Add initial implementation of passwd(1)

No shadow support yet.

Makefile

@@ -3,15 +3,17 @@ include config.mk
 .POSIX:
 .SUFFIXES: .c .o
 
-HDR = arg.h config.def.h proc.h reboot.h rtc.h util.h
+HDR = arg.h config.def.h passwd.h proc.h reboot.h rtc.h text.h util.h
 LIB = \
 	util/agetcwd.o        \
+	util/agetline.o       \
 	util/apathmax.o       \
 	util/ealloc.o         \
 	util/eprintf.o        \
 	util/estrtol.o        \
 	util/estrtoul.o       \
 	util/explicit_bzero.o \
+	util/passwd.o         \
 	util/proc.o           \
 	util/putword.o        \
 	util/recurse.o        \
@@ -43,6 +45,7 @@ SRC = \
 	mount.c             \
 	mountpoint.c        \
 	pagesize.c          \
+	passwd.c            \
 	pidof.c             \
 	pivot_root.c        \
 	ps.c                \

README

@@ -8,9 +8,9 @@ The following programs are currently implemented:
 
     chvt clear ctrlaltdel dd df  dmesg eject fallocate free getty halt
     hwclock id  insmod killall5 login  lsmod lsusb mknod  mkswap mount
-    mountpoint  pagesize pidof  pivot_root  ps respawn  rmmod stat  su
+    mountpoint pagesize passwd pidof  pivot_root ps respawn rmmod stat
-    swapoff swapon  switch_root sysctl truncate umount  unshare uptime
+    su  swapoff  swapon  switch_root sysctl  truncate  umount  unshare
-    watch who
+    uptime watch who
 
 The complement  of ubase  is sbase[1] which  mostly follows  POSIX and
 provides all the portable tools.  Together they are intended to form a

TODO

@@ -9,7 +9,6 @@ Tools to be implemented
  * losetup(8)
  * lspci
  * mkswap [-L]
- * passwd
  * adduser
  * addgroup
  * rmuser

passwd.c

@@ -0,0 +1,142 @@
+/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "passwd.h"
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s login\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	char *pass, *cryptpass1, *cryptpass2, *cryptpass3;
+	char *p;
+	char template[] = "/tmp/pw.XXXXXX";
+	struct passwd *pw;
+	int ffd, tfd;
+	int r;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc != 1)
+		usage();
+
+	errno = 0;
+	pw = getpwnam(argv[0]);
+	if (errno)
+		eprintf("getpwnam: %s:", argv[0]);
+	else if (!pw)
+		eprintf("who are you?\n");
+
+	switch (pw->pw_passwd[0]) {
+	case '!':
+	case '*':
+		eprintf("denied\n");
+	}
+
+	if (pw->pw_passwd[0] == '\0')
+		goto newpass;
+
+	if (pw->pw_passwd[0] == 'x' && pw->pw_passwd[1] == '\0')
+		eprintf("no shadow support\n");
+
+	/* Flush pending input */
+	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
+
+	pass = getpass("Current password: ");
+	putchar('\n');
+	if (!pass)
+		eprintf("getpass:");
+	p = crypt(pass, pw->pw_passwd);
+	if (!p)
+		eprintf("crypt:");
+	cryptpass1 = estrdup(p);
+	if (strcmp(cryptpass1, pw->pw_passwd) != 0)
+		eprintf("incorrect password\n");
+
+newpass:
+	/* Flush pending input */
+	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
+
+	pass = getpass("Enter new password: ");
+	putchar('\n');
+	if (!pass)
+		eprintf("getpass:");
+	p = crypt(pass, pw->pw_passwd);
+	if (!p)
+		eprintf("crypt:");
+	cryptpass2 = estrdup(p);
+	if (strcmp(cryptpass1, cryptpass2) == 0)
+		eprintf("password left unchanged\n");
+
+	/* Flush pending input */
+	ioctl(STDIN_FILENO, TCFLSH, (void *)0);
+
+	pass = getpass("Retype new password: ");
+	putchar('\n');
+	if (!pass)
+		eprintf("getpass:");
+	p = crypt(pass, pw->pw_passwd);
+	if (!p)
+		eprintf("crypt:");
+	cryptpass3 = estrdup(p);
+	if (strcmp(cryptpass2, cryptpass3) != 0)
+		eprintf("passwords don't match\n");
+
+	pw->pw_passwd = cryptpass3;
+
+	ffd = open("/etc/passwd", O_RDWR);
+	if (ffd < 0)
+		eprintf("open %s:", "/etc/passwd");
+
+	tfd = mkostemp(template, O_RDWR);
+	if (tfd < 0)
+		eprintf("mkstemp:");
+
+	r = pw_copy(ffd, tfd, pw);
+	if (r < 0) {
+		unlink(template);
+		exit(EXIT_FAILURE);
+	}
+
+	r = lseek(ffd, 0, SEEK_SET);
+	if (r < 0) {
+		unlink(template);
+		exit(EXIT_FAILURE);
+	}
+	r = lseek(tfd, 0, SEEK_SET);
+	if (r < 0) {
+		unlink(template);
+		exit(EXIT_FAILURE);
+	}
+
+	r = pw_copy(tfd, ffd, NULL);
+	if (r < 0) {
+		unlink(template);
+		exit(EXIT_FAILURE);
+	}
+
+	close(tfd);
+	close(ffd);
+	unlink(template);
+	free(cryptpass3);
+	free(cryptpass2);
+	free(cryptpass1);
+
+	return EXIT_SUCCESS;
+}

passwd.h

@@ -0,0 +1,4 @@
+/* See LICENSE file for copyright and license details. */
+/* passwd.c */
+int pw_scan(char *, struct passwd *);
+int pw_copy(int, int, const struct passwd *);

text.h

@@ -0,0 +1,11 @@
+/* See LICENSE file for copyright and license details. */
+
+struct linebuf {
+	char **lines;
+	long nlines;
+	long capacity;
+};
+#define EMPTY_LINEBUF {NULL, 0, 0,}
+void getlines(FILE *, struct linebuf *);
+
+ssize_t agetline(char **, size_t *, FILE *);

util/agetline.c

@@ -0,0 +1,13 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../text.h"
+#include "../util.h"
+
+ssize_t
+agetline(char **p, size_t *size, FILE *fp)
+{
+	return getline(p, size, fp);
+}

util/passwd.c

@@ -0,0 +1,113 @@
+/* See LICENSE file for copyright and license details. */
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../text.h"
+#include "../util.h"
+
+int
+pw_scan(char *bp, struct passwd *pw)
+{
+	char *p;
+
+	memset(pw, 0, sizeof(*pw));
+
+	/* login name */
+	p = strsep(&bp, ":");
+	if (!p || *p == '\0')
+		goto corrupt;
+	pw->pw_name = p;
+
+	/* passwd */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_passwd = p;
+
+	/* uid */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_uid = estrtol(p, 10);
+
+	/* gid */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_gid = estrtol(p, 10);
+
+	/* user name or comment */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_gecos = p;
+
+	/* home directory */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_dir = p;
+
+	/* optional shell */
+	p = strsep(&bp, ":");
+	if (!p)
+		goto corrupt;
+	pw->pw_shell = p;
+
+	/* look for redundant entries */
+	p = strsep(&bp, ":");
+	if (p)
+		goto corrupt;
+
+	return 0;
+corrupt:
+	weprintf("corrupted passwd entry\n");
+	return -1;
+}
+
+int
+pw_copy(int ffd, int tfd, const struct passwd *newpw)
+{
+	struct passwd pw;
+	char *buf = NULL, *p;
+	size_t size = 0;
+	FILE *from, *to;
+
+	from = fdopen(ffd, "r");
+	if (!from) {
+		weprintf("fdopen:");
+		return -1;
+	}
+	to = fdopen(tfd, "w");
+	if (!to) {
+		weprintf("fdopen:");
+		return -1;
+	}
+	while (agetline(&buf, &size, from) != -1) {
+		p = strdup(buf);
+		if (!p) {
+			weprintf("strdup:");
+			return -1;
+		}
+		if (newpw) {
+			if (pw_scan(p, &pw) < 0)
+				return -1;
+			if (strcmp(pw.pw_name, newpw->pw_name) == 0) {
+				fprintf(to, "%s:%s:%u:%u:%s:%s:%s\n",
+					newpw->pw_name,
+					newpw->pw_passwd,
+					newpw->pw_uid,
+					newpw->pw_gid,
+					newpw->pw_gecos,
+					newpw->pw_dir,
+					newpw->pw_shell);
+					continue;
+			}
+		}
+		fprintf(to, "%s", buf);
+		free(p);
+	}
+	fflush(to);
+	return 0;
+}