POTD skeleton #29.

Signed-off-by: lns <matzeton@googlemail.com>

1 files changed, 76 insertions, 10 deletions

diff --git a/src/utils.c b/src/utils.c
index a5fa5a9..996a8a7 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -2,6 +2,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <stdarg.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -15,6 +17,7 @@
 #define _POSIX_PATH_MAX 256
 
 char *arg0 = NULL;
+static int null_fd = -1;
 
 
 static void sighandler_child(int signo)
@@ -90,18 +93,81 @@ pid_t daemonize(int stay_foreground)
     /* Set new file permissions */
     umask(0);
 
-    if (stay_foreground)
-        return pid;
+    if (!stay_foreground) {
+        /* Change the working directory to the root directory */
+        /* or another appropriated directory */
+        chdir("/");
+        /* Close all open file descriptors */
+        assert( close_fds_except(-1) == 0 );
+    } else {
+        assert( close_fds_except(0, 1, 2, -1) == 0 );
+    }
 
-    /* Change the working directory to the root directory */
-    /* or another appropriated directory */
-//    chdir("/");
+    return pid;
+}
 
-    /* Close all open file descriptors */
-    int x;
-    for (x = sysconf(_SC_OPEN_MAX); x>=0; x--) {
-//        close (x);
+int close_fds_except(int fds, ...)
+{
+    int fd;
+    long max_fd;
+    size_t i, except_count, found;
+    va_list ap;
+
+    max_fd = sysconf(_SC_OPEN_MAX);
+    if (max_fd <= 0)
+        return 1;
+
+    va_start(ap, fds);
+    {
+        int *all_fds = malloc(max_fd * sizeof(*all_fds));
+        assert(all_fds);
+        memset(all_fds, -1, max_fd * sizeof(*all_fds));
+
+        except_count = 0;
+        while ( (fd = va_arg(ap, int)) >= 0 ) {
+            all_fds[except_count++] = fd;
+        }
+
+        for (fd = max_fd; fd >= 0; --fd) {
+            found = 0;
+            for (i = 0; i < except_count; ++i) {
+                if (fd == all_fds[i])
+                    found++;
+            }
+            if (!found) {
+                close(fd);
+            }
+        }
+
+        free(all_fds);
     }
+    va_end(ap);
 
-    return pid;
+    return 0;
+}
+
+int redirect_devnull_to(int fds, ...)
+{
+    int fd, rc = 0;
+    va_list ap;
+
+    if (null_fd < 0)
+        null_fd = open("/dev/null", O_RDWR);
+    assert(null_fd >= 0);
+
+    va_start(ap, fds);
+    {
+        while ( (fd = va_arg(ap, int)) >= 0 ) {
+            if ( dup2(null_fd, fd) < 0 )
+                rc++;
+        }
+    }
+    va_end(ap);
+
+    return rc;
+}
+
+int change_user_group(const char *user, const char *group)
+{
+    return 0;
 }