diff options
| -rw-r--r-- | Python/import.c | 177 |
1 files changed, 61 insertions, 116 deletions
diff --git a/Python/import.c b/Python/import.c index 0db7e43..1101c92 100644 --- a/Python/import.c +++ b/Python/import.c @@ -904,6 +904,25 @@ rightmost_sep(Py_UCS4 *s) return found; } +/* Like rightmost_sep, but operate on unicode objects. */ +static Py_ssize_t +rightmost_sep_obj(PyObject* o) +{ + Py_ssize_t found, i; + Py_UCS4 c; + for (found = -1, i = 0; i < PyUnicode_GET_LENGTH(o); i++) { + c = PyUnicode_READ_CHAR(o, i); + if (c == SEP +#ifdef ALTSEP + || c == ALTSEP +#endif + ) + { + found = i; + } + } + return found; +} /* Given a pathname for a Python source file, fill a buffer with the pathname for the corresponding compiled file. Return the pathname @@ -915,123 +934,49 @@ rightmost_sep(Py_UCS4 *s) static PyObject* make_compiled_pathname(PyObject *pathstr, int debug) { - Py_UCS4 *pathname; - Py_UCS4 buf[MAXPATHLEN]; - size_t buflen = (size_t)MAXPATHLEN; - size_t len; - size_t i, save; - Py_UCS4 *pos; - int sep = SEP; - - pathname = PyUnicode_AsUCS4Copy(pathstr); - if (!pathname) - return NULL; - len = Py_UCS4_strlen(pathname); - - /* Sanity check that the buffer has roughly enough space to hold what - will eventually be the full path to the compiled file. The 5 extra - bytes include the slash afer __pycache__, the two extra dots, the - extra trailing character ('c' or 'o') and null. This isn't exact - because the contents of the buffer can affect how many actual - characters of the string get into the buffer. We'll do a final - sanity check before writing the extension to ensure we do not - overflow the buffer. - */ - if (len + Py_UCS4_strlen(CACHEDIR_UNICODE) + Py_UCS4_strlen(PYC_TAG_UNICODE) + 5 > buflen) { - PyMem_Free(pathname); - return NULL; - } - - /* Find the last path separator and copy everything from the start of - the source string up to and including the separator. - */ - pos = rightmost_sep(pathname); - if (pos == NULL) { - i = 0; - } - else { - sep = *pos; - i = pos - pathname + 1; - Py_UCS4_strncpy(buf, pathname, i); - } - - save = i; - buf[i++] = '\0'; - /* Add __pycache__/ */ - Py_UCS4_strcat(buf, CACHEDIR_UNICODE); - i += Py_UCS4_strlen(CACHEDIR_UNICODE) - 1; - buf[i++] = sep; - buf[i] = '\0'; - /* Add the base filename, but remove the .py or .pyw extension, since - the tag name must go before the extension. - */ - Py_UCS4_strcat(buf, pathname + save); - pos = Py_UCS4_strrchr(buf + i, '.'); - if (pos != NULL) - *++pos = '\0'; - - /* pathname is not used from here on. */ - PyMem_Free(pathname); - - Py_UCS4_strcat(buf, PYC_TAG_UNICODE); - /* The length test above assumes that we're only adding one character - to the end of what would normally be the extension. What if there - is no extension, or the string ends in '.' or '.p', and otherwise - fills the buffer? By appending 4 more characters onto the string - here, we could overrun the buffer. - - As a simple example, let's say buflen=32 and the input string is - 'xxx.py'. strlen() would be 6 and the test above would yield: - - (6 + 11 + 10 + 5 == 32) > 32 - - which is false and so the name mangling would continue. This would - be fine because we'd end up with this string in buf: - - __pycache__/xxx.cpython-32.pyc\0 - - strlen(of that) == 30 + the nul fits inside a 32 character buffer. - We can even handle an input string of say 'xxxxx' above because - that's (5 + 11 + 10 + 5 == 31) > 32 which is also false. Name - mangling that yields: - - __pycache__/xxxxxcpython-32.pyc\0 - - which is 32 characters including the nul, and thus fits in the - buffer. However, an input string of 'xxxxxx' would yield a result - string of: - - __pycache__/xxxxxxcpython-32.pyc\0 - - which is 33 characters long (including the nul), thus overflowing - the buffer, even though the first test would fail, i.e.: the input - string is also 6 characters long, so 32 > 32 is false. - - The reason the first test fails but we still overflow the buffer is - that the test above only expects to add one extra character to be - added to the extension, and here we're adding three (pyc). We - don't add the first dot, so that reclaims one of expected - positions, leaving us overflowing by 1 byte (3 extra - 1 reclaimed - dot - 1 expected extra == 1 overflowed). - - The best we can do is ensure that we still have enough room in the - target buffer before we write the extension. Because it's always - only the extension that can cause the overflow, and never the other - path bytes we've written, it's sufficient to just do one more test - here. Still, the assertion that follows can't hurt. - */ -#if 0 - printf("strlen(buf): %d; buflen: %d\n", (int)strlen(buf), (int)buflen); -#endif - len = Py_UCS4_strlen(buf); - if (len + 5 > buflen) + PyObject *result; + Py_ssize_t fname, ext, len, i, pos, taglen; + Py_ssize_t pycache_len = sizeof("__pycache__/") - 1; + int kind; + void *data; + + /* Compute the output string size. */ + len = PyUnicode_GET_LENGTH(pathstr); + /* If there is no separator, this returns -1, so + lastsep will be 0. */ + fname = rightmost_sep_obj(pathstr) + 1; + ext = fname - 1; + for(i = fname; i < len; i++) + if (PyUnicode_READ_CHAR(pathstr, i) == '.') + ext = i + 1; + if (ext < fname) + /* No dot in filename; use entire filename */ + ext = len; + + /* result = pathstr[:fname] + "__pycache__" + SEP + + pathstr[fname:ext] + tag + ".py[co]" */ + taglen = strlen(pyc_tag); + result = PyUnicode_New(ext + pycache_len + taglen + 4, + PyUnicode_MAX_CHAR_VALUE(pathstr)); + if (!result) return NULL; - buf[len] = '.'; len++; - buf[len] = 'p'; len++; - buf[len] = 'y'; len++; - buf[len] = debug ? 'c' : 'o'; len++; - assert(len <= buflen); - return PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, buf, len); + kind = PyUnicode_KIND(result); + data = PyUnicode_DATA(result); + PyUnicode_CopyCharacters(result, 0, pathstr, 0, fname); + pos = fname; + for (i = 0; i < pycache_len - 1; i++) + PyUnicode_WRITE(kind, data, pos++, "__pycache__"[i]); + PyUnicode_WRITE(kind, data, pos++, SEP); + PyUnicode_CopyCharacters(result, pos, pathstr, + fname, ext - fname); + pos += ext - fname; + for (i = 0; pyc_tag[i]; i++) + PyUnicode_WRITE(kind, data, pos++, pyc_tag[i]); + PyUnicode_WRITE(kind, data, pos++, '.'); + PyUnicode_WRITE(kind, data, pos++, 'p'); + PyUnicode_WRITE(kind, data, pos++, 'y'); + PyUnicode_WRITE(kind, data, pos++, debug ? 'c' : 'o'); + return result; } |