Add a new function libxl_read_sysfs_file_contents to handle sysfs file
specially. It would be used in later pvusb work.
Signed-off-by: Chunyan Liu <cy...@suse.com>
Acked-by: Ian Jackson <ian.jack...@eu.citrix.com>
---
tools/libxl/libxl_internal.h | 4 +++
tools/libxl/libxl_utils.c | 74 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 78 insertions(+)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 9c8519a..429ea32 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -4078,6 +4078,10 @@ void libxl__bitmap_copy_best_effort(libxl__gc *gc,
libxl_bitmap *dptr,
int libxl__count_physical_sockets(libxl__gc *gc, int *sockets);
+_hidden int libxl__read_sysfs_file_contents(libxl__gc *gc,
+ const char *filename,
+ void **data_r,
+ int *datalen_r);
#define LIBXL_QEMU_USER_PREFIX "xen-qemuuser"
#define LIBXL_QEMU_USER_BASE LIBXL_QEMU_USER_PREFIX"-domid"
diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c
index 672d3f8..b0cb9e1 100644
--- a/tools/libxl/libxl_utils.c
+++ b/tools/libxl/libxl_utils.c
@@ -396,6 +396,80 @@ int libxl_read_file_contents(libxl_ctx *ctx, const char
*filename,
return e;
}
+int libxl__read_sysfs_file_contents(libxl__gc *gc, const char *filename,
+ void **data_r, int *datalen_r)
+{
+ FILE *f = 0;
+ uint8_t *data = 0;
+ int datalen = 0;
+ int e;
+ struct stat stab;
+ ssize_t rs;
+
+ f = fopen(filename, "r");
+ if (!f) {
+ if (errno == ENOENT) return ENOENT;
+ LOGE(ERROR, "failed to open %s", filename);
+ goto xe;
+ }
+
+ if (fstat(fileno(f), &stab)) {
+ LOGE(ERROR, "failed to fstat %s", filename);
+ goto xe;
+ }
+
+ if (!S_ISREG(stab.st_mode)) {
+ LOGE(ERROR, "%s is not a plain file", filename);
+ errno = ENOTTY;
+ goto xe;
+ }
+
+ if (stab.st_size > INT_MAX) {
+ LOG(ERROR, "file %s is far too large", filename);
+ errno = EFBIG;
+ goto xe;
+ }
+
+ datalen = stab.st_size;
+
+ if (stab.st_size && data_r) {
+ data = libxl__malloc(gc, datalen);
+
+ /* For sysfs file, datalen is always PAGE_SIZE. 'read'
+ * will return the number of bytes of the actual content,
+ * rs <= datalen is expected.
+ */
+ rs = fread(data, 1, datalen, f);
+ if (rs < datalen) {
+ if (ferror(f)) {
+ LOGE(ERROR, "failed to read %s", filename);
+ goto xe;
+ }
+
+ datalen = rs;
+ data = libxl__realloc(gc, data, datalen);
+ }
+ }
+
+ if (fclose(f)) {
+ f = 0;
+ LOGE(ERROR, "failed to close %s", filename);
+ goto xe;
+ }
+
+ if (data_r) *data_r = data;
+ if (datalen_r) *datalen_r = datalen;
+
+ return 0;
+
+ xe:
+ e = errno;
+ assert(e != ENOENT);
+ if (f) fclose(f);
+ return e;
+}
+
+
#define READ_WRITE_EXACTLY(rw, zero_is_eof, constdata) \
\
int libxl_##rw##_exactly(libxl_ctx *ctx, int fd, \
--
2.1.4
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