Merge branch 'jk/read-in-full'

Code clean-up to prevent future mistakes by copying and pasting
code that checks the result of read_in_full() function.

* jk/read-in-full:
  worktree: check the result of read_in_full()
  worktree: use xsize_t to access file size
  distinguish error versus short read from read_in_full()
  avoid looking at errno for short read_in_full() returns
  prefer "!=" when checking read_in_full() result
  notes-merge: drop dead zero-write code
  files-backend: prefer "0" for write_in_full() error check

Author: gitster

builtin/get-tar-commit-id.c

@@ -26,8 +26,10 @@ int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
 		usage(builtin_get_tar_commit_id_usage);
 
 	n = read_in_full(0, buffer, HEADERSIZE);
-	if (n < HEADERSIZE)
-		die("git get-tar-commit-id: read error");
+	if (n < 0)
+		die_errno("git get-tar-commit-id: read error");
+	if (n != HEADERSIZE)
+		die_errno("git get-tar-commit-id: EOF before reading tar header");
 	if (header->typeflag[0] != 'g')
 		return 1;
 	if (!skip_prefix(content, "52 comment=", &comment))

builtin/worktree.c

@@ -38,7 +38,9 @@ static int prune_worktree(const char *id, struct strbuf *reason)
 {
 	struct stat st;
 	char *path;
-	int fd, len;
+	int fd;
+	size_t len;
+	ssize_t read_result;
 
 	if (!is_directory(git_path("worktrees/%s", id))) {
 		strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
@@ -56,10 +58,26 @@ static int prune_worktree(const char *id, struct strbuf *reason)
 			    id, strerror(errno));
 		return 1;
 	}
-	len = st.st_size;
+	len = xsize_t(st.st_size);
 	path = xmallocz(len);
-	read_in_full(fd, path, len);
+
+	read_result = read_in_full(fd, path, len);
+	if (read_result < 0) {
+		strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
+			    id, strerror(errno));
+		close(fd);
+		free(path);
+		return 1;
+	}
 	close(fd);
+
+	if (read_result != len) {
+		strbuf_addf(reason,
+			    _("Removing worktrees/%s: short read (expected %"PRIuMAX" bytes, read %"PRIuMAX")"),
+			    id, (uintmax_t)len, (uintmax_t)read_result);
+		free(path);
+		return 1;
+	}
 	while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
 		len--;
 	if (!len) {

bulk-checkin.c

@@ -115,7 +115,10 @@ static int stream_to_pack(struct bulk_checkin_state *state,
 
 		if (size && !s.avail_in) {
 			ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
-			if (read_in_full(fd, ibuf, rsize) != rsize)
+			ssize_t read_result = read_in_full(fd, ibuf, rsize);
+			if (read_result < 0)
+				die_errno("failed to read from '%s'", path);
+			if (read_result != rsize)
 				die("failed to read %d bytes from '%s'",
 				    (int)rsize, path);
 			offset += rsize;

csum-file.c

@@ -19,7 +19,7 @@ static void flush(struct sha1file *f, const void *buf, unsigned int count)
 
 		if (ret < 0)
 			die_errno("%s: sha1 file read error", f->name);
-		if (ret < count)
+		if (ret != count)
 			die("%s: sha1 file truncated", f->name);
 		if (memcmp(buf, check_buffer, count))
 			die("sha1 file '%s' validation error", f->name);

notes-merge.c

@@ -308,8 +308,6 @@ static void write_buf_to_worktree(const struct object_id *obj,
 			if (errno == EPIPE)
 				break;
 			die_errno("notes-merge");
-		} else if (!ret) {
-			die("notes-merge: disk full?");
 		}
 		size -= ret;
 		buf += ret;

pack-write.c

@@ -213,14 +213,19 @@ void fixup_pack_header_footer(int pack_fd,
 	git_SHA_CTX old_sha1_ctx, new_sha1_ctx;
 	struct pack_header hdr;
 	char *buf;
+	ssize_t read_result;
 
 	git_SHA1_Init(&old_sha1_ctx);
 	git_SHA1_Init(&new_sha1_ctx);
 
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
 		die_errno("Failed seeking to start of '%s'", pack_name);
-	if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
+	read_result = read_in_full(pack_fd, &hdr, sizeof(hdr));
+	if (read_result < 0)
 		die_errno("Unable to reread header of '%s'", pack_name);
+	else if (read_result != sizeof(hdr))
+		die_errno("Unexpected short read for header of '%s'",
+			  pack_name);
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
 		die_errno("Failed seeking to start of '%s'", pack_name);
 	git_SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));

packfile.c

@@ -442,6 +442,7 @@ static int open_packed_git_1(struct packed_git *p)
 	unsigned char sha1[20];
 	unsigned char *idx_sha1;
 	long fd_flag;
+	ssize_t read_result;
 
 	if (!p->index_data && open_pack_index(p))
 		return error("packfile %s index unavailable", p->pack_name);
@@ -483,7 +484,10 @@ static int open_packed_git_1(struct packed_git *p)
 		return error("cannot set FD_CLOEXEC");
 
 	/* Verify we recognize this pack file format. */
-	if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
+	read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
+	if (read_result < 0)
+		return error_errno("error reading from %s", p->pack_name);
+	if (read_result != sizeof(hdr))
 		return error("file %s is far too short to be a packfile", p->pack_name);
 	if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 		return error("file %s is not a GIT packfile", p->pack_name);
@@ -500,7 +504,10 @@ static int open_packed_git_1(struct packed_git *p)
 			     p->num_objects);
 	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 		return error("end of packfile %s is unavailable", p->pack_name);
-	if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
+	read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1));
+	if (read_result < 0)
+		return error_errno("error reading from %s", p->pack_name);
+	if (read_result != sizeof(sha1))
 		return error("packfile %s signature is unavailable", p->pack_name);
 	idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
 	if (hashcmp(sha1, idx_sha1))

pkt-line.c

@@ -258,7 +258,7 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 	}
 
 	/* And complain if we didn't get enough bytes to satisfy the read. */
-	if (ret < size) {
+	if (ret != size) {
 		if (options & PACKET_READ_GENTLE_ON_EOF)
 			return -1;
 

refs/files-backend.c

@@ -3035,7 +3035,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		} else if (update &&
 			   (write_in_full(get_lock_file_fd(&lock->lk),
 				oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) < 0 ||
-			    write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 1 ||
+			    write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
 			    close_ref_gently(lock) < 0)) {
 			status |= error("couldn't write %s",
 					get_lock_file_path(&lock->lk));

sha1_file.c

@@ -1748,10 +1748,15 @@ static int index_core(unsigned char *sha1, int fd, size_t size,
 		ret = index_mem(sha1, "", size, type, path, flags);
 	} else if (size <= SMALL_FILE_SIZE) {
 		char *buf = xmalloc(size);
-		if (size == read_in_full(fd, buf, size))
-			ret = index_mem(sha1, buf, size, type, path, flags);
+		ssize_t read_result = read_in_full(fd, buf, size);
+		if (read_result < 0)
+			ret = error_errno("read error while indexing %s",
+					  path ? path : "<unknown>");
+		else if (read_result != size)
+			ret = error("short read while indexing %s",
+				    path ? path : "<unknown>");
 		else
-			ret = error_errno("short read");
+			ret = index_mem(sha1, buf, size, type, path, flags);
 		free(buf);
 	} else {
 		void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);