| /* |
| * csum-file.c |
| * |
| * Copyright (C) 2005 Linus Torvalds |
| * |
| * Simple file write infrastructure for writing SHA1-summed |
| * files. Useful when you write a file that you want to be |
| * able to verify hasn't been messed with afterwards. |
| */ |
| #include "cache.h" |
| #include "progress.h" |
| #include "csum-file.h" |
| |
| static void flush(struct hashfile *f, const void *buf, unsigned int count) |
| { |
| if (0 <= f->check_fd && count) { |
| unsigned char check_buffer[8192]; |
| ssize_t ret = read_in_full(f->check_fd, check_buffer, count); |
| |
| if (ret < 0) |
| die_errno("%s: sha1 file read error", f->name); |
| if (ret != count) |
| die("%s: sha1 file truncated", f->name); |
| if (memcmp(buf, check_buffer, count)) |
| die("sha1 file '%s' validation error", f->name); |
| } |
| |
| for (;;) { |
| int ret = xwrite(f->fd, buf, count); |
| if (ret > 0) { |
| f->total += ret; |
| display_throughput(f->tp, f->total); |
| buf = (char *) buf + ret; |
| count -= ret; |
| if (count) |
| continue; |
| return; |
| } |
| if (!ret) |
| die("sha1 file '%s' write error. Out of diskspace", f->name); |
| die_errno("sha1 file '%s' write error", f->name); |
| } |
| } |
| |
| void hashflush(struct hashfile *f) |
| { |
| unsigned offset = f->offset; |
| |
| if (offset) { |
| the_hash_algo->update_fn(&f->ctx, f->buffer, offset); |
| flush(f, f->buffer, offset); |
| f->offset = 0; |
| } |
| } |
| |
| int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int flags) |
| { |
| int fd; |
| |
| hashflush(f); |
| the_hash_algo->final_fn(f->buffer, &f->ctx); |
| if (result) |
| hashcpy(result, f->buffer); |
| if (flags & CSUM_HASH_IN_STREAM) |
| flush(f, f->buffer, the_hash_algo->rawsz); |
| if (flags & CSUM_FSYNC) |
| fsync_or_die(f->fd, f->name); |
| if (flags & CSUM_CLOSE) { |
| if (close(f->fd)) |
| die_errno("%s: sha1 file error on close", f->name); |
| fd = 0; |
| } else |
| fd = f->fd; |
| if (0 <= f->check_fd) { |
| char discard; |
| int cnt = read_in_full(f->check_fd, &discard, 1); |
| if (cnt < 0) |
| die_errno("%s: error when reading the tail of sha1 file", |
| f->name); |
| if (cnt) |
| die("%s: sha1 file has trailing garbage", f->name); |
| if (close(f->check_fd)) |
| die_errno("%s: sha1 file error on close", f->name); |
| } |
| free(f); |
| return fd; |
| } |
| |
| void hashwrite(struct hashfile *f, const void *buf, unsigned int count) |
| { |
| while (count) { |
| unsigned left = sizeof(f->buffer) - f->offset; |
| unsigned nr = count > left ? left : count; |
| |
| if (f->do_crc) |
| f->crc32 = crc32(f->crc32, buf, nr); |
| |
| if (nr == sizeof(f->buffer)) { |
| /* |
| * Flush a full batch worth of data directly |
| * from the input, skipping the memcpy() to |
| * the hashfile's buffer. In this block, |
| * f->offset is necessarily zero. |
| */ |
| the_hash_algo->update_fn(&f->ctx, buf, nr); |
| flush(f, buf, nr); |
| } else { |
| /* |
| * Copy to the hashfile's buffer, flushing only |
| * if it became full. |
| */ |
| memcpy(f->buffer + f->offset, buf, nr); |
| f->offset += nr; |
| left -= nr; |
| if (!left) |
| hashflush(f); |
| } |
| |
| count -= nr; |
| buf = (char *) buf + nr; |
| } |
| } |
| |
| struct hashfile *hashfd(int fd, const char *name) |
| { |
| return hashfd_throughput(fd, name, NULL); |
| } |
| |
| struct hashfile *hashfd_check(const char *name) |
| { |
| int sink, check; |
| struct hashfile *f; |
| |
| sink = open("/dev/null", O_WRONLY); |
| if (sink < 0) |
| die_errno("unable to open /dev/null"); |
| check = open(name, O_RDONLY); |
| if (check < 0) |
| die_errno("unable to open '%s'", name); |
| f = hashfd(sink, name); |
| f->check_fd = check; |
| return f; |
| } |
| |
| struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp) |
| { |
| struct hashfile *f = xmalloc(sizeof(*f)); |
| f->fd = fd; |
| f->check_fd = -1; |
| f->offset = 0; |
| f->total = 0; |
| f->tp = tp; |
| f->name = name; |
| f->do_crc = 0; |
| the_hash_algo->init_fn(&f->ctx); |
| return f; |
| } |
| |
| void hashfile_checkpoint(struct hashfile *f, struct hashfile_checkpoint *checkpoint) |
| { |
| hashflush(f); |
| checkpoint->offset = f->total; |
| the_hash_algo->clone_fn(&checkpoint->ctx, &f->ctx); |
| } |
| |
| int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint) |
| { |
| off_t offset = checkpoint->offset; |
| |
| if (ftruncate(f->fd, offset) || |
| lseek(f->fd, offset, SEEK_SET) != offset) |
| return -1; |
| f->total = offset; |
| f->ctx = checkpoint->ctx; |
| f->offset = 0; /* hashflush() was called in checkpoint */ |
| return 0; |
| } |
| |
| void crc32_begin(struct hashfile *f) |
| { |
| f->crc32 = crc32(0, NULL, 0); |
| f->do_crc = 1; |
| } |
| |
| uint32_t crc32_end(struct hashfile *f) |
| { |
| f->do_crc = 0; |
| return f->crc32; |
| } |