sched/task: Implement execle and execve

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

binfmt/binfmt_exec.c

@@ -212,6 +212,9 @@ errout:
  *              program.
  *   argv     - A pointer to an array of string arguments. The end of the
  *              array is indicated with a NULL entry.
+ *   envp     - An array of character pointers to null-terminated strings
+ *              that provide the environment for the new process image.
+ *              The environment array is terminated by a null pointer.
  *   exports  - The address of the start of the caller-provided symbol
  *              table. This symbol table contains the addresses of symbols
  *              exported by the caller and made available for linking the
@@ -226,11 +229,12 @@ errout:
  ****************************************************************************/
 
 int exec(FAR const char *filename, FAR char * const *argv,
-         FAR const struct symtab_s *exports, int nexports)
+         FAR char * const *envp, FAR const struct symtab_s *exports,
+         int nexports)
 {
   int ret;
 
-  ret = exec_spawn(filename, argv, NULL, exports, nexports, NULL);
+  ret = exec_spawn(filename, argv, envp, exports, nexports, NULL);
   if (ret < 0)
     {
       set_errno(-ret);

include/nuttx/binfmt/binfmt.h

@@ -309,6 +309,9 @@ int exec_module(FAR const struct binary_s *binp,
  *              program.
  *   argv     - A pointer to an array of string arguments. The end of the
  *              array is indicated with a NULL entry.
+ *   envp     - An array of character pointers to null-terminated strings
+ *              that provide the environment for the new process image.
+ *              The environment array is terminated by a null pointer.
  *   exports  - The address of the start of the caller-provided symbol
  *              table. This symbol table contains the addresses of symbols
  *              exported by the caller and made available for linking the
@@ -322,7 +325,8 @@ int exec_module(FAR const struct binary_s *binp,
  ****************************************************************************/
 
 int exec(FAR const char *filename, FAR char * const *argv,
-         FAR const struct symtab_s *exports, int nexports);
+         FAR char * const *envp, FAR const struct symtab_s *exports,
+         int nexports);
 
 /****************************************************************************
  * Name: exec_spawn

include/sys/syscall_lookup.h

@@ -151,7 +151,7 @@ SYSCALL_LOOKUP(up_assert,                  2)
 #endif
 #ifdef CONFIG_LIBC_EXECFUNCS
   SYSCALL_LOOKUP(posix_spawn,              6)
-  SYSCALL_LOOKUP(execv,                    2)
+  SYSCALL_LOOKUP(execve,                   3)
 #endif
 #endif
 

include/unistd.h

@@ -368,7 +368,10 @@ int     lchown(FAR const char *path, uid_t owner, gid_t group);
 
 #ifdef CONFIG_LIBC_EXECFUNCS
 int     execl(FAR const char *path, FAR const char *arg0, ...);
+int     execle(FAR const char *path, FAR const char *arg0, ...);
 int     execv(FAR const char *path, FAR char * const argv[]);
+int     execve(FAR const char *path, FAR char *const argv[],
+               FAR char *const envp[]);
 #endif
 
 /* Byte operations */

libs/libc/unistd/Make.defs

@@ -39,7 +39,7 @@ CSRCS += lib_chdir.c lib_getcwd.c lib_restoredir.c
 endif
 
 ifeq ($(CONFIG_LIBC_EXECFUNCS),y)
-CSRCS += lib_execl.c
+CSRCS += lib_execl.c lib_execle.c lib_execv.c
 endif
 
 ifneq ($(CONFIG_DISABLE_MOUNTPOINTS),y)

libs/libc/unistd/lib_execle.c

@@ -0,0 +1,183 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_execle.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "libc.h"
+
+#ifdef CONFIG_LIBC_EXECFUNCS
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* This is an artificial limit to detect error conditions where an argv[]
+ * list is not properly terminated.
+ */
+
+#define MAX_EXECL_ARGS 256
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: execle
+ *
+ * Description:
+ *   The standard 'exec' family of functions will replace the current process
+ *   image with a new process image. The new image will be constructed from a
+ *   regular, executable file called the new process image file. There will
+ *   be no return from a successful exec, because the calling process image
+ *   is overlaid by the new process image.
+ *
+ *   Simplified 'execl()' and 'execv()' functions are provided by NuttX for
+ *   compatibility.  NuttX is a tiny embedded RTOS that does not support
+ *   processes and hence the concept of overlaying a tasks process image with
+ *   a new process image does not make any sense.  In NuttX, these functions
+ *   are wrapper functions that:
+ *
+ *     1. Call the non-standard binfmt function 'exec', and then
+ *     2. exit(0).
+ *
+ *   Note the inefficiency when 'exec[l|v]()' is called in the normal, two-
+ *   step process:  (1) first call vfork() to create a new thread, then (2)
+ *   call 'exec[l|v]()' to replace the new thread with a program from the
+ *   file system.  Since the new thread will be terminated by the
+ *   'exec[l|v]()' call, it really served no purpose other than to support
+ *   Unix compatility.
+ *
+ *   The non-standard binfmt function 'exec()' needs to have (1) a symbol
+ *   table that provides the list of symbols exported by the base code, and
+ *   (2) the number of symbols in that table.  This information is currently
+ *   provided to 'exec()' from 'exec[l|v]()' via NuttX configuration setting:
+ *
+ *     CONFIG_LIBC_EXECFUNCS         : Enable exec[l|v] support
+ *     CONFIG_EXECFUNCS_SYMTAB_ARRAY : Symbol table name used by exec[l|v]
+ *     CONFIG_EXECFUNCS_NSYMBOLS_VAR : Variable holding number of symbols in
+ *                                     the table
+ *
+ *   As a result of the above, the current implementations of 'execl()' and
+ *   'execv()' suffer from some incompatibilities that may or may not be
+ *   addressed in a future version of NuttX.  Other than just being an
+ *   inefficient use of MCU resource, the most serious of these is that
+ *   the exec'ed task will not have the same task ID as the vfork'ed
+ *   function.  So the parent function cannot know the ID of the exec'ed
+ *   task.
+ *
+ * Input Parameters:
+ *   path - The path to the program to be executed.  If CONFIG_LIBC_ENVPATH
+ *     is defined in the configuration, then this may be a relative path
+ *     from the current working directory.  Otherwise, path must be the
+ *     absolute path to the program.
+ *   ... - A list of the string arguments to be recevied by the
+ *     program.  Zero indicates the end of the list.
+ *
+ * Returned Value:
+ *   This function does not return on success.  On failure, it will return
+ *   -1 (ERROR) and will set the 'errno' value appropriately.
+ *
+ ****************************************************************************/
+
+int execle(FAR const char *path, FAR const char *arg0, ...)
+{
+  FAR char *arg = (FAR char *)arg0;
+  FAR char **argv;
+  FAR char **envp;
+  size_t nargs;
+  va_list ap;
+  int argc;
+  int ret;
+
+  /* Count the number of arguments */
+
+  va_start(ap, arg0);
+  nargs = 0;
+
+  while (arg != NULL)
+    {
+      /* Yes.. increment the number of arguments.  Here is a sanity
+       * check to prevent running away with an unterminated argv[] list.
+       * MAX_EXECL_ARGS should be sufficiently large that this never
+       * happens in normal usage.
+       */
+
+      if (++nargs > MAX_EXECL_ARGS)
+        {
+          set_errno(E2BIG);
+          va_end(ap);
+          return ERROR;
+        }
+
+      arg = va_arg(ap, FAR char *);
+    }
+
+  envp = va_arg(ap, FAR char **);
+  va_end(ap);
+
+  /* Allocate a temporary argv[] array */
+
+  argv = (FAR char **)lib_malloc((nargs + 1) * sizeof(FAR char *));
+  if (argv == NULL)
+    {
+      set_errno(ENOMEM);
+      return ERROR;
+    }
+
+  argv[0] = (FAR char *)arg0;
+
+  /* Collect the arguments into the argv[] array */
+
+  va_start(ap, arg0);
+  for (argc = 1; argc <= nargs; argc++)
+    {
+      argv[argc] = va_arg(ap, FAR char *);
+    }
+
+  va_end(ap);
+
+  /* Then let execv() do the real work */
+
+  ret = execv(path, argv, envp);
+
+  /* Free the allocated argv[] list */
+
+  lib_free(argv);
+  return ret;
+}
+
+#endif /* CONFIG_LIBC_EXECFUNCS */

libs/libc/unistd/lib_execv.c

@@ -0,0 +1,101 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_execv.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <unistd.h>
+
+#ifdef CONFIG_LIBC_EXECFUNCS
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: execv
+ *
+ * Description:
+ *   The standard 'exec' family of functions will replace the current process
+ *   image with a new process image. The new image will be constructed from a
+ *   regular, executable file called the new process image file. There will
+ *   be no return from a successful exec, because the calling process image
+ *   is overlaid by the new process image.
+ *
+ *   Simplified 'execl()' and 'execv()' functions are provided by NuttX for
+ *   compatibility.  NuttX is a tiny embedded RTOS that does not support
+ *   processes and hence the concept of overlaying a tasks process image with
+ *   a new process image does not make any sense.  In NuttX, these functions
+ *   are wrapper functions that:
+ *
+ *     1. Call the non-standard binfmt function 'exec', and then
+ *     2. exit(0).
+ *
+ *   Note the inefficiency when 'exec[l|v]()' is called in the normal, two-
+ *   step process:  (1) first call vfork() to create a new thread, then (2)
+ *   call 'exec[l|v]()' to replace the new thread with a program from the
+ *   file system.  Since the new thread will be terminated by the
+ *   'exec[l|v]()' call, it really served no purpose other than to support
+ *   Unix compatility.
+ *
+ *   The non-standard binfmt function 'exec()' needs to have (1) a symbol
+ *   table that provides the list of symbols exported by the base code, and
+ *   (2) the number of symbols in that table.  This information is currently
+ *   provided to 'exec()' from 'exec[l|v]()' via NuttX configuration
+ *   settings:
+ *
+ *     CONFIG_LIBC_EXECFUNCS          : Enable exec[l|v] support
+ *     CONFIG_EXECFUNCS_HAVE_SYMTAB   : Defined if there is a pre-defined
+ *                                      symbol table
+ *     CONFIG_EXECFUNCS_SYMTAB_ARRAY  : Symbol table name used by exec[l|v]
+ *     CONFIG_EXECFUNCS_NSYMBOLS_VAR  : Variable holding number of symbols
+ *                                      in the table
+ *
+ *   As a result of the above, the current implementations of 'execl()' and
+ *   'execv()' suffer from some incompatibilities that may or may not be
+ *   addressed in a future version of NuttX.  Other than just being an
+ *   inefficient use of MCU resource, the most serious of these is that
+ *   the exec'ed task will not have the same task ID as the vfork'ed
+ *   function.  So the parent function cannot know the ID of the exec'ed
+ *   task.
+ *
+ * Input Parameters:
+ *   path - The path to the program to be executed.  If CONFIG_LIBC_ENVPATH
+ *     is defined in the configuration, then this may be a relative path
+ *     from the current working directory.  Otherwise, path must be the
+ *     absolute path to the program.
+ *   argv - A pointer to an array of string arguments.  The end of the
+ *     array is indicated with a NULL entry.
+ *
+ * Returned Value:
+ *   This function does not return on success.  On failure, it will return
+ *   -1 (ERROR) and will set the 'errno' value appropriately.
+ *
+ ****************************************************************************/
+
+int execv(FAR const char *path, FAR char * const argv[])
+{
+  return execve(path, argv, NULL);
+}
+
+#endif /* CONFIG_LIBC_EXECFUNCS */

sched/task/Make.defs

@@ -45,7 +45,7 @@ endif
 
 ifneq ($(CONFIG_BINFMT_DISABLE),y)
 ifeq ($(CONFIG_LIBC_EXECFUNCS),y)
-CSRCS += task_execv.c task_posixspawn.c
+CSRCS += task_execve.c task_posixspawn.c
 endif
 endif
 

sched/task/task_execve.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * sched/task/task_execv.c
+ * sched/task/task_execve.c
  *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
@@ -100,6 +100,9 @@
  *     absolute path to the program.
  *   argv - A pointer to an array of string arguments.  The end of the
  *     array is indicated with a NULL entry.
+ *   envp - An array of character pointers to null-terminated strings that
+ *     provide the environment for the new process image. The environment
+ *     array is terminated by a null pointer.
  *
  * Returned Value:
  *   This function does not return on success.  On failure, it will return
@@ -107,7 +110,8 @@
  *
  ****************************************************************************/
 
-int execv(FAR const char *path, FAR char * const argv[])
+int execve(FAR const char *path, FAR char * const argv[],
+           FAR char *const envp[])
 {
   FAR const struct symtab_s *symtab;
   int nsymbols;
@@ -119,7 +123,7 @@ int execv(FAR const char *path, FAR char * const argv[])
 
   /* Start the task */
 
-  ret = exec(path, (FAR char * const *)argv, symtab, nsymbols);
+  ret = exec(path, argv, envp, symtab, nsymbols);
   if (ret < 0)
     {
       serr("ERROR: exec failed: %d\n", get_errno());

syscall/syscall.csv

@@ -24,7 +24,7 @@
 "dup2","unistd.h","","int","int","int"
 "eventfd","sys/eventfd.h","defined(CONFIG_EVENT_FD)","int","unsigned int","int"
 "exec","nuttx/binfmt/binfmt.h","!defined(CONFIG_BINFMT_DISABLE) && !defined(CONFIG_BUILD_KERNEL)","int","FAR const char *","FAR char * const *","FAR const struct symtab_s *","int"
-"execv","unistd.h","!defined(CONFIG_BINFMT_DISABLE) && defined(CONFIG_LIBC_EXECFUNCS)","int","FAR const char *","FAR char * const []|FAR char * const *"
+"execve","unistd.h","!defined(CONFIG_BINFMT_DISABLE) && defined(CONFIG_LIBC_EXECFUNCS)","int","FAR const char *","FAR char * const []|FAR char * const *","FAR char * const []|FAR char * const *"
 "exit","stdlib.h","","noreturn","int"
 "fchmod","sys/stat.h","","int","int","mode_t"
 "fchown","unistd.h","","int","int","uid_t","gid_t"