Content-type: text/html Man page of exec_with_loader

exec_with_loader

Section: System Calls (2)
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NAME

exec_with_loader - Executes a file with a loader  

SYNOPSIS

int exec_with_loader (        int flags,
       const char *loader,
       const char *file,
       char * const argv[ ],
       char * const envp[ ] );
 

PARAMETERS

Specifies flags to be passed to the loader. Points to a pathname that identifies a regular, executable, process image file that contains the loader. This image file must be a nonshared image. Points to a pathname that identifies a regular, executable process image file. This image file must be a call-shared image. Specifies an array of character pointers to null-terminated strings. Specifies an array of character pointers to null-terminated strings, constituting the environment for the new process.  

DESCRIPTION

The exec_with_loader() function replaces the current process image with a new process image, in a manner similar to what the exec functions do. Both the loader parameter and the file parameter point to pathnames that identify regular, executable files called new process image files. Whereas the exec functions construct the new process image from the file identified by the file parameter, exec_with_loader() instead constructs the new process image from the file identified by the loader parameter. Throughout this manual page, the regular, executable, process image file specified by the loader parameter is referred to as the program loader, and the regular, executable, process image file specified by the file parameter is referred to as the file. The loader image cannot be linked at the default user addresses. You must find another place to link it. One acceptable place to link the loader image is at the address space defined for the loader in the /usr/shlilb/so_locations file.

Once the exec_with_loader() function successfully loads the program loader, it transfers control to the program loader and effectively passes the file parameter on to the loader. Under normal usage, the program loader will then load (that is, merge) the file into the newly constructed process image, along with any object files upon which the program (that is, the file) depends. The typical use of exec_with_loader() is to load programs that contain unresolved external references, for example, programs that require the use of a shared library.

The exec_with_loader() function implements and preserves all of the semantics of the exec functions, with respect to the file. These include the handling of the argv and envp parameters, command interpreters, close-on-exec processing, signals, set user ID and set group ID processing, the process attributes and error returns.

The loader parameter may be null, in which case the exec_with_loader() function loads the default program loader, found in the /sbin/loader file. The exec_with_loader() function always loads the default program loader, even if the loader parameter points to a valid loader file, if the set user ID mode bit of the file is set (see the chmod() function) and the owner ID of the file is not equal to the effective user ID of the process, or if the set group ID mode bit of the file is set and the group ID of the file is not equal to the effective group ID of the process. The setting of the set user ID or set group ID mode bits on the loader have no effect whatsoever.  

RETURN VALUES

If the exec_with_loader() function returns to the calling process image, an error has occurred; the return value is -1, and errno is set to indicate the error.  

ERRORS

If the exec_with_loader() function fails, errno may be set to one of the following values: Search permission is denied for a directory listed in either file's path prefix, or either file denies execution permission, or either file is not a regular file and the implementation does not support execution of files of its type. Note that the exec_with_loader() function references two files, one specified by the loader parameter and one specified by the file parameter. The length of the loader or file parameters exceeds PATH_MAX, or a pathname component is longer than NAME_MAX and _POSIX_NO_TRUNC is in effect for that file. One or more components of either file's pathname does not exist, or the loader or file parameter points to an empty string. Note that the exec_with_loader() function references two files, one specified by the loader parameter and one specified by the file parameter. A component of either file's path prefix is not a directory. Note that the exec_with_loader() function references two files, one specified by the loader parameter and one specified by the file parameter. The file specified by the loader parameter has the appropriate access permission but is not in the proper format. The loader or file parameter is an invalid address. Too many symbolic links were encountered in pathname resolution. Insufficient memory is available.  

RELATED INFORMATION

Functions: exec(2) delim off


 

Index

NAME
SYNOPSIS
PARAMETERS
DESCRIPTION
RETURN VALUES
ERRORS
RELATED INFORMATION

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Time: 02:40:13 GMT, October 02, 2010