swap_*(): add more error tests

diff --git a/slstatus.c b/slstatus.c
index c92da0da6d12a6eef6ba34d8f3ff39293936b746..ccb7cbeb02918e32d0cddbd8b1ec0dbf375c9c60 100644 (file)
--- a/slstatus.c
+++ b/slstatus.c
@@ -439,9 +439,15 @@ swap_free(void)
                warn("Failed to open file /proc/meminfo");
                return smprintf(UNKNOWN_STR);
        }
-       bytes_read = fread(buf, sizeof(char), sizeof(buf), fp);
+
+       if ((bytes_read = fread(buf, sizeof(char), sizeof(buf), fp)) == 0) {
+               warn("swap_free: read error");
+               fclose(fp);
+       }
+
        buf[bytes_read] = '\0';
        fclose(fp);
+
        if (bytes_read == 0 || bytes_read == sizeof(buf)) {
                warn("Failed to read from /proc/meminfo");
                return smprintf(UNKNOWN_STR);
@@ -473,9 +479,11 @@ swap_perc(void)
                warn("Failed to open file /proc/meminfo");
                return smprintf(UNKNOWN_STR);
        }
+
        bytes_read = fread(buf, sizeof(char), sizeof(buf), fp);
        buf[bytes_read] = '\0';
        fclose(fp);
+
        if (bytes_read == 0 || bytes_read == sizeof(buf)) {
                warn("Failed to read from /proc/meminfo");
                return smprintf(UNKNOWN_STR);
@@ -487,12 +495,17 @@ swap_perc(void)
                return smprintf(UNKNOWN_STR);
        }
 
-       match = strstr(buf, "SwapCached");
+       if ((match = strstr(buf, "SwapCached")) == NULL) {
+               return smprintf("%s", UNKNOWN_STR);
+       }
        sscanf(match, "SwapCached: %ld kB\n", &cached);
 
-       match = strstr(buf, "SwapFree");
+       if ((match = strstr(buf, "SwapFree")) == NULL) {
+               return smprintf("%s", UNKNOWN_STR);
+       }
        sscanf(match, "SwapFree: %ld kB\n", &free);
 
+
        return smprintf("%d%%", 100 * (total - free - cached) / total);
 }