PWN-Hunter/android_hardware_samsung
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lights: Cleanup read/write API

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* Use O_WRONLY for write
 * Return errno for write
 * Log all failures
 * Fix read_int():
   We would always treat strtol(...) = 0 as an error,
   although the real value can very well be 0.
   Check the end pointer to fix this.

Change-Id: Id2bc9acc103a7a6400dd06f3904af37cbb0b5174
This commit is contained in:
Christopher N. Hesse 2017-03-04 15:16:56 +01:00
parent b5b9500a62
commit 209f5deec3
1 changed files with 43 additions and 35 deletions
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78
liblights/lights_helper.c
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@ -28,38 +28,44 @@
* Reads an Integer from a file.
*
* @param path The absolute path string.
* @return The Integer with decimal base, -1 on error.
* @return The Integer with decimal base, -1 or errno on error.
*/
int read_int(char const *path)
{
int fd, len;
int num_bytes = 10;
char buf[11];
int retval;
int ret;
fd = open(path, O_RDONLY);
if (fd < 0) {
ALOGE("%s: failed to open %s", __func__, path);
goto fail;
ret = errno;
ALOGE("%s: failed to open %s (%s)", __func__, path, strerror(errno));
goto exit;
}
len = read(fd, buf, num_bytes - 1);
if (len < 0) {
ALOGE("%s: failed to read from %s", __func__, path);
goto fail;
ret = errno;
ALOGE("%s: failed to read from %s (%s)", __func__, path, strerror(errno));
goto exit;
}
buf[len] = '\0';
close(fd);
// no endptr, decimal base
retval = strtol(buf, NULL, 10);
return retval == 0 ? -1 : retval;
// decimal base
char *endptr = NULL;
ret = strtol(buf, &endptr, 10);
if (ret == 0 && endptr == NULL) {
ret = -1;
ALOGE("%s: failed to extract number from string %s", __func__, buf);
goto exit;
}
fail:
exit:
if (fd >= 0)
close(fd);
return -1;
return ret;
}
/*
@ -67,38 +73,40 @@ fail:
*
* @param path The absolute path string.
* @param value The Integer value to be written.
* @return 0 on success, -1 or errno on error.
* @return 0 on success, errno on error.
*/
int write_int(char const *path, const int value)
{
int fd;
static int already_warned;
int fd, len;
int ret = 0;
already_warned = 0;
ALOGV("write_int: path %s, value %d", path, value);
fd = open(path, O_RDWR);
if (fd >= 0) {
char buffer[20];
int bytes = sprintf(buffer, "%d", value);
int amt = write(fd, buffer, bytes);
close(fd);
return amt == -1 ? -errno : 0;
} else {
if (already_warned == 0) {
ALOGE("write_int failed to open %s", path);
already_warned = 1;
}
return -errno;
fd = open(path, O_WRONLY);
if (fd < 0) {
ret = errno;
ALOGE("%s: failed to open %s (%s)", __func__, path, strerror(errno));
goto exit;
}
char buffer[20];
int bytes = sprintf(buffer, "%d", value);
len = write(fd, buffer, bytes);
if (len < 0) {
ret = errno;
ALOGE("%s: failed to write to %s (%s)", __func__, path, strerror(errno));
goto exit;
}
exit:
if (fd >= 0)
close(fd);
return ret;
}
/*
* Set the current button brightness via sysfs.
*
* @param brightness The brightness value.
* @return 0 on success, -1 or errno on error.
* @return 0 on success, errno on error.
*/
inline int set_cur_button_brightness(const int brightness)
{
@ -129,7 +137,7 @@ inline int get_max_panel_brightness()
* Set the current panel brightness via sysfs.
*
* @param brightness The (scaled) brightness value.
* @return 0 on success, -1 or errno on error.
* @return 0 on success, errno on error.
*/
inline int set_cur_panel_brightness(const int brightness)
{
@ -140,7 +148,7 @@ inline int set_cur_panel_brightness(const int brightness)
* Set the maximum panel brightness via sysfs.
*
* @param brightness The brightness value.
* @return 0 on success, -1 or errno on error.
* @return 0 on success, errno on error.
*/
inline int set_max_panel_brightness(const int brightness)
{