library api's: _util_ (utility helper interfaces) namespace overhaul.

1 files changed, 135 insertions, 0 deletions

diff --git a/src/util/slbt_dump_machine.c b/src/util/slbt_dump_machine.c
new file mode 100644
index 0000000..bf86315
--- /dev/null
+++ b/src/util/slbt_dump_machine.c
@@ -0,0 +1,135 @@
+/*******************************************************************/
+/*  slibtool: a skinny libtool implementation, written in C        */
+/*  Copyright (C) 2016--2024  SysDeer Technologies, LLC            */
+/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */
+/*******************************************************************/
+
+#include <stdio.h>
+#include <limits.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <sys/wait.h>
+
+#include <slibtool/slibtool.h>
+#include "slibtool_spawn_impl.h"
+#include "slibtool_snprintf_impl.h"
+
+static void slbt_util_dump_machine_child(
+	char *	program,
+	int	fd[2])
+{
+	char *	compiler;
+	char *	argv[3];
+
+	close(fd[0]);
+
+	if ((compiler = strrchr(program,'/')))
+		compiler++;
+	else
+		compiler = program;
+
+	argv[0] = compiler;
+	argv[1] = "-dumpmachine";
+	argv[2] = 0;
+
+	if ((fd[0] = openat(AT_FDCWD,"/dev/null",O_RDONLY,0)) >= 0)
+		if (dup2(fd[0],0) == 0)
+			if (dup2(fd[1],1) == 1)
+				execvp(program,argv);
+
+	_exit(EXIT_FAILURE);
+}
+
+int slbt_util_dump_machine(
+	const char *	compiler,
+	char *		machine,
+	size_t		buflen)
+{
+	ssize_t	ret;
+	pid_t	pid;
+	pid_t	rpid;
+	int	code;
+	int	fd[2];
+	char *	mark;
+	char	program[PATH_MAX];
+
+	/* setup */
+	if (!machine || !buflen || !--buflen) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (slbt_snprintf(program,sizeof(program),
+			"%s",compiler) < 0)
+		return -1;
+
+	/* fork */
+	if (pipe(fd))
+		return -1;
+
+	if ((pid = fork()) < 0) {
+		close(fd[0]);
+		close(fd[1]);
+		return -1;
+	}
+
+	/* child */
+	if (pid == 0)
+		slbt_util_dump_machine_child(
+			program,
+			fd);
+
+	/* parent */
+	close(fd[1]);
+
+	mark = machine;
+
+	for (; buflen; ) {
+		ret = read(fd[0],mark,buflen);
+
+		while ((ret < 0) && (errno == EINTR))
+			ret = read(fd[0],mark,buflen);
+
+		if (ret > 0) {
+			buflen -= ret;
+			mark   += ret;
+
+		} else if (ret == 0) {
+			close(fd[0]);
+			buflen = 0;
+
+		} else {
+			close(fd[0]);
+			return -1;
+		}
+	}
+
+	/* execve verification */
+	rpid = waitpid(
+		pid,
+		&code,
+		0);
+
+	if ((rpid != pid) || code) {
+		errno = ESTALE;
+		return -1;
+	}
+
+	/* newline verification */
+	if ((mark == machine) || (*--mark != '\n')) {
+		errno = ERANGE;
+		return -1;
+	}
+
+	*mark = 0;
+
+	/* portbld <--> unknown synonym? */
+	if ((mark = strstr(machine,"-portbld-")))
+		memcpy(mark,"-unknown",8);
+
+	/* all done */
+	return 0;
+}