Raspberries/mraa
Private
Public Access
2
0
Fork 0
Code Activity

pwm: use posix open instead of fopen

Browse Source 
* Add safety to output char arrays and filepaths.

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Thomas Ingleby
2014-05-20 10:41:47 +01:00
committed by Brendan Le Foll
parent e2f72540ef
commit fa7180cb91
1 changed files with 79 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

131
src/pwm/pwm.c
View File

@@ -15,7 +15,7 @@
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND/
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
@@ -26,6 +26,8 @@
#include "pwm.h"
#define MAX_SIZE 64
/**
* A structure representing a PWM pin
*/
@@ -33,17 +35,18 @@ struct _pwm {
/*@{*/
int pin; /**< the pin number, as known to the os. */
int chipid; /**< the chip id, which the pwm resides */
FILE *duty_fp; /**< File pointer to duty file */
int duty_fp; /**< File pointer to duty file */
/*@}*/
};
static int
maa_pwm_setup_duty_fp(maa_pwm_context dev)
{
char bu[64];
sprintf(bu, "/sys/class/pwm/pwmchip%d/pwm%d/duty_cycle", dev->chipid, dev->pin);
char bu[MAX_SIZE];
snprintf(bu,MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/duty_cycle", dev->chipid, dev->pin);
if ((dev->duty_fp = fopen(bu, "r+b")) == NULL) {
dev->duty_fp = open(bu, O_RDWR);
if (dev->duty_fp == -1) {
return 1;
}
return 0;
@@ -52,31 +55,34 @@ maa_pwm_setup_duty_fp(maa_pwm_context dev)
static maa_result_t
maa_pwm_write_period(maa_pwm_context dev, int period)
{
FILE *period_f;
char bu[64];
sprintf(bu, "/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
char bu[MAX_SIZE];
snprintf(bu,MAX_SIZE ,"/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
if ((period_f = fopen(bu, "r+b")) == NULL) {
int period_f = open(bu, O_RDWR);
if (period_f == -1) {
fprintf(stderr, "Failed to open period for writing!\n");
return MAA_ERROR_INVALID_RESOURCE;
}
fprintf(period_f, "%d", period);
fclose(period_f);
if (ferror(period_f) != 0)
char out[MAX_SIZE];
int length = snprintf(out, MAX_SIZE, "%d", dev->pin);
if (write(period_f, out, length*sizeof(char)) == -1) {
close(period_f);
return MAA_ERROR_INVALID_RESOURCE;
}
close(period_f);
return MAA_SUCCESS;
}
static maa_result_t
maa_pwm_write_duty(maa_pwm_context dev, int duty)
{
if (dev->duty_fp == NULL) {
if (dev->duty_fp == -1) {
maa_pwm_setup_duty_fp(dev);
}
fprintf(dev->duty_fp, "%d", duty);
rewind(dev->duty_fp);
fflush(dev->duty_fp);
if (ferror(dev->duty_fp) != 0)
char bu[64];
int length = sprintf(bu, "%d", duty);
if (write(dev->duty_fp, bu, length * sizeof(char)) == -1)
return MAA_ERROR_INVALID_RESOURCE;
return MAA_SUCCESS;
}
@@ -84,17 +90,20 @@ maa_pwm_write_duty(maa_pwm_context dev, int duty)
static int
maa_pwm_get_period(maa_pwm_context dev)
{
FILE *period_f;
char bu[64];
char output[16];
char bu[MAX_SIZE];
char output[MAX_SIZE];
snprintf(bu,MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
sprintf(bu, "/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
if ((period_f = fopen(bu, "rb")) == NULL) {
int period_f = open(bu, O_RDWR);
if (period_f == -1) {
fprintf(stderr, "Failed to open period for reading!\n");
return 0;
}
fgets(output, 16, period_f);
fclose(period_f);
off_t size = lseek(period_f, 0, SEEK_END);
lseek(period_f, 0, SEEK_SET);
read(period_f, output, size + 1);
close(period_f);
int ret = strtol(output, NULL, 10);
return ret;
@@ -103,12 +112,15 @@ maa_pwm_get_period(maa_pwm_context dev)
static int
maa_pwm_get_duty(maa_pwm_context dev)
{
if (dev->duty_fp == NULL) {
if (dev->duty_fp == -1) {
maa_pwm_setup_duty_fp(dev);
} else {
lseek(dev->duty_fp, 0, SEEK_SET);
}
char output[16];
fgets(output, 16, dev->duty_fp);
fseek(dev->duty_fp, SEEK_SET, 0);
off_t size = lseek(dev->duty_fp, 0, SEEK_END);
lseek(dev->duty_fp, 0, SEEK_SET);
char output[MAX_SIZE];
read(dev->duty_fp, output, size+1);
int ret = strtol(output, NULL, 10);
return ret;
@@ -131,23 +143,27 @@ maa_pwm_init_raw(int chipin, int pin)
maa_pwm_context dev = (maa_pwm_context) malloc(sizeof(struct _pwm));
if (dev == NULL)
return NULL;
dev->duty_fp == -1;
dev->chipid = chipin;
dev->pin = pin;
FILE *export_f;
char buffer[64];
snprintf(buffer, 64, "/sys/class/pwm/pwmchip%d/export", dev->chipid);
if ((export_f = fopen(buffer, "w")) == NULL) {
char buffer[MAX_SIZE];
snprintf(buffer, MAX_SIZE, "/sys/class/pwm/pwmchip%d/export", dev->chipid);
int export_f = open(buffer, O_WRONLY);
if (export_f == -1) {
fprintf(stderr, "Failed to open export for writing!\n");
free(dev);
return NULL;
} else {
fprintf(export_f, "%d", dev->pin);
fclose(export_f);
maa_pwm_setup_duty_fp(dev);
}
char out[MAX_SIZE];
int size = snprintf(out, MAX_SIZE, "%d", dev->pin);
if (write(export_f, out, size*sizeof(char)) == -1) {
fprintf(stderr, "Failed to write to export! Potentially already enabled\n");
}
close(export_f);
maa_pwm_setup_duty_fp(dev);
return dev;
}
@@ -209,36 +225,47 @@ maa_pwm_enable(maa_pwm_context dev, int enable)
} else {
status = enable;
}
FILE *enable_f;
char bu[64];
sprintf(bu, "/sys/class/pwm/pwmchip%d/pwm%d/enable", dev->chipid, dev->pin);
char bu[MAX_SIZE];
snprintf(bu,MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/enable", dev->chipid, dev->pin);
if ((enable_f = fopen(bu, "w")) == NULL) {
int enable_f = open(bu, O_RDWR);
if (enable_f == -1) {
fprintf(stderr, "Failed to open enable for writing!\n");
return MAA_ERROR_INVALID_RESOURCE;
}
fprintf(enable_f, "%d", status);
fclose(enable_f);
if (ferror(enable_f) != 0)
char out[2];
int size = snprintf(out, sizeof(out), "%d", enable);
if (write(enable_f, out, size * sizeof(char)) == -1) {
fprintf(stderr, "Failed to write to enable!\n");
close(enable_f);
return MAA_ERROR_INVALID_RESOURCE;
}
close(enable_f);
return MAA_SUCCESS;
}
maa_result_t
maa_pwm_unexport(maa_pwm_context dev)
{
FILE *unexport_f;
char buffer[64];
snprintf(buffer, 64, "/sys/class/pwm/pwmchip%d/unexport", dev->chipid);
char filepath[MAX_SIZE];
snprintf(filepath, MAX_SIZE, "/sys/class/pwm/pwmchip%d/unexport", dev->chipid);
if ((unexport_f = fopen(buffer, "w")) == NULL) {
int unexport_f = open(filepath, O_WRONLY);
if (unexport_f == -1) {
fprintf(stderr, "Failed to open unexport for writing!\n");
return MAA_ERROR_INVALID_RESOURCE;
}
fprintf(unexport_f, "%d", dev->pin);
fclose(unexport_f);
if (ferror(unexport_f) != 0)
char out[MAX_SIZE];
int size = snprintf(out, MAX_SIZE, "%d", dev->pin);
if (write(unexport_f, out, size*sizeof(char)) == -1) {
fprintf(stderr, "Failed to write to unexport!\n");
close(unexport_f);
return MAA_ERROR_INVALID_RESOURCE;
}
close(unexport_f);
return MAA_SUCCESS;
}