Author: bapt (ports committer)
Date: Thu Dec 15 22:07:36 2011
New Revision: 228545
URL: http://svn.freebsd.org/changeset/base/228545

Log:
  Modify pw_copy:
  - if pw is NULL and oldpw is not NULL then the oldpw is deleted
  - if pw->pw_name != oldpw->pw_name but pw->pw_uid == oldpw->pw_uid
  then it renames the user
  
  add new gr_* functions so now gr_util API is similar to pw_util API,
  this allow to manipulate groups in a safe way.
  
  Reviewed by:  des
  Approved by:  des
  MFC after:    1 month

Modified:
  head/lib/libutil/gr_util.c
  head/lib/libutil/libutil.h
  head/lib/libutil/pw_util.c

Modified: head/lib/libutil/gr_util.c
==============================================================================
--- head/lib/libutil/gr_util.c  Thu Dec 15 22:05:23 2011        (r228544)
+++ head/lib/libutil/gr_util.c  Thu Dec 15 22:07:36 2011        (r228545)
@@ -28,23 +28,319 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
 
+#include <ctype.h>
+#include <err.h>
+#include <fcntl.h>
 #include <grp.h>
 #include <inttypes.h>
 #include <libutil.h>
+#include <paths.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 struct group_storage {
        struct group     gr;
        char            *members[];
 };
 
+static int lockfd = -1;
+static char group_dir[PATH_MAX];
+static char group_file[PATH_MAX];
+static char tempname[PATH_MAX];
+static int initialized;
+
 static const char group_line_format[] = "%s:%s:%ju:";
 
 /*
+ * Initialize statics
+ */
+int
+gr_init(const char *dir, const char *group)
+{
+       if (dir == NULL) {
+               strcpy(group_dir, _PATH_ETC);
+       } else {
+               if (strlen(dir) >= sizeof(group_dir)) {
+                       errno = ENAMETOOLONG;
+                       return (-1);
+               }
+               strcpy(group_dir, dir);
+       }
+
+       if (group == NULL) {
+               if (dir == NULL) {
+                       strcpy(group_file, _PATH_GROUP);
+               } else if (snprintf(group_file, sizeof(group_file), "%s/group",
+                       group_dir) > (int)sizeof(group_file)) {
+                       errno = ENAMETOOLONG;
+                       return (-1);
+               }
+       } else {
+               if (strlen(group) >= sizeof(group_file)) {
+                       errno = ENAMETOOLONG;
+                       return (-1);
+               }
+               strcpy(group_file, group);
+       }
+       initialized = 1;
+       return (0);
+}
+
+/*
+ * Lock the group file
+ */
+int
+gr_lock(void)
+{
+       if (*group_file == '\0')
+               return (-1);
+
+       for (;;) {
+               struct stat st;
+
+               lockfd = open(group_file, O_RDONLY, 0);
+               if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1)
+                       err(1, "%s", group_file);
+               if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
+                       if (errno == EWOULDBLOCK) {
+                               errx(1, "the group file is busy");
+                       } else {
+                               err(1, "could not lock the group file: ");
+                       }
+               }
+               if (fstat(lockfd, &st) == -1)
+                       err(1, "fstat() failed: ");
+               if (st.st_nlink != 0)
+                       break;
+               close(lockfd);
+               lockfd = -1;
+       }
+       return (lockfd);
+}
+
+/*
+ * Create and open a presmuably safe temp file for editing group data
+ */
+int
+gr_tmp(int mfd)
+{
+       char buf[8192];
+       ssize_t nr;
+       const char *p;
+       int tfd;
+
+       if (*group_file == '\0')
+               return (-1);
+       if ((p = strrchr(group_file, '/')))
+               ++p;
+       else
+               p = group_file;
+       if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
+               (int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
+               errno = ENAMETOOLONG;
+               return (-1);
+       }
+       if ((tfd = mkstemp(tempname)) == -1)
+               return (-1);
+       if (mfd != -1) {
+               while ((nr = read(mfd, buf, sizeof(buf))) > 0)
+                       if (write(tfd, buf, (size_t)nr) != nr)
+                               break;
+               if (nr != 0) {
+                       unlink(tempname);
+                       *tempname = '\0';
+                       close(tfd);
+                       return (-1);
+               }
+       }
+       return (tfd);
+}
+
+/*
+ * Copy the group file from one descriptor to another, replacing, deleting
+ * or adding a single record on the way.
+ */
+int
+gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
+{
+       char buf[8192], *end, *line, *p, *q, *r, t;
+       struct group *fgr;
+       const struct group *sgr;
+       size_t len;
+       int eof, readlen;
+
+       sgr = gr;
+       if (gr == NULL) {
+               line = NULL;
+               if (old_gr == NULL)
+                       return (-1);
+               sgr = old_gr;
+       } else if ((line = gr_make(gr)) == NULL)
+               return (-1);
+
+       eof = 0;
+       len = 0;
+       p = q = end = buf;
+       for (;;) {
+               /* find the end of the current line */
+               for (p = q; q < end && *q != '\0'; ++q)
+                       if (*q == '\n')
+                               break;
+
+               /* if we don't have a complete line, fill up the buffer */
+               if (q >= end) {
+                       if (eof)
+                               break;
+                       if ((size_t)(q - p) >= sizeof(buf)) {
+                               warnx("group line too long");
+                               errno = EINVAL; /* hack */
+                               goto err;
+                       }
+                       if (p < end) {
+                               q = memmove(buf, p, end -p);
+                               end -= p - buf;
+                       } else {
+                               p = q = end = buf;
+                       }
+                       readlen = read(ffd, end, sizeof(buf) - (end -buf));
+                       if (readlen == -1)
+                               goto err;
+                       else
+                               len = (size_t)readlen;
+                       if (len == 0 && p == buf)
+                               break;
+                       end += len;
+                       len = end - buf;
+                       if (len < (ssize_t)sizeof(buf)) {
+                               eof = 1;
+                               if (len > 0 && buf[len -1] != '\n')
+                                       ++len, *end++ = '\n';
+                       }
+                       continue;
+               }
+
+               /* is it a blank line or a comment? */
+               for (r = p; r < q && isspace(*r); ++r)
+                       /* nothing */;
+               if (r == q || *r == '#') {
+                       /* yep */
+                       if (write(tfd, p, q -p + 1) != q - p + 1)
+                               goto err;
+                       ++q;
+                       continue;
+               }
+
+               /* is it the one we're looking for? */
+
+               t = *q;
+               *q = '\0';
+
+               fgr = gr_scan(r);
+
+               /* fgr is either a struct group for the current line,
+                * or NULL if the line is malformed.
+                */
+
+               *q = t;
+               if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
+                       /* nope */
+                       if (fgr != NULL)
+                               free(fgr);
+                       if (write(tfd, p, q - p + 1) != q - p + 1)
+                               goto err;
+                       ++q;
+                       continue;
+               }
+               if (old_gr && !gr_equal(fgr, old_gr)) {
+                       warnx("entry inconsistent");
+                       free(fgr);
+                       errno = EINVAL; /* hack */
+                       goto err;
+               }
+               free(fgr);
+
+               /* it is, replace or remove it */
+               if (line != NULL) {
+                       len = strlen(line);
+                       if (write(tfd, line, len) != (int) len)
+                               goto err;
+               } else {
+                       /* when removed, avoid the \n */
+                       q++;
+               }
+               /* we're done, just copy the rest over */
+               for (;;) {
+                       if (write(tfd, q, end - q) != end - q)
+                               goto err;
+                       q = buf;
+                       readlen = read(ffd, buf, sizeof(buf));
+                       if (readlen == 0)
+                               break;
+                       else
+                               len = (size_t)readlen;
+                       if (readlen == -1)
+                               goto err;
+                       end = buf + len;
+               }
+               goto done;
+       }
+
+       /* if we got here, we didn't find the old entry */
+       if (line == NULL) {
+               errno = ENOENT;
+               goto err;
+       }
+       len = strlen(line);
+       if ((size_t)write(tfd, line, len) != len ||
+          write(tfd, "\n", 1) != 1)
+               goto err;
+ done:
+       if (line != NULL)
+               free(line);
+       return (0);
+ err:
+       if (line != NULL)
+               free(line);
+       return (-1);
+}
+
+/*
+ * Regenerate the group file
+ */
+int
+gr_mkdb(void)
+{
+       return (rename(tempname, group_file));
+}
+
+/*
+ * Clean up. Preserver errno for the caller's convenience.
+ */
+void
+gr_fini(void)
+{
+       int serrno;
+
+       if (!initialized)
+               return;
+       initialized = 0;
+       serrno = errno;
+       if (*tempname != '\0') {
+               unlink(tempname);
+               *tempname = '\0';
+       }
+       if (lockfd != -1)
+               close(lockfd);
+       errno = serrno;
+}
+
+/*
  * Compares two struct group's.
  */
 int

Modified: head/lib/libutil/libutil.h
==============================================================================
--- head/lib/libutil/libutil.h  Thu Dec 15 22:05:23 2011        (r228544)
+++ head/lib/libutil/libutil.h  Thu Dec 15 22:07:36 2011        (r228545)
@@ -152,9 +152,15 @@ int        pw_tmp(int _mfd);
 #endif
 
 #ifdef _GRP_H_
+int    gr_copy(int __ffd, int _tfd, const struct group *_gr, struct group 
*_old_gr);
+struct group *gr_dup(const struct group *gr);
 int    gr_equal(const struct group *gr1, const struct group *gr2);
+void   gr_fini(void);
+int    gr_init(const char *_dir, const char *_master);
+int    gr_lock(void);
 char   *gr_make(const struct group *gr);
-struct group *gr_dup(const struct group *gr);
+int    gr_mkdb(void);
+int    gr_tmp(int _mdf);
 struct group *gr_scan(const char *line);
 #endif
 

Modified: head/lib/libutil/pw_util.c
==============================================================================
--- head/lib/libutil/pw_util.c  Thu Dec 15 22:05:23 2011        (r228544)
+++ head/lib/libutil/pw_util.c  Thu Dec 15 22:07:36 2011        (r228545)
@@ -410,18 +410,25 @@ pw_make(const struct passwd *pw)
 }
 
 /*
- * Copy password file from one descriptor to another, replacing or adding
- * a single record on the way.
+ * Copy password file from one descriptor to another, replacing, deleting
+ * or adding a single record on the way.
  */
 int
 pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
 {
        char buf[8192], *end, *line, *p, *q, *r, t;
        struct passwd *fpw;
+       const struct passwd *spw;
        size_t len;
        int eof, readlen;
 
-       if ((line = pw_make(pw)) == NULL)
+       spw = pw;
+       if (pw == NULL) {
+               line = NULL;
+               if (old_pw == NULL)
+                       return (-1);
+               spw = old_pw;
+       } else if ((line = pw_make(pw)) == NULL)
                return (-1);
 
        eof = 0;
@@ -489,7 +496,7 @@ pw_copy(int ffd, int tfd, const struct p
                 */
 
                *q = t;
-               if (fpw == NULL || strcmp(fpw->pw_name, pw->pw_name) != 0) {
+               if (fpw == NULL || fpw->pw_uid != spw->pw_uid) {
                        /* nope */
                        if (fpw != NULL)
                                free(fpw);
@@ -506,11 +513,15 @@ pw_copy(int ffd, int tfd, const struct p
                }
                free(fpw);
 
-               /* it is, replace it */
-               len = strlen(line);
-               if (write(tfd, line, len) != (int)len)
-                       goto err;
-
+               /* it is, replace or remove it */
+               if (line != NULL) {
+                       len = strlen(line);
+                       if (write(tfd, line, len) != (int)len)
+                               goto err;
+               } else {
+                       /* when removed, avoid the \n */
+                       q++;
+               }
                /* we're done, just copy the rest over */
                for (;;) {
                        if (write(tfd, q, end - q) != end - q)
@@ -528,16 +539,22 @@ pw_copy(int ffd, int tfd, const struct p
                goto done;
        }
 
-       /* if we got here, we have a new entry */
+       /* if we got here, we didn't find the old entry */
+       if (line == NULL) {
+               errno = ENOENT;
+               goto err;
+       }
        len = strlen(line);
        if ((size_t)write(tfd, line, len) != len ||
            write(tfd, "\n", 1) != 1)
                goto err;
  done:
-       free(line);
+       if (line != NULL)
+               free(line);
        return (0);
  err:
-       free(line);
+       if (line != NULL)
+               free(line);
        return (-1);
 }
 
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