X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/53a941d3f97a50964587c6e9533b1e43e74a57a8..fb6a9f13a40d1b9e797b4fe858a06cfdbcc1109b:/common/util.c

diff --git a/common/util.c b/common/util.c
index d78dd78d..a3f931cd 100644
--- a/common/util.c
+++ b/common/util.c
@@ -9,19 +9,18 @@
  *
  * This file is part of Trivial IP Encryption (TrIPE).
  *
- * TrIPE is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * TrIPE is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your
+ * option) any later version.
  *
- * TrIPE 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 General Public License for more details.
+ * TrIPE 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 General Public License
+ * for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with TrIPE; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 /*----- Header files ------------------------------------------------------*/
@@ -31,7 +30,14 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <pwd.h>
+#include <grp.h>
+
 #include <mLib/dstr.h>
+#include <mLib/report.h>
 
 #include "util.h"
 
@@ -63,6 +69,88 @@ void u_quotify(dstr *d, const char *p)
     }
     dstr_putc(d, '\"');
   }
+  dstr_putz(d);
+}
+
+/* --- @u_getuser@ --- *
+ *
+ * Arguments:	@const char *name@ = user name or id requested
+ *		@gid_t *gg@ = where to store corresponding gid
+ *
+ * Returns:	Corresponding uid.
+ *
+ * Use:		Resolves a user name into a uid.  Dies on failure; suitable
+ *		for use in argument parsing.
+ */
+
+uid_t u_getuser(const char *name, gid_t *gg)
+{
+  struct passwd *pw;
+  char *p;
+  unsigned long i = strtoul(name, &p, 0);
+
+  if (!*p)
+    pw = getpwuid(i);
+  else
+    pw = getpwnam(name);
+  if (!pw)
+    die(EXIT_FAILURE, "user `%s' not found", name);
+  if (gg && *gg == -1)
+    *gg = pw->pw_gid;
+  return (pw->pw_uid);
+}
+
+/* --- @u_getgroup@ --- *
+ *
+ * Arguments:	@const char *name@ = user name or id requested
+ *
+ * Returns:	Corresponding gid.
+ *
+ * Use:		Resolves a group name into a gid.  Dies on failure; suitable
+ *		for use in argument parsing.
+ */
+
+gid_t u_getgroup(const char *name)
+{
+  struct group *gr;
+  char *p;
+  unsigned long i = strtoul(name, &p, 0);
+
+  if (!*p)
+    gr = getgrgid(i);
+  else
+    gr = getgrnam(name);
+  if (!gr)
+    die(EXIT_FAILURE, "group `%s' not found", name);
+  return (gr->gr_gid);
+}
+
+/* --- @u_setugid@ --- *
+ *
+ * Arguments:	@uid_t u@ = user to set
+ *		@gid_t g@ = group to set
+ *
+ * Returns:	---
+ *
+ * Use:		Sets user and group to the given values; aborts on failure.
+ */
+
+void u_setugid(uid_t u, gid_t g)
+{
+  uid_t cu = geteuid();
+
+  if (cu == 0 && g != (gid_t)-1) {
+    if (setgid(g) || (getuid() == 0 && setgroups(1, &g))) {
+      die(EXIT_FAILURE, "couldn't setgid to %u: %s",
+	  (unsigned)g, strerror(errno));
+    }
+  }
+  if (u != (uid_t)-1) {
+    if (setuid(u)) {
+      die(EXIT_FAILURE, "couldn't setuid to %u: %s",
+	  (unsigned)u, strerror(errno));
+    }
+  }
 }
 
 /*----- That's all, folks -------------------------------------------------*/