[binutils-gdb] Fix GDBHISTSIZE test failure on i686

[Patrick Palka <ppalka at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0fc26cafacfff9f53d898bb73495b384b80d6d31

commit 0fc26cafacfff9f53d898bb73495b384b80d6d31
Author: Patrick Palka <patrick@parcs.ath.cx>
Date:   Tue Jun 23 10:01:38 2015 -0400

    Fix GDBHISTSIZE test failure on i686
    
    The test
    
      test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
    
    was failing on i686 because the condition in init_history() for
    determining whether to map a large GDBHISTSIZE value to infinity was
    
      long var = strtol (tmpenv);
      if (var > INT_MAX)
        history_size = unlimited;
    
    but this condition is never true on i686 because INT_MAX == LONG_MAX.
    So in order to properly map large out-of-range values of GDBHISTSIZE to
    infinity on targets where LONG_MAX > INT_MAX as well as on i686, we have
    to instead change the above condition to
    
      if (var > INT_MAX
          || (var == INT_MAX && errno == ERANGE))
        history_size = unlimited;
    
    gdb/ChangeLog:
    
    	* top.c (init_history): Look at errno after calling strtol to
    	properly map large GDBHISTSIZE values to infinity.

Diff:
---
 gdb/ChangeLog |  5 +++++
 gdb/top.c     | 10 +++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5690c2a..99ff2fb 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2015-06-23  Patrick Palka  <patrick@parcs.ath.cx>
+
+	* top.c (init_history): Look at errno after calling strtol to
+	properly map large GDBHISTSIZE values to infinity.
+
 2015-06-23  Doug Evans  <dje@google.com>
 
 	* inferior.h (struct inferior_suspend_state): Delete, unused.
diff --git a/gdb/top.c b/gdb/top.c
index 6ae84ab..77fe096 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1685,10 +1685,13 @@ init_history (void)
   if (tmpenv)
     {
       long var;
+      int saved_errno;
       char *endptr;
 
       tmpenv = skip_spaces (tmpenv);
+      errno = 0;
       var = strtol (tmpenv, &endptr, 10);
+      saved_errno = errno;
       endptr = skip_spaces (endptr);
 
       /* If GDBHISTSIZE is non-numeric then ignore it.  If GDBHISTSIZE is the
@@ -1700,7 +1703,12 @@ init_history (void)
 	;
       else if (*tmpenv == '\0'
 	       || var < 0
-	       || var > INT_MAX)
+	       || var > INT_MAX
+	       /* On targets where INT_MAX == LONG_MAX, we have to look at
+		  errno after calling strtol to distinguish between a value that
+		  is exactly INT_MAX and an overflowing value that was clamped
+		  to INT_MAX.  */
+	       || (var == INT_MAX && saved_errno == ERANGE))
 	history_size_setshow_var = -1;
       else
 	history_size_setshow_var = var;