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, unsigned int flags)
  36{
  37        int fd;
  38        unsigned offset = f->offset;
  39
  40        if (offset) {
  41                SHA1_Update(&f->ctx, f->buffer, offset);
  42                sha1flush(f, offset);
  43                f->offset = 0;
  44        }
  45        if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
  46                /* write checksum and close fd */
  47                SHA1_Final(f->buffer, &f->ctx);
  48                if (result)
  49                        hashcpy(result, f->buffer);
  50                sha1flush(f, 20);
  51                if (flags & CSUM_FSYNC)
  52                        fsync_or_die(f->fd, f->name);
  53                if (close(f->fd))
  54                        die("%s: sha1 file error on close (%s)",
  55                            f->name, strerror(errno));
  56                fd = 0;
  57        } else
  58                fd = f->fd;
  59        free(f);
  60        return fd;
  61}
  62
  63int sha1write(struct sha1file *f, void *buf, unsigned int count)
  64{
  65        if (f->do_crc)
  66                f->crc32 = crc32(f->crc32, buf, count);
  67        while (count) {
  68                unsigned offset = f->offset;
  69                unsigned left = sizeof(f->buffer) - offset;
  70                unsigned nr = count > left ? left : count;
  71
  72                memcpy(f->buffer + offset, buf, nr);
  73                count -= nr;
  74                offset += nr;
  75                buf = (char *) buf + nr;
  76                left -= nr;
  77                if (!left) {
  78                        SHA1_Update(&f->ctx, f->buffer, offset);
  79                        sha1flush(f, offset);
  80                        offset = 0;
  81                }
  82                f->offset = offset;
  83        }
  84        return 0;
  85}
  86
  87struct sha1file *sha1fd(int fd, const char *name)
  88{
  89        return sha1fd_throughput(fd, name, NULL);
  90}
  91
  92struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
  93{
  94        struct sha1file *f = xmalloc(sizeof(*f));
  95        f->fd = fd;
  96        f->offset = 0;
  97        f->total = 0;
  98        f->tp = tp;
  99        f->name = name;
 100        f->do_crc = 0;
 101        SHA1_Init(&f->ctx);
 102        return f;
 103}
 104
 105void crc32_begin(struct sha1file *f)
 106{
 107        f->crc32 = crc32(0, Z_NULL, 0);
 108        f->do_crc = 1;
 109}
 110
 111uint32_t crc32_end(struct sha1file *f)
 112{
 113        f->do_crc = 0;
 114        return f->crc32;
 115}