SSH and telnet library

[monitor.git] / pyssh / fssa.py

diff --git a/pyssh/fssa.py b/pyssh/fssa.py
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+++ b/pyssh/fssa.py
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+# vi:et:ts=4:tw=0
+""" fssa.py
+
+    Search for an ssh-agent for the calling user and attach to it
+    if found.
+
+    Tested on poxix only
+"""
+# This is a Python port of Steve Allen's fsa.sh script found
+# at http://www.ucolick.org/~sla/ssh/sshcron.html
+# Ported by Mark W. Alexander <slash@dotnetslash.net>
+
+import os
+if os.name == 'posix':
+    import pwd, stat, sys
+    from commands import getoutput
+    def fssa(key=None):
+        """ fssa(key=None)
+
+        Searches /tmp/ssh-* owned by the calling user for ssh-agent
+        sockets. If key is provided, only sockets matching the key will be
+        considered. If key is not provided, the calling users username
+        will be used instead.
+        """
+        user, pw, uid, gid, gecos, home, shell = pwd.getpwuid(os.getuid())
+        if key is None:
+            key = user
+
+        # Find /tmp/ssh-* dirs owned by this user
+        candidate_dirs=[]
+        for filename in os.listdir('/tmp'):
+            file_stat = os.stat("/tmp/%s" % (filename))
+            if file_stat[stat.ST_UID] == os.getuid() \
+            and stat.S_ISDIR(file_stat[stat.ST_MODE]) \
+            and filename.find('ssh-') == 0:
+                candidate_dirs.append("/tmp/%s" % filename)
+
+        candidate_sockets=[]
+        for d in candidate_dirs:
+            for f in os.listdir(d):
+                file_stat = os.stat("%s/%s" % (d, f))
+                if file_stat[stat.ST_UID] == os.getuid() \
+                and stat.S_ISSOCK(file_stat[stat.ST_MODE]) \
+                and f.find('agent.') == 0:
+                    candidate_sockets.append("%s/%s" % (d, f))
+        alive = None
+        # order by pid, prefering sockets where the parent pid
+        # is gone. This gives preference to agents running in the
+        # background and reaped by init (maybe). Only works on
+        # systems with a /proc filesystem
+        if stat.S_ISDIR(os.stat("/proc")[stat.ST_MODE]):
+            reorder=[]
+            for s in candidate_sockets:
+                pid = s[s.find('.')+1:]
+                try:
+                    stat.S_ISDIR(os.stat("/proc/%s" % pid)[stat.ST_MODE])
+                    reorder.append(s)
+                except:
+                    reorder.insert(0,s)
+            candidate_sockets = reorder
+
+        for s in candidate_sockets:
+            os.environ['SSH_AUTH_SOCK'] = s
+            try:
+                pubkey = getoutput("ssh-add -l 2>/dev/null")
+            except:
+                continue
+            if pubkey.find(key):
+                alive = 1
+                break
+            os.environ.pop('SSH_AUTH_SOCK')
+        if alive:
+            return pubkey
+        else:
+            return None