[snapshot/master] Revert "user mmap for hasher.c"

[Peter Palfrader <peter@palfrader.org>]

This reverts commit 1c75e02a1810e1d7cb0df4b5485061bc9c2e2447.

This mmap thing isn't any faster and it's more error prone (suddenly we
need to worry about filesizes etc.).
---
 fsck/check-1/hasher.c |   42 +++++++++++++++---------------------------
 1 files changed, 15 insertions(+), 27 deletions(-)

diff --git a/fsck/check-1/hasher.c b/fsck/check-1/hasher.c
index 20151f9..9d37a06 100644
--- a/fsck/check-1/hasher.c
+++ b/fsck/check-1/hasher.c
@@ -1,6 +1,5 @@
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <sys/mman.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -12,7 +11,7 @@
 #include <Python.h>
 
 #define SHA1SIZE 20
-#define MAX_MMAP (64*1024*1024)
+#define BLOCKSIZE (64*1024)
 
 
 static PyObject *HasherError;
@@ -36,16 +35,13 @@ static PyObject *HasherError;
 static PyObject *hash_file(PyObject *self, PyObject *args)
 {
 	const char *filename;
-	int fd;
-	struct stat st_buf;
-	unsigned char *map;
+	int fd, num_read;
+	unsigned char ibuf[BLOCKSIZE];
 	unsigned char obuf[SHA1SIZE];
 	SHA_CTX ctx;
 	PyObject *res = NULL;
 	PyThreadState *_save;
 	char res_s[2*SHA1SIZE + 1];
-	size_t this_len = 0;
-	off_t off = 0;
 	int r;
 
 	if (!PyArg_ParseTuple(args, "s", &filename))
@@ -56,7 +52,6 @@ static PyObject *hash_file(PyObject *self, PyObject *args)
 
 	fd = open(filename, O_RDONLY | O_LARGEFILE);
 	if (fd < 0) py_err("Cannot open file", filename);
-	if (fstat(fd, &st_buf) < 0) py_err("Cannot fstat file", filename);
 
 	posix_fadvise(fd, 0, 0, POSIX_FADV_NOREUSE);
 	//posix_fadvise(fd, 0, 0, POSIX_FADV_WILLNEED);
@@ -64,28 +59,21 @@ static PyObject *hash_file(PyObject *self, PyObject *args)
 
 	if (SHA1_Init(&ctx) != 1)
 		py_err("SHA1_Init()", NULL);
-
-	while (off < st_buf.st_size) {
-		this_len = st_buf.st_size - off;
-		if (this_len > MAX_MMAP) this_len = MAX_MMAP;
-		map = mmap(NULL, this_len, PROT_READ, MAP_SHARED, fd, off);
-		if (map == MAP_FAILED) py_err("mmap failed", filename);
-
-		//posix_madvise(map, this_len, POSIX_MADV_WILLNEED);
-		posix_madvise(map, this_len, POSIX_MADV_SEQUENTIAL);
-
-		if (SHA1_Update(&ctx, map, this_len) != 1)
+	while ((num_read = read(fd, ibuf, BLOCKSIZE))) {
+		if (num_read < 0) {
+			if (errno == EINTR)
+				continue;
+			else
+				py_err("During read", filename);
+		}
+		if (SHA1_Update(&ctx, ibuf, num_read) != 1)
 			py_err("SHA1_Update", NULL);
-
-		posix_madvise(map, this_len, POSIX_MADV_DONTNEED);
-		if (munmap(map, this_len) < 0) py_err("munmap failed", filename);
-		off += this_len;
 	}
-	posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
-	if (close(fd) < 0)
-		py_err("Cannot close bar", filename);
 	if (SHA1_Final(obuf, &ctx) != 1)
 		py_err("SHA1_Final", NULL);
+	posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
+	if (close(fd) < 0)
+		py_err("Cannot open bar", filename);
 
 	r = snprintf(res_s, sizeof(res_s),
 	             "%02x%02x%02x%02x%02x"
@@ -97,7 +85,7 @@ static PyObject *hash_file(PyObject *self, PyObject *args)
 	    obuf[10], obuf[11], obuf[12], obuf[13], obuf[14],
 	    obuf[15], obuf[16], obuf[17], obuf[18], obuf[19]);
 	if (r >= sizeof(res_s)) {
-		printf("%d vs %ld\n", r, sizeof(res_s));
+		printf("%d vs %d\n", r, sizeof(res_s));
 		py_err("snprintf failure", filename);
 	}
 
-- 
1.5.6.5