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                        display_throughput(f->tp, ret);
  22                        buf = (char *) buf + ret;
  23                        count -= ret;
  24                        if (count)
  25                                continue;
  26                        return;
  27                }
  28                if (!ret)
  29                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  30                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  31        }
  32}
  33
  34int sha1close(struct sha1file *f, unsigned char *result, int final)
  35{
  36        int fd;
  37        unsigned offset = f->offset;
  38        if (offset) {
  39                SHA1_Update(&f->ctx, f->buffer, offset);
  40                sha1flush(f, offset);
  41                f->offset = 0;
  42        }
  43        if (final) {
  44                /* write checksum and close fd */
  45                SHA1_Final(f->buffer, &f->ctx);
  46                if (result)
  47                        hashcpy(result, f->buffer);
  48                sha1flush(f, 20);
  49                if (close(f->fd))
  50                        die("%s: sha1 file error on close (%s)",
  51                            f->name, strerror(errno));
  52                fd = 0;
  53        } else
  54                fd = f->fd;
  55        free(f);
  56        return fd;
  57}
  58
  59int sha1write(struct sha1file *f, void *buf, unsigned int count)
  60{
  61        if (f->do_crc)
  62                f->crc32 = crc32(f->crc32, buf, count);
  63        while (count) {
  64                unsigned offset = f->offset;
  65                unsigned left = sizeof(f->buffer) - offset;
  66                unsigned nr = count > left ? left : count;
  67
  68                memcpy(f->buffer + offset, buf, nr);
  69                count -= nr;
  70                offset += nr;
  71                buf = (char *) buf + nr;
  72                left -= nr;
  73                if (!left) {
  74                        SHA1_Update(&f->ctx, f->buffer, offset);
  75                        sha1flush(f, offset);
  76                        offset = 0;
  77                }
  78                f->offset = offset;
  79        }
  80        return 0;
  81}
  82
  83struct sha1file *sha1fd(int fd, const char *name)
  84{
  85        return sha1fd_throughput(fd, name, NULL);
  86}
  87
  88struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
  89{
  90        struct sha1file *f;
  91        unsigned len;
  92
  93        f = xmalloc(sizeof(*f));
  94
  95        len = strlen(name);
  96        if (len >= PATH_MAX)
  97                die("you wascally wabbit, you");
  98        f->namelen = len;
  99        memcpy(f->name, name, len+1);
 100
 101        f->fd = fd;
 102        f->error = 0;
 103        f->offset = 0;
 104        f->tp = tp;
 105        f->do_crc = 0;
 106        SHA1_Init(&f->ctx);
 107        return f;
 108}
 109
 110void crc32_begin(struct sha1file *f)
 111{
 112        f->crc32 = crc32(0, Z_NULL, 0);
 113        f->do_crc = 1;
 114}
 115
 116uint32_t crc32_end(struct sha1file *f)
 117{
 118        f->do_crc = 0;
 119        return f->crc32;
 120}