| /* |
| * 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 "git-compat-util.h" |
| #include "progress.h" |
| #include "csum-file.h" |
| #include "hash.h" |
| #include "wrapper.h" |
| |
| static void verify_buffer_or_die(struct hashfile *f, |
| const void *buf, |
| unsigned int count) |
| { |
| ssize_t ret = read_in_full(f->check_fd, f->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, f->check_buffer, count)) |
| die("sha1 file '%s' validation error", f->name); |
| } |
| |
| static void flush(struct hashfile *f, const void *buf, unsigned int count) |
| { |
| if (0 <= f->check_fd && count) |
| verify_buffer_or_die(f, buf, count); |
| |
| if (write_in_full(f->fd, buf, count) < 0) { |
| if (errno == ENOSPC) |
| die("sha1 file '%s' write error. Out of diskspace", f->name); |
| die_errno("sha1 file '%s' write error", f->name); |
| } |
| |
| f->total += count; |
| display_throughput(f->tp, f->total); |
| } |
| |
| void hashflush(struct hashfile *f) |
| { |
| unsigned offset = f->offset; |
| |
| if (offset) { |
| if (!f->skip_hash) |
| the_hash_algo->update_fn(&f->ctx, f->buffer, offset); |
| flush(f, f->buffer, offset); |
| f->offset = 0; |
| } |
| } |
| |
| static void free_hashfile(struct hashfile *f) |
| { |
| free(f->buffer); |
| free(f->check_buffer); |
| free(f); |
| } |
| |
| int finalize_hashfile(struct hashfile *f, unsigned char *result, |
| enum fsync_component component, unsigned int flags) |
| { |
| int fd; |
| |
| hashflush(f); |
| |
| if (f->skip_hash) |
| hashclr(f->buffer); |
| else |
| 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_component_or_die(component, 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_hashfile(f); |
| return fd; |
| } |
| |
| void hashwrite(struct hashfile *f, const void *buf, unsigned int count) |
| { |
| while (count) { |
| unsigned left = f->buffer_len - f->offset; |
| unsigned nr = count > left ? left : count; |
| |
| if (f->do_crc) |
| f->crc32 = crc32(f->crc32, buf, nr); |
| |
| if (nr == f->buffer_len) { |
| /* |
| * 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. |
| */ |
| if (!f->skip_hash) |
| 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_check(const char *name) |
| { |
| int sink, check; |
| struct hashfile *f; |
| |
| sink = xopen("/dev/null", O_WRONLY); |
| check = xopen(name, O_RDONLY); |
| f = hashfd(sink, name); |
| f->check_fd = check; |
| f->check_buffer = xmalloc(f->buffer_len); |
| |
| return f; |
| } |
| |
| static struct hashfile *hashfd_internal(int fd, const char *name, |
| struct progress *tp, |
| size_t buffer_len) |
| { |
| 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; |
| f->skip_hash = 0; |
| the_hash_algo->init_fn(&f->ctx); |
| |
| f->buffer_len = buffer_len; |
| f->buffer = xmalloc(buffer_len); |
| f->check_buffer = NULL; |
| |
| return f; |
| } |
| |
| struct hashfile *hashfd(int fd, const char *name) |
| { |
| /* |
| * Since we are not going to use a progress meter to |
| * measure the rate of data passing through this hashfile, |
| * use a larger buffer size to reduce fsync() calls. |
| */ |
| return hashfd_internal(fd, name, NULL, 128 * 1024); |
| } |
| |
| struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp) |
| { |
| /* |
| * Since we are expecting to report progress of the |
| * write into this hashfile, use a smaller buffer |
| * size so the progress indicators arrive at a more |
| * frequent rate. |
| */ |
| return hashfd_internal(fd, name, tp, 8 * 1024); |
| } |
| |
| 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; |
| } |
| |
| int hashfile_checksum_valid(const unsigned char *data, size_t total_len) |
| { |
| unsigned char got[GIT_MAX_RAWSZ]; |
| git_hash_ctx ctx; |
| size_t data_len = total_len - the_hash_algo->rawsz; |
| |
| if (total_len < the_hash_algo->rawsz) |
| return 0; /* say "too short"? */ |
| |
| the_hash_algo->init_fn(&ctx); |
| the_hash_algo->update_fn(&ctx, data, data_len); |
| the_hash_algo->final_fn(got, &ctx); |
| |
| return hasheq(got, data + data_len); |
| } |