131 lines
3.5 KiB
C
131 lines
3.5 KiB
C
/* ******************************************************************************
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*
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*
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* This program and the accompanying materials are made available under the
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* terms of the Apache License, Version 2.0 which is available at
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* https://www.apache.org/licenses/LICENSE-2.0.
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*
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* See the NOTICE file distributed with this work for additional
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* information regarding copyright ownership.
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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* SPDX-License-Identifier: Apache-2.0
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******************************************************************************/
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//
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// Methods to lookup files in $PATH
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// adopted from https://stackoverflow.com/questions/2718915/check-if-file-exists-including-on-path
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//
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#ifndef LIBND4J_FILES_H
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#define LIBND4J_FILES_H
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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void *malloc_check(const char *what, size_t n);
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char *strsave(const char *s, const char *lim);
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char ** shellpath(void);
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void freeshellpath (char *shellpath[]);
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unsigned maxpathlen(char *path[], const char *base);
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bool file_exists(char *name);
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void *malloc_check(const char *what, size_t n) {
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void *p = malloc(n);
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if (p == NULL) {
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fprintf(stderr, "Cannot allocate %zu bytes to %s\n", n, what);
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exit(2);
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}
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return p;
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}
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char *strsave(const char *s, const char *lim) {
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if (lim == NULL)
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lim = s + strlen(s);
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char *p = (char *) malloc_check("save string", lim - s + 1);
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strncpy(p, s, lim-s);
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p[lim-s] = '\0';
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return p;
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}
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char ** shellpath(void) {
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const char *path = getenv("PATH");
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if (!path)
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path = "./";
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char **vector = // size is overkill
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(char **) malloc_check("hold path elements", strlen(path) * sizeof(*vector));
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const char *p = path;
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int next = 0;
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while (p) {
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#ifdef _WIN32
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char *q = strchr(p, ';'); // windows uses ; as delimiter
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#else
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char *q = strchr(p, ':'); // linux and derivatives use : as delimiter
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#endif
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vector[next++] = strsave(p, q);
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p = q ? q + 1 : NULL;
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}
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vector[next] = NULL;
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return vector;
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}
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void freeshellpath (char *shellpath[]) {
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for (int i = 0; shellpath[i]; i++)
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free(shellpath[i]);
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free(shellpath);
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}
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unsigned maxpathlen(char *path[], const char *base) {
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unsigned blen = strlen(base);
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unsigned n = 0;
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for (int i = 0; path[i]; i++) {
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unsigned pn = strlen(path[i]);
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if (pn > n) n = pn;
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}
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return blen+n+1;
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}
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bool file_exists(char *name){
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printf("Trying file: [%s]\n", name);
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FILE *file;
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if (file = fopen(name, "r")) {
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fclose(file);
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return true;
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}
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return false;
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}
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bool checkFileInPath(const char *file) {
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char *path = getenv("PATH");
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char **listed = shellpath();
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size_t maxlen = maxpathlen(listed, file)+1;
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char *buf = (char *) malloc_check("hold path", maxlen);
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bool found = false;
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for (int i = 0; listed[i]; i++) {
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if (strlen(listed[i]) > 0) {
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#ifdef _WIN32
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snprintf(buf, maxlen, "%s\\%s", listed[i], file);
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#else
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snprintf(buf, maxlen, "%s/%s", listed[i], file);
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#endif
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if (file_exists(buf)) {
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found = true;
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break;
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}
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}
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}
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free(buf);
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freeshellpath(listed);
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return found;
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}
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#endif //LIBND4J_FILES_H
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