74 lines
1.9 KiB
C
Executable file
74 lines
1.9 KiB
C
Executable file
/* execvp() - execute with PATH search and prepared arguments
|
|
* Author: Kees J. Bot
|
|
* 21 Jan 1994
|
|
*/
|
|
|
|
#define _MINIX_SOURCE
|
|
|
|
#define nil 0
|
|
#define execve _execve
|
|
#define execvp _execvp
|
|
#define sbrk _sbrk
|
|
#define stat _stat
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
#include <sys/stat.h>
|
|
|
|
extern char * const **_penviron; /* The default environment. */
|
|
|
|
int execvp(const char *file, char * const *argv)
|
|
/* Execute the file with a path search on $PATH, just like the shell. The
|
|
* search continues on the errors ENOENT (not there), and EACCES (file not
|
|
* executable or leading directories protected.)
|
|
* Unlike other execvp implementations there is no default path, and no shell
|
|
* is started for scripts. One is supposed to define $PATH, and use #!/bin/sh.
|
|
*/
|
|
{
|
|
struct stat sb;
|
|
const char *path; /* $PATH */
|
|
char *full; /* Full name to try. */
|
|
char *f;
|
|
size_t full_size;
|
|
int err= ENOENT; /* Error return on failure. */
|
|
|
|
if (strchr(file, '/') != nil || (path= getenv("PATH")) == nil)
|
|
path= "";
|
|
|
|
/* Compute the maximum length the full name may have, and align. */
|
|
full_size= strlen(path) + 1 + strlen(file) + 1 + sizeof(char *) - 1;
|
|
full_size&= ~(sizeof(char *) - 1);
|
|
|
|
/* Claim space. */
|
|
if ((full= (char *) sbrk(full_size)) == (char *) -1) {
|
|
errno= E2BIG;
|
|
return -1;
|
|
}
|
|
|
|
/* For each directory in the path... */
|
|
do {
|
|
f= full;
|
|
while (*path != 0 && *path != ':') *f++= *path++;
|
|
|
|
if (f > full) *f++= '/';
|
|
|
|
strcpy(f, file);
|
|
|
|
/* Stat first, small speed-up, better for ptrace. */
|
|
if (stat(full, &sb) == -1) continue;
|
|
|
|
(void) execve(full, argv, *_penviron);
|
|
|
|
/* Prefer more interesting errno values then "not there". */
|
|
if (errno != ENOENT) err= errno;
|
|
|
|
/* Continue only on some errors. */
|
|
if (err != ENOENT && err != EACCES) break;
|
|
} while (*path++ != 0);
|
|
|
|
(void) sbrk(-full_size);
|
|
errno= err;
|
|
return -1;
|
|
}
|