process: add subprocess-based bits

Signed-off-by: Chris Larson <chris_larson@mentor.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/lib/bb/process.py b/lib/bb/process.py
new file mode 100644
index 000000000..b022e4c8f
--- /dev/null
+++ b/lib/bb/process.py
@@ -0,0 +1,107 @@
+import subprocess
+import signal
+import logging
+
+logger = logging.getLogger('BitBake.Process')
+
+def subprocess_setup():
+    # Python installs a SIGPIPE handler by default. This is usually not what
+    # non-Python subprocesses expect.
+    print('in preexec hook')
+    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+class CmdError(RuntimeError):
+    def __init__(self, command):
+        self.command = command
+
+    def __str__(self):
+        if not isinstance(self.command, basestring):
+            cmd = subprocess.list2cmdline(self.command)
+        else:
+            cmd = self.command
+
+        return "Execution of '%s' failed" % cmd
+
+class NotFoundError(CmdError):
+    def __str__(self):
+        return CmdError.__str__(self) + ": command not found"
+
+class ExecutionError(CmdError):
+    def __init__(self, command, exitcode, stdout = None, stderr = None):
+        CmdError.__init__(self, command)
+        self.exitcode = exitcode
+        self.stdout = stdout
+        self.stderr = stderr
+
+    def __str__(self):
+        message = ""
+        if self.stderr:
+            message += self.stderr
+        if self.stdout:
+            message += self.stdout
+        if message:
+            message = ":\n" + message
+        return (CmdError.__str__(self) +
+                " with exit code %s" % self.exitcode + message)
+
+class Popen(subprocess.Popen):
+    defaults = {
+        "close_fds": True,
+        "preexec_fn": subprocess_setup,
+        "stdout": subprocess.PIPE,
+        "stderr": subprocess.STDOUT,
+        "stdin": subprocess.PIPE,
+        "shell": False,
+    }
+
+    def __init__(self, *args, **kwargs):
+        options = dict(self.defaults)
+        options.update(kwargs)
+        subprocess.Popen.__init__(self, *args, **options)
+
+def _logged_communicate(pipe, log, input):
+    bufsize = 512
+    hasoutput = pipe.stdout is not None or pipe.stderr is not None
+    if hasoutput:
+        outdata, errdata = [], []
+        while pipe.poll() is None:
+            if pipe.stdout is not None:
+                data = pipe.stdout.read(bufsize)
+                if data is not None:
+                    outdata.append(data)
+                    log.write(data)
+
+            if pipe.stderr is not None:
+                data = pipe.stderr.read(bufsize)
+                if data is not None:
+                    errdata.append(data)
+                    log.write(data)
+        return ''.join(outdata), ''.join(errdata)
+
+def run(cmd, input=None, **options):
+    """Convenience function to run a command and return its output, raising an
+    exception when the command fails"""
+
+    if isinstance(cmd, basestring) and not "shell" in options:
+        options["shell"] = True
+
+    log = options.get('log')
+    if log:
+        del options['log']
+
+    try:
+        pipe = Popen(cmd, **options)
+    except OSError, exc:
+        if exc.errno == 2:
+            raise NotFoundError(cmd)
+        else:
+            raise
+
+    if log:
+        stdout, stderr = _logged_communicate(pipe, log, input)
+    else:
+        stdout, stderr = pipe.communicate(input)
+
+    if pipe.returncode != 0:
+        raise ExecutionError(cmd, pipe.returncode, stdout, stderr)
+    return stdout, stderr