/***
*execvpe.c - execute a file with given environ; search along PATH
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _execvpe() - execute a file with given environ
*
*Revision History:
* 10-17-83 RN written
* 10-29-85 TC added execvpe 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
* 10-18-88 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.
* 10-26-88 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.
* 11-20-89 GJF Fixed copyright. Added const attribute to types of
* filename, argvector and envptr. Also, added "#include
* <jstring.h>" under KANJI switch (same as 5-17-89 change
* to CRT version).
* 03-08-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>. Also,
* cleaned up the formatting a bit.
* 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.
* 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 <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
/***
*int _execvpe(filename, argvector, envvector) - execute a file
*
*Purpose:
* Executes a file with given arguments and environment.
* try to execute the file. start with the name itself (directory '.'),
* and if that doesn't work start prepending pathnames from the
* environment until one works or we run out. if the file is a pathname,
* don't go to the environment to get alternate paths. If a needed text
* file is busy, wait a little while and try again before despairing
* completely
*
*Entry:
* char *filename - file to execute
* char **argvector - vector of arguments
* char **envvector - vector of environment variables
*
*Exit:
* destroys the calling process (hopefully)
* if fails, returns -1
*
*Exceptions:
*
*******************************************************************************/
int _CALLTYPE1 _execvpe (
REG3 const char *filename,
const char * const *argvector,
const char * const *envptr
)
{
REG1 char *env;
char *bbuf = NULL;
REG2 char *buf;
char *pfin;
assert(filename != NULL);
assert(*filename != '\0');
assert(argvector != NULL);
assert(*argvector != NULL);
assert(**argvector != '\0');
_execve(filename,argvector,envptr);
/* In a SBCS build, _mbschr will map to strchr. */
if ( (errno != ENOENT)
|| (_mbschr(filename, SLASHCHAR) != NULL)
|| (_mbschr(filename, XSLASHCHAR) != NULL)
|| *filename && *(filename+1) == ':'
|| !(env=getenv("PATH")) )
goto reterror;
/* allocate a buffer to hold alternate pathnames for the executable
*/
if ( (buf = bbuf = (char *)malloc(_MAX_PATH)) == NULL ) goto reterror;
do {
/* copy a component into bbuf[], taking care not to overflow it
*/
/* UNDONE: make sure ';' isn't 2nd byte of DBCS char */
while ( (*env) && (*env != ';') && (buf < bbuf+_MAX_PATH-2) )
*buf++ = *env++;
*buf = '\0';
pfin = --buf;
buf = bbuf;
#ifdef _MBCS
if (*pfin == SLASHCHAR) {
if (pfin != _mbsrchr(buf,SLASHCHAR))
/* *pfin is the second byte of a double-byte
* character
*/
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 _execve()).
*/
if ( (strlen(buf) + strlen(filename)) < _MAX_PATH )
strcat(buf, filename);
else
break;
_execve(buf, argvector, envptr);
if ( (errno != ENOENT)
#ifdef _MBCS
&& (!ISPSLASH(buf) || !ISPSLASH(buf+1)) )
#else
&& (!ISSLASH(*buf) || !ISSLASH(*(buf+1))) )
#endif
break;
} while ( *env && env++ );
reterror:
if (bbuf != NULL)
free(bbuf);
return(-1);
}
