csum-file.con commit Merge branch 'sw/pull-ipv46-passthru' (c2b6135)
   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 flush(struct sha1file *f, const void *buf, unsigned int count)
  15{
  16        if (0 <= f->check_fd && count)  {
  17                unsigned char check_buffer[8192];
  18                ssize_t ret = read_in_full(f->check_fd, check_buffer, count);
  19
  20                if (ret < 0)
  21                        die_errno("%s: sha1 file read error", f->name);
  22                if (ret != count)
  23                        die("%s: sha1 file truncated", f->name);
  24                if (memcmp(buf, check_buffer, count))
  25                        die("sha1 file '%s' validation error", f->name);
  26        }
  27
  28        for (;;) {
  29                int ret = xwrite(f->fd, buf, count);
  30                if (ret > 0) {
  31                        f->total += ret;
  32                        display_throughput(f->tp, f->total);
  33                        buf = (char *) buf + ret;
  34                        count -= ret;
  35                        if (count)
  36                                continue;
  37                        return;
  38                }
  39                if (!ret)
  40                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  41                die_errno("sha1 file '%s' write error", f->name);
  42        }
  43}
  44
  45void sha1flush(struct sha1file *f)
  46{
  47        unsigned offset = f->offset;
  48
  49        if (offset) {
  50                git_SHA1_Update(&f->ctx, f->buffer, offset);
  51                flush(f, f->buffer, offset);
  52                f->offset = 0;
  53        }
  54}
  55
  56int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)
  57{
  58        int fd;
  59
  60        sha1flush(f);
  61        git_SHA1_Final(f->buffer, &f->ctx);
  62        if (result)
  63                hashcpy(result, f->buffer);
  64        if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
  65                /* write checksum and close fd */
  66                flush(f, f->buffer, 20);
  67                if (flags & CSUM_FSYNC)
  68                        fsync_or_die(f->fd, f->name);
  69                if (close(f->fd))
  70                        die_errno("%s: sha1 file error on close", f->name);
  71                fd = 0;
  72        } else
  73                fd = f->fd;
  74        if (0 <= f->check_fd) {
  75                char discard;
  76                int cnt = read_in_full(f->check_fd, &discard, 1);
  77                if (cnt < 0)
  78                        die_errno("%s: error when reading the tail of sha1 file",
  79                                  f->name);
  80                if (cnt)
  81                        die("%s: sha1 file has trailing garbage", f->name);
  82                if (close(f->check_fd))
  83                        die_errno("%s: sha1 file error on close", f->name);
  84        }
  85        free(f);
  86        return fd;
  87}
  88
  89void sha1write(struct sha1file *f, const void *buf, unsigned int count)
  90{
  91        while (count) {
  92                unsigned offset = f->offset;
  93                unsigned left = sizeof(f->buffer) - offset;
  94                unsigned nr = count > left ? left : count;
  95                const void *data;
  96
  97                if (f->do_crc)
  98                        f->crc32 = crc32(f->crc32, buf, nr);
  99
 100                if (nr == sizeof(f->buffer)) {
 101                        /* process full buffer directly without copy */
 102                        data = buf;
 103                } else {
 104                        memcpy(f->buffer + offset, buf, nr);
 105                        data = f->buffer;
 106                }
 107
 108                count -= nr;
 109                offset += nr;
 110                buf = (char *) buf + nr;
 111                left -= nr;
 112                if (!left) {
 113                        git_SHA1_Update(&f->ctx, data, offset);
 114                        flush(f, data, offset);
 115                        offset = 0;
 116                }
 117                f->offset = offset;
 118        }
 119}
 120
 121struct sha1file *sha1fd(int fd, const char *name)
 122{
 123        return sha1fd_throughput(fd, name, NULL);
 124}
 125
 126struct sha1file *sha1fd_check(const char *name)
 127{
 128        int sink, check;
 129        struct sha1file *f;
 130
 131        sink = open("/dev/null", O_WRONLY);
 132        if (sink < 0)
 133                die_errno("unable to open /dev/null");
 134        check = open(name, O_RDONLY);
 135        if (check < 0)
 136                die_errno("unable to open '%s'", name);
 137        f = sha1fd(sink, name);
 138        f->check_fd = check;
 139        return f;
 140}
 141
 142struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 143{
 144        struct sha1file *f = xmalloc(sizeof(*f));
 145        f->fd = fd;
 146        f->check_fd = -1;
 147        f->offset = 0;
 148        f->total = 0;
 149        f->tp = tp;
 150        f->name = name;
 151        f->do_crc = 0;
 152        git_SHA1_Init(&f->ctx);
 153        return f;
 154}
 155
 156void sha1file_checkpoint(struct sha1file *f, struct sha1file_checkpoint *checkpoint)
 157{
 158        sha1flush(f);
 159        checkpoint->offset = f->total;
 160        checkpoint->ctx = f->ctx;
 161}
 162
 163int sha1file_truncate(struct sha1file *f, struct sha1file_checkpoint *checkpoint)
 164{
 165        off_t offset = checkpoint->offset;
 166
 167        if (ftruncate(f->fd, offset) ||
 168            lseek(f->fd, offset, SEEK_SET) != offset)
 169                return -1;
 170        f->total = offset;
 171        f->ctx = checkpoint->ctx;
 172        f->offset = 0; /* sha1flush() was called in checkpoint */
 173        return 0;
 174}
 175
 176void crc32_begin(struct sha1file *f)
 177{
 178        f->crc32 = crc32(0, NULL, 0);
 179        f->do_crc = 1;
 180}
 181
 182uint32_t crc32_end(struct sha1file *f)
 183{
 184        f->do_crc = 0;
 185        return f->crc32;
 186}