diff options
| -rw-r--r-- | lib/portability.c | 15 | ||||
| -rwxr-xr-x | scripts/genconfig.sh | 6 |
2 files changed, 20 insertions, 1 deletions
diff --git a/lib/portability.c b/lib/portability.c index 4da49dd6..78e500b1 100644 --- a/lib/portability.c +++ b/lib/portability.c @@ -6,7 +6,20 @@ #include "toys.h" -#if !defined(__uClinux__) +// We can't fork() on nommu systems, and vfork() requires an exec() or exit() +// before resuming the parent (because they share a heap until then). And no, +// we can't implement our own clone() call that does the equivalent of fork() +// because nommu heaps use physical addresses so if we copy the heap all our +// pointers are wrong. (You need an mmu in order to map two heaps to the same +// address range without interfering with each other.) In the absence of +// a portable way to tell malloc() to start a new heap without freeing the old +// one, you pretty much need the exec().) + +// So we exec ourselves (via /proc/self/exe, if anybody knows a way to +// re-exec self without depending on the filesystem, I'm all ears), +// and use the arguments to signal reentry. + +#if CFG_TOYBOX_FORK pid_t xfork(void) { pid_t pid = fork(); diff --git a/scripts/genconfig.sh b/scripts/genconfig.sh index 313c7c70..031e97e0 100755 --- a/scripts/genconfig.sh +++ b/scripts/genconfig.sh @@ -83,6 +83,12 @@ EOF #error nope #endif EOF + + # nommu support + probesymbol TOYBOX_FORK << EOF + #include <unistd.h> + int main(int argc, char *argv[]) { return fork(); } +EOF } genconfig() |