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, unsigned int count)
  15{
  16        void *buf = f->buffer;
  17
  18        for (;;) {
  19                int ret = xwrite(f->fd, buf, count);
  20                if (ret > 0) {
  21                        f->total += ret;
  22                        display_throughput(f->tp, f->total);
  23                        buf = (char *) buf + ret;
  24                        count -= ret;
  25                        if (count)
  26                                continue;
  27                        return;
  28                }
  29                if (!ret)
  30                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  31                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  32        }
  33}
  34
  35int sha1close(struct sha1file *f, unsigned char *result, int final)
  36{
  37        int fd;
  38        unsigned offset = f->offset;
  39        if (offset) {
  40                SHA1_Update(&f->ctx, f->buffer, offset);
  41                sha1flush(f, offset);
  42                f->offset = 0;
  43        }
  44        if (final) {
  45                /* write checksum and close fd */
  46                SHA1_Final(f->buffer, &f->ctx);
  47                if (result)
  48                        hashcpy(result, f->buffer);
  49                sha1flush(f, 20);
  50                if (close(f->fd))
  51                        die("%s: sha1 file error on close (%s)",
  52                            f->name, strerror(errno));
  53                fd = 0;
  54        } else
  55                fd = f->fd;
  56        free(f);
  57        return fd;
  58}
  59
  60int sha1write(struct sha1file *f, void *buf, unsigned int count)
  61{
  62        if (f->do_crc)
  63                f->crc32 = crc32(f->crc32, buf, count);
  64        while (count) {
  65                unsigned offset = f->offset;
  66                unsigned left = sizeof(f->buffer) - offset;
  67                unsigned nr = count > left ? left : count;
  68
  69                memcpy(f->buffer + offset, buf, nr);
  70                count -= nr;
  71                offset += nr;
  72                buf = (char *) buf + nr;
  73                left -= nr;
  74                if (!left) {
  75                        SHA1_Update(&f->ctx, f->buffer, offset);
  76                        sha1flush(f, offset);
  77                        offset = 0;
  78                }
  79                f->offset = offset;
  80        }
  81        return 0;
  82}
  83
  84struct sha1file *sha1fd(int fd, const char *name)
  85{
  86        return sha1fd_throughput(fd, name, NULL);
  87}
  88
  89struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
  90{
  91        struct sha1file *f = xmalloc(sizeof(*f));
  92        f->fd = fd;
  93        f->offset = 0;
  94        f->total = 0;
  95        f->tp = tp;
  96        f->name = name;
  97        f->do_crc = 0;
  98        SHA1_Init(&f->ctx);
  99        return f;
 100}
 101
 102void crc32_begin(struct sha1file *f)
 103{
 104        f->crc32 = crc32(0, Z_NULL, 0);
 105        f->do_crc = 1;
 106}
 107
 108uint32_t crc32_end(struct sha1file *f)
 109{
 110        f->do_crc = 0;
 111        return f->crc32;
 112}