compat: Add setproctitle from LXC

2 files changed, 192 insertions, 0 deletions

diff --git a/compat/setproctitle.c b/compat/setproctitle.c
new file mode 100644
index 00000000..f5ff0ac0
--- /dev/null
+++ b/compat/setproctitle.c
@@ -0,0 +1,156 @@
+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2008
+ *
+ * Authors:
+ * Daniel Lezcano <daniel.lezcano at free.fr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "config.h"
+
+#define prctl_arg(x) ((unsigned long)x)
+
+/*
+ * Sets the process title to the specified title. Note that this may fail if
+ * the kernel doesn't support PR_SET_MM_MAP (kernels <3.18).
+ */
+int setproctitle(const char *fmt, ...)
+{
+	char title[1024], *tp, *progname;
+	va_list args;
+	int fd, i;
+	char *buf_ptr, *tmp_proctitle;
+	char buf[BUFSIZ];
+	int ret = 0;
+	ssize_t bytes_read = 0;
+	size_t len;
+	static char *proctitle = NULL;
+
+#if 0
+	progname = getprogname();
+#else
+	progname = "dhcpcd";
+#endif
+	tp = title;
+	tp += snprintf(title, sizeof(title), "%s: ", progname);
+
+	va_start(args, fmt);
+	vsnprintf(tp, sizeof(title) - strlen(progname), fmt, args);
+	va_end(args);
+
+	/*
+	 * We don't really need to know all of this stuff, but unfortunately
+	 * PR_SET_MM_MAP requires us to set it all at once, so we have to
+	 * figure it out anyway.
+	 */
+	unsigned long start_data, end_data, start_brk, start_code, end_code,
+	    start_stack, arg_start, arg_end, env_start, env_end;
+	long brk_val;
+	struct prctl_mm_map prctl_map;
+
+	fd = open("/proc/self/stat", O_RDONLY);
+	if (fd == -1)
+		return -1;
+	bytes_read = read(fd, buf, sizeof(buf) - 1);
+	close(fd);
+	if (bytes_read == -1)
+		return -1;
+
+	buf[bytes_read] = '\0';
+
+	/* Skip the first 25 fields, column 26-28 are start_code, end_code,
+	 * and start_stack */
+	buf_ptr = strchr(buf, ' ');
+	for (i = 0; i < 24; i++) {
+		if (!buf_ptr)
+			return -1;
+		buf_ptr = strchr(buf_ptr + 1, ' ');
+	}
+	if (!buf_ptr)
+		return -1;
+
+	i = sscanf(buf_ptr, "%lu %lu %lu", &start_code, &end_code, &start_stack);
+	if (i != 3)
+		return -1;
+
+	/* Skip the next 19 fields, column 45-51 are start_data to arg_end */
+	for (i = 0; i < 19; i++) {
+		if (!buf_ptr)
+			return -1;
+		buf_ptr = strchr(buf_ptr + 1, ' ');
+	}
+
+	if (!buf_ptr)
+		return -1;
+
+	i = sscanf(buf_ptr, "%lu %lu %lu %*u %*u %lu %lu", &start_data,
+		   &end_data, &start_brk, &env_start, &env_end);
+	if (i != 5)
+		return -1;
+
+	/* Include the null byte here, because in the calculations below we
+	 * want to have room for it. */
+	len = strlen(title) + 1;
+
+	tmp_proctitle = realloc(proctitle, len);
+	if (!tmp_proctitle)
+		return -1;
+
+	proctitle = tmp_proctitle;
+
+	arg_start = (unsigned long)proctitle;
+	arg_end = arg_start + len;
+
+	brk_val = syscall(__NR_brk, 0);
+
+	prctl_map = (struct prctl_mm_map){
+	    .start_code = start_code,
+	    .end_code = end_code,
+	    .start_stack = start_stack,
+	    .start_data = start_data,
+	    .end_data = end_data,
+	    .start_brk = start_brk,
+	    .brk = (unsigned long long)brk_val,
+	    .arg_start = arg_start,
+	    .arg_end = arg_end,
+	    .env_start = env_start,
+	    .env_end = env_end,
+	    .auxv = NULL,
+	    .auxv_size = 0,
+	    .exe_fd = (unsigned int)-1,
+	};
+
+	ret = prctl(PR_SET_MM, prctl_arg(PR_SET_MM_MAP), prctl_arg(&prctl_map),
+		    prctl_arg(sizeof(prctl_map)), prctl_arg(0));
+	if (ret == 0)
+		(void)strlcpy((char *)arg_start, title, len);
+	return ret;
+}
diff --git a/compat/setproctitle.h b/compat/setproctitle.h
new file mode 100644
index 00000000..2fe685f1
--- /dev/null
+++ b/compat/setproctitle.h
@@ -0,0 +1,36 @@
+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2008
+ *
+ * Authors:
+ * Daniel Lezcano <daniel.lezcano at free.fr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef SETPROCTITLE_H
+#define SETPROCTITLE_H
+
+#ifndef __printflike
+#if __GNUC__ > 2 || defined(__INTEL_COMPILER)
+#define	__printflike(a, b) __attribute__((format(printf, a, b)))
+#else
+#define	__printflike(a, b)
+#endif
+#endif /* !__printflike */
+
+__printflike(1, 2) int setproctitle(const char *, ...);
+#endif