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e18088451d
Also, make the writing of the SHA1 as a end-header be conditional: not every user will necessarily want to write the SHA1 to the file itself, even though current users do (but we migh end up using the same helper functions for the object files themselves, that don't do this). This also makes the packed index file contain the SHA1 of the packed data file at the end (just before its own SHA1). That way you can validate the pairing of the two if you want to.
127 lines
2.6 KiB
C
127 lines
2.6 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 "csum-file.h"
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static int sha1flush(struct sha1file *f, unsigned int count)
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{
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void *buf = f->buffer;
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for (;;) {
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int ret = write(f->fd, buf, count);
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if (ret > 0) {
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buf += ret;
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count -= ret;
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if (count)
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continue;
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return 0;
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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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if (errno == EAGAIN || errno == EINTR)
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continue;
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die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
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}
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}
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int sha1close(struct sha1file *f, unsigned char *result, int update)
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{
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unsigned offset = f->offset;
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if (offset) {
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SHA1_Update(&f->ctx, f->buffer, offset);
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sha1flush(f, offset);
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}
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SHA1_Final(f->buffer, &f->ctx);
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if (result)
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memcpy(result, f->buffer, 20);
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if (update)
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sha1flush(f, 20);
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if (close(f->fd))
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die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
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return 0;
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}
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int sha1write(struct sha1file *f, 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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memcpy(f->buffer + offset, buf, nr);
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count -= nr;
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offset += nr;
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left -= nr;
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if (!left) {
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SHA1_Update(&f->ctx, f->buffer, offset);
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sha1flush(f, 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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return 0;
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}
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struct sha1file *sha1create(const char *fmt, ...)
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{
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struct sha1file *f;
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unsigned len;
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va_list arg;
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int fd;
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f = xmalloc(sizeof(*f));
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va_start(arg, fmt);
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len = vsnprintf(f->name, sizeof(f->name), fmt, arg);
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va_end(arg);
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if (len >= PATH_MAX)
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die("you wascally wabbit, you");
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f->namelen = len;
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fd = open(f->name, O_CREAT | O_EXCL | O_WRONLY, 0644);
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if (fd < 0)
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die("unable to open %s (%s)", f->name, strerror(errno));
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f->fd = fd;
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f->error = 0;
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f->offset = 0;
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SHA1_Init(&f->ctx);
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return f;
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}
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int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
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{
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z_stream stream;
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unsigned long maxsize;
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void *out;
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memset(&stream, 0, sizeof(stream));
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deflateInit(&stream, Z_DEFAULT_COMPRESSION);
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maxsize = deflateBound(&stream, size);
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out = xmalloc(maxsize);
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/* Compress it */
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stream.next_in = in;
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stream.avail_in = size;
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stream.next_out = out;
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stream.avail_out = maxsize;
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while (deflate(&stream, Z_FINISH) == Z_OK)
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/* nothing */;
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deflateEnd(&stream);
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size = stream.total_out;
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sha1write(f, out, size);
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free(out);
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return size;
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}
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