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/*
* csum-file.c
*
* Copyright (C) 2005 Linus Torvalds
*
* Simple file write infrastructure for writing SHA1-summed
* files. Useful when you write a file that you want to be
* able to verify hasn't been messed with afterwards.
*/
#include "cache.h"
#include "csum-file.h"
static int sha1flush(struct sha1file *f, unsigned int count)
{
void *buf = f->buffer;
for (;;) {
int ret = write(f->fd, buf, count);
if (ret > 0) {
buf += ret;
count -= ret;
if (count)
continue;
return 0;
}
if (!ret)
die("sha1 file write error. Out of diskspace");
if (errno == EAGAIN || errno == EINTR)
continue;
die("sha1 file write error (%s)", strerror(errno));
}
}
int sha1close(struct sha1file *f)
{
unsigned offset = f->offset;
if (offset) {
SHA1_Update(&f->ctx, f->buffer, offset);
sha1flush(f, offset);
}
SHA1_Final(f->buffer, &f->ctx);
sha1flush(f, 20);
return 0;
}
int sha1write(struct sha1file *f, void *buf, unsigned int count)
{
while (count) {
unsigned offset = f->offset;
unsigned left = sizeof(f->buffer) - offset;
unsigned nr = count > left ? left : count;
memcpy(f->buffer + offset, buf, nr);
count -= nr;
offset += nr;
left -= nr;
if (!left) {
SHA1_Update(&f->ctx, f->buffer, offset);
sha1flush(f, offset);
offset = 0;
}
f->offset = offset;
}
return 0;
}
struct sha1file *sha1create(const char *fmt, ...)
{
static char filename[PATH_MAX];
struct sha1file *f;
unsigned len;
va_list arg;
int fd;
va_start(arg, fmt);
len = vsnprintf(filename, PATH_MAX, fmt, arg);
va_end(arg);
if (len >= PATH_MAX)
die("you wascally wabbit, you");
fd = open(filename, O_CREAT | O_EXCL | O_WRONLY, 0644);
if (fd < 0)
die("unable to open %s (%s)", filename, strerror(errno));
f = xmalloc(sizeof(*f));
f->fd = fd;
f->error = 0;
f->offset = 0;
SHA1_Init(&f->ctx);
return f;
}
int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
{
z_stream stream;
unsigned long maxsize;
void *out;
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, Z_DEFAULT_COMPRESSION);
maxsize = deflateBound(&stream, size);
out = xmalloc(maxsize);
/* Compress it */
stream.next_in = in;
stream.avail_in = size;
stream.next_out = out;
stream.avail_out = maxsize;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
size = stream.total_out;
sha1write(f, out, size);
free(out);
return size;
}
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