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 int 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 += ret;
  21                        count -= ret;
  22                        if (count)
  23                                continue;
  24                        return 0;
  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                memcpy(result, f->buffer, 20);
  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        while (count) {
  53                unsigned offset = f->offset;
  54                unsigned left = sizeof(f->buffer) - offset;
  55                unsigned nr = count > left ? left : count;
  56
  57                memcpy(f->buffer + offset, buf, nr);
  58                count -= nr;
  59                offset += nr;
  60                buf += nr;
  61                left -= nr;
  62                if (!left) {
  63                        SHA1_Update(&f->ctx, f->buffer, offset);
  64                        sha1flush(f, offset);
  65                        offset = 0;
  66                }
  67                f->offset = offset;
  68        }
  69        return 0;
  70}
  71
  72struct sha1file *sha1create(const char *fmt, ...)
  73{
  74        struct sha1file *f;
  75        unsigned len;
  76        va_list arg;
  77        int fd;
  78
  79        f = xmalloc(sizeof(*f));
  80
  81        va_start(arg, fmt);
  82        len = vsnprintf(f->name, sizeof(f->name), fmt, arg);
  83        va_end(arg);
  84        if (len >= PATH_MAX)
  85                die("you wascally wabbit, you");
  86        f->namelen = len;
  87
  88        fd = open(f->name, O_CREAT | O_EXCL | O_WRONLY, 0666);
  89        if (fd < 0)
  90                die("unable to open %s (%s)", f->name, strerror(errno));
  91        f->fd = fd;
  92        f->error = 0;
  93        f->offset = 0;
  94        SHA1_Init(&f->ctx);
  95        return f;
  96}
  97
  98struct sha1file *sha1fd(int fd, const char *name)
  99{
 100        struct sha1file *f;
 101        unsigned len;
 102
 103        f = xmalloc(sizeof(*f));
 104
 105        len = strlen(name);
 106        if (len >= PATH_MAX)
 107                die("you wascally wabbit, you");
 108        f->namelen = len;
 109        memcpy(f->name, name, len+1);
 110
 111        f->fd = fd;
 112        f->error = 0;
 113        f->offset = 0;
 114        SHA1_Init(&f->ctx);
 115        return f;
 116}
 117
 118int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
 119{
 120        z_stream stream;
 121        unsigned long maxsize;
 122        void *out;
 123
 124        memset(&stream, 0, sizeof(stream));
 125        deflateInit(&stream, Z_DEFAULT_COMPRESSION);
 126        maxsize = deflateBound(&stream, size);
 127        out = xmalloc(maxsize);
 128
 129        /* Compress it */
 130        stream.next_in = in;
 131        stream.avail_in = size;
 132
 133        stream.next_out = out;
 134        stream.avail_out = maxsize;
 135
 136        while (deflate(&stream, Z_FINISH) == Z_OK)
 137                /* nothing */;
 138        deflateEnd(&stream);
 139
 140        size = stream.total_out;
 141        sha1write(f, out, size);
 142        free(out);
 143        return size;
 144}
 145
 146