Init

bin/ldd.c

@@ -0,0 +1,117 @@
+/* @(#)ldd.c 1.1 94/10/31 SMI */
+
+/*
+ * List Dynamic Dependencies
+ */
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <a.out.h>
+#include <link.h>
+#include <sys/wait.h>
+#include <sys/file.h>
+
+char *nargv[] = {0, 0};			/* dummy argument vector */
+
+char *malloc();				/* malloc return value */
+
+main(argc, argv, envp)
+	int argc;			/* count of arguments */
+	char *argv[];			/* argument values */
+	char *envp[];			/* array of environment strings */
+{
+	unsigned int i, j;		/* general temporaries */
+	int fd;				/* file descriptor on targets */
+	int pid;			/* child process id */
+	char **nenvp;			/* new environment */
+	struct exec exec;		/* template for inspecting target */
+	union wait status;		/* dummy for wait() */
+	struct exec a;
+
+	/*
+	 * Initial sanity check.
+	 */
+	if (argc <= 1) {
+		(void) fprintf(stderr, "Usage: ldd file ... \n");
+		exit(1);
+	}
+	(void) setlinebuf(stdout);
+	(void) setlinebuf(stderr);
+
+	/*
+	 * Add an environment variable.  Count the number of existing
+	 * ones, and then allocate up a new vector of environment strings
+	 * and add ours to it.
+	 */
+	for (i = 0; envp[i]; i++)
+		;
+	if ((nenvp = (char **)malloc((i + 2) * sizeof (char *))) == NULL) {
+		perror("ldd: out of memory for environment");
+		exit(1);
+	}
+	nenvp[0] = "LD_TRACE_LOADED_OBJECTS=placeholder";
+	for (j = 0; j < (i + 1); j++)
+		nenvp[j + 1] = envp[j];
+
+	/*
+	 * For each argument, examine it and determine if it is an
+	 * executable with a __DYNAMIC structure and an entry point.
+	 * If it is, simply execute it and let the dynamic linker
+	 * report its status.
+	 */
+	for (i = 1; i < argc; i++) {
+		if ((fd = open(argv[i], O_RDONLY)) == -1) {
+			fprintf(stderr, "ldd: %s unreadable: ", argv[1]);
+			perror("");
+			continue;
+		}
+		j = read(fd, (char *)&exec, sizeof (struct exec));
+		(void) close(fd);
+		if (j != sizeof (struct exec)) {
+			(void) fprintf(stderr, "ldd: %s: not an executable\n",
+			    argv[i]);
+			continue;
+		}
+		if (N_BADMAG(exec)) {
+			(void) fprintf(stderr, "ldd: %s: not an executable\n",
+			    argv[i]);
+			continue;
+		}
+		if (!exec.a_dynamic) {
+			(void) printf("%s: statically linked\n", argv[i]);
+			continue;
+		}
+		if (exec.a_entry == 0) {
+			(void) fprintf("%s: not an executable\n", argv[i]);
+			continue;
+		}
+		if ((pid = fork()) == 0) {
+			if (argc > 2)
+				(void) printf("%s:\n", argv[i]);
+			execve(argv[i], nargv, nenvp);
+			(void) fprintf(stderr,
+			    "ldd: %s execution failed: ", argv[i]);
+			perror("");
+			continue;
+		} else
+			if (pid != -1) {
+				while (wait(&status) != pid)
+					;
+				if (status.w_T.w_Termsig)
+					(void) fprintf(stderr,
+			"ldd: %s execution failed due to signal %d %s\n", 
+					    argv[i], 
+					    status.w_T.w_Termsig,
+					    status.w_T.w_Coredump ? 
+					    "(core dumped)" : "");
+				else if (status.w_T.w_Retcode)
+					(void) printf(stderr,
+			"ldd: %s execution failed: exit status %d\n",
+					    argv[i], 
+					    status.w_T.w_Retcode);
+			} else 
+				perror("ldd: fork() failed");
+	}
+	exit(0);
+	/*NOTREACHED*/
+}