git/t/helper/test-delta.c
Jeff King d65930c5a9 test-delta: read input into a heap buffer
We currently read the input to test-delta by mmap()-ing it.
However, memory-checking tools like valgrind and ASan are
less able to detect reads/writes past the end of an mmap'd
buffer, because the OS is likely to give us extra bytes to
pad out the final page size. So instead, let's read into a
heap buffer.

As a bonus, this also makes it possible to write tests with
empty bases, as mmap() will complain about a zero-length
map.

This is based on a patch by Jann Horn <jannh@google.com>
which actually aligned the data at the end of a page, and
followed it with another page marked with mprotect(). That
would detect problems even without a tool like ASan, but it
was significantly more complex and may have introduced
portability problems. By comparison, this approach pushes
the complexity onto existing memory-checking tools.

Note that this could be done even more simply by using
strbuf_read_file(), but that would defeat the purpose:
strbufs generally overallocate (and at the very least
include a trailing NUL which we do not care about), which
would defeat most memory checkers.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-30 10:30:21 -07:00

79 lines
1.8 KiB
C

/*
* test-delta.c: test code to exercise diff-delta.c and patch-delta.c
*
* (C) 2005 Nicolas Pitre <nico@fluxnic.net>
*
* This code is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "test-tool.h"
#include "git-compat-util.h"
#include "delta.h"
#include "cache.h"
static const char usage_str[] =
"test-tool delta (-d|-p) <from_file> <data_file> <out_file>";
int cmd__delta(int argc, const char **argv)
{
int fd;
struct stat st;
void *from_buf, *data_buf, *out_buf;
unsigned long from_size, data_size, out_size;
if (argc != 5 || (strcmp(argv[1], "-d") && strcmp(argv[1], "-p"))) {
fprintf(stderr, "usage: %s\n", usage_str);
return 1;
}
fd = open(argv[2], O_RDONLY);
if (fd < 0 || fstat(fd, &st)) {
perror(argv[2]);
return 1;
}
from_size = st.st_size;
from_buf = xmalloc(from_size);
if (read_in_full(fd, from_buf, from_size) < 0) {
perror(argv[2]);
close(fd);
return 1;
}
close(fd);
fd = open(argv[3], O_RDONLY);
if (fd < 0 || fstat(fd, &st)) {
perror(argv[3]);
return 1;
}
data_size = st.st_size;
data_buf = xmalloc(data_size);
if (read_in_full(fd, data_buf, data_size) < 0) {
perror(argv[3]);
close(fd);
return 1;
}
close(fd);
if (argv[1][1] == 'd')
out_buf = diff_delta(from_buf, from_size,
data_buf, data_size,
&out_size, 0);
else
out_buf = patch_delta(from_buf, from_size,
data_buf, data_size,
&out_size);
if (!out_buf) {
fprintf(stderr, "delta operation failed (returned NULL)\n");
return 1;
}
fd = open (argv[4], O_WRONLY|O_CREAT|O_TRUNC, 0666);
if (fd < 0 || write_in_full(fd, out_buf, out_size) < 0) {
perror(argv[4]);
return 1;
}
return 0;
}