/***
*spawnvpe.c - spawn a child process with given environ (search PATH)
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _spawnvpe() - spawn a child process with given environ (search
* PATH)
*
*Revision History:
* 04-15-84 DFW written
* 10-29-85 TC added spawnvpe capability
* 11-19-86 SKS handle both kinds of slashes
* 12-01-86 JMB added Kanji file name support under conditional KANJI
* switches. Corrected header info. Removed bogus check
* for env = b after call to strncpy
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 09-05-88 SKS Treat EACCES the same as ENOENT -- keep trying
* 10-17-88 GJF Removed copy of PATH string to local array, changed
* bbuf to be a malloc-ed buffer. Removed bogus limits
* on the size of that PATH string.
* 10-25-88 GJF Don't search PATH when relative pathname is given (per
* Stevesa). Also, if the name built from PATH component
* and filename is a UNC name, allow any error.
* 05-17-89 MT Added "include <jstring.h>" under KANJI switch
* 05-24-89 PHG Reduce _amblksiz to use minimal memory (DOS only)
* 08-29-89 GJF Use _getpath() to retrieve PATH components, fixing
* several problems in handling unusual or bizarre
* PATH's.
* 11-20-89 GJF Added const attribute to types of filename, argv and
* envptr.
* 03-08-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>
* 07-24-90 SBM Removed redundant includes, replaced <assertm.h> by
* <assert.h>
* 09-27-90 GJF New-style function declarator.
* 01-17-91 GJF ANSI naming.
* 09-25-91 JCR Changed ifdef "OS2" to "_DOS_" (unused in 32-bit tree)
* 11-30-92 KRS Port _MBCS code from 16-bit tree.
*
*******************************************************************************/
#include <cruntime.h>
#include <errno.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <internal.h>
#include <process.h>
#include <mbstring.h>
#define SLASH "\\"
#define SLASHCHAR '\\'
#define XSLASHCHAR '/'
#define DELIMITER ";"
#ifdef _MBCS
/* note, the macro below assumes p is to pointer to a single-byte character
* or the 1st byte of a double-byte character, in a string.
*/
#define ISPSLASH(p) ( ((p) == _mbschr((p), SLASHCHAR)) || ((p) == \
_mbschr((p), XSLASHCHAR)) )
#else
#define ISSLASH(c) ( ((c) == SLASHCHAR) || ((c) == XSLASHCHAR) )
#endif
/***
*_spawnvpe(modeflag, filename, argv, envptr) - spawn a child process
*
*Purpose:
* Spawns a child process with the given arguments and environ,
* searches along PATH for given file until found.
* Formats the parameters and calls _spawnve to do the actual work. The
* NULL environment pointer indicates that the new process will inherit
* the parents process's environment. NOTE - at least one argument must
* be present. This argument is always, by convention, the name of the
* file being spawned.
*
*Entry:
* int modeflag - defines mode of spawn (WAIT, NOWAIT, or OVERLAY)
* only WAIT and OVERLAY supported
* char *filename - name of file to execute
* char **argv - vector of parameters
* char **envptr - vector of environment variables
*
*Exit:
* returns exit code of spawned process
* if fails, returns -1
*
*Exceptions:
*
*******************************************************************************/
int _CALLTYPE1 _spawnvpe (
int modeflag,
REG3 const char *filename,
const char * const *argv,
const char * const *envptr
)
{
int i;
REG1 char *env;
REG2 char *buf = NULL;
char *pfin;
#ifdef _DOS_
int tempamblksiz; /* old _amblksiz */
#endif
assert(filename != NULL);
assert(*filename != '\0');
assert(argv != NULL);
assert(*argv != NULL);
assert(**argv != '\0');
#ifdef _DOS_
tempamblksiz = _amblksiz;
_amblksiz = 0x10; /* reduce _amblksiz for efficient mallocs */
#endif
if (
(i = _spawnve(modeflag, filename, argv, envptr)) != -1
/* everything worked just fine; return i */
|| (errno != ENOENT)
/* couldn't spawn the process, return failure */
/* In a SBCS build, _mbschr will map to strchr. */
|| (_mbschr(filename, XSLASHCHAR) != NULL)
/* filename contains a '/', return failure */
#ifdef _DOS_
|| (_mbschr(filename,SLASHCHAR) != NULL)
/* filename contains a '\', return failure */
|| *filename && *(filename+1) == ':'
/* drive specification, return failure */
#endif
|| !(env = getenv("PATH"))
/* no PATH environment string name, return failure */
|| ( (buf = (char *)malloc(_MAX_PATH)) == NULL )
/* cannot allocate buffer to build alternate pathnames, return
* failure */
) {
#ifdef _DOS_
_amblksiz = tempamblksiz; /* restore old _amblksiz */
#endif
goto done;
}
#ifdef _DOS_
_amblksiz = tempamblksiz; /* restore old _amblksiz */
#endif
/* could not find the file as specified, search PATH. try each
* component of the PATH until we get either no error return, or the
* error is not ENOENT and the component is not a UNC name, or we run
* out of components to try.
*/
while ( (env = _getpath(env, buf, _MAX_PATH - 1)) && (*buf) ) {
pfin = buf + strlen(buf) - 1;
/* if necessary, append a '/'
*/
#ifdef _MBCS
if (*pfin == SLASHCHAR) {
if (pfin != _mbsrchr(buf,SLASHCHAR))
/* fin is the second byte of a double-byte char */
strcat(buf, SLASH );
}
else if (*pfin !=XSLASHCHAR)
strcat(buf, SLASH);
#else
if (*pfin != SLASHCHAR && *pfin != XSLASHCHAR)
strcat(buf, SLASH);
#endif
/* check that the final path will be of legal size. if so,
* build it. otherwise, return to the caller (return value
* and errno rename set from initial call to _spawnve()).
*/
if ( (strlen(buf) + strlen(filename)) < _MAX_PATH )
strcat(buf, filename);
else
break;
/* try spawning it. if successful, or if errno comes back with a
* value other than ENOENT and the pathname is not a UNC name,
* return to the caller.
*/
if ( (i = _spawnve(modeflag, buf, argv, envptr)) != -1
|| ((errno != ENOENT)
#ifdef _MBCS
&& (!ISPSLASH(buf) || !ISPSLASH(buf+1))) )
#else
&& (!ISSLASH(*buf) || !ISSLASH(*(buf+1)))) )
#endif
break;
}
done:
if (buf != NULL) free(buf);
return(i);
}
