Andrew's git - gitweb.git/blob

   1/*
   2 * csum-file.c
   3 *
   4 * Copyright (C) 2005 Linus Torvalds
   5 *
   6 * Simple file write infrastructure for writing SHA1-summed
   7 * files. Useful when you write a file that you want to be
   8 * able to verify hasn't been messed with afterwards.
   9 */
  10#include "cache.h"
  11#include "progress.h"
  12#include "csum-file.h"
  13
  14static void sha1flush(struct sha1file *f, void *buf, unsigned int count)
  15{
  16        for (;;) {
  17                int ret = xwrite(f->fd, buf, count);
  18                if (ret > 0) {
  19                        f->total += ret;
  20                        display_throughput(f->tp, f->total);
  21                        buf = (char *) buf + ret;
  22                        count -= ret;
  23                        if (count)
  24                                continue;
  25                        return;
  26                }
  27                if (!ret)
  28                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  29                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  30        }
  31}
  32
  33int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)
  34{
  35        int fd;
  36        unsigned offset = f->offset;
  37
  38        if (offset) {
  39                SHA1_Update(&f->ctx, f->buffer, offset);
  40                sha1flush(f, f->buffer, offset);
  41                f->offset = 0;
  42        }
  43        SHA1_Final(f->buffer, &f->ctx);
  44        if (result)
  45                hashcpy(result, f->buffer);
  46        if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
  47                /* write checksum and close fd */
  48                sha1flush(f, f->buffer, 20);
  49                if (flags & CSUM_FSYNC)
  50                        fsync_or_die(f->fd, f->name);
  51                if (close(f->fd))
  52                        die("%s: sha1 file error on close (%s)",
  53                            f->name, strerror(errno));
  54                fd = 0;
  55        } else
  56                fd = f->fd;
  57        free(f);
  58        return fd;
  59}
  60
  61int sha1write(struct sha1file *f, void *buf, unsigned int count)
  62{
  63        while (count) {
  64                unsigned offset = f->offset;
  65                unsigned left = sizeof(f->buffer) - offset;
  66                unsigned nr = count > left ? left : count;
  67                void *data;
  68
  69                if (f->do_crc)
  70                        f->crc32 = crc32(f->crc32, buf, nr);
  71
  72                if (nr == sizeof(f->buffer)) {
  73                        /* process full buffer directly without copy */
  74                        data = buf;
  75                } else {
  76                        memcpy(f->buffer + offset, buf, nr);
  77                        data = f->buffer;
  78                }
  79
  80                count -= nr;
  81                offset += nr;
  82                buf = (char *) buf + nr;
  83                left -= nr;
  84                if (!left) {
  85                        SHA1_Update(&f->ctx, data, offset);
  86                        sha1flush(f, data, offset);
  87                        offset = 0;
  88                }
  89                f->offset = offset;
  90        }
  91        return 0;
  92}
  93
  94struct sha1file *sha1fd(int fd, const char *name)
  95{
  96        return sha1fd_throughput(fd, name, NULL);
  97}
  98
  99struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 100{
 101        struct sha1file *f = xmalloc(sizeof(*f));
 102        f->fd = fd;
 103        f->offset = 0;
 104        f->total = 0;
 105        f->tp = tp;
 106        f->name = name;
 107        f->do_crc = 0;
 108        SHA1_Init(&f->ctx);
 109        return f;
 110}
 111
 112void crc32_begin(struct sha1file *f)
 113{
 114        f->crc32 = crc32(0, Z_NULL, 0);
 115        f->do_crc = 1;
 116}
 117
 118uint32_t crc32_end(struct sha1file *f)
 119{
 120        f->do_crc = 0;
 121        return f->crc32;
 122}