1 files changed, 124 insertions, 0 deletions
diff --git a/src/libs6/s6_supervise_link.c b/src/libs6/s6_supervise_link.c
new file mode 100644
index 0000000..4724421
--- /dev/null
+++ b/src/libs6/s6_supervise_link.c
@@ -0,0 +1,124 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include <skalibs/bitarray.h>
+#include <skalibs/tai.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#include <s6/ftrigr.h>
+#include <s6/ftrigw.h>
+#include <s6/s6-supervise.h>
+
+static inline void do_unlink (char const *const scandir, char const *names, size_t nameslen, uint32_t killopts)
+{
+  while (nameslen)
+  {
+    size_t len = strlen(names) + 1 ;
+    s6_supervise_unlink(scandir, names, killopts) ;
+    names += len ; nameslen -= len ;
+  }
+}
+
+int s6_supervise_link (char const *scandir, char const *const *servicedirs, size_t n, char const *prefix, uint32_t options, tain_t const *deadline, tain_t *stamp)
+{
+  size_t maxlen = 0 ;
+  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)) ;
+
+  for (size_t i = 0 ; i < n ; i++)
+  {
+    struct stat st ;
+    size_t len = strlen(servicedirs[i]) ;
+    int h ;
+    char subdir[len + 5] ;
+    if (len > maxlen) maxlen = len ;
+    h = s6_svc_ok(servicedirs[i]) ;
+    if (h < 0) return -1 ;
+    if (h) bitarray_set(locked, i) ;
+    memcpy(subdir, servicedirs[i], len) ;
+    memcpy(subdir + len, "/log", 5) ;
+    if (stat(subdir, &st) < 0)
+    {
+      if (errno != ENOENT) return -1 ;
+    }
+    else
+    {
+      int r ;
+      if (!S_ISDIR(st.st_mode)) return (errno = ENOTDIR, -1) ;
+      r = s6_svc_ok(subdir) ;
+      if (r < 0) return -1 ;
+      if (r != h) return (errno = EINVAL, -1) ;
+      bitarray_set(logged, i) ;
+      ntotal++ ;
+    }
+  } 
+
+  {
+    ftrigr_t a = FTRIGR_ZERO ;
+    stralloc rpsa = STRALLOC_ZERO ;
+    stralloc lnames = STRALLOC_ZERO ;
+    gid_t gid = options & 2 ? -1 : getegid() ;
+    size_t scandirlen = strlen(scandir) ;
+    size_t prefixlen = strlen(prefix) ;
+    unsigned int m = 0 ;
+    size_t i = 0 ;
+    size_t lstart = 0 ;
+    uint32_t killopts = 0 ;
+    int r ;
+    uint16_t ids[ntotal] ;
+    char lname[scandirlen + prefixlen + maxlen + 2] ;
+    char fn[maxlen + 1 + sizeof(S6_SUPERVISE_EVENTDIR)] ;
+    char *p ;
+    if (!ftrigr_startf(&a, deadline, stamp)) return -1 ;
+    memcpy(lname, scandir, scandirlen) ;
+    lname[scandirlen] = '/' ;
+    memcpy(lname + scandirlen + 1, prefix, prefixlen) ;
+    for (i = 0 ; i < n ; i++) if (!bitarray_peek(locked, i))
+    {
+      size_t len = strlen(servicedirs[i]) ;
+      memcpy(fn, servicedirs[i], len) ;
+      memcpy(fn + len, S6_SUPERVISE_EVENTDIR, sizeof(S6_SUPERVISE_EVENTDIR)) ;
+      if (!ftrigw_fifodir_make(fn, gid, options & 1)) goto err ;
+      ids[m] = ftrigr_subscribe(&a, fn, "s", 0, deadline, stamp) ;
+      if (!ids[m++]) goto err ;
+      fn[len] = 0 ;
+      p = basename(fn) ;
+      len = strlen(p) ;
+      memcpy(lname + scandirlen + 1 + prefixlen, p, len + 1) ;
+      rpsa.len = 0 ;
+      lstart = lnames.len ;
+      if (!sarealpath(&rpsa, servicedirs[i]) || !stralloc_0(&rpsa)) goto err ;
+      if (!stralloc_catb(&lnames, lname + scandirlen + 1, prefixlen + len + 1)) goto err ;
+      if (symlink(rpsa.s, lname) < 0) goto errl ;
+    }
+    stralloc_free(&rpsa) ;
+    r = s6_svc_writectl(scandir, S6_SVSCAN_CTLDIR, "a", 1) ;
+    if (r <= 0) goto errsa ;
+    killopts = 3 ;
+    if (ftrigr_wait_and(&a, ids, m, deadline, stamp) < 0) goto errsa ;
+    ftrigr_end(&a) ;
+    stralloc_free(&lnames) ;
+    return m ;
+
+   errl:
+    lnames.len = lstart ;
+   err:
+    stralloc_free(&rpsa) ;
+   errsa:
+    ftrigr_end(&a) ;
+    do_unlink(scandir, lnames.s, lnames.len, killopts) ;
+    stralloc_free(&lnames) ;
+    return -1 ;
+  }
+}