widl: add pseudo random build file generation

Signed-off-by: Marko Semet <marko@marko10-000.de>

tools/widl/parser.l

@@ -543,7 +543,7 @@ int do_import(char *fname)
     line_number = 1;
 
     name = xstrdup( "widl.XXXXXX" );
-    if((fd = mkstemps( name, 0 )) == -1)
+    if((fd = pseudorandom_tempfile(name)) == -1)
         error("Could not generate a temp name from %s\n", name);
 
     temp_name = name;
@@ -584,7 +584,7 @@ static void switch_to_acf(void)
     line_number = 1;
 
     name = xstrdup( "widl.XXXXXX" );
-    if((fd = mkstemps( name, 0 )) == -1)
+    if((fd = pseudorandom_tempfile(name)) == -1)
         error("Could not generate a temp name from %s\n", name);
 
     temp_name = name;

tools/widl/utils.c

@@ -474,3 +474,187 @@ void align_output( unsigned int align )
     memset( output_buffer + output_buffer_pos, 0, size );
     output_buffer_pos += size;
 }
+
+/* xorshift* random generator. Source: https://en.wikipedia.org/wiki/Xorshift#xorshift* */
+static uint64_t pseudorandom_state = 1;
+static const char* pseudorandom_source = NULL;
+static size_t pseudorandom_source_size = 0;
+
+static uint64_t pseudorandom_algo(uint64_t* generator_state, uint64_t add_to_state)
+{
+    uint64_t tmp = (*generator_state) + add_to_state;
+    tmp ^= tmp >> 12;
+    tmp ^= tmp << 25;
+    tmp ^= tmp >> 27;
+    (*generator_state) = tmp;
+    return tmp * UINT64_C(0x2545F4914F6CDD1D);
+}
+
+uint64_t pseudorandom(uint64_t add_to_state)
+{
+    return pseudorandom_algo(&pseudorandom_state, add_to_state);
+}
+
+char pseudorandom_char(void)
+{
+    char tmp;
+    tmp = (char) (pseudorandom(0) % 62);
+    if (tmp < 10)
+    {
+        return '0' + tmp;
+    }
+    else if (tmp < 36)
+    {
+        return 'A' + (tmp - 10);
+    }
+    else
+    {
+        return 'a' + (tmp - 36);
+    }
+}
+
+int pseudorandom_tempfile(char* file)
+{
+    /* variables */
+    int result;
+
+    int counter;
+    char *filename_pos;
+
+    char *debug_filename;
+    FILE *debug_file;
+
+    /* replaces Xs */
+    for (filename_pos = file; (*filename_pos) != 0; filename_pos++)
+    {
+        if ((*filename_pos) == 'X')
+        {
+            (*filename_pos) = pseudorandom_char();
+        }
+    }
+
+    /* try to open file */
+    counter = 0;
+    do
+    {
+        result = open(file, O_CREAT | O_EXCL | O_RDWR, 0600);
+        if (result != -1)
+        {
+            break;
+        }
+        sleep(5);
+        counter++;
+    } while (counter <= 12);
+
+    /* add deebug info */
+    if ((result != -1) && (getenv("SOURCE_RANDOM_DEBUG") != NULL))
+    {
+        debug_filename = strmake("%s.random_debug", file);
+        debug_file = fopen(debug_filename, "wb");
+        fwrite(pseudorandom_source, 1, pseudorandom_source_size, debug_file);
+        fclose(debug_file);
+        free(debug_filename);
+    }
+    return result;
+}
+
+void init_random_generator(int argc, char **argv)
+{
+    /* variables */
+    uint64_t generator_state;
+
+    void *argv_data;
+    size_t argv_size;
+
+    unsigned int counter;
+    void *env_data;
+    size_t env_size;
+    char **tmp_envs;
+
+    char *buffer_pos;
+    char **env;
+    size_t length;
+
+    unsigned int i;
+    size_t j;
+
+    /* process environment */
+    generator_state = 1;
+    env_size = 0;
+    {
+        /* sort environment variables */
+        counter = 0;
+        for (env = environ; (*env) != NULL; env++)
+        {
+            counter++;
+            env_size += strlen(*env) + 1;
+        }
+        tmp_envs = (char**) malloc(sizeof(char*) * counter);
+        for (i = 0; i < counter; i++)
+        {
+            tmp_envs[i] = (char*) (environ[i]);
+        }
+        qsort(tmp_envs, counter, sizeof(char*), (int(*)(const void*, const void*)) &strcmp);
+
+        /* and copy them */
+        env_data = malloc(env_size * sizeof(char));
+        buffer_pos = env_data;
+        for (i = 0; i < counter; i++)
+        {
+            length = strlen(tmp_envs[i]) + 1;
+            memcpy(buffer_pos, tmp_envs[i], length);
+            buffer_pos += length;
+        }
+
+        /* add sorted environment to random generator */
+        for (j = 0; j < env_size; j++)
+        {
+            pseudorandom_algo(&generator_state, ((unsigned char*) env_data)[j]);
+        }
+
+        /* free temp environment */
+        free(tmp_envs);
+    }
+
+    /* copy argv */
+    argv_size = 0;
+    for (i = 0; i < argc; i++)
+    {
+        argv_size += strlen(argv[i]) + 1;
+    }
+    argv_data = malloc(sizeof(char) * argv_size);
+    buffer_pos = argv_data;
+    for (i = 0; i < argc; i++)
+    {
+        length = strlen(argv[i]) + 1;
+        memcpy(buffer_pos, argv[i], length);
+        buffer_pos += length;
+    }
+
+    /* add arguments to gnerator */
+    for (j = 0; j < argv_size; j++)
+    {
+        pseudorandom_algo(&generator_state, ((unsigned char*) argv_data)[j]);
+    }
+
+    /* add debug if required */
+    if (getenv("SOURCE_RANDOM_DEBUG") != NULL)
+    {
+        /* gen field */
+        pseudorandom_source_size = env_size + argv_size + sizeof(generator_state);
+        buffer_pos = malloc(sizeof(char) * pseudorandom_source_size);
+        pseudorandom_source = buffer_pos;
+
+        /* copy data into it */
+        memcpy(buffer_pos, env_data, env_size);
+        buffer_pos += env_size;
+        memcpy(buffer_pos, argv_data, argv_size);
+        buffer_pos += argv_size;
+        memcpy(buffer_pos, &generator_state, sizeof(generator_state));
+    }
+
+    /* set state and free rest */
+    free(env_data);
+    free(argv_data);
+    pseudorandom_state = generator_state;
+}

tools/widl/utils.h

@@ -24,6 +24,7 @@
 #include "widltypes.h"
 
 #include <stddef.h>	/* size_t */
+#include <stdint.h>
 
 void *xmalloc(size_t);
 void *xrealloc(void *, size_t);
@@ -72,6 +73,11 @@ extern void put_pword( unsigned int val );
 extern void put_str( int indent, const char *format, ... ) __attribute__((format (printf, 2, 3)));
 extern void align_output( unsigned int align );
 
+extern uint64_t pseudorandom(uint64_t add_to_state);
+extern char pseudorandom_char(void);
+extern int pseudorandom_tempfile(char* file);
+extern void init_random_generator(int argc, char **argv);
+
 /* typelibs expect the minor version to be stored in the higher bits and
  * major to be stored in the lower bits */
 #define MAKEVERSION(major, minor) ((((minor) & 0xffff) << 16) | ((major) & 0xffff))

tools/widl/widl.c

@@ -607,6 +607,7 @@ int main(int argc,char *argv[])
 #ifdef SIGHUP
   signal( SIGHUP, exit_on_signal );
 #endif
+  init_random_generator(argc, argv);
   init_argv0_dir( argv[0] );
 
   {
@@ -948,7 +949,7 @@ int main(int argc,char *argv[])
         strcpy( name, header_name );
         strcat( name, ".XXXXXX" );
 
-        if ((fd = mkstemps( name, 0 )) == -1)
+        if ((fd = pseudorandom_tempfile(name)) == -1)
             error("Could not generate a temp name from %s\n", name);
 
         temp_name = name;