data-fd-util: accept size == SIZE_MAX and translate that to strlen

Like what we already do at other places

src/shared/bus-util.c

@@ -627,7 +627,7 @@ static int method_dump_memory_state_by_fd(sd_bus_message *message, void *userdat
         if (r < 0)
                 return r;
 
-        fd = acquire_data_fd(dump, dump_size, 0);
+        fd = acquire_data_fd_full(dump, dump_size, /* flags = */ 0);
         if (fd < 0)
                 return fd;
 

src/shared/data-fd-util.c

@@ -25,7 +25,7 @@
 /* If memfd/pipe didn't work out, then let's use a file in /tmp up to a size of 1M. If it's large than that use /var/tmp instead. */
 #define DATA_FD_TMP_LIMIT (1U * U64_MB)
 
-int acquire_data_fd(const void *data, size_t size, DataFDFlags flags) {
+int acquire_data_fd_full(const void *data, size_t size, DataFDFlags flags) {
         _cleanup_close_ int fd = -EBADF;
         ssize_t n;
         int r;
@@ -51,6 +51,9 @@ int acquire_data_fd(const void *data, size_t size, DataFDFlags flags) {
          * It sucks a bit that depending on the situation we return very different objects here, but that's Linux I
          * figure. */
 
+        if (size == SIZE_MAX)
+                size = strlen(data);
+
         if (size == 0 && !FLAGS_SET(flags, ACQUIRE_NO_DEV_NULL))
                 /* As a special case, return /dev/null if we have been called for an empty data block */
                 return RET_NERRNO(open("/dev/null", O_RDONLY|O_CLOEXEC|O_NOCTTY));

src/shared/data-fd-util.h

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <stddef.h>
+#include <stdint.h>
 
 typedef enum DataFDFlags {
         ACQUIRE_NO_DEV_NULL = 1 << 0,
@@ -11,6 +12,10 @@ typedef enum DataFDFlags {
         ACQUIRE_NO_REGULAR  = 1 << 4,
 } DataFDFlags;
 
-int acquire_data_fd(const void *data, size_t size, DataFDFlags flags);
+int acquire_data_fd_full(const void *data, size_t size, DataFDFlags flags);
+static inline int acquire_data_fd(const void *data) {
+        return acquire_data_fd_full(data, SIZE_MAX, 0);
+}
+
 int copy_data_fd(int fd);
 int memfd_clone_fd(int fd, const char *name, int mode);