setpwnam: use xmkstemp() and lckpwdf()

Get rid private locking schema and use libc instead.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/login-utils/Makefile.am b/login-utils/Makefile.am
index 11f2b07d10bb9844f1f3b26a6e3bf201366d283c..8328c66ab685ab7677f8f6881bcde8cc17185797 100644 (file)
--- a/login-utils/Makefile.am
+++ b/login-utils/Makefile.am
@@ -55,7 +55,8 @@ chfn_chsh_common = \
        islocal.h \
        setpwnam.c \
        setpwnam.h \
-       $(top_srcdir)/lib/env.c
+       $(top_srcdir)/lib/env.c \
+       $(top_srcdir)/lib/fileutils.c
 login_SOURCES = \
        login.c \
        logindefs.c \

diff --git a/login-utils/setpwnam.c b/login-utils/setpwnam.c
index 0e0c0478d4ecb97742c4625543cc44a43122885a..6f3f4920a7f674f9b097262171dea6ae12b6501d 100644 (file)
--- a/login-utils/setpwnam.c
+++ b/login-utils/setpwnam.c
@@ -47,6 +47,7 @@
 #include <fcntl.h>
 #include <paths.h>
 #include <pwd.h>
+#include <shadow.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -58,6 +59,7 @@
 #include <unistd.h>
 
 #include "c.h"
+#include "fileutils.h"
 #include "setpwnam.h"
 
 static void pw_init(void);
@@ -71,47 +73,26 @@ static void pw_init(void);
 int setpwnam(struct passwd *pwd)
 {
        FILE *fp = NULL, *pwf = NULL;
-       int x, save_errno, fd, ret;
+       int save_errno;
        int found;
-       int oldumask;
        int namelen;
        int buflen = 256;
        int contlen, rc;
        char *linebuf = NULL;
-
-       oldumask = umask(0);    /* Create with exact permissions */
+       char *tmpname = NULL;
 
        pw_init();
 
-       /* sanity check */
-       for (x = 0; x < 3; x++) {
-               if (x > 0)
-                       sleep(1);
-               fd = open(PTMPTMP_FILE, O_WRONLY | O_CREAT | O_EXCL, 0644);
-               if (fd == -1) {
-                       umask(oldumask);
-                       return -1;
-               }
-               ret = link(PTMPTMP_FILE, PTMP_FILE);
-               unlink(PTMPTMP_FILE);
-               if (ret == -1)
-                       close(fd);
-               else
-                       break;
-       }
-       umask(oldumask);
-       if (ret == -1)
+       if ((fp = xmkstemp(&tmpname)) == NULL)
                return -1;
 
        /* ptmp should be owned by root.root or root.wheel */
-       if (chown(PTMP_FILE, (uid_t) 0, (gid_t) 0) < 0)
-               return -1;
-
-       /* open ptmp for writing and passwd for reading */
-       fp = fdopen(fd, "w");
-       if (!fp)
+       if (fchown(fileno(fp), (uid_t) 0, (gid_t) 0) < 0)
                goto fail;
 
+       /* acquire exclusive lock */
+       if (lckpwdf() < 0)
+               goto fail;
        pwf = fopen(PASSWD_FILE, "r");
        if (!pwf)
                goto fail;
@@ -159,13 +140,14 @@ int setpwnam(struct passwd *pwd)
                fputs(linebuf, fp);
        }
 
+       /* xmkstemp is too restrictive by default for passwd file */
+       if (fchmod(fileno(fp), 0644) < 0)
+               goto fail;
        rc = fclose(fp);
        fp = NULL;
        if (rc < 0)
                goto fail;
 
-       close(fd);
-       fd = -1;
        fclose(pwf);    /* I don't think I want to know if this failed */
        pwf = NULL;
 
@@ -179,21 +161,23 @@ int setpwnam(struct passwd *pwd)
        /* we don't care if we can't create the backup file */
        ignore_result(link(PASSWD_FILE, PASSWD_FILE ".OLD"));
        /* we DO care if we can't rename to the passwd file */
-       if (rename(PTMP_FILE, PASSWD_FILE) < 0)
+       if (rename(tmpname, PASSWD_FILE) < 0)
                goto fail;
        /* finally:  success */
+       ulckpwdf();
        return 0;
 
  fail:
        save_errno = errno;
+       ulckpwdf();
        if (fp != NULL)
                fclose(fp);
+       if (tmpname != NULL)
+               unlink(tmpname);
+       free(tmpname);
        if (pwf != NULL)
                fclose(pwf);
-       if (fd >= 0)
-               close(fd);
        free(linebuf);
-       unlink(PTMP_FILE);
        errno = save_errno;
        return -1;
 }