This will be useful for host/target tools that use stdin as
a fall back to read from when no file name is supplied.
Code is taken from the barebox version in lib/libfile.c.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
scripts/common.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++
scripts/common.h | 2 ++
2 files changed, 70 insertions(+)
diff --git a/scripts/common.c b/scripts/common.c
index 49c468a1ea35..a6eee968b79d 100644
--- a/scripts/common.c
+++ b/scripts/common.c
@@ -97,6 +97,50 @@ void *read_file(const char *filename, size_t *size)
return NULL;
}
+/**
+ * read_fd - read from a file descriptor to an allocated buffer
+ * @filename: The file descriptor to read
+ * @size: After successful return contains the size of the file
+ *
+ * This function reads a file descriptor from offset 0 until EOF to an
+ * allocated buffer.
+ *
+ * Return: On success, returns a nul-terminated buffer with the file's
+ * contents that should be deallocated with free().
+ * On error, NULL is returned and errno is set to an error code.
+ */
+void *read_fd(int fd, size_t *out_size)
+{
+ struct stat st;
+ ssize_t ret;
+ void *buf;
+
+ ret = fstat(fd, &st);
+ if (ret < 0)
+ return NULL;
+
+ /* For user convenience, we always nul-terminate the buffer in
+ * case it contains a string. As we don't want to assume the string
+ * to be either an array of char or wchar_t, we just unconditionally
+ * add 2 bytes as terminator. As the two byte terminator needs to be
+ * aligned, we just make it three bytes
+ */
+ buf = malloc(st.st_size + 3);
+ if (!buf)
+ return NULL;
+
+ ret = pread_full(fd, buf, st.st_size, 0);
+ if (ret < 0) {
+ free(buf);
+ return NULL;
+ }
+
+ memset(buf + st.st_size, '\0', 3);
+ *out_size = st.st_size;
+
+ return buf;
+}
+
int write_file(const char *filename, const void *buf, size_t size)
{
int fd, ret = 0;
@@ -147,6 +191,30 @@ int read_full(int fd, void *buf, size_t size)
return insize;
}
+/*
+ * pread_full - read to filedescriptor at offset
+ *
+ * Like pread, but this function only returns less bytes than
+ * requested when the end of file is reached.
+ */
+int pread_full(int fd, void *buf, size_t size, loff_t offset)
+{
+ size_t insize = size;
+ int now;
+
+ while (size) {
+ now = pread(fd, buf, size, offset);
+ if (now == 0)
+ break;
+ if (now < 0)
+ return now;
+ size -= now;
+ buf += now;
+ }
+
+ return insize - size;
+}
+
int write_full(int fd, const void *buf, size_t size)
{
size_t insize = size;
diff --git a/scripts/common.h b/scripts/common.h
index 399729c338f3..a0d16606b5d9 100644
--- a/scripts/common.h
+++ b/scripts/common.h
@@ -3,8 +3,10 @@
int read_file_2(const char *filename, size_t *size, void **outbuf, size_t max_size);
void *read_file(const char *filename, size_t *size);
+void *read_fd(int fd, size_t *out_size);
int write_file(const char *filename, const void *buf, size_t size);
int read_full(int fd, void *buf, size_t size);
+int pread_full(int fd, void *buf, size_t size, loff_t offset);
int write_full(int fd, const void *buf, size_t size);
#endif /* __COMMON_H */
--
2.39.5
