ignored and caught signals for a process.

1 files changed, 59 insertions, 0 deletions

diff --git a/sigs.py b/sigs.py
new file mode 100755
index 0000000..abad48f
--- /dev/null
+++ b/sigs.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""
+Prints the registered signals for a Linux process.
+"""
+import signal, subprocess, sys
+
+keyword = sys.argv[1]
+try:
+    pid = int(keyword)
+except ValueError:
+    pids = subprocess.check_output(["pgrep", keyword],
+            universal_newlines=True).split()
+    if len(pids) == 1:
+        pid = int(pids[0])
+    else:
+        if not pids:
+            print("No such process: %s", keyword)
+        else:
+            print("More than one process:", *pids)
+        sys.exit(1)
+
+def bits(n):
+    i = 0
+    while n:
+        if n & 1:
+            yield i
+        n >>= 1
+        i += 1
+
+def print_sigs(sigset):
+    # Note 32 and 33 are unusable, those are used by nptl(7):
+    sigs = {
+        32: "(NPTL thread cancellation)",
+        33: "(NPTL POSIX timers)",
+    }
+    for name in dir(signal):
+        if not name.startswith("SIG") or name.startswith("SIG_"):
+            continue
+        signum = int(getattr(signal, name))
+        sigs[signum] = name
+    for bit in bits(sigset):
+        signum = bit + 1
+        if signal.SIGRTMIN < signum <= signal.SIGRTMAX:
+            signame = "SIGRTMIN+%d" % (signum - signal.SIGRTMIN)
+        elif signum in sigs:
+            signame = sigs[signum]
+        else:
+            signame = "(signal %d)" % signum
+        print(" %016x %2d %s" % (1 << bit, signum, signame))
+
+with open("/proc/%d/status" % pid) as f:
+    for line in f:
+        if not any(line.startswith("Sig%s" % suffix)
+                for suffix in ("Pnd", "Blk", "Ign", "Cgt")):
+            continue
+        key, val = line.split()
+        sigset = int(val, 16)
+        print("%s %016x" % (key, sigset))
+        print_sigs(sigset)