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, 117 insertions, 0 deletions

diff --git a/src/supervision/s6-svlink.c b/src/supervision/s6-svlink.c
new file mode 100644
index 0000000..159f817
--- /dev/null
+++ b/src/supervision/s6-svlink.c
@@ -0,0 +1,117 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <libgen.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/tai.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#include <s6/supervise.h>
+
+#define USAGE "s6-svlink [ -d | -D ] [ -f ] [ -P ] [ -t timeout ] scandir servicedir [ name ]"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+static inline void checkscandir (char const *s)
+{
+  int r ;
+  int fd ;
+  size_t len = strlen(s) ;
+  char fn[len + 6 + sizeof(S6_SVSCAN_CTLDIR)] ;
+  memcpy(fn, s, len) ;
+  memcpy(fn + len, "/" S6_SVSCAN_CTLDIR "/lock", 6 + sizeof(S6_SVSCAN_CTLDIR)) ;
+  fd = open_read(fn) ;
+  if (fd < 0) strerr_diefu2sys(111, "open ", fn) ;
+  r = fd_islocked(fd) ;
+  if (r < 0) strerr_diefu2sys(111, "check lock on ", fn) ;
+  if (!r) strerr_dief2x(1, "s6-svscan not running on ", s) ;
+  fd_close(fd) ;
+}
+
+static inline void checkservicedir (char const *s)
+{
+  int r ;
+  struct stat st ;
+  size_t len = strlen(s) ;
+  char fn[len + 9] ;
+  memcpy(fn, s, len) ;
+  memcpy(fn + len, "/run", 4) ;
+  if (stat(fn, &st) == -1) strerr_diefu2sys(111, "stat ", fn) ;
+  if (!(st.st_mode & S_IXUSR)) strerr_dief2x(100, fn, " is not executable") ;
+  r = s6_svc_ok(s) ;
+  if (r < 0) strerr_diefu2sys(111, "check supervision status of ", s) ;
+  if (r) strerr_warnw2x("supervisor already running on ", s) ;
+  memcpy(fn + len + 1, "log", 4) ;
+  if (stat(fn, &st) == -1)
+  {
+    if (errno != ENOENT) strerr_diefu2sys(111, "stat ", fn) ;
+  }
+  else
+  {
+    if (!S_ISDIR(st.st_mode)) strerr_dief2x(100, fn, " is not a directory") ;
+    memcpy(fn + len + 4, "/run", 5) ;
+    if (stat(fn, &st) == -1) strerr_diefu2sys(111, "stat ", fn) ;
+    if (!(st.st_mode & S_IXUSR)) strerr_dief2x(100, fn, " is not executable") ;
+    fn[len + 4] = 0 ;
+    r = s6_svc_ok(fn) ;
+    if (r < 0) strerr_diefu2sys(111, "check supervision status of ", fn) ;
+    if (r) strerr_warnw2x("supervisor already running on ", fn) ;
+  } 
+}
+
+int main (int argc, char const *const *argv)
+{
+  tain tto = TAIN_INFINITE_RELATIVE ;
+  uint32_t options = 0 ;
+  char const *name ;
+  PROG = "s6-svlink" ;
+  {
+    unsigned int t = 0 ;
+    subgetopt l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "dDfPt:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'd' : options |= 12 ; break ;
+        case 'D' : options |= 4 ; options &= ~8U ; break ;
+        case 'f' : options |= 1 ; break ;
+        case 'P' : options |= 2 ; break ;
+        case 't' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (t) tain_from_millisecs(&tto, t) ;
+  }
+  if (argc < 2) dieusage() ;
+
+  if (argv[2]) name = argv[2] ;
+  else
+  {
+    stralloc sa = STRALLOC_ZERO ;
+    if (!stralloc_cats(&sa, argv[1]) || !stralloc_0(&sa))
+      strerr_diefu1sys(111, "stralloc_cats") ;
+    name = basename(sa.s) ;
+  }
+  if (!argv[0][0]) strerr_dief1x(100, "invalid scandir") ;
+  if (!argv[1][0]) strerr_dief1x(100, "invalid servicedir") ;
+  if (!name[0] || name[0] == '.' || name[0] == '/')
+    strerr_dief1x(100, "invalid name") ;
+  checkscandir(argv[0]) ;
+
+  tain_now_set_stopwatch_g() ;
+  tain_add_g(&tto, &tto) ;
+
+  if (s6_supervise_link_names_g(argv[0], argv + 1, &name, 1, options, &tto) == -1)
+    strerr_diefu6sys(errno == ETIMEDOUT ? 99 : 111, "link servicedir ", argv[1], " into scandir ", argv[0], " with name ", name) ;
+  return 0 ;
+}