* sysdeps/unix/sysv/linux/getsysstats.c (next_line): Make sure there

	are always at least 4 bytes in the returned line.

2009-04-15  Jakub Jelinek  <jakub@redhat.com>

	* sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs): Check
	__libc_use_alloca (8192), if the stack is too small use 512 bytes
	instead of 8K.  Stop searching in /proc/stat after hitting first
	line not starting with cpu.
	(next_line): Truncate too long
	lines at buffer size * 3/4 instead of pretending there were line
	breaks inside of large lines.

diff --git a/ChangeLog b/ChangeLog
index 38cf5bc..bf3e96f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2009-04-15  Ulrich Drepper  <drepper@redhat.com>
+
+       * sysdeps/unix/sysv/linux/getsysstats.c (next_line): Make sure there
+       are always at least 4 bytes in the returned line.
+
+2009-04-15  Jakub Jelinek  <jakub@redhat.com>
+
+       * sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs): Check
+       __libc_use_alloca (8192), if the stack is too small use 512 bytes
+       instead of 8K.  Stop searching in /proc/stat after hitting first
+       line not starting with cpu.
+       (next_line): Truncate too long
+       lines at buffer size * 3/4 instead of pretending there were line
+       breaks inside of large lines.
+
 2009-04-14  Ulrich Drepper  <drepper@redhat.com>
 
        * sysdeps/x86_64/mp_clz_tab.c: New file.

diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c
index 28f52c0..97e20d2 100644 (file)
--- a/sysdeps/unix/sysv/linux/getsysstats.c
+++ b/sysdeps/unix/sysv/linux/getsysstats.c
@@ -93,15 +93,42 @@ next_line (int fd, char *const buffer, char **cp, char **re,
                return NULL;
 
              *re += n;
+
+             nl = memchr (*cp, '\n', *re - *cp);
+             while (nl == NULL && *re == buffer_end)
+               {
+                 /* Truncate too long lines.  */
+                 *re = buffer + 3 * (buffer_end - buffer) / 4;
+                 n = read_not_cancel (fd, *re, buffer_end - *re);
+                 if (n < 0)
+                   return NULL;
+
+                 nl = memchr (*re, '\n', n);
+                 **re = '\n';
+                 *re += n;
+               }
            }
+         else
+           nl = memchr (*cp, '\n', *re - *cp);
 
          res = *cp;
-         nl = memchr (*cp, '\n', *re - *cp);
        }
 
       if (nl == NULL)
        nl = *re - 1;
     }
+  else if (nl + 5 >= *re)
+    {
+      memmove (buffer, nl, *re - nl);
+      *re = buffer + (*re - nl);
+      nl = *cp = buffer;
+
+      ssize_t n = read_not_cancel (fd, *re, buffer_end - *re);
+      if (n < 0)
+       return NULL;
+
+      *re += n;
+    }
 
   *cp = nl + 1;
   assert (*cp <= *re);
@@ -115,8 +142,9 @@ __get_nprocs ()
 {
   /* XXX Here will come a test for the new system call.  */
 
-  char buffer[8192];
-  char *const buffer_end = buffer + sizeof (buffer);
+  const size_t buffer_size = __libc_use_alloca (8192) ? 8192 : 512;
+  char *buffer = alloca (buffer_size);
+  char *buffer_end = buffer + buffer_size;
   char *cp = buffer_end;
   char *re = buffer_end;
   int result = 1;
@@ -134,7 +162,11 @@ __get_nprocs ()
 
       char *l;
       while ((l = next_line (fd, buffer, &cp, &re, buffer_end)) != NULL)
-       if (strncmp (l, "cpu", 3) == 0 && isdigit (l[3]))
+       /* The current format of /proc/stat has all the cpu* entries
+          at the front.  We assume here that stays this way.  */
+       if (strncmp (l, "cpu", 3) != 0)
+         break;
+       else if (isdigit (l[3]))
          ++result;
 
       close_not_cancel_no_status (fd);