add buf_size parameter tolibgamma_list_methods

Signed-off-by: Mattias Andrée <maandree@operamail.com>

3 files changed, 40 insertions, 36 deletions

diff --git a/src/libgamma-facade.c b/src/libgamma-facade.c
index 25a7ba8..528a2fd 100644
--- a/src/libgamma-facade.c
+++ b/src/libgamma-facade.c
@@ -159,6 +159,9 @@ static int libgamma_list_method_test(int method, int operation)
  * List available adjustment methods by their order of preference based on the environment
  * 
  * @param  methods    Output array of methods, should be able to hold `GAMMA_METHOD_COUNT` elements
+ * @þaram  buf_size   The number of elements that fits in `methods`, it should be `GAMMA_METHOD_COUNT`,
+ *                    This is used to avoid writing outside the output buffer if this library adds new
+ *                    adjustment methods without the users of the library recompiling
  * @param  operation  Allowed values:
  *                      0: Methods that the environment suggests will work, excluding fake.
  *                      1: Methods that the environment suggests will work, including fake.
@@ -166,9 +169,10 @@ static int libgamma_list_method_test(int method, int operation)
  *                      3: All real methods.
  *                      4: All methods.
  *                    Other values invoke undefined behaviour.
- * @return            The number of element that have been stored in `methods`
+ * @return            The number of element that have been stored in `methods`, or should
+ *                    have been stored if the buffer was large enought
  */
-size_t libgamma_list_methods(int* restrict methods, int operation)
+size_t libgamma_list_methods(int* restrict methods, size_t buf_size, int operation)
 {
 #ifdef HAVE_NO_GAMMA_METHODS
   (void) methods;
@@ -178,28 +182,28 @@ size_t libgamma_list_methods(int* restrict methods, int operation)
   size_t n = 0;
   
 #ifdef HAVE_GAMMA_METHOD_X_RANDR
-  if (libgamma_list_method_test(GAMMA_METHOD_X_RANDR, operation))
-    methods[n++] = GAMMA_METHOD_X_RANDR;
+  if (libgamma_list_method_test(GAMMA_METHOD_X_RANDR, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_X_RANDR;
 #endif
 #ifdef HAVE_GAMMA_METHOD_X_VIDMODE
-  if (libgamma_list_method_test(GAMMA_METHOD_X_VIDMODE, operation))
-    methods[n++] = GAMMA_METHOD_X_VIDMODE;
+  if (libgamma_list_method_test(GAMMA_METHOD_X_VIDMODE, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_X_VIDMODE;
 #endif
 #ifdef HAVE_GAMMA_METHOD_LINUX_DRM
-  if (libgamma_list_method_test(GAMMA_METHOD_LINUX_DRM, operation))
-    methods[n++] = GAMMA_METHOD_LINUX_DRM;
+  if (libgamma_list_method_test(GAMMA_METHOD_LINUX_DRM, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_LINUX_DRM;
 #endif
 #ifdef HAVE_GAMMA_METHOD_W32_GDI
-  if (libgamma_list_method_test(GAMMA_METHOD_W32_GDI, operation))
-    methods[n++] = GAMMA_METHOD_W32_GDI;
+  if (libgamma_list_method_test(GAMMA_METHOD_W32_GDI, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_W32_GDI;
 #endif
 #ifdef HAVE_GAMMA_METHOD_QUARTZ_CORE_GRAPHICS
-  if (libgamma_list_method_test(GAMMA_METHOD_QUARTZ_CORE_GRAPHICS, operation))
-    methods[n++] = GAMMA_METHOD_QUARTZ_CORE_GRAPHICS;
+  if (libgamma_list_method_test(GAMMA_METHOD_QUARTZ_CORE_GRAPHICS, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_QUARTZ_CORE_GRAPHICS;
 #endif
 #ifdef HAVE_GAMMA_METHOD_DUMMY
-  if (libgamma_list_method_test(GAMMA_METHOD_DUMMY, operation))
-    methods[n++] = GAMMA_METHOD_DUMMY;
+  if (libgamma_list_method_test(GAMMA_METHOD_DUMMY, operation) && (n++ < buf_size))
+    methods[n - 1] = GAMMA_METHOD_DUMMY;
 #endif
   
   return n;
diff --git a/src/libgamma-facade.h b/src/libgamma-facade.h
index ecc3b13..f3d6ef8 100644
--- a/src/libgamma-facade.h
+++ b/src/libgamma-facade.h
@@ -77,6 +77,9 @@ typedef double libgamma_gamma_rampsd_fun(double encoding);
  * List available adjustment methods by their order of preference based on the environment
  * 
  * @param  methods    Output array of methods, should be able to hold `GAMMA_METHOD_COUNT` elements
+ * @þaram  buf_size   The number of elements that fits in `methods`, it should be `GAMMA_METHOD_COUNT`,
+ *                    This is used to avoid writing outside the output buffer if this library adds new
+ *                    adjustment methods without the users of the library recompiling
  * @param  operation  Allowed values:
  *                      0: Methods that the environment suggests will work, excluding fake.
  *                      1: Methods that the environment suggests will work, including fake.
@@ -84,9 +87,10 @@ typedef double libgamma_gamma_rampsd_fun(double encoding);
  *                      3: All real methods.
  *                      4: All methods.
  *                    Other values invoke undefined behaviour.
- * @return            The number of element that have been stored in `methods`
+ * @return            The number of element that have been stored in `methods`, or should
+ *                    have been stored if the buffer was large enought
  */
-size_t libgamma_list_methods(int* restrict methods, int operation);
+size_t libgamma_list_methods(int* restrict methods, size_t buf_size, int operation);
 
 /**
  * Return the capabilities of an adjustment method
diff --git a/test/test.c b/test/test.c
index 9dc3b1b..4b499b3 100644
--- a/test/test.c
+++ b/test/test.c
@@ -18,35 +18,31 @@
 #include <libgamma.h>
 
 #include <stdio.h>
+#include <stdlib.h>
 
 
 int main(void)
 {
-  int methods[GAMMA_METHOD_COUNT];
-  size_t n = libgamma_list_methods(methods, 0);
+  int* methods = malloc(GAMMA_METHOD_COUNT * sizeof(int));
+  size_t n = libgamma_list_methods(methods, GAMMA_METHOD_COUNT, 0);
   size_t i;
   
+  if (n > GAMMA_METHOD_COUNT)
+    {
+      printf("Warning: you should to recompile the program, libgamma has been updated.\n");
+      methods = realloc(methods, n * sizeof(int));
+      libgamma_list_methods(methods, n, 0);
+    }
+  
   for (i = 0; i < n; i++)
     switch (methods[i])
       {
-      case GAMMA_METHOD_DUMMY:
-	printf("dummy\n");
-	break;
-      case GAMMA_METHOD_X_RANDR:
-	printf("RandR X extension\n");
-	break;
-      case GAMMA_METHOD_X_VIDMODE:
-	printf("VidMode X extension\n");
-	break;
-      case GAMMA_METHOD_LINUX_DRM:
-	printf("Linux DRM\n");
-	break;
-      case GAMMA_METHOD_W32_GDI:
-	printf("Windows GDI\n");
-	break;
-      case GAMMA_METHOD_QUARTZ_CORE_GRAPHICS:
-	printf("Quartz using Core Graphics\n");
-	break;
+      case GAMMA_METHOD_DUMMY:                 printf("dummy\n");                       break;
+      case GAMMA_METHOD_X_RANDR:               printf("RandR X extension\n");           break;
+      case GAMMA_METHOD_X_VIDMODE:             printf("VidMode X extension\n");         break;
+      case GAMMA_METHOD_LINUX_DRM:             printf("Linux DRM\n");                   break;
+      case GAMMA_METHOD_W32_GDI:               printf("Windows GDI\n");                 break;
+      case GAMMA_METHOD_QUARTZ_CORE_GRAPHICS:  printf("Quartz using Core Graphics\n");  break;
       default:
 #if GAMMA_METHOD_COUNT != 6
 # warning List of adjustment methods is out of date