From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chunyan Liu Subject: [PATCH V4 2/7] libxl_read_file_contents: add new entry to read sysfs file Date: Wed, 10 Jun 2015 11:20:36 +0800 Message-ID: <1433906441-3280-3-git-send-email-cyliu@suse.com> References: <1433906441-3280-1-git-send-email-cyliu@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1433906441-3280-1-git-send-email-cyliu@suse.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: george.dunlap@eu.citrix.com, wei.liu2@citrix.com, Ian.Jackson@eu.citrix.com, ian.campbell@citrix.com, Chunyan Liu List-Id: xen-devel@lists.xenproject.org Sysfs file has size=4096 but actual file content is less than that. Current libxl_read_file_contents will treat it as error when file size and actual file content differs, so reading sysfs file content with this function always fails. Add a new entry libxl_read_sysfs_file_contents to handle sysfs file specially. It would be used in later pvusb work. Signed-off-by: Chunyan Liu --- Changes: - instead of hacking lixbl_read_file_contents for sysfs file, add a new entry libxl_read_sysfs_file_contents to do the work. tools/libxl/libxl_utils.c | 24 ++++++++++++++++++++---- tools/libxl/libxl_utils.h | 2 ++ 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c index f6be2d7..d0d56c2 100644 --- a/tools/libxl/libxl_utils.c +++ b/tools/libxl/libxl_utils.c @@ -322,8 +322,10 @@ out: return rc; } -int libxl_read_file_contents(libxl_ctx *ctx, const char *filename, - void **data_r, int *datalen_r) { +static int libxl_read_file_contents_core(libxl_ctx *ctx, const char *filename, + void **data_r, int *datalen_r, + bool is_sysfs_file) +{ GC_INIT(ctx); FILE *f = 0; uint8_t *data = 0; @@ -360,15 +362,16 @@ int libxl_read_file_contents(libxl_ctx *ctx, const char *filename, if (stab.st_size && data_r) { data = malloc(datalen); + memset(data, 0, datalen); if (!data) goto xe; rs = fread(data, 1, datalen, f); - if (rs != datalen) { + if (rs != datalen && !(feof(f) && is_sysfs_file)) { if (ferror(f)) LOGE(ERROR, "failed to read %s", filename); else if (feof(f)) LOG(ERROR, "%s changed size while we were reading it", - filename); + filename); else abort(); goto xe; @@ -396,6 +399,19 @@ int libxl_read_file_contents(libxl_ctx *ctx, const char *filename, return e; } +int libxl_read_file_contents(libxl_ctx *ctx, const char *filename, + void **data_r, int *datalen_r) +{ + return libxl_read_file_contents_core(ctx, filename, data_r, datalen_r, 0); +} + +int libxl_read_sysfs_file_contents(libxl_ctx *ctx, const char *filename, + void **data_r, int *datalen_r) +{ + return libxl_read_file_contents_core(ctx, filename, data_r, datalen_r, 1); +} + + #define READ_WRITE_EXACTLY(rw, zero_is_eof, constdata) \ \ int libxl_##rw##_exactly(libxl_ctx *ctx, int fd, \ diff --git a/tools/libxl/libxl_utils.h b/tools/libxl/libxl_utils.h index 1c1761d..7639662 100644 --- a/tools/libxl/libxl_utils.h +++ b/tools/libxl/libxl_utils.h @@ -38,6 +38,8 @@ int libxl_is_stubdom(libxl_ctx *ctx, uint32_t domid, uint32_t *target_domid); int libxl_create_logfile(libxl_ctx *ctx, const char *name, char **full_name); int libxl_string_to_backend(libxl_ctx *ctx, char *s, libxl_disk_backend *backend); +int libxl_read_sysfs_file_contents(libxl_ctx *ctx, const char *filename, + void **data_r, int *datalen_r); int libxl_read_file_contents(libxl_ctx *ctx, const char *filename, void **data_r, int *datalen_r); /* Reads the contents of the plain file filename into a mallocd -- 2.1.4