From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001
From: Vladimir Azarov <avm@intermediate-node.net>
Date: Tue, 1 Oct 2024 15:47:05 +0200
Subject: Initial version

---
 src/ldso/dl_iterate_phdr.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 src/ldso/dl_iterate_phdr.c

(limited to 'src/ldso/dl_iterate_phdr.c')

diff --git a/src/ldso/dl_iterate_phdr.c b/src/ldso/dl_iterate_phdr.c
new file mode 100644
index 0000000..9546dd3
--- /dev/null
+++ b/src/ldso/dl_iterate_phdr.c
@@ -0,0 +1,47 @@
+#include <elf.h>
+#include <link.h>
+#include "pthread_impl.h"
+#include "libc.h"
+
+#define AUX_CNT 38
+
+extern weak hidden const size_t _DYNAMIC[];
+
+static int static_dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
+{
+	unsigned char *p;
+	ElfW(Phdr) *phdr, *tls_phdr=0;
+	size_t base = 0;
+	size_t n;
+	struct dl_phdr_info info;
+	size_t i, aux[AUX_CNT] = {0};
+
+	for (i=0; libc.auxv[i]; i+=2)
+		if (libc.auxv[i]<AUX_CNT) aux[libc.auxv[i]] = libc.auxv[i+1];
+
+	for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
+		phdr = (void *)p;
+		if (phdr->p_type == PT_PHDR)
+			base = aux[AT_PHDR] - phdr->p_vaddr;
+		if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
+			base = (size_t)_DYNAMIC - phdr->p_vaddr;
+		if (phdr->p_type == PT_TLS)
+			tls_phdr = phdr;
+	}
+	info.dlpi_addr  = base;
+	info.dlpi_name  = "/proc/self/exe";
+	info.dlpi_phdr  = (void *)aux[AT_PHDR];
+	info.dlpi_phnum = aux[AT_PHNUM];
+	info.dlpi_adds  = 0;
+	info.dlpi_subs  = 0;
+	if (tls_phdr) {
+		info.dlpi_tls_modid = 1;
+		info.dlpi_tls_data = __tls_get_addr((tls_mod_off_t[]){1,0});
+	} else {
+		info.dlpi_tls_modid = 0;
+		info.dlpi_tls_data = 0;
+	}
+	return (callback)(&info, sizeof (info), data);
+}
+
+weak_alias(static_dl_iterate_phdr, dl_iterate_phdr);
-- 
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