filebuf: handle write error in lock_file

pks-t · Edward Thomson · commit 18c4ae70d154 · 2016-04-11T15:58:56.000-04:00
When writing to a file with locking not check if writing the
locked file actually succeeds. Fix the issue by returning error
code and message when writing fails.
diff --git a/src/filebuf.c b/src/filebuf.c
@@ -70,6 +70,7 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)
 		git_file source;
 		char buffer[FILEIO_BUFSIZE];
 		ssize_t read_bytes;
+		int error;
 
 		source = p_open(file->path_original, O_RDONLY);
 		if (source < 0) {
@@ -80,7 +81,8 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)
 		}
 
 		while ((read_bytes = p_read(source, buffer, sizeof(buffer))) > 0) {
-			p_write(file->fd, buffer, read_bytes);
+			if ((error = p_write(file->fd, buffer, read_bytes)) < 0)
+				break;
 			if (file->compute_digest)
 				git_hash_update(&file->digest, buffer, read_bytes);
 		}
@@ -90,6 +92,9 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)
 		if (read_bytes < 0) {
 			giterr_set(GITERR_OS, "Failed to read file '%s'", file->path_original);
 			return -1;
+		} else if (error < 0) {
+			giterr_set(GITERR_OS, "Failed to write file '%s'", file->path_lock);
+			return -1;
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -70,6 +70,7 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)`
`70`	`70`	`git_file source;`
`71`	`71`	`char buffer[FILEIO_BUFSIZE];`
`72`	`72`	`ssize_t read_bytes;`
	`73`	`+ int error;`
`73`	`74`
`74`	`75`	`source = p_open(file->path_original, O_RDONLY);`
`75`	`76`	`if (source < 0) {`
`@@ -80,7 +81,8 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)`
`80`	`81`	`}`
`81`	`82`
`82`	`83`	`while ((read_bytes = p_read(source, buffer, sizeof(buffer))) > 0) {`
`83`		`- p_write(file->fd, buffer, read_bytes);`
	`84`	`+ if ((error = p_write(file->fd, buffer, read_bytes)) < 0)`
	`85`	`+ break;`
`84`	`86`	`if (file->compute_digest)`
`85`	`87`	`git_hash_update(&file->digest, buffer, read_bytes);`
`86`	`88`	`}`
`@@ -90,6 +92,9 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)`
`90`	`92`	`if (read_bytes < 0) {`
`91`	`93`	`giterr_set(GITERR_OS, "Failed to read file '%s'", file->path_original);`
`92`	`94`	`return -1;`
	`95`	`+ } else if (error < 0) {`
	`96`	`+ giterr_set(GITERR_OS, "Failed to write file '%s'", file->path_lock);`
	`97`	`+ return -1;`
`93`	`98`	`}`
`94`	`99`	`}`
`95`	`100`