s6-svlink, s6-svunlink, .h changes

 Renamed from s6-svdir-(un)link.
 Doc added. Full functionality added.
 Still need to be tested.
 Unrelated: .h names simplified.

Signed-off-by: Laurent Bercot <ska@appnovation.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/src/libs6/s6_supervise_unlink_names.c b/src/libs6/s6_supervise_unlink_names.c
new file mode 100644
index 0000000..a0b424d
--- /dev/null
+++ b/src/libs6/s6_supervise_unlink_names.c
@@ -0,0 +1,98 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/bitarray.h>
+
+#include <s6/ftrigr.h>
+#include <s6/supervise.h>
+
+static uint16_t registerit (ftrigr_t *a, char *fn, size_t len, tain const *deadline, tain *stamp)
+{
+  memcpy(fn + len, "/" S6_SUPERVISE_EVENTDIR, sizeof(S6_SUPERVISE_EVENTDIR) + 1) ;
+  return ftrigr_subscribe(a, fn, "x", 0, deadline, stamp) ;
+}
+
+/*
+  options: bit 0: wait for s6-supervise to exit
+*/
+
+int s6_supervise_unlink_names (char const *scdir, char const *const *names, size_t n, uint32_t options, tain const *deadline, tain *stamp)
+{
+  size_t scdirlen = strlen(scdir) ;
+  size_t ntotal = n ;
+  unsigned char locked[bitarray_div8(n)] ;
+  unsigned char logged[bitarray_div8(n)] ;
+  if (!n) return 0 ;
+  memset(locked, 0, bitarray_div8(n)) ;
+  memset(logged, 0, bitarray_div8(n)) ;
+
+  if (options & 1) for (size_t i = 0 ; i < n ; i++)
+  {
+    struct stat st ;
+    size_t nlen = strlen(names[i]) ;
+    int h ;
+    char fn[scdirlen + nlen + 6] ;
+    memcpy(fn, scdir, scdirlen) ;
+    fn[scdirlen] = '/' ;
+    memcpy(fn + scdirlen + 1, names[i], nlen + 1) ;
+    h = s6_svc_ok(fn) ;
+    if (h < 0) return -1 ;
+    if (h) bitarray_set(locked, i) ;
+    memcpy(fn + scdirlen + 1 + nlen, "/log", 5) ;
+    if (stat(fn, &st) < 0)
+    {
+      if (errno != ENOENT) return -1 ;
+    }
+    else
+    {
+      int r ;
+      if (!S_ISDIR(st.st_mode)) return (errno = ENOTDIR, -1) ;
+      r = s6_svc_ok(fn) ;
+      if (r < 0) return -1 ;
+      if (r != h) return (errno = EINVAL, -1) ;
+      bitarray_set(logged, i) ;
+      ntotal++ ;
+    }
+  } 
+
+  {
+    ftrigr_t a = FTRIGR_ZERO ;
+    unsigned int m = 0 ;
+    uint16_t ids[ntotal] ;
+    if (options & 1 && !ftrigr_startf(&a, deadline, stamp)) return -1 ;
+    for (size_t i = 0 ; i < n ; i++)
+    {
+      size_t nlen = strlen(names[i]) ;
+      char fn[scdirlen + nlen + 6 + sizeof(S6_SUPERVISE_EVENTDIR)] ;
+      memcpy(fn, scdir, scdirlen) ;
+      fn[scdirlen] = '/' ;
+      memcpy(fn + scdirlen + 1, names[i], nlen) ;
+      if (options & 1 && bitarray_peek(locked, i))
+      {
+        ids[m] = registerit(&a, fn, scdirlen + 1 + nlen, deadline, stamp) ;
+        if (ids[m]) m++ ;
+        if (bitarray_peek(logged, i))
+        {
+          memcpy(fn + scdirlen + 1 + nlen, "/log", 4) ;
+          ids[m] = registerit(&a, fn, scdirlen + 5 + nlen, deadline, stamp) ;
+          if (ids[m]) m++ ;
+        }
+      }
+      fn[scdirlen + 1 + nlen] = 0 ;
+      unlink_void(fn) ;
+    }
+    s6_svc_writectl(scdir, S6_SVSCAN_CTLDIR, "an", 2) ;
+    if (options & 1)
+    {
+      ftrigr_wait_and(&a, ids, m, deadline, stamp) ;
+      ftrigr_end(&a) ;
+    }
+    return m ;
+  }
+}