Blob Blame History Raw
diff --git a/src/os/linux/vm/os_linux.cpp b/src/os/linux/vm/os_linux.cpp
--- openjdk/hotspot/src/os/linux/vm/os_linux.cpp
+++ openjdk/hotspot/src/os/linux/vm/os_linux.cpp
@@ -2763,39 +2763,47 @@
 // writing thread stacks don't use growable mappings (i.e. those
 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
 // only applies to the main thread.
-
-static
-bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
-
-  char buf[128];
-  int fd, sz;
-
-  if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
+static bool
+get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
+{
+  FILE *f = fopen("/proc/self/maps", "r");
+  if (f == NULL)
     return false;
-  }
-
-  const char kw[] = "[stack]";
-  const int kwlen = sizeof(kw)-1;
-
-  // Address part of /proc/self/maps couldn't be more than 128 bytes
-  while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
-     if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
-        // Extract addresses
-        if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
-           uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
-           if (sp >= *bottom && sp <= *top) {
-              ::close(fd);
-              return true;
-           }
+
+  while (!feof(f)) {
+    size_t dummy;
+    char *str = NULL;
+    ssize_t len = getline(&str, &dummy, f);
+    if (len == -1) {
+      fclose(f);
+      if (str != NULL)
+	free(str);
+      return false;
+    }
+
+    if (len > 0 && str[len-1] == '\n') {
+      str[len-1] = 0;
+      len--;
+    }
+
+    static const char *stack_str = "[stack]";
+    if (len > (ssize_t)strlen(stack_str)
+       && (strcmp(str + len - strlen(stack_str), stack_str) == 0)) {
+      if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
+        uintptr_t sp = (uintptr_t)__builtin_frame_address(0);
+        if (sp >= *bottom && sp <= *top) {
+          free(str);
+          fclose(f);
+          return true;
         }
-     }
-  }
-
- ::close(fd);
+      }
+    }
+    free(str);
+  }
+  fclose(f);
   return false;
 }
 
-
 // If the (growable) stack mapping already extends beyond the point
 // where we're going to put our guard pages, truncate the mapping at
 // that point by munmap()ping it.  This ensures that when we later
diff --git a/src/share/vm/runtime/os.cpp b/src/share/vm/runtime/os.cpp
--- openjdk/hotspot/src/share/vm/runtime/os.cpp
+++ openjdk/hotspot/src/share/vm/runtime/os.cpp
@@ -1353,43 +1353,6 @@
   return result;
 }
 
-// Read file line by line, if line is longer than bsize,
-// skip rest of line.
-int os::get_line_chars(int fd, char* buf, const size_t bsize){
-  size_t sz, i = 0;
-
-  // read until EOF, EOL or buf is full
-  while ((sz = (int) read(fd, &buf[i], 1)) == 1 && i < (bsize-2) && buf[i] != '\n') {
-     ++i;
-  }
-
-  if (buf[i] == '\n') {
-    // EOL reached so ignore EOL character and return
-
-    buf[i] = 0;
-    return (int) i;
-  }
-
-  buf[i+1] = 0;
-
-  if (sz != 1) {
-    // EOF reached. if we read chars before EOF return them and
-    // return EOF on next call otherwise return EOF
-
-    return (i == 0) ? -1 : (int) i;
-  }
-
-  // line is longer than size of buf, skip to EOL
-  char ch;
-  while (read(fd, &ch, 1) == 1 && ch != '\n') {
-    // Do nothing
-  }
-
-  // return initial part of line that fits in buf.
-  // If we reached EOF, it will be returned on next call.
-
-  return (int) i;
-}
 
 void os::SuspendedThreadTask::run() {
   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");

diff --git a/src/share/vm/runtime/os.hpp b/src/share/vm/runtime/os.hpp
--- openjdk/hotspot/src/share/vm/runtime/os.hpp
+++ openjdk/hotspot/src/share/vm/runtime/os.hpp
@@ -672,10 +672,6 @@
   // Hook for os specific jvm options that we don't want to abort on seeing
   static bool obsolete_option(const JavaVMOption *option);
 
-  // Read file line by line. If line is longer than bsize,
-  // rest of line is skipped. Returns number of bytes read or -1 on EOF
-  static int get_line_chars(int fd, char *buf, const size_t bsize);
-
   // Extensions
 #include "runtime/os_ext.hpp"