Add s6-svdir-link and s6-svdir-unlink

 Not tested yet; not documented yet; to come soon.

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

1 files changed, 136 insertions, 0 deletions

diff --git a/src/libs6/s6_supervise_link_names.c b/src/libs6/s6_supervise_link_names.c
new file mode 100644
index 0000000..8cba399
--- /dev/null
+++ b/src/libs6/s6_supervise_link_names.c
@@ -0,0 +1,136 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.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 *scdir, char const *const *names, size_t n, uint32_t killopts)
+{
+  for (size_t i = 0 ; i < n ; i++)
+    s6_supervise_unlink(scdir, names[i], killopts) ;
+}
+
+static uint16_t registerit (ftrigr_t *a, char *fn, size_t len, gid_t gid, uint32_t options, tain const *deadline, tain *stamp)
+{
+  if (options & 4)
+  {
+    int fd ;
+    memcpy(fn + len, "/down", 6) ;
+    fd = open_trunc(fn) ;
+    if (fd < 0) return 0 ;
+    fd_close(fd) ;
+  }
+  memcpy(fn + len, "/" S6_SUPERVISE_EVENTDIR, 1 + sizeof(S6_SUPERVISE_EVENTDIR)) ;
+  if (!ftrigw_fifodir_make(fn, gid, options & 1)) return 0 ;
+  return ftrigr_subscribe(a, fn, "s", 0, deadline, stamp) ;
+}
+
+int s6_supervise_link_names (char const *scdir, char const *const *servicedirs, char const *const *names, size_t n, uint32_t options, tain const *deadline, tain *stamp)
+{
+  size_t maxnlen = 0, 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]) ;
+    size_t nlen = strlen(names[i]) ;
+    int h ;
+    char subdir[len + 5] ;
+    if (nlen > maxnlen) maxnlen = nlen ;
+    if (len > maxlen) maxlen = nlen ;
+    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 ;
+    gid_t gid = options & 2 ? -1 : getegid() ;
+    size_t scdirlen = strlen(scdir) ;
+    unsigned int m = 0 ;
+    size_t i = 0 ;
+    uint32_t killopts = 0 ;
+    int r ;
+    uint16_t ids[ntotal] ;
+    char lname[scdirlen + maxnlen + 2] ;
+    char fn[maxlen + 5 + (sizeof(S6_SUPERVISE_EVENTDIR) > 5 ? sizeof(S6_SUPERVISE_EVENTDIR) : 5)] ;
+    if (!ftrigr_startf(&a, deadline, stamp)) return -1 ;
+    memcpy(lname, scdir, scdirlen) ;
+    lname[scdirlen] = '/' ;
+    for (; i < n ; i++)
+    {
+      char const *src = servicedirs[i] ;
+      size_t len = strlen(servicedirs[i]) ;
+      int h = bitarray_peek(locked, i) ;
+      memcpy(fn, servicedirs[i], len) ;
+      if (!h)
+      {
+        ids[m] = registerit(&a, fn, len, gid, options, deadline, stamp) ;
+        if (!ids[m++]) goto err ;
+        if (bitarray_peek(logged, i))
+        {
+          memcpy(fn + len, "/log", 4) ;
+          ids[m] = registerit(&a, fn, len + 4, gid, options, deadline, stamp) ;
+          if (!ids[m++]) goto err ;
+        }
+      }
+      fn[len] = 0 ;
+      strcpy(lname + scdirlen + 1, names[i]) ;
+      if (servicedirs[i][0] != '/')
+      {
+        rpsa.len = 0 ;
+        if (sarealpath(&rpsa, servicedirs[i]) < 0 || !stralloc_0(&rpsa)) goto err ;
+        src = rpsa.s ;
+      }
+      if (symlink(src, lname) < 0 && (!h || errno != EEXIST)) goto err ;
+    }
+    stralloc_free(&rpsa) ;
+    r = s6_svc_writectl(scdir, 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) ;
+    return m ;
+
+   err:
+    stralloc_free(&rpsa) ;
+   errsa:
+    ftrigr_end(&a) ;
+    do_unlink(scdir, names, i, killopts | (options & 4)) ;
+  }
+  return -1 ;
+}