Recognize pyc files even if they don't end in pyc.

Patch #103067 with modifications as discussed in email.

diff --git a/Misc/NEWS b/Misc/NEWS
index 8f6610615615d9cdea2c23dc45ace89cb689fa5f..d2dfbec7d1b32ac1eda522ecb0bcda3e3e709c71 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -3,6 +3,14 @@ What's New in Python 2.1 alpha 1?
 
 Core language, builtins, and interpreter
 
+- The interpreter accepts now bytecode files on the command line even
+  if they do not have a .pyc or .pyo extension. On Linux, after executing
+
+  echo ':pyc:M::\x87\xc6\x0d\x0a::/usr/local/bin/python:' > /proc/sys/fs/binfmt_misc/register
+
+  any byte code file can be used as an executable (i.e. as an argument
+  to execve(2)).
+
 - %[xXo] formats of negative Python longs now produce a sign
   character.  In 1.6 and earlier, they never produced a sign,
   and raised an error if the value of the long was too large

diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index e29e719d10946630fae582b493c5d2f8cb47573b..45d21dd772090b7b0f26a2fdf283cbb5ac7d4d24 100644 (file)
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -546,6 +546,38 @@ PyRun_SimpleFile(FILE *fp, char *filename)
        return PyRun_SimpleFileEx(fp, filename, 0);
 }
 
+/* Check whether a file maybe a pyc file: Look at the extension,
+   the file type, and, if we may close it, at the first few bytes. */
+
+static int
+maybe_pyc_file(FILE *fp, char* filename, char* ext, int closeit)
+{
+       if (strcmp(ext, ".pyc") == 0 || strcmp(ext, ".pyo") == 0)
+               return 1;
+
+#ifdef macintosh
+       /* On a mac, we also assume a pyc file for types 'PYC ' and 'APPL' */
+       if (PyMac_getfiletype(filename) == 'PYC '
+           || PyMac_getfiletype(filename) == 'APPL')
+               return 1;
+#endif /* macintosh */
+
+       /* Only look into the file if we are allowed to close it, since
+          it then should also be seekable. */
+       if (closeit) {
+               /* Read only two bytes of the magic. If the file was opened in
+                  text mode, the bytes 3 and 4 of the magic (\r\n) might not
+                  be read as they are on disk. */
+               unsigned int halfmagic = PyImport_GetMagicNumber() & 0xFFFF;
+               unsigned char buf[2];
+               if (fread(buf, 1, 2, fp) == 2 
+                   && (buf[1]<<8 | buf[0]) == halfmagic)
+                       return 1;
+               fseek(fp, 0, SEEK_SET);
+       }
+       return 0;
+} 
+
 int
 PyRun_SimpleFileEx(FILE *fp, char *filename, int closeit)
 {
@@ -557,13 +589,7 @@ PyRun_SimpleFileEx(FILE *fp, char *filename, int closeit)
                return -1;
        d = PyModule_GetDict(m);
        ext = filename + strlen(filename) - 4;
-       if (strcmp(ext, ".pyc") == 0 || strcmp(ext, ".pyo") == 0
-#ifdef macintosh
-       /* On a mac, we also assume a pyc file for types 'PYC ' and 'APPL' */
-           || PyMac_getfiletype(filename) == 'PYC '
-           || PyMac_getfiletype(filename) == 'APPL'
-#endif /* macintosh */
-               ) {
+       if (maybe_pyc_file(fp, filename, ext, closeit)) {
                /* Try to run a pyc file. First, re-open in binary */
                if (closeit)
                        fclose(fp);