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 = write(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                if (errno == EAGAIN || errno == EINTR)
  29                        continue;
  30                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  31        }
  32}
  33
  34int sha1close(struct sha1file *f, unsigned char *result, int update)
  35{
  36        unsigned offset = f->offset;
  37        if (offset) {
  38                SHA1_Update(&f->ctx, f->buffer, offset);
  39                sha1flush(f, offset);
  40        }
  41        SHA1_Final(f->buffer, &f->ctx);
  42        if (result)
  43                memcpy(result, f->buffer, 20);
  44        if (update)
  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        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 += 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        SHA1_Init(&f->ctx);
  97        return f;
  98}
  99
 100struct sha1file *sha1fd(int fd, const char *name)
 101{
 102        struct sha1file *f;
 103        unsigned len;
 104
 105        f = xmalloc(sizeof(*f));
 106
 107        len = strlen(name);
 108        if (len >= PATH_MAX)
 109                die("you wascally wabbit, you");
 110        f->namelen = len;
 111        memcpy(f->name, name, len+1);
 112
 113        f->fd = fd;
 114        f->error = 0;
 115        f->offset = 0;
 116        SHA1_Init(&f->ctx);
 117        return f;
 118}
 119
 120int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
 121{
 122        z_stream stream;
 123        unsigned long maxsize;
 124        void *out;
 125
 126        memset(&stream, 0, sizeof(stream));
 127        deflateInit(&stream, Z_DEFAULT_COMPRESSION);
 128        maxsize = deflateBound(&stream, size);
 129        out = xmalloc(maxsize);
 130
 131        /* Compress it */
 132        stream.next_in = in;
 133        stream.avail_in = size;
 134
 135        stream.next_out = out;
 136        stream.avail_out = maxsize;
 137
 138        while (deflate(&stream, Z_FINISH) == Z_OK)
 139                /* nothing */;
 140        deflateEnd(&stream);
 141
 142        size = stream.total_out;
 143        sha1write(f, out, size);
 144        free(out);
 145        return size;
 146}
 147
 148