gno/lib/libc/stdlib/environ.c

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/*
* These routines were written by Devin Reade for GNO 2.0.1.
*
* $Id: environ.c,v 1.2 1997/09/21 06:21:07 gdr Exp $
*
* This file is formatted with tab stops every 3 columns.
*/
#ifdef __ORCAC__
segment "libc_stdlb";
#endif
#pragma databank 1
#include <stddef.h>
#include <types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <gsos.h>
#include <orca.h>
#include <shell.h>
typedef struct stackelm {
struct stackelm *next;
char **env;
} stack_elm;
char **environ = NULL;
static short __environ_initialized = 0;
static short __use_environ = 0;
static short __in_environInit = 0;
static stack_elm *env_stack = NULL;
static char *__findenv(const char *name, int *offset);
static char *getvar(const char *name);
static int setvar(char *name, const char *value);
static void unsetvar (const char *name);
/*
* int environPush(void);
*
* Pre: none
*
* Post: The current state of the shell variable list is saved. This
* affects both the internal and the list pointed to by environ.
*
* Returns 0 on success, -1 otherwise.
*/
int
environPush(void) {
stack_elm *p;
PushVariablesGSPB parmBlock;
parmBlock.pCount = 0;
PushVariablesGS(&parmBlock);
/* if we're not using environ, then we're finished */
if(!__use_environ) return 0;
/* push environ onto the environment stack */
if ((p = (stack_elm *) malloc (sizeof(stack_elm))) == NULL)
return -1;
p->next = env_stack;
env_stack = p;
env_stack->env = environ;
/* zero the new environment and initialize */
environ = NULL;
__environ_initialized = 0;
if (environInit() != 0) { /* environInit failed; restore old environ */
__environ_initialized = 1;
environ = env_stack->env;
p = env_stack;
env_stack = env_stack->next;
free(p);
return -1;
}
return 0;
}
/*
* void environPop(void);
*
* Pre: none
*
* Post: The shell variable list is restored to the state that it was in
* when the most recent environPush() call was made. This affects both
* the internal version, and the list pointed to by environ.
*/
void
environPop(void) {
stack_elm *s;
char **p, **q;
PushVariablesGSPB parmBlock;
parmBlock.pCount = 0;
PopVariablesGS(&parmBlock);
/* if we're not using environ, then we're finished */
if(!__use_environ) return;
if(!env_stack) return; /* empty stack */
/* restore environ to its previous value */
p = environ;
environ = (env_stack) ? env_stack->env : NULL;
s = env_stack;
env_stack = (env_stack) ? env_stack->next : NULL;
/* free up each element in the discarded environment */
q = p;
while (q && *q) {
free(*q);
q++;
}
/* free the discarded environment */
if (p) free(p);
/* free the discarded environment stack element */
if (s) free(s);
return;
}
/*
* static int setvar (char *name, const char *value);
*
* Purpose: to set shell variable <name> to <value>. This affects only
* the internal representation, not that of the environ variable.
*
* Pre: <name> and <value> are null-terminated strings
*
* Post: <name> is set to <value>. Returns 0 on success, -1 on failure
*
* Acknowledgements: This routine is modified from code written by
* Dave Tribby [ GEnie: D.TRIBBY Internet: tribby@cup.hp.com ]
* for the "evaluate" shell utility for the Orca shell. Used
* with permission.
*/
static int
setvar(char *name, const char *value) {
int error;
GSString255Ptr var_value; /* Holds variable sized string */
SetGSPB set_var_pb;
static GSString255 var_name;
/* Shell call requires three parameters */
set_var_pb.pCount = 3;
/* Create GSOS string that holds the name of the variable */
/* Truncate value if > size of GSString255 */
var_name.length = strlen(name);
if (var_name.length > sizeof(var_name.text)) {
var_name.length = sizeof(var_name.text);
strncpy(var_name.text, name, sizeof(var_name.text));
} else {
strcpy(var_name.text, name);
}
set_var_pb.name = &var_name;
/* Allocate a GS string large enough to hold the value */
var_value = (GSString255Ptr) malloc(strlen(value)+sizeof(Word));
if (var_value == NULL) return (-1);
var_value->length = strlen(value);
strcpy(var_value->text, value);
set_var_pb.value = var_value;
set_var_pb.export = 1;
/* Make the shell call to set the variable */
SetGS(&set_var_pb);
error = toolerror();
free (var_value);
if (error) {
return -1;
} else {
return 0;
}
} /* setvar */
/*
* static void unsetvar (const char *name);
*
* Pre: <name> points to the name of the shell variable to be deleted. It
* may have a trailing '='.
*
* Post: The variable is deleted from the shell's internal environment.
* Any further references to it will return a NULL pointer.
*/
static void
unsetvar (const char *name) {
UnsetVariableGSPB parmblock;
GSString255 parmname;
/*
** delete the internal version
*/
/* set up the parameters */
parmblock.pCount = 1;
parmblock.name = &parmname;
parmname.length = strlen(name);
if (parmname.length > 254) parmname.length = 254;
strncpy(parmname.text,name,parmname.length);
if (parmname.text[parmname.length -1] == '=') {
parmname.text[parmname.length -1] = (char) NULL;
} else {
parmname.text[parmname.length] = (char) NULL;
}
UnsetVariableGS(&parmblock);
return;
}
/*
* static char *getvar (const char *name);
*
* Purpose: to get the value of shell variable <name>, using the internal
* (not environ) representation.
*
* Pre: <name> is a null-terminated string
*
* Post: returns a pointer to the value of <name>. If the variable has
* not been set or if the program is executing from an environment
* where shell variables do not exist, a NULL value is returned.
*
* Acknowledgements: This routine is modified from code written by
* Dave Tribby [ GEnie: D.TRIBBY Internet: tribby@cup.hp.com ]
* for the "evaluate" shell utility for the Orca shell. Used
* with permission.
*/
static char *getvar(const char *name) {
ReadVariableGSPB get_var_pb;
static ResultBuf255 var_value;
static GSString255 var_name;
char *result;
int length;
/* Shell call requires three parameters */
get_var_pb.pCount = 3;
/* Create GSOS string that holds the name of the variable */
/* Truncate value if > size of GSString255 */
var_name.length = strlen(name);
if (var_name.length > sizeof(var_name.text)) {
var_name.length = sizeof(var_name.text);
strncpy(var_name.text, name, sizeof(var_name.text));
} else {
strcpy(var_name.text, name);
}
get_var_pb.name = &var_name;
/* initialize the result buffer */
var_value.bufSize = sizeof (GSString255);
get_var_pb.value = &var_value;
/* Make the shell call to get the variable */
ReadVariableGS(&get_var_pb);
/* failed if tool error or not for export */
if (toolerror() || (get_var_pb.export == 0)) return (NULL);
/* get length of variable value */
length = ((ResultBuf255Ptr) get_var_pb.value)->bufString.length;
/* failed if variable not defined (length zero) */
if (length == 0) return (NULL);
/* set the NULL terminator */
result = (((ResultBuf255Ptr) get_var_pb.value)->bufString.text);
result[length] = (char) NULL;
return (result);
} /* getvar */
/* int environInit (void)
*
* Purpose: to initialize environ. This need not be done if the calling
* program does not need to access environ directly [that is, if it
* restricts itself to using getenv(), setenv(), putenv(), and
* unsetenv() ]
*
* Pre: none
*
* Post: the environment environ is initialized, and contains entries for
* all defined internal shell variables. Returns 0 on success,
* non-zero otherwise.
*/
int environInit (void) {
static ReadIndexedGSPB parmBuffer;
static ResultBuf255 nameBuffer, valueBuffer;
unsigned int nameLength, valueLength;
char *name;
char *value;
/* make sure we only do this once */
if (__environ_initialized) return 0;
__environ_initialized = 1;
__use_environ = 1;
__in_environInit = 1;
/*
** initialize the parameter block
*/
parmBuffer.pCount = 4;
parmBuffer.index = 1;
nameBuffer.bufSize = sizeof (GSString255);
valueBuffer.bufSize = sizeof (GSString255);
parmBuffer.name = &nameBuffer;
parmBuffer.value = &valueBuffer;
/* get space for our name and value buffers */
name = (char *) malloc (255 * sizeof(char));
if (!name) {
__in_environInit = 0;
return 1;
}
value = (char *) malloc (255 * sizeof(char));
if (!value) {
free(name);
__in_environInit = 0;
return 1;
}
/*
** add each variable into environ as they appear in the shell
** environment
*/
ReadIndexedGS (&parmBuffer);
nameLength = nameBuffer.bufString.length;
while (nameLength != 0) {
valueLength = valueBuffer.bufString.length;
/* copy the name and value */
strncpy (name, nameBuffer.bufString.text, nameLength);
name[nameLength] = (char) NULL;
strncpy (value, valueBuffer.bufString.text, valueLength);
value[valueLength] = (char) NULL;
/* try to place it in environ */
if (setenv(name, value, 1) != 0) {
free(name);
free(value);
__in_environInit = 0;
return 1;
}
/* get the next shell variable and continue ... */
parmBuffer.index++;
ReadIndexedGS (&parmBuffer);
nameLength = nameBuffer.bufString.length;
}
free(name);
free(value);
__in_environInit = 0;
return 0;
} /* environInit() */
/*
* int putenv (const char *str)
*
* Purpose: Take a string of the form NAME=value and stick it into the
* environment.
*
* Pre: <str> is a null-terminated string of the form NAME=value
*
* Post: returns zero if successful. A non-zero value indicates that
* space to expand the environment pointer table could not be
* acquired; in this case, the string has not been added
*
* Warning:
* Certain naming restrictions may apply if the environment variable
* is referenced by shell programs
*/
int putenv (const char *str) {
char *name, *value;
size_t l_str;
int result;
/* get space for our buffer */
l_str = strlen(str);
name = (char *) malloc (l_str + 1);
if (!name) return -1;
strcpy(name,str);
/* replace the '=' with a null and set value */
for (value=name; (*value) && (*value != '='); value++);
if (*value == '=') { /* found the end of name */
*value = (char) NULL;
value++;
result = (*value) ? setenv(name,value,1) : -1;
} else {
result = -1;
}
free(name);
return result;
}
/*
* char *getenv (const char *NAME)
*
* Purpose: search the environment for a string of the format NAME=VALUE
*
* Pre: NAME is the name of the variable for which the value is to be
* retrieved. It may end with an extra '=' which is not part of the
* name.
*
* Post: returns a pointer to the value of NAME. If NAME is not defined, it
* returns NULL. getenv() is case sensitive to NAME.
*/
char *getenv(const char *name) {
char *result;
size_t length;
length = strlen(name);
if (!length) return NULL;
if(name[length-1] == '=') {
char *tmp_name;
if ((tmp_name = malloc(length+1)) == NULL) return NULL;
strcpy(tmp_name,name);
tmp_name[length-1] = (char) NULL;
result = getvar(tmp_name);
free(tmp_name);
} else {
result = getvar(name);
}
return result;
}
/*
* static char *__findenv(const char *name, int *offset);
*
* Pre: <name> is a null-terminated string, which may end with '='.
*
* Post: returns a pointer to the value associated with <name> in the
* environment, if any, else it returns NULL. Sets <offset> to
* be the offset of the name/value combination in the environmental
* array (environ), for use by setenv(3) and unsetenv(3). It
* explicitly removes '=' in argument <name>.
*
* Acknowledgements: This is based on UCB code; see the above legalese.
*/
static char *__findenv(const char *name, int *offset) {
unsigned int len;
char **P, *C;
if (environ==NULL) {
return NULL;
}
for (C = name, len = 0; *C && (*C != '='); C++, len++);
for (P = environ; *P; P++) {
if (!strncmp(*P, name, len)) {
C = *P + len;
if (*C == '=') {
*offset = P - environ;
C++;
return(C);
}
}
}
return(NULL);
}
/*
* int setenv (const char *name, const char *value, int rewrite);
*
* Pre: <name> is the name of the environment variable to be set with
* value <value>. <rewrite> is either unset (zero) or set (non-
* zero).
*
* Post: If <name> does not previously exist, then it is added to the
* environment with value <value>. If <name> has been previously
* set, then <rewrite> is tested: If <rewrite> is non-zero then
* the old value is replaced, otherwise the call has no effect.
*
* Returns zero on success or if <name> already exists and <rewrite>
* is not set. Returns -1 and sets errno on failure.
*/
int setenv (const char *name, const char *value, int rewrite) {
static int alloced; /* if allocated space before */
char *C;
size_t l_value, l_name;
int offset;
char *tmp_name;
char *tmp_str;
if (*value == '=') value++; /* ignore any prepended '=' in value */
l_name = strlen(name); /* get the string lengths */
l_value = strlen(value);
if(name[l_name-1] == '=') l_name--; /* ignore any appended '=' in name */
if ((l_name == 0) || (l_value == 0)) { /* bad args! */
errno = EINVAL;
return -1;
}
/*
** make a copy of the name
*/
tmp_name = (char *) malloc (l_name+1); /* allocate necessary memory */
if (tmp_name == NULL) return -1;
strncpy(tmp_name, name, l_name); /* do the copy */
tmp_name[l_name] = '\0';
/*
** make a string of the form name=value, if necessary
*/
if (__use_environ) { /* are we using the environ structure? */
tmp_str = (char *) malloc (l_name + l_value + 2);
if (!tmp_str) {
free(tmp_name);
errno = ENOMEM;
return -1;
}
strcpy (tmp_str,tmp_name);
strcat (tmp_str,"=");
strcat (tmp_str,value);
}
/*
** Change the internal version
*/
if ((!__in_environInit) && ((rewrite) || (getenv(tmp_name) == NULL))) {
if (setvar(tmp_name, value)) {
int tmp_err = errno;
free(tmp_name);
if (__use_environ) free(tmp_str);
errno = tmp_err;
return -1;
}
}
if (__use_environ==0) {
free(tmp_name);
return 0;
}
/*
** Change the external (environ) version
*/
C = __findenv(tmp_name, &offset); /* find if already exists */
if (C!=NULL) {
if (!rewrite) {
free(tmp_name);
free(tmp_str);
return 0;
}
if (strlen(C) >= l_value) { /* old larger; copy over */
while (*value) {
*C = *value;
C++;
value++;
}
free(tmp_name);
free(tmp_str);
return 0;
}
} else { /* not found; create new slot */
int cnt;
char **P;
cnt = 0;
if (environ) for (P = environ; *P; P++) cnt++;
if (alloced) { /* done before; just increase size */
P = (char **) realloc ((char *)environ,
(size_t)(sizeof(char *) * (cnt + 2)));
if (!P) { /* realloc failed */
unsetvar(tmp_name);
free(tmp_name);
free(tmp_str);
errno = ENOMEM;
return -1;
} else {
environ = P;
}
} else { /* first time; get new space */
alloced = 1; /* copy old entries into it */
P = (char **) malloc ((size_t) (sizeof(char *) * (cnt + 2)));
if (!P) {
unsetvar(tmp_name);
free(tmp_name);
free(tmp_str);
errno = ENOMEM;
return -1;
}
/*
* original was:
* bcopy(environ, P, cnt * sizeof(char *));
* changed so that we could use the standard Orca libraries
* for non-gno implementations.
*/
if (environ) memcpy(P, environ, cnt * sizeof(char *));
environ = P;
}
environ[cnt + 1] = NULL;
offset = cnt;
}
/* we've got the new slot, now add it in */
environ[offset] = tmp_str;
free(tmp_name);
return 0;
}
/*
* void unsetenv (const char *name);
*
* Pre: <name> points to the name of the shell variable to be deleted. It
* may have a trailing '='.
*
* Post: The variable is deleted. Any further references to it will return
* a NULL pointer. This routine unsets both the internal and, if it's
* initialized, the environ representations.
*
* Acknowledgements: Contains BSD code. See the above legalese.
*/
void unsetenv (const char *name) {
char **P;
int offset;
/*
** delete the internal version
*/
unsetvar(name);
if(!__use_environ) return;
/*
** delete the environ version, if necessary.
*/
while (__findenv(name, &offset)!=NULL) { /* if set multiple times */
free(environ[offset]);
for (P = &environ[offset];; P++)
if (!(*P = *(P + 1)))
break;
}
return;
}