Check preopens only if needed

* Use `constructor` to eliminate them if unnecessary
tyfkda · Oct 28, 2024 · c4c31a6 · c4c31a6
1 parent c4ca0e3
commit c4c31a6
Show file tree

Hide file tree

Showing 5 changed files with 50 additions and 43 deletions.
diff --git a/libsrc/_wasm/crt0/_start.c b/libsrc/_wasm/crt0/_start.c
@@ -5,22 +5,6 @@
 
 extern void __wasm_call_ctors(void);
 
-int __max_preopen_fd = 3;
-
-static int find_preopens(void) {
-  for (int fd = 3; ; ++fd) {
-    Prestat prestat;
-    int result = fd_prestat_get(fd, &prestat);
-    if (result != 0)
-      return fd;
-
-    // char buf[256];
-    // fd_prestat_dir_name(fd, buf, prestat.u.dir.pr_name_len);  // TODO: Confirm prestat.u.dir.pr_name_len < sizeof(buf)
-    // buf[prestat.u.dir.pr_name_len] = '\0';
-    // fprintf(stderr, "preopens: %d, %s\n", fd, buf);
-  }
-}
-
 void _start(void) {
 #define main  __main_argc_argv
   extern int main(int, char**);
@@ -38,8 +22,6 @@ void _start(void) {
   }
   argv[argc] = NULL;
 
-  __max_preopen_fd = find_preopens();
-
   __wasm_call_ctors();
 
   int ec = main(argc, argv);

diff --git a/libsrc/_wasm/unistd/_detect_preopen.c b/libsrc/_wasm/unistd/_detect_preopen.c
@@ -0,0 +1,20 @@
+#include "../wasi.h"
+
+int __max_preopen_fd = 3;
+
+__attribute__((constructor))
+static void find_preopens(void) {
+  for (int fd = 3; ; ++fd) {
+    Prestat prestat;
+    int result = fd_prestat_get(fd, &prestat);
+    if (result != 0) {
+      __max_preopen_fd = fd;
+      return;
+    }
+
+    // char buf[256];
+    // fd_prestat_dir_name(fd, buf, prestat.u.dir.pr_name_len);  // TODO: Confirm prestat.u.dir.pr_name_len < sizeof(buf)
+    // buf[prestat.u.dir.pr_name_len] = '\0';
+    // fprintf(stderr, "preopens: %d, %s\n", fd, buf);
+  }
+}
diff --git a/libsrc/_wasm/unistd/_set_stat.c b/libsrc/_wasm/unistd/_set_stat.c
@@ -0,0 +1,27 @@
+#include "sys/stat.h"
+#include "../wasi.h"
+
+void _set_stat(Filestat *fs, struct stat *st) {
+  mode_t mode = 0;
+  switch (fs->filetype) {
+  case FILETYPE_BLOCK_DEVICE:  mode = S_IFBLK; break;
+  case FILETYPE_CHARACTER_DEVICE:  mode = S_IFCHR; break;
+  case FILETYPE_DIRECTORY:  mode = S_IFDIR; break;
+  case FILETYPE_REGULAR_FILE:  mode = S_IFREG; break;
+  case FILETYPE_SOCKET_DGRAM:  mode = S_IFSOCK; break;
+  case FILETYPE_SOCKET_STREAM:  mode = S_IFSOCK; break;
+  case FILETYPE_SYMBOLIC_LINK:  mode = S_IFLNK; break;
+  }
+
+  st->st_dev = fs->dev;
+  st->st_ino = fs->ino;
+  st->st_mode = mode;
+  st->st_nlink = fs->nlink;
+  st->st_uid = 0;
+  st->st_gid = 0;
+  st->st_rdev = 0;
+  st->st_size = fs->size;
+  st->st_blksize = 0;
+  st->st_blocks = 0;
+  // TODO: atim, mtim, ctim
+}
diff --git a/libsrc/_wasm/unistd/fstat.c b/libsrc/_wasm/unistd/fstat.c
@@ -1,11 +1,12 @@
 #include "sys/stat.h"
 #include "../wasi.h"
 
+extern void _set_stat(Filestat *fs, struct stat *st);
+
 int fstat(int fd, struct stat *st) {
   Filestat fs;
   uint32_t result = fd_filestat_get(fd, &fs);
   if (result == 0) {
-    extern void _set_stat(Filestat *fs, struct stat *st);
     _set_stat(&fs, st);
     return 0;
   }

diff --git a/libsrc/_wasm/unistd/stat.c b/libsrc/_wasm/unistd/stat.c
@@ -4,30 +4,7 @@
 
 extern int __max_preopen_fd;
 
-void _set_stat(Filestat *fs, struct stat *st) {
-  mode_t mode = 0;
-  switch (fs->filetype) {
-  case FILETYPE_BLOCK_DEVICE:  mode = S_IFBLK; break;
-  case FILETYPE_CHARACTER_DEVICE:  mode = S_IFCHR; break;
-  case FILETYPE_DIRECTORY:  mode = S_IFDIR; break;
-  case FILETYPE_REGULAR_FILE:  mode = S_IFREG; break;
-  case FILETYPE_SOCKET_DGRAM:  mode = S_IFSOCK; break;
-  case FILETYPE_SOCKET_STREAM:  mode = S_IFSOCK; break;
-  case FILETYPE_SYMBOLIC_LINK:  mode = S_IFLNK; break;
-  }
-
-  st->st_dev = fs->dev;
-  st->st_ino = fs->ino;
-  st->st_mode = mode;
-  st->st_nlink = fs->nlink;
-  st->st_uid = 0;
-  st->st_gid = 0;
-  st->st_rdev = 0;
-  st->st_size = fs->size;
-  st->st_blksize = 0;
-  st->st_blocks = 0;
-  // TODO: atim, mtim, ctim
-}
+extern void _set_stat(Filestat *fs, struct stat *st);
 
 int stat(const char *fn, struct stat *st) {
   memset(st, 0, sizeof(st));