1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* Copyright 1997 Thierry Bousch
* Licensed under the Gnu Public License, Version 2
*
* $Id: functions.c,v 1.2 1997/04/16 18:16:29 bousch Exp $
*
* Builtin and external functions
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "saml.h"
#include "saml-parse.h"
#include "samuel.h"
typedef struct builtin_function {
const char *name;
int (*fn)(mref_t result, int argc, mref_t *argv);
} BFN;
BFN bfns[] = {
{ "det", fn_determinant },
{ "getpid", fn_getpid },
{ "sqrt", fn_sqrt },
{ "variables", fn_variables },
{ 0, 0 }
};
#define FN_PREFIX "fn_"
int execute_function (const char* cmd, int nb_args)
{
char *command, *p, **argv;
int i, argc, fd[2], child, retval;
mref_t result = mref_new();
FILE *fp;
BFN *t;
for (t = bfns; t->name; t++)
if (strcmp(t->name,cmd) == 0) {
mref_t arglist[nb_args];
for (i = nb_args-1; i >= 0; i--)
arglist[i] = pop_mref();
retval = (*t->fn)(result, nb_args, arglist);
for (i = nb_args-1; i >= 0; i--)
mref_free(arglist[i]);
push_mref(result);
return retval;
}
/* Not a builtin function */
if (pipe(fd) < 0) {
perror("samuel: pipe");
retval = -1;
goto exit_fn;
}
if ((child = fork()) < 0) {
perror("fork");
retval = -1;
goto exit_fn;
}
if (child == 0) {
/*
* This is the child. We copy the command in writable space,
* compute the number of arguments (argc), and allocate
* space for the arguments (argv), and finally, exec.
*/
close(fd[0]);
if (dup2(fd[1],1) < 0)
perror("samuel: dup2");
command = alloca(strlen(cmd)+strlen(FN_PREFIX)+1);
if (strncmp(cmd, "induce ", 7) == 0) {
/* Magic. That's for subscripted literals */
strcpy(command, cmd);
} else {
/* Normal case, prepend "fn_" before the name */
strcpy(command, FN_PREFIX);
strcat(command, cmd);
}
argc = 1 + nb_args;
for (p = command; *p; p++)
if (*p == ' ') ++argc;
argv = alloca((argc+1)*sizeof(char*));
argv[0] = command;
argv[argc] = NULL;
argc = 1;
for (p = command; *p; p++)
if (*p == ' ') {
*p = '\0';
argv[argc++] = p+1;
}
/* Beware: the arguments are popped from last to first */
for (i = nb_args-1; i >= 0; i--) {
p = mref_string(pop_mref());
p = strcpy(alloca(strlen(p)+1), p);
argv[argc+i] = p;
}
execvp(command, argv);
perror("samuel: execvp");
_exit(127);
}
/* This is the parent process */
close(fd[1]);
if ((fp = fdopen(fd[0],"r")) == NULL) {
perror("samuel: fdopen");
retval = -1;
goto exit_fn;
}
saml_init_lexer_fd(fp);
retval = saml_parse(result, mr_model);
fclose(fp);
/* Wait for the child to terminate */
while (waitpid(child,NULL,0) < 0 && errno == EINTR)
;
exit_fn:
/* Update the stack */
while (nb_args--)
mref_free(pop_mref());
push_mref(result);
return retval;
}
/*
* Miscillaneous builtin functions
*/
int fn_determinant (mref_t result, int n2, mref_t *argv)
{
int i, j, n;
mref_t line, matrix;
/* Check that n2 is a square */
for (n = 0; n*n < n2; n++)
;
if (n*n != n2) {
fprintf(stderr, "fn_determinant: not square\n");
return 1;
}
line = mref_new();
matrix = mref_new();
mref_array(matrix, ST_MATRIX, n);
mref_array(line, ST_LINE, n);
for (i = 0; i < n; i++) {
for (j = 0; j < n; j++)
mref_setitem(line, j, argv[n*i+j]);
mref_setitem(matrix, i, line);
}
mref_det(result, matrix);
mref_free(line);
mref_free(matrix);
return 0;
}
int fn_getpid (mref_t result, int argc, mref_t *argv)
{
char buffer[24];
sprintf(buffer, "%d", getpid());
mref_build(result, ST_INTEGER, buffer);
mref_promote(result, mr_model);
return 0;
}
int fn_sqrt (mref_t result, int argc, mref_t *argv)
{
if (argc != 1) {
fprintf(stderr, "Usage: fn_sqrt <number>\n");
return 1;
}
/* Convert to a string, and convert back to an integer */
mref_build(result, ST_INTEGER, mref_string(argv[0]));
if (mref_type(result) == ST_VOID) {
fprintf(stderr, "fn_sqrt: non-numeric argument\n");
return 1;
}
mref_sqrt(result, result);
if (mref_type(result) == ST_VOID) {
fprintf(stderr, "fn_sqrt: negative number\n");
return 1;
}
mref_promote(result, mr_model);
return 0;
}
|
