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Diffstat (limited to 'nuttx/libc/unistd/lib_execv.c')
| -rw-r--r-- | nuttx/libc/unistd/lib_execv.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/nuttx/libc/unistd/lib_execv.c b/nuttx/libc/unistd/lib_execv.c new file mode 100644 index 000000000..cad8ee307 --- /dev/null +++ b/nuttx/libc/unistd/lib_execv.c @@ -0,0 +1,168 @@ +/**************************************************************************** + * libc/unistd/lib_execv.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 <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/binfmt/binfmt.h> + +#ifdef CONFIG_LIBC_EXECFUNCS + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ +/* If CONFIG_LIBC_EXECFUNCS is defined in the configuration, then the + * following must also be defined: + */ + +/* Symbol table used by exec[l|v] */ + +#ifndef CONFIG_EXECFUNCS_SYMTAB +# error "CONFIG_EXECFUNCS_SYMTAB must be defined" +#endif + +/* Number of Symbols in the Table */ + +#ifndef CONFIG_EXECFUNCS_NSYMBOLS +# error "CONFIG_EXECFUNCS_NSYMBOLS must be defined" +#endif + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +extern struct symtab_s CONFIG_EXECFUNCS_SYMTAB; + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Global 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 suport + * 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. + * 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[]) +{ + int ret; + + /* Start the task */ + + ret = exec(path, (FAR const char **)argv, + &CONFIG_EXECFUNCS_SYMTAB, CONFIG_EXECFUNCS_NSYMBOLS); + + if (ret < 0) + { + sdbg("exec failed: %d\n", errno); + return ERROR; + } + + /* Then exit */ + + exit(0); + + /* We should not get here, but might be needed by some compilers. Other, + * smarter compilers might complain that this code is unreachable. You just + * can't win. + */ + + return ERROR; +} + +#endif /* CONFIG_LIBC_EXECFUNCS */
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