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 "csum-file.h"
  12
  13static void sha1flush(struct sha1file *f, unsigned int count)
  14{
  15        void *buf = f->buffer;
  16
  17        for (;;) {
  18                int ret = xwrite(f->fd, buf, count);
  19                if (ret > 0) {
  20                        buf = (char *) buf + ret;
  21                        count -= ret;
  22                        if (count)
  23                                continue;
  24                        return;
  25                }
  26                if (!ret)
  27                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  28                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  29        }
  30}
  31
  32int sha1close(struct sha1file *f, unsigned char *result, int final)
  33{
  34        unsigned offset = f->offset;
  35        if (offset) {
  36                SHA1_Update(&f->ctx, f->buffer, offset);
  37                sha1flush(f, offset);
  38                f->offset = 0;
  39        }
  40        if (!final)
  41                return 0;       /* only want to flush (no checksum write, no close) */
  42        SHA1_Final(f->buffer, &f->ctx);
  43        if (result)
  44                hashcpy(result, f->buffer);
  45        sha1flush(f, 20);
  46        if (close(f->fd))
  47                die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
  48        free(f);
  49        return 0;
  50}
  51
  52int sha1write(struct sha1file *f, void *buf, unsigned int count)
  53{
  54        if (f->do_crc)
  55                f->crc32 = crc32(f->crc32, buf, count);
  56        while (count) {
  57                unsigned offset = f->offset;
  58                unsigned left = sizeof(f->buffer) - offset;
  59                unsigned nr = count > left ? left : count;
  60
  61                memcpy(f->buffer + offset, buf, nr);
  62                count -= nr;
  63                offset += nr;
  64                buf = (char *) buf + nr;
  65                left -= nr;
  66                if (!left) {
  67                        SHA1_Update(&f->ctx, f->buffer, offset);
  68                        sha1flush(f, offset);
  69                        offset = 0;
  70                }
  71                f->offset = offset;
  72        }
  73        return 0;
  74}
  75
  76struct sha1file *sha1fd(int fd, const char *name)
  77{
  78        struct sha1file *f;
  79        unsigned len;
  80
  81        f = xmalloc(sizeof(*f));
  82
  83        len = strlen(name);
  84        if (len >= PATH_MAX)
  85                die("you wascally wabbit, you");
  86        f->namelen = len;
  87        memcpy(f->name, name, len+1);
  88
  89        f->fd = fd;
  90        f->error = 0;
  91        f->offset = 0;
  92        f->do_crc = 0;
  93        SHA1_Init(&f->ctx);
  94        return f;
  95}
  96
  97void crc32_begin(struct sha1file *f)
  98{
  99        f->crc32 = crc32(0, Z_NULL, 0);
 100        f->do_crc = 1;
 101}
 102
 103uint32_t crc32_end(struct sha1file *f)
 104{
 105        f->do_crc = 0;
 106        return f->crc32;
 107}