return n/a instead of exiting if a specific value cannot be read

slstatus.c

@@ -79,7 +79,7 @@ get_battery()
     /* open battery now file */
     if (!(fp = fopen(batterynowfile, "r"))) {
         fprintf(stderr, "Error opening battery file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read value */
@@ -91,7 +91,7 @@ get_battery()
     /* open battery full file */
     if (!(fp = fopen(batteryfullfile, "r"))) {
         fprintf(stderr, "Error opening battery file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read value */
@@ -117,7 +117,7 @@ get_cpu_temperature()
     /* open temperature file */
     if (!(fp = fopen(tempfile, "r"))) {
         fprintf(stderr, "Could not open temperature file.\n");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* extract temperature */
@@ -141,7 +141,7 @@ get_cpu_usage()
     /* open stat file */
     if (!(fp = fopen("/proc/stat","r"))) {
         fprintf(stderr, "Error opening stat file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read values */
@@ -156,7 +156,7 @@ get_cpu_usage()
     /* open stat file */
     if (!(fp = fopen("/proc/stat","r"))) {
         fprintf(stderr, "Error opening stat file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read values */
@@ -183,8 +183,8 @@ get_datetime()
     /* get time in format */
     time(&tm);
     if(!strftime(buf, bufsize, timeformat, localtime(&tm))) {
-      fprintf(stderr, "Strftime failed.\n");
-        exit(1);
+        fprintf(stderr, "Strftime failed.\n");
+        return smprintf("n/a");
     }
 
     /* return time */
@@ -202,7 +202,7 @@ get_ram_usage()
     /* open meminfo file */
     if (!(fp = fopen("/proc/meminfo", "r"))) {
         fprintf(stderr, "Error opening meminfo file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read the values */
@@ -283,7 +283,7 @@ get_wifi_signal()
     /* open wifi file */
     if(!(fp = fopen(path, "r"))) {
         fprintf(stderr, "Error opening wifi operstate file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* read the status */
@@ -294,13 +294,13 @@ get_wifi_signal()
 
     /* check if interface down */
     if(strcmp(status, "up\n") != 0){
-        return "n/a";
+        return smprintf("n/a");
     }
 
     /* open wifi file */
     if (!(fp = fopen("/proc/net/wireless", "r"))) {
         fprintf(stderr, "Error opening wireless file.");
-        exit(1);
+        return smprintf("n/a");
     }
 
     /* extract the signal strength */