Processing (Linux): return errors more actively

fix assertion errors

Author: CarterLi

src/common/processing_linux.c

@@ -245,7 +245,7 @@ const char* ffProcessGetBasicInfoLinux(pid_t pid, FFstrbuf* name, pid_t* ppid, i
         snprintf(procFilePath, sizeof(procFilePath), "/proc/%d/stat", (int)pid);
         char buf[PROC_FILE_BUFFSIZ];
         ssize_t nRead = ffReadFileData(procFilePath, sizeof(buf) - 1, buf);
-        if(nRead < 0)
+        if(nRead <= 8)
             return "ffReadFileData(/proc/pid/stat, PROC_FILE_BUFFSIZ-1, buf) failed";
         buf[nRead] = '\0';
 
@@ -268,7 +268,7 @@ const char* ffProcessGetBasicInfoLinux(pid_t pid, FFstrbuf* name, pid_t* ppid, i
     {
         snprintf(procFilePath, sizeof(procFilePath), "/proc/%d/comm", (int)pid);
         ssize_t nRead = ffReadFileBuffer(procFilePath, name);
-        if(nRead < 0)
+        if(nRead <= 0)
             return "ffReadFileBuffer(/proc/pid/comm, name) failed";
         ffStrbufTrimRightSpace(name);
     }