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![brian m. carlson](/assets/img/avatar_default.png)
For all of our SHA-1 implementations and most of our SHA-256 implementations, the hash context we use is a real struct. For these implementations, it's possible to copy a hash context by making a copy of the struct. However, for our libgcrypt implementation, our hash context is a pointer. Consequently, copying it does not lead to an independent hash context like we intended. Fortunately, however, libgcrypt provides us with a handy function to copy hash contexts. Let's add a cloning function to the hash algorithm API, and use it in the one place we need to make a hash context copy. With this change, our libgcrypt SHA-256 implementation is fully functional with all of our other hash implementations. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
187 lines
4.1 KiB
C
187 lines
4.1 KiB
C
/*
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* csum-file.c
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*
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* Copyright (C) 2005 Linus Torvalds
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*
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* Simple file write infrastructure for writing SHA1-summed
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* files. Useful when you write a file that you want to be
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* able to verify hasn't been messed with afterwards.
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*/
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#include "cache.h"
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#include "progress.h"
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#include "csum-file.h"
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static void flush(struct hashfile *f, const void *buf, unsigned int count)
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{
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if (0 <= f->check_fd && count) {
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unsigned char check_buffer[8192];
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ssize_t ret = read_in_full(f->check_fd, check_buffer, count);
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if (ret < 0)
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die_errno("%s: sha1 file read error", f->name);
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if (ret != count)
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die("%s: sha1 file truncated", f->name);
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if (memcmp(buf, check_buffer, count))
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die("sha1 file '%s' validation error", f->name);
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}
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for (;;) {
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int ret = xwrite(f->fd, buf, count);
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if (ret > 0) {
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f->total += ret;
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display_throughput(f->tp, f->total);
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buf = (char *) buf + ret;
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count -= ret;
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if (count)
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continue;
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return;
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}
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if (!ret)
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die("sha1 file '%s' write error. Out of diskspace", f->name);
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die_errno("sha1 file '%s' write error", f->name);
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}
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}
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void hashflush(struct hashfile *f)
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{
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unsigned offset = f->offset;
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if (offset) {
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the_hash_algo->update_fn(&f->ctx, f->buffer, offset);
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flush(f, f->buffer, offset);
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f->offset = 0;
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}
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}
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int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int flags)
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{
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int fd;
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hashflush(f);
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the_hash_algo->final_fn(f->buffer, &f->ctx);
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if (result)
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hashcpy(result, f->buffer);
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if (flags & CSUM_HASH_IN_STREAM)
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flush(f, f->buffer, the_hash_algo->rawsz);
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if (flags & CSUM_FSYNC)
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fsync_or_die(f->fd, f->name);
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if (flags & CSUM_CLOSE) {
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if (close(f->fd))
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die_errno("%s: sha1 file error on close", f->name);
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fd = 0;
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} else
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fd = f->fd;
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if (0 <= f->check_fd) {
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char discard;
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int cnt = read_in_full(f->check_fd, &discard, 1);
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if (cnt < 0)
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die_errno("%s: error when reading the tail of sha1 file",
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f->name);
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if (cnt)
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die("%s: sha1 file has trailing garbage", f->name);
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if (close(f->check_fd))
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die_errno("%s: sha1 file error on close", f->name);
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}
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free(f);
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return fd;
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}
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void hashwrite(struct hashfile *f, const void *buf, unsigned int count)
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{
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while (count) {
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unsigned offset = f->offset;
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unsigned left = sizeof(f->buffer) - offset;
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unsigned nr = count > left ? left : count;
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const void *data;
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if (f->do_crc)
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f->crc32 = crc32(f->crc32, buf, nr);
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if (nr == sizeof(f->buffer)) {
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/* process full buffer directly without copy */
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data = buf;
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} else {
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memcpy(f->buffer + offset, buf, nr);
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data = f->buffer;
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}
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count -= nr;
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offset += nr;
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buf = (char *) buf + nr;
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left -= nr;
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if (!left) {
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the_hash_algo->update_fn(&f->ctx, data, offset);
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flush(f, data, offset);
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offset = 0;
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}
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f->offset = offset;
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}
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}
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struct hashfile *hashfd(int fd, const char *name)
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{
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return hashfd_throughput(fd, name, NULL);
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}
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struct hashfile *hashfd_check(const char *name)
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{
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int sink, check;
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struct hashfile *f;
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sink = open("/dev/null", O_WRONLY);
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if (sink < 0)
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die_errno("unable to open /dev/null");
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check = open(name, O_RDONLY);
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if (check < 0)
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die_errno("unable to open '%s'", name);
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f = hashfd(sink, name);
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f->check_fd = check;
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return f;
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}
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struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp)
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{
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struct hashfile *f = xmalloc(sizeof(*f));
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f->fd = fd;
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f->check_fd = -1;
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f->offset = 0;
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f->total = 0;
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f->tp = tp;
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f->name = name;
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f->do_crc = 0;
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the_hash_algo->init_fn(&f->ctx);
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return f;
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}
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void hashfile_checkpoint(struct hashfile *f, struct hashfile_checkpoint *checkpoint)
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{
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hashflush(f);
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checkpoint->offset = f->total;
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the_hash_algo->clone_fn(&checkpoint->ctx, &f->ctx);
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}
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int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint)
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{
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off_t offset = checkpoint->offset;
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if (ftruncate(f->fd, offset) ||
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lseek(f->fd, offset, SEEK_SET) != offset)
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return -1;
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f->total = offset;
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f->ctx = checkpoint->ctx;
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f->offset = 0; /* hashflush() was called in checkpoint */
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return 0;
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}
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void crc32_begin(struct hashfile *f)
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{
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f->crc32 = crc32(0, NULL, 0);
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f->do_crc = 1;
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}
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uint32_t crc32_end(struct hashfile *f)
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{
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f->do_crc = 0;
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return f->crc32;
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}
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