Use a specific error message for errno == EAGAIN when setuid() et al fails.

On Linux systems setuid() will fail with errno set to EAGAIN if changing
to the new uid would result in a resource limit violation.

diff --git a/set_perms.c b/set_perms.c
index 34b6ce08fdfb97551c9ce283d7b5c94a502d6475..3cd6bc566bc692aa13d249e75788a6d6ff0535c3 100644 (file)
--- a/set_perms.c
+++ b/set_perms.c
@@ -81,13 +81,17 @@ void
 set_perms(perm)
     int perm;
 {
+    const char *errstr;
+
     if (perm == current_perm)
        return;
 
     switch (perm) {
        case PERM_ROOT:
-                               if (setresuid(ROOT_UID, ROOT_UID, ROOT_UID))
-                                   errorx(1, "setresuid(ROOT_UID, ROOT_UID, ROOT_UID) failed, your operating system may have a broken setresuid() function\nTry running configure with --disable-setresuid");
+                               if (setresuid(ROOT_UID, ROOT_UID, ROOT_UID)) {
+                                   errstr = "setresuid(ROOT_UID, ROOT_UID, ROOT_UID)";
+                                   goto bad;
+                               }
                                (void) setresgid(-1, user_gid, -1);
                                if (current_perm == PERM_RUNAS)
                                    restore_groups();
@@ -95,24 +99,30 @@ set_perms(perm)
 
        case PERM_USER:
                                (void) setresgid(-1, user_gid, -1);
-                               if (setresuid(user_uid, user_uid, ROOT_UID))
-                                   error(1, "setresuid(user_uid, user_uid, ROOT_UID)");
+                               if (setresuid(user_uid, user_uid, ROOT_UID)) {
+                                   errstr = "setresuid(user_uid, user_uid, ROOT_UID)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_FULL_USER:
                                /* headed for exec() */
                                (void) setgid(user_gid);
-                               if (setresuid(user_uid, user_uid, user_uid))
-                                   error(1, "setresuid(user_uid, user_uid, user_uid)");
+                               if (setresuid(user_uid, user_uid, user_uid)) {
+                                   errstr = "setresuid(user_uid, user_uid, user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_RUNAS:
                                runas_setgroups();
                                (void) setresgid(-1, runas_gr ?
                                    runas_gr->gr_gid : runas_pw->pw_gid, -1);
-                               if (setresuid(-1,
-                                   runas_pw ? runas_pw->pw_uid : user_uid, -1))
-                                   error(1, "unable to change to runas uid");
+                               if (setresuid(-1, runas_pw ? runas_pw->pw_uid :
+                                   user_uid, -1)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_FULL_RUNAS:
@@ -120,8 +130,10 @@ set_perms(perm)
                                runas_setup();
                                if (setresuid(def_stay_setuid ?
                                    user_uid : runas_pw->pw_uid,
-                                   runas_pw->pw_uid, runas_pw->pw_uid))
-                                   error(1, "unable to change to runas uid");
+                                   runas_pw->pw_uid, runas_pw->pw_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_SUDOERS:
@@ -137,20 +149,30 @@ set_perms(perm)
                                 * work on all OS's.
                                 */
                                if (SUDOERS_UID == ROOT_UID) {
-                                   if ((SUDOERS_MODE & 040) && setresuid(ROOT_UID, 1, ROOT_UID))
-                                       error(1, "setresuid(ROOT_UID, 1, ROOT_UID)");
+                                   if ((SUDOERS_MODE & 040) && setresuid(ROOT_UID, 1, ROOT_UID)) {
+                                       errstr = "setresuid(ROOT_UID, 1, ROOT_UID)";
+                                       goto bad;
+                                   }
                                } else {
-                                   if (setresuid(ROOT_UID, SUDOERS_UID, ROOT_UID))
-                                       error(1, "setresuid(ROOT_UID, SUDOERS_UID, ROOT_UID)");
+                                   if (setresuid(ROOT_UID, SUDOERS_UID, ROOT_UID)) {
+                                       errstr = "setresuid(ROOT_UID, SUDOERS_UID, ROOT_UID)";
+                                       goto bad;
+                                   }
                                }
                                break;
        case PERM_TIMESTAMP:
-                               if (setresuid(ROOT_UID, timestamp_uid, ROOT_UID))
-                                   error(1, "setresuid(ROOT_UID, timestamp_uid, ROOT_UID)");
+                               if (setresuid(ROOT_UID, timestamp_uid, ROOT_UID)) {
+                                   errstr = "setresuid(ROOT_UID, timestamp_uid, ROOT_UID)";
+                                   goto bad;
+                               }
                                break;
     }
 
     current_perm = perm;
+    return;
+bad:
+    errorx(1, "%s: %s", errstr,
+       errno == EAGAIN ? "too many processes" : strerror(errno));
 }
 
 #else
@@ -166,15 +188,21 @@ void
 set_perms(perm)
     int perm;
 {
+    const char *errstr;
+
     if (perm == current_perm)
        return;
 
     switch (perm) {
        case PERM_ROOT:
-                               if (setreuid(-1, ROOT_UID))
-                                   errorx(1, "setreuid(-1, ROOT_UID) failed, your operating system may have a broken setreuid() function\nTry running configure with --disable-setreuid");
-                               if (setuid(ROOT_UID))
-                                   error(1, "setuid(ROOT_UID)");
+                               if (setreuid(-1, ROOT_UID)) {
+                                   errstr = "setreuid(-1, ROOT_UID)";
+                                   goto bad;
+                               }
+                               if (setuid(ROOT_UID)) {
+                                   errstr = "setuid(ROOT_UID)";
+                                   goto bad;
+                               }
                                (void) setregid(-1, user_gid);
                                if (current_perm == PERM_RUNAS)
                                    restore_groups();
@@ -182,15 +210,19 @@ set_perms(perm)
 
        case PERM_USER:
                                (void) setregid(-1, user_gid);
-                               if (setreuid(ROOT_UID, user_uid))
-                                   error(1, "setreuid(ROOT_UID, user_uid)");
+                               if (setreuid(ROOT_UID, user_uid)) {
+                                   errstr = "setreuid(ROOT_UID, user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_FULL_USER:
                                /* headed for exec() */
                                (void) setgid(user_gid);
-                               if (setreuid(user_uid, user_uid))
-                                   error(1, "setreuid(user_uid, user_uid)");
+                               if (setreuid(user_uid, user_uid)) {
+                                   errstr = "setreuid(user_uid, user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_RUNAS:
@@ -198,16 +230,20 @@ set_perms(perm)
                                (void) setregid(-1, runas_gr ?
                                    runas_gr->gr_gid : runas_pw->pw_gid);
                                if (setreuid(-1,
-                                   runas_pw ? runas_pw->pw_uid : user_uid))
-                                   error(1, "unable to change to runas uid");
+                                   runas_pw ? runas_pw->pw_uid : user_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_FULL_RUNAS:
                                /* headed for exec(), assume euid == ROOT_UID */
                                runas_setup();
                                if (setreuid(def_stay_setuid ? user_uid :
-                                   runas_pw->pw_uid, runas_pw->pw_uid))
-                                   error(1, "unable to change to runas uid");
+                                   runas_pw->pw_uid, runas_pw->pw_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_SUDOERS:
@@ -223,20 +259,30 @@ set_perms(perm)
                                 * work on all OS's.
                                 */
                                if (SUDOERS_UID == ROOT_UID) {
-                                   if ((SUDOERS_MODE & 040) && setreuid(ROOT_UID, 1))
-                                       error(1, "setreuid(ROOT_UID, 1)");
+                                   if ((SUDOERS_MODE & 040) && setreuid(ROOT_UID, 1)) {
+                                       errstr = "setreuid(ROOT_UID, 1)";
+                                       goto bad;
+                                   }
                                } else {
-                                   if (setreuid(ROOT_UID, SUDOERS_UID))
-                                       error(1, "setreuid(ROOT_UID, SUDOERS_UID)");
+                                   if (setreuid(ROOT_UID, SUDOERS_UID)) {
+                                       errstr = "setreuid(ROOT_UID, SUDOERS_UID)";
+                                       goto bad;
+                                   }
                                }
                                break;
        case PERM_TIMESTAMP:
-                               if (setreuid(ROOT_UID, timestamp_uid))
-                                   error(1, "setreuid(ROOT_UID, timestamp_uid)");
+                               if (setreuid(ROOT_UID, timestamp_uid)) {
+                                   errstr = "setreuid(ROOT_UID, timestamp_uid)";
+                                   goto bad;
+                               }
                                break;
     }
 
     current_perm = perm;
+    return;
+bad:
+    errorx(1, "%s: %s", errstr,
+       errno == EAGAIN ? "too many processes" : strerror(errno));
 }
 
 # else /* !HAVE_SETRESUID && !HAVE_SETREUID */
@@ -250,6 +296,8 @@ void
 set_perms(perm)
     int perm;
 {
+    const char *errstr;
+
     if (perm == current_perm)
        return;
 
@@ -258,10 +306,14 @@ set_perms(perm)
      * for these calls differ on various systems, we set
      * real and effective uids to ROOT_UID initially to be safe.
      */
-    if (seteuid(ROOT_UID))
-       error(1, "seteuid(ROOT_UID)");
-    if (setuid(ROOT_UID))
-       error(1, "setuid(ROOT_UID)");
+    if (seteuid(ROOT_UID)) {
+       errstr = "seteuid(ROOT_UID)";
+       goto bad;
+    }
+    if (setuid(ROOT_UID)) {
+       errstr = "setuid(ROOT_UID)";
+       goto bad;
+    }
 
     switch (perm) {
        case PERM_ROOT:
@@ -273,30 +325,38 @@ set_perms(perm)
 
        case PERM_USER:
                                (void) setegid(user_gid);
-                               if (seteuid(user_uid))
-                                   error(1, "seteuid(user_uid)");
+                               if (seteuid(user_uid)) {
+                                   errstr = "seteuid(user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_FULL_USER:
                                /* headed for exec() */
                                (void) setgid(user_gid);
-                               if (setuid(user_uid))
-                                   error(1, "setuid(user_uid)");
+                               if (setuid(user_uid)) {
+                                   errstr = "setuid(user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_RUNAS:
                                runas_setgroups();
                                (void) setegid(runas_gr ?
                                    runas_gr->gr_gid : runas_pw->pw_gid);
-                               if (seteuid(runas_pw ? runas_pw->pw_uid : user_uid))
-                                   error(1, "unable to change to runas uid");
+                               if (seteuid(runas_pw ? runas_pw->pw_uid : user_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_FULL_RUNAS:
                                /* headed for exec() */
                                runas_setup();
-                               if (setuid(runas_pw->pw_uid))
-                                   error(1, "unable to change to runas uid");
+                               if (setuid(runas_pw->pw_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_SUDOERS:
@@ -311,20 +371,30 @@ set_perms(perm)
                                 * work on all OS's.
                                 */
                                if (SUDOERS_UID == ROOT_UID) {
-                                   if ((SUDOERS_MODE & 040) && seteuid(1))
-                                       error(1, "seteuid(1)");
+                                   if ((SUDOERS_MODE & 040) && seteuid(1)) {
+                                       errstr = "seteuid(1)";
+                                       goto bad;
+                                   }
                                } else {
-                                   if (seteuid(SUDOERS_UID))
-                                       error(1, "seteuid(SUDOERS_UID)");
+                                   if (seteuid(SUDOERS_UID)) {
+                                       errstr = "seteuid(SUDOERS_UID)";
+                                       goto bad;
+                                   }
                                }
                                break;
        case PERM_TIMESTAMP:
-                               if (seteuid(timestamp_uid))
-                                   error(1, "seteuid(timestamp_uid)");
+                               if (seteuid(timestamp_uid)) {
+                                   errstr = "seteuid(timestamp_uid)";
+                                   goto bad;
+                               }
                                break;
     }
 
     current_perm = perm;
+    return;
+bad:
+    errorx(1, "%s: %s", errstr,
+       errno == EAGAIN ? "too many processes" : strerror(errno));
 }
 
 # else /* !HAVE_SETRESUID && !HAVE_SETREUID && !HAVE_SETEUID */
@@ -338,27 +408,35 @@ void
 set_perms(perm)
     int perm;
 {
+    const char *errstr;
+
     if (perm == current_perm)
        return;
 
     switch (perm) {
        case PERM_ROOT:
-                               if (setuid(ROOT_UID))
-                                       error(1, "setuid(ROOT_UID)");
+                               if (setuid(ROOT_UID)) {
+                                   errstr = "setuid(ROOT_UID)";
+                                   goto bad;
+                               }
                                if (current_perm == PERM_RUNAS)
                                    restore_groups();
                                break;
 
        case PERM_FULL_USER:
                                (void) setgid(user_gid);
-                               if (setuid(user_uid))
-                                   error(1, "setuid(user_uid)");
+                               if (setuid(user_uid)) {
+                                   errstr = "setuid(user_uid)";
+                                   goto bad;
+                               }
                                break;
                                
        case PERM_FULL_RUNAS:
                                runas_setup();
-                               if (setuid(runas_pw->pw_uid))
-                                   error(1, "unable to change to runas uid");
+                               if (setuid(runas_pw->pw_uid)) {
+                                   errstr = "unable to change to runas uid";
+                                   goto bad;
+                               }
                                break;
 
        case PERM_USER:
@@ -370,6 +448,10 @@ set_perms(perm)
     }
 
     current_perm = perm;
+    return;
+bad:
+    errorx(1, "%s: %s", errstr,
+       errno == EAGAIN ? "too many processes" : strerror(errno));
 }
 #  endif /* HAVE_SETEUID */
 # endif /* HAVE_SETREUID */