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 update)
  33{
  34        unsigned offset = f->offset;
  35        if (offset) {
  36                SHA1_Update(&f->ctx, f->buffer, offset);
  37                sha1flush(f, offset);
  38        }
  39        SHA1_Final(f->buffer, &f->ctx);
  40        if (result)
  41                hashcpy(result, f->buffer);
  42        if (update)
  43                sha1flush(f, 20);
  44        if (close(f->fd))
  45                die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
  46        free(f);
  47        return 0;
  48}
  49
  50int sha1write(struct sha1file *f, void *buf, unsigned int count)
  51{
  52        if (f->do_crc)
  53                f->crc32 = crc32(f->crc32, buf, count);
  54        while (count) {
  55                unsigned offset = f->offset;
  56                unsigned left = sizeof(f->buffer) - offset;
  57                unsigned nr = count > left ? left : count;
  58
  59                memcpy(f->buffer + offset, buf, nr);
  60                count -= nr;
  61                offset += nr;
  62                buf = (char *) buf + nr;
  63                left -= nr;
  64                if (!left) {
  65                        SHA1_Update(&f->ctx, f->buffer, offset);
  66                        sha1flush(f, offset);
  67                        offset = 0;
  68                }
  69                f->offset = offset;
  70        }
  71        return 0;
  72}
  73
  74struct sha1file *sha1create(const char *fmt, ...)
  75{
  76        struct sha1file *f;
  77        unsigned len;
  78        va_list arg;
  79        int fd;
  80
  81        f = xmalloc(sizeof(*f));
  82
  83        va_start(arg, fmt);
  84        len = vsnprintf(f->name, sizeof(f->name), fmt, arg);
  85        va_end(arg);
  86        if (len >= PATH_MAX)
  87                die("you wascally wabbit, you");
  88        f->namelen = len;
  89
  90        fd = open(f->name, O_CREAT | O_EXCL | O_WRONLY, 0666);
  91        if (fd < 0)
  92                die("unable to open %s (%s)", f->name, strerror(errno));
  93        f->fd = fd;
  94        f->error = 0;
  95        f->offset = 0;
  96        f->do_crc = 0;
  97        SHA1_Init(&f->ctx);
  98        return f;
  99}
 100
 101struct sha1file *sha1fd(int fd, const char *name)
 102{
 103        struct sha1file *f;
 104        unsigned len;
 105
 106        f = xmalloc(sizeof(*f));
 107
 108        len = strlen(name);
 109        if (len >= PATH_MAX)
 110                die("you wascally wabbit, you");
 111        f->namelen = len;
 112        memcpy(f->name, name, len+1);
 113
 114        f->fd = fd;
 115        f->error = 0;
 116        f->offset = 0;
 117        f->do_crc = 0;
 118        SHA1_Init(&f->ctx);
 119        return f;
 120}
 121
 122int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
 123{
 124        z_stream stream;
 125        unsigned long maxsize;
 126        void *out;
 127
 128        memset(&stream, 0, sizeof(stream));
 129        deflateInit(&stream, zlib_compression_level);
 130        maxsize = deflateBound(&stream, size);
 131        out = xmalloc(maxsize);
 132
 133        /* Compress it */
 134        stream.next_in = in;
 135        stream.avail_in = size;
 136
 137        stream.next_out = out;
 138        stream.avail_out = maxsize;
 139
 140        while (deflate(&stream, Z_FINISH) == Z_OK)
 141                /* nothing */;
 142        deflateEnd(&stream);
 143
 144        size = stream.total_out;
 145        sha1write(f, out, size);
 146        free(out);
 147        return size;
 148}
 149
 150void crc32_begin(struct sha1file *f)
 151{
 152        f->crc32 = crc32(0, Z_NULL, 0);
 153        f->do_crc = 1;
 154}
 155
 156uint32_t crc32_end(struct sha1file *f)
 157{
 158        f->do_crc = 0;
 159        return f->crc32;
 160}