Add stage 4 hook support

1 files changed, 34 insertions, 42 deletions

diff --git a/src/misc/s6-linux-init-umountall.c b/src/misc/s6-linux-init-umountall.c
index 24b22fc..93b0966 100644
--- a/src/misc/s6-linux-init-umountall.c
+++ b/src/misc/s6-linux-init-umountall.c
@@ -1,70 +1,62 @@
 /* ISC license. */
 
+#include <errno.h>
 #include <string.h>
+#include <stdio.h>
+#include <mntent.h>
 #include <sys/mount.h>
 
-#include <skalibs/bytestr.h>
-#include <skalibs/buffer.h>
 #include <skalibs/strerr2.h>
 #include <skalibs/stralloc.h>
-#include <skalibs/djbunix.h>
 #include <skalibs/skamisc.h>
 
-#define BUFSIZE 4096
-#define MAXLINES 512
+#define MAXLINES 99
+
+#define EXCLUDEN 3
+static char const *exclude_type[EXCLUDEN] = { "devtmpfs", "proc", "sysfs" } ;
 
 int main (int argc, char const *const *argv)
 {
-  stralloc mountpoints[MAXLINES] ;
-  char buf[BUFSIZE] ;
-  buffer b ;
+  size_t mountpoints[MAXLINES] ;
+  unsigned int got[EXCLUDEN] = { 0, 0, 0 } ;
   stralloc sa = STRALLOC_ZERO ;
   unsigned int line = 0 ;
+  FILE *fp ;
   int e = 0 ;
-  int r ;
-  int fd ;
 
   PROG = "s6-linux-init-umountall" ;
 
-
- /*
-    We need to go through /proc/mounts *in reverse order*, because later mounts
-    may depend on earlier mounts.
-    The getmntent() family of functions has obviously not been designed for that
-    use case at all, and it is actually more difficult to use it than to do the
-    /proc/mounts parsing by hand. So, we do it by hand with skalibs functions.
-    That's how you can tell a good API from a terrible one.
- */
-
-  fd = open_readb("/proc/mounts") ;
-  if (fd < 0) strerr_diefu1sys(111, "open /proc/mounts") ;
-  memset(mountpoints, 0, sizeof(mountpoints)) ;
-  buffer_init(&b, &buffer_read, fd, buf, BUFSIZE) ;
+  fp = setmntent("/proc/mounts", "r") ;
+  if (!fp) strerr_diefu1sys(111, "open /proc/mounts") ;
   for (;;)
   {
-    size_t n, p ;
-    if (line >= MAXLINES) strerr_dief1x(111, "/proc/mounts too big") ;
-    sa.len = 0 ;
-    r = skagetln(&b, &sa, '\n') ;
-    if (r <= 0) break ;
-    p = byte_chr(sa.s, sa.len, ' ') ;
-    if (p >= sa.len) strerr_dief1x(111, "bad /proc/mounts format") ;
-    p++ ;
-    n = byte_chr(sa.s + p, sa.len - p, ' ') ;
-    if (n == sa.len - p) strerr_dief1x(111, "bad /proc/mounts format") ;
-    if (!stralloc_catb(&mountpoints[line], sa.s + p, n) || !stralloc_0(&mountpoints[line]))
-      strerr_diefu1sys(111, "store mount point") ;
-    line++ ;
+    struct mntent *p ;
+    unsigned int i = 0 ;
+    errno = 0 ;
+    p = getmntent(fp) ;
+    if (!p) break ;
+    for (; i < EXCLUDEN ; i++)
+      if (!strcmp(p->mnt_type, exclude_type[i]))
+      {
+        got[i]++ ;
+        break ;
+      }
+    if (i < EXCLUDEN && got[i] == 1) continue ;
+    if (line >= MAXLINES)
+      strerr_dief1x(100, "too many mount points") ;
+    mountpoints[line++] = sa.len ;
+    if (!stralloc_cats(&sa, p->mnt_dir) || !stralloc_0(&sa))
+      strerr_diefu1sys(111, "add mount point to list") ;
   }
-  fd_close(fd) ;
-  stralloc_free(&sa) ;
-  if (r < 0) strerr_diefu1sys(111, "read /proc/mounts") ;
+  if (errno) strerr_diefu1sys(111, "read /proc/mounts") ;
+  endmntent(fp) ;
 
   while (line--)
-    if (umount(mountpoints[line].s) == -1)
+    if (umount(sa.s + mountpoints[line]) == -1)
     {
       e++ ;
-      strerr_warnwu2sys("umount ", mountpoints[line].s) ;
+      strerr_warnwu2sys("umount ", sa.s + mountpoints[line]) ;
     }
+  stralloc_free(&sa) ;
   return e ;
 }