Currently we wrap our fd inside a FILE* stream to make use of vfprintf,
but the man page leaves the question of errno and signal handling in
doubt. It is documented as returning a negative value and setting
ferror(), but we have been interpreting errno to handle signal
restarting. As that is in doubt, reduce it to a sprintf and reuse our
common interrupt handling write() that already returns -errno.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Katarzyna Dec <katarzyna.dec@xxxxxxxxx>
---
lib/igt_sysfs.c | 37 ++++++++++++++++++++++++++-----------
1 file changed, 26 insertions(+), 11 deletions(-)
diff --git a/lib/igt_sysfs.c b/lib/igt_sysfs.c
index 8efe889be..b39da4c2a 100644
--- a/lib/igt_sysfs.c
+++ b/lib/igt_sysfs.c
@@ -387,22 +387,37 @@ int igt_sysfs_scanf(int dir, const char *attr, const char *fmt, ...)
int igt_sysfs_vprintf(int dir, const char *attr, const char *fmt, va_list ap)
{
- FILE *file;
- int fd;
- int ret = -1;
+ char stack[128], *buf = stack;
+ va_list tmp;
+ int ret, fd;
fd = openat(dir, attr, O_WRONLY);
if (fd < 0)
- return -1;
+ return -errno;
- file = fdopen(fd, "w");
- if (file) {
- do {
- ret = vfprintf(file, fmt, ap);
- } while (ret == -1 && errno == EINTR);
- fclose(file);
+ va_copy(tmp, ap);
+ ret = vsnprintf(buf, sizeof(stack), fmt, tmp);
+ va_end(tmp);
+ if (ret < 0)
+ return -EINVAL;
+
+ if (ret > sizeof(stack)) {
+ int len = ret + 1;
+
+ buf = malloc(len);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = vsnprintf(buf, ret, fmt, ap);
+ if (ret > len) {
+ free(buf);
+ return -EINVAL;
+ }
}
- close(fd);
+
+ ret = writeN(fd, buf, ret);
+ if (buf != stack)
+ free(buf);
return ret;
}
--
2.19.0.rc1
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