Embedded systems support: no python on board but ssh access is available

README.md

@@ -15,7 +15,7 @@ can be run directly.
 Usage:
 
 ```
-ps_mem [-h|--help] [-p PID,...] [-s|--split-args] [-t|--total] [-w N]
+ps_mem [-h|--help] [-H [user@]host] [-p PID,...] [-s|--split-args] [-t|--total] [-w N]
        [-d|--discriminate-by-pid] [-S|--swap]
 ```
 
@@ -48,3 +48,17 @@ for i in $(ps -e -o user= | sort | uniq); do
   printf '%-20s%10s\n' $i $(sudo ps_mem --total -p $(pgrep -d, -u $i))
 done
 ```
+
+For embedded systems with no python on board with ssh access you could:
+
+```sh
+ps_mem.py -H root@192.168.31.95 -p 15106
+
+ Private  +   Shared  =  RAM used	Program
+
+ 78.4 MiB +   1.5 MiB =  79.9 MiB	cobalt_loader
+
+---------------------------------
+                         79.9 MiB
+=================================
+```

ps_mem.1

@@ -28,6 +28,9 @@ Show help message
 \-\-version
 Show version info
 .TP
+\-H [user@]host
+Connect to the remote host via SSH (key-based auth is required)
+.TP
 \-p PID[,PID2,...PIDN]
 Show memory consumption for the specified processes
 .TP

ps_mem.py

@@ -112,6 +112,39 @@ def write(self, data):
    def close(self):
        self.stream.close()
 
+class SSHProc:
+    def __init__(self, host, proc):
+        self.host = host
+        self.proc = proc
+
+    def path(self, *args):
+        return os.path.join(self.proc, *(str(a) for a in args))
+
+    def listdir(self, path):
+        import subprocess as sp
+        return sp.Popen(f"ssh {self.host} ls {path}".split(),
+                        stdout=sp.PIPE, stdin=sp.DEVNULL, stderr=sp.DEVNULL,
+                        encoding='utf-8').stdout.read().split()
+
+    def exists(self, path):
+        import subprocess as sp
+        return sp.Popen(f"ssh {self.host} test -f {path}".split(),
+                        stdout=sp.DEVNULL, stdin=sp.DEVNULL, stderr=sp.DEVNULL,
+                        encoding='utf-8').wait() == 0
+
+    def readlink(self, path):
+        import subprocess as sp
+        return sp.Popen(f"ssh {self.host} readlink -f {path}".split(),
+                        stdout=sp.PIPE, stdin=sp.DEVNULL, stderr=sp.DEVNULL,
+                        encoding='utf-8').stdout.read()
+
+    def open(self, *args):
+        import subprocess as sp
+        path = self.path(*args)
+        return sp.Popen(f"ssh {self.host} cat {path}".split(),
+                        stdout=sp.PIPE, stdin=sp.DEVNULL, stderr=sp.DEVNULL,
+                        encoding='utf-8').stdout
+
 class Proc:
     def __init__(self):
         uname = os.uname()
@@ -120,6 +153,15 @@ def __init__(self):
         else:
             self.proc = '/proc'
 
+    def listdir(self, path):
+        return os.listdir(path)
+
+    def exists(self, path):
+        return os.path.exists(path)
+
+    def readlink(self, path):
+        return os.readlink(path)
+
     def path(self, *args):
         return os.path.join(self.proc, *(str(a) for a in args))
 
@@ -139,8 +181,6 @@ def open(self, *args):
                 raise LookupError
             raise
 
-proc = Proc()
-
 
 #
 #   Functions
@@ -150,6 +190,12 @@ def parse_options():
     help_msg = 'Show program core memory usage.'
     parser = argparse.ArgumentParser(prog='ps_mem', description=help_msg)
     parser.add_argument('--version', action='version', version='3.14')
+    parser.add_argument(
+        '-H', '--host',
+        dest='host',
+        action='store',
+        help='The host to SSH to',
+    )
     parser.add_argument(
         '-s', '--split-args',
         action='store_true',
@@ -199,6 +245,7 @@ def parse_options():
             parser.error('Seconds must be positive! (%s)' % args.watch)
 
     return (
+        args.host,
         args.split_args,
         args.pids_to_show,
         args.watch,
@@ -244,9 +291,9 @@ def getMemStats(pid):
 
     Swap = 0
 
-    if os.path.exists(proc.path(pid, 'smaps')):  # stat
+    if proc.exists(proc.path(pid, 'smaps')):  # stat
         smaps = 'smaps'
-        if os.path.exists(proc.path(pid, 'smaps_rollup')):
+        if proc.exists(proc.path(pid, 'smaps_rollup')):
             smaps = 'smaps_rollup' # faster to process
         lines = proc.open(pid, smaps).readlines()  # open
         # Note we checksum smaps as maps is usually but
@@ -308,7 +355,7 @@ def getCmdName(pid, split_args, discriminate_by_pid, exe_only=False):
 
     path = proc.path(pid, 'exe')
     try:
-        path = os.readlink(path)
+        path = proc.readlink(path)
         # Some symlink targets were seen to contain NULs on RHEL 5 at least
         # https://github.com/pixelb/scripts/pull/10, so take string up to NUL
         path = path.split('\0')[0]
@@ -408,7 +455,7 @@ def val_accuracy(show_swap):
             return 1, swap_accuracy
         return 0, swap_accuracy
     elif kv[:2] == (2,6):
-        if os.path.exists(proc.path(pid, 'smaps')):
+        if proc.exists(proc.path(pid, 'smaps')):
             swap_accuracy = 1
             if proc.open(pid, 'smaps').read().find("Pss:")!=-1:
                 return 2, swap_accuracy
@@ -417,7 +464,7 @@ def val_accuracy(show_swap):
         if (2,6,1) <= kv <= (2,6,9):
             return -1, swap_accuracy
         return 0, swap_accuracy
-    elif kv[0] > 2 and os.path.exists(proc.path(pid, 'smaps')):
+    elif kv[0] > 2 and proc.exists(proc.path(pid, 'smaps')):
         swap_accuracy = 1
         if show_swap and proc.open(pid, 'smaps').read().find("SwapPss:")!=-1:
             swap_accuracy = 2
@@ -482,7 +529,7 @@ def get_memory_usage(pids_to_show, split_args, discriminate_by_pid,
     mem_ids = {}
     count = {}
     swaps = {}
-    for pid in os.listdir(proc.path('')):
+    for pid in proc.listdir(proc.path('')):
         if not pid.isdigit():
             continue
         pid = int(pid)
@@ -613,9 +660,15 @@ def main():
     sys.stdout = Unbuffered(sys.stdout)
     sys.stderr = Unbuffered(sys.stderr)
 
-    split_args, pids_to_show, watch, only_total, discriminate_by_pid, \
+    host, split_args, pids_to_show, watch, only_total, discriminate_by_pid, \
     show_swap = parse_options()
 
+    global proc
+    if host:
+       proc = SSHProc(host, "/proc")
+    else:
+       proc = Proc()
+
     verify_environment(pids_to_show)
 
     if not only_total: