gno/lib/libc/sys/exec.c

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/*
* exec(2) library calls. Written as part of lenviron by Devin Reade
* for GNO v2.0.3. Incorporated into libc as of GNO v2.0.6.
*
* $Id: exec.c,v 1.2 1997/09/21 16:17:20 gdr Exp $
*
* This file is formatted with tabs every 3 columns. The remainder of
* the comments in this section are from the lenviron v1.1.3 implementation.
* Of course, the GNO distribution headers now reflect these changes.
*
*************************************************************************
*
* These calls will only work with the GNO kernel! They were tested with
* GNO v2.0.3 and later, but _might_ work with other versions.
*
* These have been implemented using the standard Unix declarations. In
* particular, the prototype for execve(2) does _not_ match that of
* Procyon's distribution of GNO v2.0.5 and earlier.
*
* If you wish to make use of the execve call as provided with the GNO
* v2.0.5 (and earlier) distribution, that call is still available as the
* function
*
* int _execve(const char *path, const char *params);
*
* Note that execle(2) is not currently implemented. exect(2) probably
* never will be so implemented.
*
* Note that the current version of gsh parses $PATH backwards for some
* reason. For consistency, execvp() and execlp() will do the same for now.
* If gsh gets fixed or if you switch to a shell that parses $PATH front-to-
* back, just undefine BACKWARDS within this file an recompile. The
* appropriate code has already been tested.
*/
#ifdef __ORCAC__
segment "libc_sys__";
#endif
/*
* Use bits 1, 2, 6 (== decimal 71) for optimization. In Orca/C v2.1.0,
* bits 0, 4 and 5 are still reported to be buggy.
*
* Around variadic routines, we also add in optimization bit 3 (== 78).
*/
#include <sys/types.h>
#include <types.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <orca.h>
#include <gno/gno.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>
#include <stdarg.h>
#define PARMSGUESS 10 /* initial length of argv array in execl, execlp */
#define BACKWARDS /* undefine this for shells that parse $PATH */
/* front to back. gsh as of Dec 93 needs this */
/* defined. */
pascal int Kexecve(char *pathname, char *cmdline, int *errno)
inline(0x1D03,0xE10008);
/*
* int isRootPath(const char *name);
*
* Pre: <name> is a file name
*
* Post: Return TRUE if the name is the full specification of a path name
* to a file starting at the root of the file system, otherwise
* return FALSE. Note that no test for existence is carried out;
* this routine only judges whether or not the given name is a valid
* one file starting at the root of the file system.
*
* Caveat: Unlike the Unix filesystem, "/" is not recognised as a complete
* file (or directory) name. Therefore, it will return FALSE if the
* the name is one character long and isn't "*" or "@" or a digit.
*/
/* allowable start of full file/device/prefix names */
static char* PfxBrkStr = "/:0123456789.*@";
int
isRootPath(const char *name) {
char *p;
p = strchr(PfxBrkStr, *name);
if (p == NULL) return FALSE;
switch (*p) {
case '/': /* FALLTHROUGH */
case ':':
/* "zero" length volume/prefix names not allowed */
if (*(p+1) == '\0') return FALSE;
else return TRUE;
/* NOTREACHED */
case '.':
/* "zero" length volume/prefix names not allowed. "./" and ".:" fail */
switch (*(p+1)) {
case '\0': /* FALLTHROUGH */
case '/': /* FALLTHROUGH */
case ':':
return FALSE;
default:
return TRUE;
}
/* NOTREACHED */
case '*': /* FALLTHROUGH */
case '@':
switch (*(p+1)) {
case '\0': /* FALLTHROUGH */
case '/': /* FALLTHROUGH */
case ':':
return TRUE;
default:
return FALSE;
}
/* NOTREACHED */
default:
/* it must be starting with a digit */
return TRUE;
}
}
/*
* char *buildCmd (char *const *argv);
*
* Pre: argv is a pointer to an array of strings, ending with a NULL pointer
*
* Post: Returns a pointer to a string consisting of all of the elements of
* argv, delimited by single spaces. Returns NULL if memory for the
* string cannot be allocated. If argv[0] == NULL, buildCmd() will
* return a pointer to a zero-length string. If it returns NULL,
* errno is also set to ENOMEM.
*
* Any GS/OS prefix (numerical or otherwise) on argv[0] will be stripped.
*/
char *
buildCmd (char *const *argv) {
char *comdbuf; /* pointer to the command line buffer */
size_t comdsize; /* length of the command line buffer */
int i;
char *s; /* a temporary pointer */
char delim; /* delimiter for pathnames (':' or '/') */
/* allocate memory for command line */
comdsize = 1;
i = 0;
while (argv[i] != NULL) {
comdsize = comdsize + strlen(argv[i]) + 1;
i++;
}
if ((comdbuf = malloc (comdsize)) == NULL) return NULL;
/* build command line from argv */
i = 0;
if (argv[i] == NULL) {
comdbuf[0] = (char) NULL;
} else {
/* find delimiter */
delim = (strchr(argv[0],':') == NULL) ? '/' : ':';
/* drop leading prefix */
s = argv[i];
while (*s) s++;
while ((s>argv[i]) && (*s != delim)) s--;
if (*s==delim) s++;
strcpy(comdbuf,s);
i++;
while (argv[i] != NULL) {
strcat(comdbuf, " ");
strcat(comdbuf, argv[i]);
i++;
}
}
return comdbuf;
}
/* int _fileExists (const char *file, const char *path)
*
* Pre: file is a file name, path is a full legal directory name
*
* Post: Returns 1 if file is in path, returns 0 and errno set on failure.
* Possible errno values on return are 0, ENOMEM, and ENOENT.
*
* Notes: If <path> is a zero-length string (not NULL!), then existence
* of <file> will be tested based on <file> being a partial pathname.
*
* _fileExists() will also fail if file is either a full path name or
* a zero-length string.
*/
static int
_fileExists (const char *file, const char *path) {
static char *buffer = NULL;
static size_t buffersize = 0;
size_t pathlen, length;
char delim;
char *tp;
delim = (strchr(path,':') == NULL) ? '/' : ':'; /* find delimiter */
/* <file> is a full pathname or empty string? Fail! */
if ((*file == '\0') || (isRootPath(file))) {
errno = ENOENT;
return 0;
}
/* calculate length of path prefix and full pathname */
pathlen = strlen(path);
length = strlen(file) + pathlen + 2;
/*
* Allocate more mem for buffer, if necessary. This fragment's behavior
* is dependant on the implementation of realloc and is not necessarily
* portable. It assumes that realloc() called with a NULL pointer behaves
* the same as malloc().
*/
if (length > buffersize) {
tp = (char *) realloc (buffer, length);
if (tp == NULL) {
if (buffer) free (buffer);
buffer = NULL;
buffersize = 0;
errno = ENOMEM;
return 0;
}
buffer = tp;
}
strcpy(buffer,path); /* make copy of path, */
if (pathlen) {
if (buffer[pathlen-1] != delim) { /* delimiter and terminate */
buffer[pathlen] = delim;
buffer[pathlen+1] = '\0';
}
} else {
*buffer = '\0';
}
strcat(buffer,file);
if (access(buffer, F_OK) == 0) { /* file found */
errno = 0;
return 1;
} /* else ... */
errno = ENOENT;
return 0;
}
/*
* char *buildPath (const char *filename);
*
* Pre: <filename> is the name of the file which we wish to locate.
*
* Post: If <filename> resides within $PATH, then buildPath will return a
* malloc'd pointer to the full pathname of the file.
* If <filename> cannot be found with $PATH, buildPath the default
* which is to search "/bin", then "/usr/bin". On error, NULL is
* returned and errno is set either to ENOENT or ENOMEM, as appropriate.
*
* If <filename> is in fact a full pathname, then a pointer to a malloc'd
* copy of the filename is returned; in this case, no test for existence
* is done <filename> is considered to be a full pathname if it
* begins with any of '/', ':', '.', '@', '*', or a digit.
* If any of '/', ':', or '.' is the first character, the
* filename must have a length of at least two characters.
*
* Caveat: There is a conditional compilation in this function; gsh currently
* parses the $PATH variable backwards, so for compatibility buildPath
* will also do a backwards parse if BACKWARDS is defined. Otherwise,
* $PATH will be parsed front-to-back.
*/
char *
buildPath (const char *filename) {
char *pathptr; /* pointer to the PATH shell variable */
char *path; /* pointer to the current PATH token */
char *buffptr; /* where we will store the full pathname */
size_t pathlen; /* for calculating space for malloc() */
char delim[2]; /* delimiter for pathnames. */
/* Assumption: if a path doesn't */
/* contain any '/' chars, the */
/* delimiter is ':'. */
#ifdef BACKWARDS
static char *default_path = "/usr/bin /bin";
char *path_copy;
#else
static char *default_path = "/bin /usr/bin";
#endif
/*
* if for some weird and wonderful reason, filename is a full pathname,
* then just return a pointer to a copy of it. In this case no test
* for existence is done.
*/
if (isRootPath(filename)) {
buffptr = (char *) malloc (strlen(filename) + 1);
if (buffptr == NULL) return NULL;
strcpy (buffptr,filename);
return buffptr;
}
/* get the value of the PATH shell variable */
pathptr = getenv ("PATH");
if (pathptr == NULL || *pathptr == '\0') {
/* PATH doesn't exist -- use default */
pathptr = default_path;
}
/* define the pathname delimiter */
(strstr(pathptr,"/") == NULL) ? strcpy (delim, ":") : strcpy (delim, "/");
/*
* search paths for filename -- backwards or forwards as appropriate
*/
#ifdef BACKWARDS
/* make a copy of the path */
pathlen = strlen(pathptr) + 1;
if ((path_copy = (char *) malloc((size_t) strlen(pathptr) + 1))==NULL) {
errno = ENOMEM;
return NULL;
}
strcpy(path_copy,pathptr);
path = path_copy + pathlen;
/* look for the file */
while (path>=path_copy) {
while ((path>path_copy) && (*path != ' ')) path--;
if (path>path_copy) { /* not done parsing $PATH */
if (_fileExists(filename, path+1)) { /* found it! */
path++;
break;
} else { /* not found; terminate string and try again */
*path = '\0';
}
} else {
/*
* at this point, path points to either first listed directory or
* whitespace; check it
*/
if (isprint(*path) && _fileExists(filename, path)) { /* found it! */
break;
} else {
free(path_copy); /* not in $PATH; parse failed */
errno = ENOENT;
return NULL;
}
}
}
#else
path = strtok (pathptr, " ");
while (path != NULL) {
if (_fileExists(filename, path)) break;
path = strtok (NULL, NULL);
}
/* filename not within listed paths */
if (path == NULL) {
errno = ENOENT;
return NULL;
}
#endif /* BACKWARDS */
/* allocate the buffer */
pathlen = strlen(filename) + strlen(path) + 2;
if ((buffptr = malloc (pathlen)) == NULL) {
#ifdef BACKWARDS
free(path_copy);
#endif
return NULL;
}
/* build the full pathname */
strcpy (buffptr,path);
strcat (buffptr,delim);
strcat (buffptr,filename);
#ifdef BACKWARDS
free(path_copy);
#endif
return buffptr;
}
/*
* int buildEnv (char *const *envp);
*
* Pre: envp is a pointer to an array of strings of the format NAME=VALUE.
*
* Post: On success, the strings in envp are added to the environment via
* putenv(), and 0 is returned. Returns -1 and sets errno=ENOMEM
* on failure.
*/
int
buildEnv (char *const *envp) {
while (*envp != NULL) {
if (putenv(*envp) == -1) return -1;
envp++;
}
return 0;
}
/*
* This function provides the functionality of the execve() routine
* provided with the GNO distribution. Unfortunately, GNO's version
* uses a non-standard prototype. (That's why execve is given a
* different prototype in this library.
*/
#if 0 /* it resides in trap.asm */
int _execve(const char *path, const char *params) {
return(Kexecve(path, params, &errno));
}
#endif
/*
* exec -- this function has been obsoleted, but is provided for
* backward compatibility
*/
#pragma databank 1
static void
_exec_child (const char *filename, const char *cmdline) {
_execve(filename, cmdline);
_exit(-1);
}
#pragma databank 0
int
exec (const char *filename, const char *cmdline) {
return fork2 (_exec_child, 1024, 0, "forked child of exec(2)", 4,
filename, cmdline);
}
/*
* The next functions (execv, execvp, execve, execl, execlp) are as per
* their man page descriptions. On error, errno could be set to any of
* ENOMEM, EIO, ENOENT. Note that there is no execle; Orca/C pukes on
* its declaration.
*/
int
execv(const char *path, char * const *argv) {
char *comd;
/* BUG BUG BUG BUG! -- this should be using <path> ! */
/* build the command line */
if ((comd = buildCmd (argv)) == NULL) return -1;
/* execute it */
return (Kexecve(path, comd, &errno));
}
int
execvp(const char *file, char * const *argv) {
char *comd;
char *path;
/* build the path name, if necessary */
path = buildPath (file);
/* build the command line */
if ((comd = buildCmd (argv)) == NULL) return -1;
/* execute it */
return(Kexecve(path, comd, &errno));
}
int
execve (const char *path, char * const *argv, char * const *envp) {
char *comd;
/* build the command line */
if ((comd = buildCmd (argv)) == NULL) return -1;
/* build the environment */
if (buildEnv(envp) == -1) return -1;
/* execute it */
return(Kexecve(path, comd, &errno));
}
/* no stack repair code on variadic function definitions */
#pragma optimize 78
#pragma debug 0
int
execl(const char *path, const char *arg, ...) {
va_list list;
char **argv;
char *p;
char **q;
int i=0;
size_t vect_length;
int result;
/* allocate memory for initial guess of number of parameters */
argv = (char **) malloc (sizeof(char *) * PARMSGUESS);
if (argv==NULL) return -1;
vect_length = PARMSGUESS;
/* build the array */
p = arg;
va_start (list, arg);
while (p && *p) {
argv[i] = p; i++;
p = va_arg(list, char* );
/* reallocate memory if necessary */
if (i>=vect_length) {
vect_length += PARMSGUESS;
q = (char **) realloc(argv,vect_length);
if (p == NULL) {
free(argv);
errno = ENOMEM;
return -1;
}
argv = q;
}
}
argv[i] = (char *) NULL;
va_end(list);
result = execv(path,argv);
/* execvp failed; free argv */
free(argv);
return result;
}
int
execlp(const char *file, const char *arg, ...) {
va_list list;
char **argv;
char *p;
char **q;
int i=0;
size_t vect_length;
int result;
/* allocate memory for initial guess of number of parameters */
argv = (char **) malloc (sizeof(char *) * PARMSGUESS);
if (argv==NULL) return -1;
vect_length = PARMSGUESS;
/* build the array */
p = arg;
va_start (list, arg);
while (p && *p) {
argv[i] = p; i++;
p = va_arg(list, char* );
/* reallocate memory if necessary */
if (i>=vect_length) {
vect_length += PARMSGUESS;
q = (char **) realloc(argv,vect_length);
if (p == NULL) {
free(argv);
errno = ENOMEM;
return -1;
}
argv = q;
}
}
argv[i] = (char *) NULL;
va_end(list);
result = execvp(file,argv);
/* execvp failed; free argv */
free(argv);
return result;
}