coverity: Fix issues found by coverity scan

* Fix a few resource leaks in error conditions
* Makes strtol() calls safer in pwm module
* Make sure buffer is terminated after read() in aio

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/aio/aio.c

@@ -114,7 +114,7 @@ mraa_aio_init(unsigned int aio_channel)
 unsigned int
 mraa_aio_read(mraa_aio_context dev)
 {
-    char buffer[16];
+    char buffer[17];
     unsigned int shifter_value = 0;
 
     if (dev->adc_in_fp == -1) {
@@ -125,13 +125,15 @@ mraa_aio_read(mraa_aio_context dev)
     if (read(dev->adc_in_fp, buffer, sizeof(buffer)) < 1) {
         syslog(LOG_ERR, "Failed to read a sensible value");
     }
+    // force NULL termination of string
+    buffer[16] = '\0';
     lseek(dev->adc_in_fp, 0, SEEK_SET);
 
     errno = 0;
     char *end;
     unsigned int analog_value = (unsigned int) strtoul(buffer, &end, 10);
     if (end == &buffer[0]) {
-        syslog(LOG_ERR, "%s is not a decimal number", buffer);
+        syslog(LOG_ERR, "value is not a decimal number");
     }
     else if (errno != 0) {
         syslog(LOG_ERR, "errno was set");

src/gpio/gpio.c

@@ -87,6 +87,11 @@ mraa_gpio_init_raw(int pin)
     int length;
 
     mraa_gpio_context dev = (mraa_gpio_context) malloc(sizeof(struct _gpio));
+    if (dev == NULL) {
+        syslog(LOG_CRIT, "Failed to allocate memory for context");
+        return NULL;
+    }
+
     memset(dev, 0, sizeof(struct _gpio));
     dev->value_fp = -1;
     dev->isr_value_fp = -1;
@@ -102,6 +107,7 @@ mraa_gpio_init_raw(int pin)
         int export = open(SYSFS_CLASS_GPIO "/export", O_WRONLY);
         if (export == -1) {
             syslog(LOG_ERR, "Failed to open export for writing");
+	    free(dev);
             return NULL;
         }
         length = snprintf(bu, sizeof(bu), "%d", dev->pin);
@@ -556,6 +562,7 @@ mraa_gpio_use_mmaped(mraa_gpio_context dev, mraa_boolean_t mmap_en)
             fd = open(mmp->mem_dev, O_RDWR);
             if (fd < 1) {
                 syslog(LOG_ERR, "Unable to open memory device");
+                close(fd);
                 return MRAA_ERROR_INVALID_RESOURCE;
             }
             dev->reg_sz = mmp->mem_sz;

src/i2c/i2c.c

@@ -55,8 +55,10 @@ mraa_i2c_init_raw(unsigned int bus)
             return NULL;
     }
     mraa_i2c_context dev = (mraa_i2c_context) malloc(sizeof(struct _i2c));
-    if (dev == NULL)
+    if (dev == NULL) {
+        syslog(LOG_CRIT, "Failed to allocate memory for context");
         return NULL;
+    }
 
     char filepath[32];
     snprintf(filepath, 32, "/dev/i2c-%u", bus);
@@ -96,9 +98,6 @@ uint8_t
 mraa_i2c_read_byte(mraa_i2c_context dev)
 {
     uint8_t byte = i2c_smbus_read_byte(dev->fh);
-    if (byte < 0) {
-        return -1;
-    }
     return byte;
 }
 

src/intel_edison_fab_c.c

@@ -69,6 +69,7 @@ mraa_intel_edison_pinmode_change(int sysfs, int mode)
     char mode_buf[MAX_MODE_SIZE];
     int length = sprintf(mode_buf, "mode%u",mode);
     if (write(modef, mode_buf, length*sizeof(char)) == -1) {
+        close(modef);
         return MRAA_ERROR_INVALID_RESOURCE;
     }
     close(modef);
@@ -404,6 +405,7 @@ mraa_intel_edison_fab_c()
     if (tristate == NULL) {
         syslog(LOG_CRIT, "Intel Edison Failed to initialise Arduino board TriState,\
                 check i2c devices! FATAL\n");
+        free(b);
         return NULL;
     }
     mraa_gpio_dir(tristate, MRAA_GPIO_OUT);

src/intel_galileo_rev_g.c

@@ -153,9 +153,10 @@ mraa_intel_galileo_gen2_gpio_mode_replace(mraa_gpio_context dev, gpio_mode_t mod
     }
     if (value != -1) {
         sta = mraa_gpio_dir(pullup_e, MRAA_GPIO_OUT);
-        sta = mraa_gpio_write(pullup_e, value);
+        sta += mraa_gpio_write(pullup_e, value);
         if (sta != MRAA_SUCCESS) {
             syslog(LOG_ERR, "Galileo Gen 2: Error Setting pullup");
+            close(drive);
             return sta;
         }
     }

src/pwm/pwm.c

@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <limits.h>
 
 #include "pwm.h"
 #include "mraa_internal.h"
@@ -100,9 +101,18 @@ mraa_pwm_read_period(mraa_pwm_context dev)
 
     read(period_f, output, size + 1);
     close(period_f);
-    int ret = strtol(output, NULL, 10);
 
-    return ret;
+    char *endptr;
+    long int ret = strtol(output, &endptr, 10);
+    if ('\0' != *endptr) {
+        syslog(LOG_ERR, "error in string converstion");
+        return -1;
+    }
+    else if (ret > INT_MAX || ret < INT_MIN) {
+        syslog(LOG_ERR, "number is invalid");
+        return -1;
+    }
+    return (int) ret;
 }
 
 static int
@@ -118,8 +128,17 @@ mraa_pwm_read_duty(mraa_pwm_context dev)
     char output[MAX_SIZE];
     read(dev->duty_fp, output, size+1);
 
-    int ret = strtol(output, NULL, 10);
+    char *endptr;
-    return ret;
+    long int ret = strtol(output, &endptr, 10);
+    if ('\0' != *endptr) {
+        syslog(LOG_ERR, "error in string converstion");
+        return -1;
+    }
+    else if (ret > INT_MAX || ret < INT_MIN) {
+        syslog(LOG_ERR, "number is invalid");
+        return -1;
+    }
+    return (int) ret;
 }
 
 mraa_pwm_context
@@ -178,6 +197,7 @@ mraa_pwm_init_raw(int chipin, int pin)
         if (write(export_f, out, size*sizeof(char)) == -1) {
             syslog(LOG_WARNING, "Failed to write to export! Potentially already enabled");
             close(export_f);
+            free(dev);
             return NULL;
         }
         dev->owner = 1;