зеркало из https://github.com/microsoft/git.git
148 строки
2.9 KiB
C
148 строки
2.9 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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buf += 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, 0666);
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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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struct sha1file *sha1fd(int fd, const char *name)
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{
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struct sha1file *f;
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unsigned len;
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f = xmalloc(sizeof(*f));
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len = strlen(name);
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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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memcpy(f->name, name, len+1);
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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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