short i/o: fix calls to write to use xwrite or write_in_full

We have a number of badly checked write() calls.  Often we are
expecting write() to write exactly the size we requested or fail,
this fails to handle interrupts or short writes.  Switch to using
the new write_in_full().  Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xwrite().

Note, the changes to config handling are much larger and handled
in the next patch in the sequence.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-rerere.c

@@ -51,9 +51,11 @@ static int write_rr(struct path_list *rr, int out_fd)
 	int i;
 	for (i = 0; i < rr->nr; i++) {
 		const char *path = rr->items[i].path;
-		write(out_fd, rr->items[i].util, 40);
-		write(out_fd, "\t", 1);
-		write(out_fd, path, strlen(path) + 1);
+		int length = strlen(path) + 1;
+		if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
+		    write_in_full(out_fd, "\t", 1) != 1 ||
+		    write_in_full(out_fd, path, length) != length)
+			die("unable to write rerere record");
 	}
 	close(out_fd);
 	return commit_lock_file(&write_lock);
@@ -244,7 +246,8 @@ static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 {
 	int i;
 	for (i = 0; i < nbuf; i++)
-		write(1, ptr[i].ptr, ptr[i].size);
+		if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
+			return -1;
 	return 0;
 }
 

builtin-tar-tree.c

@@ -82,7 +82,7 @@ int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
 	if (memcmp(content, "52 comment=", 11))
 		return 1;
 
-	n = xwrite(1, content + 11, 41);
+	n = write_in_full(1, content + 11, 41);
 	if (n < 41)
 		die("git-get-tar-commit-id: write error");
 

commit.c

@@ -249,8 +249,10 @@ int write_shallow_commits(int fd, int use_pack_protocol)
 			if (use_pack_protocol)
 				packet_write(fd, "shallow %s", hex);
 			else {
-				write(fd, hex,  40);
-				write(fd, "\n", 1);
+				if (write_in_full(fd, hex,  40) != 40)
+					break;
+				if (write_in_full(fd, "\n", 1) != 1)
+					break;
 			}
 		}
 	return count;

daemon.c

@@ -102,7 +102,7 @@ static void logreport(int priority, const char *err, va_list params)
 	buf[buflen++] = '\n';
 	buf[buflen] = '\0';
 
-	write(2, buf, buflen);
+	write_in_full(2, buf, buflen);
 }
 
 static void logerror(const char *err, ...)

diff.c

@@ -1389,7 +1389,7 @@ static void prep_temp_blob(struct diff_tempfile *temp,
 	fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
 	if (fd < 0)
 		die("unable to create temp-file");
-	if (write(fd, blob, size) != size)
+	if (write_in_full(fd, blob, size) != size)
 		die("unable to write temp-file");
 	close(fd);
 	temp->name = temp->tmp_path;

entry.c

@@ -89,7 +89,7 @@ static int write_entry(struct cache_entry *ce, char *path, struct checkout *stat
 			return error("git-checkout-index: unable to create file %s (%s)",
 				path, strerror(errno));
 		}
-		wrote = write(fd, new, size);
+		wrote = write_in_full(fd, new, size);
 		close(fd);
 		free(new);
 		if (wrote != size)
@@ -104,7 +104,7 @@ static int write_entry(struct cache_entry *ce, char *path, struct checkout *stat
 				return error("git-checkout-index: unable to create "
 						 "file %s (%s)", path, strerror(errno));
 			}
-			wrote = write(fd, new, size);
+			wrote = write_in_full(fd, new, size);
 			close(fd);
 			free(new);
 			if (wrote != size)

http-fetch.c

@@ -71,7 +71,7 @@ static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 	int posn = 0;
 	struct object_request *obj_req = (struct object_request *)data;
 	do {
-		ssize_t retval = write(obj_req->local,
+		ssize_t retval = xwrite(obj_req->local,
 				       (char *) ptr + posn, size - posn);
 		if (retval < 0)
 			return posn;

http-push.c

@@ -195,7 +195,7 @@ static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 	int posn = 0;
 	struct transfer_request *request = (struct transfer_request *)data;
 	do {
-		ssize_t retval = write(request->local_fileno,
+		ssize_t retval = xwrite(request->local_fileno,
 				       (char *) ptr + posn, size - posn);
 		if (retval < 0)
 			return posn;

imap-send.c

@@ -236,7 +236,7 @@ socket_read( Socket_t *sock, char *buf, int len )
 static int
 socket_write( Socket_t *sock, const char *buf, int len )
 {
-	int n = write( sock->fd, buf, len );
+	int n = write_in_full( sock->fd, buf, len );
 	if (n != len) {
 		socket_perror( "write", sock, n );
 		close( sock->fd );

index-pack.c

@@ -814,7 +814,7 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
 		char buf[48];
 		int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 				   report, sha1_to_hex(sha1));
-		xwrite(1, buf, len);
+		write_in_full(1, buf, len);
 
 		/*
 		 * Let's just mimic git-unpack-objects here and write

merge-recursive.c

@@ -517,7 +517,7 @@ static int mkdir_p(const char *path, unsigned long mode)
 static void flush_buffer(int fd, const char *buf, unsigned long size)
 {
 	while (size > 0) {
-		long ret = xwrite(fd, buf, size);
+		long ret = write_in_full(fd, buf, size);
 		if (ret < 0) {
 			/* Ignore epipe */
 			if (errno == EPIPE)

read-cache.c

@@ -870,7 +870,7 @@ static int ce_write_flush(SHA_CTX *context, int fd)
 	unsigned int buffered = write_buffer_len;
 	if (buffered) {
 		SHA1_Update(context, write_buffer, buffered);
-		if (write(fd, write_buffer, buffered) != buffered)
+		if (write_in_full(fd, write_buffer, buffered) != buffered)
 			return -1;
 		write_buffer_len = 0;
 	}
@@ -919,15 +919,15 @@ static int ce_flush(SHA_CTX *context, int fd)
 
 	/* Flush first if not enough space for SHA1 signature */
 	if (left + 20 > WRITE_BUFFER_SIZE) {
-		if (write(fd, write_buffer, left) != left)
+		if (write_in_full(fd, write_buffer, left) != left)
 			return -1;
 		left = 0;
 	}
 
 	/* Append the SHA1 signature at the end */
 	SHA1_Final(write_buffer + left, context);
 	left += 20;
-	return (write(fd, write_buffer, left) != left) ? -1 : 0;
+	return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
 }
 
 static void ce_smudge_racily_clean_entry(struct cache_entry *ce)

refs.c

@@ -332,7 +332,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master)
 	}
 	lockpath = mkpath("%s.lock", git_HEAD);
 	fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);	
-	written = write(fd, ref, len);
+	written = write_in_full(fd, ref, len);
 	close(fd);
 	if (written != len) {
 		unlink(lockpath);
@@ -968,7 +968,7 @@ static int log_ref_write(struct ref_lock *lock,
 			sha1_to_hex(sha1),
 			committer);
 	}
-	written = len <= maxlen ? write(logfd, logrec, len) : -1;
+	written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
 	free(logrec);
 	close(logfd);
 	if (written != len)
@@ -987,8 +987,8 @@ int write_ref_sha1(struct ref_lock *lock,
 		unlock_ref(lock);
 		return 0;
 	}
-	if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
-	    write(lock->lock_fd, &term, 1) != 1
+	if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
+	    write_in_full(lock->lock_fd, &term, 1) != 1
 		|| close(lock->lock_fd) < 0) {
 		error("Couldn't write %s", lock->lk->filename);
 		unlock_ref(lock);

sha1_file.c

@@ -1611,20 +1611,13 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
 
 static int write_buffer(int fd, const void *buf, size_t len)
 {
-	while (len) {
-		ssize_t size;
+	ssize_t size;
 
-		size = write(fd, buf, len);
-		if (!size)
-			return error("file write: disk full");
-		if (size < 0) {
-			if (errno == EINTR || errno == EAGAIN)
-				continue;
-			return error("file write error (%s)", strerror(errno));
-		}
-		len -= size;
-		buf = (char *) buf + size;
-	}
+	size = write_in_full(fd, buf, len);
+	if (!size)
+		return error("file write: disk full");
+	if (size < 0)
+		return error("file write error (%s)", strerror(errno));
 	return 0;
 }
 

ssh-fetch.c

@@ -20,22 +20,6 @@ static int fd_out;
 static unsigned char remote_version;
 static unsigned char local_version = 1;
 
-static ssize_t force_write(int fd, void *buffer, size_t length)
-{
-	ssize_t ret = 0;
-	while (ret < length) {
-		ssize_t size = write(fd, (char *) buffer + ret, length - ret);
-		if (size < 0) {
-			return size;
-		}
-		if (size == 0) {
-			return ret;
-		}
-		ret += size;
-	}
-	return ret;
-}
-
 static int prefetches;
 
 static struct object_list *in_transit;
@@ -53,8 +37,9 @@ void prefetch(unsigned char *sha1)
 	node->item = lookup_unknown_object(sha1);
 	*end_of_transit = node;
 	end_of_transit = &node->next;
-	force_write(fd_out, &type, 1);
-	force_write(fd_out, sha1, 20);
+	/* XXX: what if these writes fail? */
+	write_in_full(fd_out, &type, 1);
+	write_in_full(fd_out, sha1, 20);
 	prefetches++;
 }
 
@@ -97,8 +82,10 @@ int fetch(unsigned char *sha1)
 static int get_version(void)
 {
 	char type = 'v';
-	write(fd_out, &type, 1);
-	write(fd_out, &local_version, 1);
+	if (write_in_full(fd_out, &type, 1) != 1 ||
+	    write_in_full(fd_out, &local_version, 1)) {
+		return error("Couldn't request version from remote end");
+	}
 	if (xread(fd_in, &remote_version, 1) < 1) {
 		return error("Couldn't read version from remote end");
 	}
@@ -109,8 +96,10 @@ int fetch_ref(char *ref, unsigned char *sha1)
 {
 	signed char remote;
 	char type = 'r';
-	write(fd_out, &type, 1);
-	write(fd_out, ref, strlen(ref) + 1);
+	int length = strlen(ref) + 1;
+	if (write_in_full(fd_out, &type, 1) != 1 ||
+	    write_in_full(fd_out, ref, length) != length)
+		return -1;
 
 	if (read_in_full(fd_in, &remote, 1) != 1)
 		return -1;

ssh-upload.c

@@ -41,7 +41,8 @@ static int serve_object(int fd_in, int fd_out) {
 		remote = -1;
 	}
 
-	write(fd_out, &remote, 1);
+	if (write_in_full(fd_out, &remote, 1) != 1)
+		return 0;
 
 	if (remote < 0)
 		return 0;
@@ -53,7 +54,7 @@ static int serve_version(int fd_in, int fd_out)
 {
 	if (xread(fd_in, &remote_version, 1) < 1)
 		return -1;
-	write(fd_out, &local_version, 1);
+	write_in_full(fd_out, &local_version, 1);
 	return 0;
 }
 
@@ -74,10 +75,11 @@ static int serve_ref(int fd_in, int fd_out)
 
 	if (get_ref_sha1(ref, sha1))
 		remote = -1;
-	write(fd_out, &remote, 1);
+	if (write_in_full(fd_out, &remote, 1) != 1)
+		return 0;
 	if (remote)
 		return 0;
-	write(fd_out, sha1, 20);
+	write_in_full(fd_out, sha1, 20);
         return 0;
 }
 

test-delta.c

@@ -68,7 +68,7 @@ int main(int argc, char *argv[])
 	}
 
 	fd = open (argv[4], O_WRONLY|O_CREAT|O_TRUNC, 0666);
-	if (fd < 0 || write(fd, out_buf, out_size) != out_size) {
+	if (fd < 0 || write_in_full(fd, out_buf, out_size) != out_size) {
 		perror(argv[4]);
 		return 1;
 	}

unpack-file.c

@@ -17,7 +17,7 @@ static char *create_temp_file(unsigned char *sha1)
 	fd = mkstemp(path);
 	if (fd < 0)
 		die("unable to create temp-file");
-	if (write(fd, buf, size) != size)
+	if (write_in_full(fd, buf, size) != size)
 		die("unable to write temp-file");
 	close(fd);
 	return path;

upload-pack.c

@@ -55,6 +55,7 @@ static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
 		/* emergency quit */
 		fd = 2;
 	if (fd == 2) {
+		/* XXX: are we happy to lose stuff here? */
 		xwrite(fd, data, sz);
 		return sz;
 	}

write_or_die.c

@@ -33,45 +33,40 @@ void read_or_die(int fd, void *buf, size_t count)
 		die("read error (%s)", strerror(errno));
 }
 
-void write_or_die(int fd, const void *buf, size_t count)
+int write_in_full(int fd, const void *buf, size_t count)
 {
 	const char *p = buf;
-	ssize_t written;
+	ssize_t total = 0;
+	ssize_t written = 0;
 
 	while (count > 0) {
 		written = xwrite(fd, p, count);
-		if (written == 0)
-			die("disk full?");
-		else if (written < 0) {
-			if (errno == EPIPE)
-				exit(0);
-			die("write error (%s)", strerror(errno));
+		if (written <= 0) {
+			if (total)
+				return total;
+			else
+				return written;
 		}
 		count -= written;
 		p += written;
+		total += written;
 	}
+
+	return total;
 }
 
-int write_in_full(int fd, const void *buf, size_t count)
+void write_or_die(int fd, const void *buf, size_t count)
 {
-	const char *p = buf;
-	ssize_t total = 0;
-	ssize_t wcount = 0;
+	ssize_t written;
 
-	while (count > 0) {
-		wcount = xwrite(fd, p, count);
-		if (wcount <= 0) {
-			if (total)
-				return total;
-			else
-				return wcount;
-		}
-		count -= wcount;
-		p += wcount;
-		total += wcount;
+	written = write_in_full(fd, buf, count);
+	if (written == 0)
+		die("disk full?");
+	else if (written < 0) {
+		if (errno == EPIPE)
+			exit(0);
+		die("write error (%s)", strerror(errno));
 	}
-
-	return wcount;
 }
 
 int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)