sim: nrun: add --env-{set,unset,clear} command line options

Provide explicit control over the program's environment with the
basic set/unset/clear options.  These are a bit clunky to use,
but they're functional.

The env set operation is split out into a separate function as it'll
be used in the next commit.

With these in place, we can adjust the custom cris testsuite to use
the now standard options and not its one-off hack.

1 files changed, 99 insertions, 0 deletions

diff --git a/sim/common/sim-options.c b/sim/common/sim-options.c
index 17e550e..f94b814 100644
--- a/sim/common/sim-options.c
+++ b/sim/common/sim-options.c
@@ -25,10 +25,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <stdlib.h>
 #include <ctype.h>
 #include <stdio.h>
+#include <unistd.h>
 #include "libiberty.h"
 #include "sim-options.h"
 #include "sim-io.h"
 #include "sim-assert.h"
+#include "environ.h"
 #include "version.h"
 #include "hashtab.h"
 
@@ -106,6 +108,9 @@ typedef enum {
   OPTION_LOAD_VMA,
   OPTION_SYSROOT,
   OPTION_ARGV0,
+  OPTION_ENV_SET,
+  OPTION_ENV_UNSET,
+  OPTION_ENV_CLEAR,
 } STANDARD_OPTIONS;
 
 static const OPTION standard_options[] =
@@ -184,10 +189,64 @@ static const OPTION standard_options[] =
       '\0', "ARGV0", "Set argv[0] to the specified string",
       standard_option_handler, NULL },
 
+  { {"env-set", required_argument, NULL, OPTION_ENV_SET},
+      '\0', "VAR=VAL", "Set the variable in the program's environment",
+      standard_option_handler, NULL },
+  { {"env-unset", required_argument, NULL, OPTION_ENV_UNSET},
+      '\0', "VAR", "Unset the variable in the program's environment",
+      standard_option_handler, NULL },
+  { {"env-clear", no_argument, NULL, OPTION_ENV_CLEAR},
+      '\0', NULL, "Clear the program's environment",
+      standard_option_handler, NULL },
+
   { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL, NULL }
 };
 
 static SIM_RC
+env_set (SIM_DESC sd, const char *arg)
+{
+  int i, varlen;
+  char *eq;
+  char **envp;
+
+  if (STATE_PROG_ENVP (sd) == NULL)
+    STATE_PROG_ENVP (sd) = dupargv (environ);
+
+  eq = strchr (arg, '=');
+  if (eq == NULL)
+    {
+      sim_io_eprintf (sd, "invalid syntax when setting env var `%s'"
+		      ": missing value", arg);
+      return SIM_RC_FAIL;
+    }
+  /* Include the = in the comparison below.  */
+  varlen = eq - arg + 1;
+
+  /* If we can find an existing variable, replace it.  */
+  envp = STATE_PROG_ENVP (sd);
+  for (i = 0; envp[i]; ++i)
+    {
+      if (strncmp (envp[i], arg, varlen) == 0)
+	{
+	  free (envp[i]);
+	  envp[i] = xstrdup (arg);
+	  break;
+	}
+    }
+
+  /* If we didn't find the var, add it.  */
+  if (envp[i] == NULL)
+    {
+      envp = xrealloc (envp, (i + 2) * sizeof (char *));
+      envp[i] = xstrdup (arg);
+      envp[i + 1] = NULL;
+      STATE_PROG_ENVP (sd) = envp;
+  }
+
+  return SIM_RC_OK;
+}
+
+static SIM_RC
 standard_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
 			 char *arg, int is_command)
 {
@@ -430,6 +489,46 @@ standard_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
       free (STATE_PROG_ARGV0 (sd));
       STATE_PROG_ARGV0 (sd) = xstrdup (arg);
       break;
+
+    case OPTION_ENV_SET:
+      return env_set (sd, arg);
+
+    case OPTION_ENV_UNSET:
+      {
+	int i, varlen;
+	char **envp;
+
+	if (STATE_PROG_ENVP (sd) == NULL)
+	  STATE_PROG_ENVP (sd) = dupargv (environ);
+
+	varlen = strlen (arg);
+
+	/* If we can find an existing variable, replace it.  */
+	envp = STATE_PROG_ENVP (sd);
+	for (i = 0; envp[i]; ++i)
+	  {
+	    char *env = envp[i];
+
+	    if (strncmp (env, arg, varlen) == 0
+		&& (env[varlen] == '\0' || env[varlen] == '='))
+	      {
+		free (envp[i]);
+		break;
+	      }
+	  }
+
+	/* If we clear the var, shift the array down.  */
+	for (; envp[i]; ++i)
+	  envp[i] = envp[i + 1];
+
+	break;
+      }
+
+    case OPTION_ENV_CLEAR:
+      freeargv (STATE_PROG_ENVP (sd));
+      STATE_PROG_ENVP (sd) = xmalloc (sizeof (char *));
+      STATE_PROG_ENVP (sd)[0] = NULL;
+      break;
     }
 
   return SIM_RC_OK;