diff options
Diffstat (limited to 'nuttx/libc/unistd/lib_execl.c')
-rw-r--r-- | nuttx/libc/unistd/lib_execl.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/nuttx/libc/unistd/lib_execl.c b/nuttx/libc/unistd/lib_execl.c new file mode 100644 index 000000000..fa50c1429 --- /dev/null +++ b/nuttx/libc/unistd/lib_execl.c @@ -0,0 +1,146 @@ +/**************************************************************************** + * libc/unistd/lib_execl.c + * + * Copyright (C) 2013 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdarg.h> +#include <unistd.h> + +#ifdef CONFIG_LIBC_EXECFUNCS + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Global Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: execl + * + * 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_SYMTAB : Symbol table used by exec[l|v] + * CONFIG_EXECFUNCS_NSYMBOLS : 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_BINFMT_EXEPATH + * 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 execl(FAR const char *path, ...) +{ + FAR char *argv[CONFIG_MAX_TASK_ARGS+1]; + va_list ap; + int argc; + + /* Collect the arguments into the argv[] array */ + + va_start(ap, path); + for (argc = 0; argc < CONFIG_MAX_TASK_ARGS; argc++) + { + argv[argc] = va_arg(ap, FAR char *); + if (argv[argc] == NULL) + { + break; + } + } + + argv[CONFIG_MAX_TASK_ARGS] = NULL; + va_end(ap); + + /* Then let execv() do the real work */ + + return execv(path, (char * const *)&argv); +} + +#endif /* CONFIG_LIBC_EXECFUNCS */
\ No newline at end of file |