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at 2025-11-06T07:20:10-08:00

Fix #437:  Use realpath to find the executable

Merge branch 'issue-437-find-self' into 'master'

Fix #437:  Use realpath to find the executable

Closes #437

See merge request cmucl/cmucl!329
 

 /*

  * From the current location of the lisp executable, create a suitable

- * default for CMUCLLIB

+ * default for CMUCLLIB.  The result is a colon-separated list

+ * directories to be used for finding the core file and for the cmucl

+ * libraries.

+ *

+ * The caller must free the returned string.

  */

-static const char *

+static char *

 default_cmucllib(const char *argv0arg)

 {

-    char *p0;

-    char *defpath;

     char *cwd;

-    char *argv0_dir = strdup(argv0arg);

+    int cwd_len;

+    char **ptr;

+    char *path;

+    int path_len;

+    char *slash;

 

-    /*

-     * From argv[0], create the appropriate directory by lopping off the

-     * executable name

-     */

+    cwd = realpath(argv0arg, NULL);

 

-    p0 = strrchr(argv0_dir, '/');

-    if (p0 == NULL) {

-	*argv0_dir = '\0';

-    } else if (p0 != argv0_dir) {

-	*p0 = '\0';

+    if (debug_lisp_search) {

+	fprintf(stderr, "Realpath of %s = %s\n", argv0arg, cwd);

+    }

+

+    if (!cwd) {

+	perror("Cannot determine realpath of lisp executable");

+	exit(1);

     }

 

     /*

-     * Create the full pathname of the directory containing the

-     * executable.  argv[0] can be an absolute or relative path.

+     * Delete the binary name from the full path, leaving just the

+     * full directory to the executable.

      */

-    if (debug_lisp_search) {

-	fprintf(stderr, "argv[0] = %s\n", argv0arg);

-	fprintf(stderr, "argv_dir = %s\n", argv0_dir);

+    slash = strrchr(cwd, '/');

+    if (slash) {

+	slash[1] = '\0';

     }

 

+    if (debug_lisp_search) {

+	fprintf(stderr, "Executable path %s\n", cwd);

+    }

 

-    if (argv0_dir[0] == '/') {

-	cwd = malloc(strlen(argv0_dir) + 2);

-	strcpy(cwd, argv0_dir);

-	strcat(cwd, "/");

-	if (debug_lisp_search) {

-	    fprintf(stderr, "absolute path, argv[0] = %s\n", cwd);

-	}

-

-    } else if (*argv0_dir != '\0') {

-	/*

-	 * argv[0] is a relative path.  Get the current directory and

-	 * append argv[0], after stripping off the executable name.

-	 */

-	cwd = malloc(FILENAME_MAX + strlen(argv0_dir) + 100);

-	getcwd_or_die(cwd, FILENAME_MAX);

-	strcat(cwd, "/");

-	if (*argv0_dir != '\0') {

-	    strcat(cwd, argv0_dir);

-	    strcat(cwd, "/");

-	}

-	if (debug_lisp_search) {

-	    fprintf(stderr, "relative path, argv[0] = %s\n", cwd);

-	}

-    } else {

-	/*

-	 * argv[0] is someplace on the user's PATH

-	 *

-	 */

-	char *path = getenv("PATH");

-	char *p1, *p2 = NULL;

-	struct stat buf;

-

-	if (debug_lisp_search) {

-	    fprintf(stderr, "User's PATH = %s\n", path ? path : "<NULL>");

-	}

-

-	cwd = malloc(FILENAME_MAX + strlen(argv0arg) + 100);

-	cwd[0] = '\0';

-

-	if (path) {

-            const char *ptr = (p0 != NULL) ? p0 : argv0arg;

-

-	    for (p1 = path; *p1 != '\0'; p1 = p2) {

-		p2 = strchr(p1, ':');

-		if (p2 == NULL)

-		    p2 = p1 + strlen(p1);

-		strncpy(cwd, p1, p2 - p1);

-		cwd[p2 - p1] = '/';

-		cwd[p2 - p1 + 1] = '\0';

-		strcpy(cwd + (p2 - p1 + 1), ptr);

-

-		if (debug_lisp_search) {

-		    fprintf(stderr, "User's PATH, trying %s\n", cwd);

-		}

-

-		if (stat(cwd, &buf) == 0) {

-

-		    if (debug_lisp_search) {

-			fprintf(stderr, "User's PATH, found %s\n", cwd);

-		    }

-		    if (access(cwd, X_OK) == 0) {

-			break;

-		    } else {

-			if (debug_lisp_search) {

-			    fprintf(stderr,

-				    " But not executable.  Continuing...\n");

-			}

-		    }

+    /*

+     * Create the appropriate value for CMUCLLIB by adding the

+     * executable path (if needed) to each entry in

+     * cmucllib_search_list.

+     */

 

-		}

+    /* First figure out how much space we need */

 

-		if (*p2 == ':') {

-		    p2++;

-		}

+    path_len = 0;

+    cwd_len = strlen(cwd);

 

-	    }

-	    if ((p1 == p2) || (p2 == NULL)) {

-		cwd[0] = '\0';

-	    } else {

-		cwd[p2 - p1 + 1] = '\0';

-	    }

-	    if (debug_lisp_search) {

-		fprintf(stderr, "User's PATH, Final cwd %s\n", cwd);

-	    }

+    ptr = cmucllib_search_list;

 

-	}

+    while (*ptr != NULL) {

+	/*

+	 * Plus 2 for the ":" and "/" we need to add and the cwd that

+	 * might be added.

+	 */

+	path_len += strlen(*ptr) + cwd_len + 2;

+	++ptr;

     }

 

-    /* Create the appropriate value for CMUCLLIB */

-

-    {

-	char **ptr;

-	int total_len;

-	int cwd_len;

-

-	/* First figure out how much space we need */

+    /* Create the colon separated list of directories */

 

-	total_len = 0;

-	cwd_len = strlen(cwd);

-

-	ptr = cmucllib_search_list;

+    path = malloc(path_len + 1);

+    if (!path) {

+	perror("Failed to malloc space for cmucllib");

+	exit(1);

+    }

+    

+    *path = '\0';

 

-	while (*ptr != NULL) {

-	    /* Plus 2 for the ":" and "/" we need to add */

-	    total_len += strlen(*ptr) + cwd_len + 2;

-	    ++ptr;

+    ptr = cmucllib_search_list;

+    while (*ptr != NULL) {

+	/*

+	 * If it's relative, add the full executable path first to

+	 * make the path absolute.

+	 */

+	if (*ptr[0] != '/') {

+	    strcat(path, cwd);

 	}

 

-	/* Create the colon separated list of directories */

-

-	defpath = malloc(total_len + 1);

-	*defpath = '\0';

-

-	ptr = cmucllib_search_list;

-	while (*ptr != NULL) {

-	    if (*ptr[0] != '/') {

-		strcat(defpath, cwd);

-	    }

-

-	    strcat(defpath, *ptr);

-

-	    if (ptr[1] != NULL) {

-		strcat(defpath, ":");

-	    }

+	strcat(path, *ptr);

 

-	    ++ptr;

+	/* Add a colon if we're not at the last entry of the search list */

+	if (ptr[1] != NULL) {

+	    strcat(path, ":");

 	}

 

-	if (strlen(defpath) > total_len) {

-	    abort();

-	}

+	++ptr;

     }

 

-    free(argv0_dir);

-    free(cwd);

+    if (strlen(path) > path_len) {

+	abort();

+    }

 

-    return (const char *) defpath;

+    free(cwd);

+    return path;

 }

 

 /*

Raymond Toy pushed to branch master at cmucl / cmucl

Commits:

1 changed file:

Changes: