fileio: add read_virtual_file_at() flavour that takes dir_fd/path pair

poettering · poettering · commit 6bfd44ee0451 · 2021-10-11T10:58:50.000+02:00
diff --git a/src/basic/fileio.c b/src/basic/fileio.c
@@ -547,12 +547,25 @@ int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *r
         return !truncated;
 }
 
-int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
+int read_virtual_file_at(
+                int dir_fd,
+                const char *filename,
+                size_t max_size,
+                char **ret_contents,
+                size_t *ret_size) {
+
         _cleanup_close_ int fd = -1;
 
-        assert(filename);
+        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
+
+        if (!filename) {
+                if (dir_fd == AT_FDCWD)
+                        return -EBADF;
+
+                return read_virtual_file_fd(dir_fd, max_size, ret_contents, ret_size);
+        }
 
-        fd = open(filename, O_RDONLY | O_NOCTTY | O_CLOEXEC);
+        fd = openat(dir_fd, filename, O_RDONLY | O_NOCTTY | O_CLOEXEC);
         if (fd < 0)
                 return -errno;
 
diff --git a/src/basic/fileio.h b/src/basic/fileio.h
@@ -69,7 +69,10 @@ static inline int read_full_file(const char *filename, char **ret_contents, size
 }
 
 int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size);
-int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size);
+int read_virtual_file_at(int dir_fd, const char *filename, size_t max_size, char **ret_contents, size_t *ret_size);
+static inline int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
+        return read_virtual_file_at(AT_FDCWD, filename, max_size, ret_contents, ret_size);
+}
 static inline int read_full_virtual_file(const char *filename, char **ret_contents, size_t *ret_size) {
         return read_virtual_file(filename, SIZE_MAX, ret_contents, ret_size);
 }

Original file line number	Diff line number	Diff line change
`@@ -69,7 +69,10 @@ static inline int read_full_file(const char filename, char *ret_contents, size`
`69`	`69`	`}`
`70`	`70`
`71`	`71`	`int read_virtual_file_fd(int fd, size_t max_size, char *ret_contents, size_t ret_size);`
`72`		`-int read_virtual_file(const char filename, size_t max_size, char ret_contents, size_t ret_size);`
	`72`	`+int read_virtual_file_at(int dir_fd, const char filename, size_t max_size, char ret_contents, size_t ret_size);`
	`73`	`+static inline int read_virtual_file(const char filename, size_t max_size, char ret_contents, size_t ret_size) {`
	`74`	`+ return read_virtual_file_at(AT_FDCWD, filename, max_size, ret_contents, ret_size);`
	`75`	`+}`
`73`	`76`	`static inline int read_full_virtual_file(const char filename, char ret_contents, size_t ret_size) {`
`74`	`77`	`return read_virtual_file(filename, SIZE_MAX, ret_contents, ret_size);`
`75`	`78`	`}`