Re: PATCH: dl_iterate_phdr()

[Alex Caudill <alex.caudill@gmail.com>]

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Sorry for the delay; I *think* this might do it ;)

On 10/18/12, Rich Felker <dalias@aerifal.cx> wrote:
> On Sun, Oct 14, 2012 at 11:47:38PM -0500, Alex Caudill wrote:
>> No kidding: I ragequit the entire internet for a solid 48 hours due to
>> this thread. Turned off my phone, dropped off the grid. I had to step
>> away and reconsider my entire approach to software and really figure
>> out if I should even be spending my time on this. It's so humbling
>> when you think you're beginning to grasp something and then realize
>> that you know NOTHING.
>>
>> Anyway, please let me finish this :)
>
> Hope you're not getting discouraged. :)
> I'd like to get both this and whatever other changed you need
> (sigreturn?) in for the next release. Let me know if you're running
> into any more problems or if you just need some time. It's not a hurry
> since I'm waiting on some testing for microblaze anyway.
>
> Rich
>

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diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index c3cb611..2802c21 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -13,6 +13,7 @@
 #include <errno.h>
 #include <limits.h>
 #include <elf.h>
+#include <link.h>
 #include <setjmp.h>
 #include <pthread.h>
 #include <ctype.h>
@@ -30,12 +31,14 @@ static char errbuf[128];
 typedef Elf32_Ehdr Ehdr;
 typedef Elf32_Phdr Phdr;
 typedef Elf32_Sym Sym;
+typedef Elf32_Addr Addr;
 #define R_TYPE(x) ((x)&255)
 #define R_SYM(x) ((x)>>8)
 #else
 typedef Elf64_Ehdr Ehdr;
 typedef Elf64_Phdr Phdr;
 typedef Elf64_Sym Sym;
+typedef Elf64_Addr Addr;
 #define R_TYPE(x) ((x)&0xffffffff)
 #define R_SYM(x) ((x)>>32)
 #endif
@@ -57,6 +60,8 @@ struct dso {
 	size_t *dynv;
 	struct dso *next, *prev;
 
+	Phdr *phdr;
+	int phnum;
 	int refcnt;
 	Sym *syms;
 	uint32_t *hashtab;
@@ -92,6 +97,7 @@ void *__install_initial_tls(void *);
 
 static struct dso *head, *tail, *libc, *fini_head;
 static char *env_path, *sys_path, *r_path;
+static unsigned long long gencnt = 0;
 static int ssp_used;
 static int runtime;
 static int ldd_mode;
@@ -324,6 +330,8 @@ static void *map_library(int fd, struct dso *dso)
 		eh->e_phoff = sizeof *eh;
 	}
 	ph = (void *)((char *)buf + eh->e_phoff);
+	dso->phdr = ph;
+	dso->phnum = eh->e_phnum;
 	for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 		if (ph->p_type == PT_DYNAMIC)
 			dyn = ph->p_vaddr;
@@ -815,18 +823,19 @@ void *__dynlink(int argc, char **argv)
 	lib->name = lib->shortname = "libc.so";
 	lib->global = 1;
 	ehdr = (void *)lib->base;
-	find_map_range((void *)(aux[AT_BASE]+ehdr->e_phoff),
-		ehdr->e_phnum, ehdr->e_phentsize, lib);
-	lib->dynv = (void *)(lib->base + find_dyn(
-		(void *)(aux[AT_BASE]+ehdr->e_phoff),
-		ehdr->e_phnum, ehdr->e_phentsize));
+	lib->phnum = ehdr->e_phnum;
+	lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
+	find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
+	lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
+                    ehdr->e_phnum, ehdr->e_phentsize));
 	decode_dyn(lib);
 
 	if (aux[AT_PHDR]) {
 		size_t interp_off = 0;
 		size_t tls_image = 0;
 		/* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
-		phdr = (void *)aux[AT_PHDR];
+		app->phdr = phdr = (void *)aux[AT_PHDR];
+		app->phnum = aux[AT_PHNUM];
 		for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
 			if (phdr->p_type == PT_PHDR)
 				app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
@@ -890,7 +899,8 @@ void *__dynlink(int argc, char **argv)
 	/* Attach to vdso, if provided by the kernel */
 	if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
 		ehdr = (void *)vdso_base;
-		phdr = (void *)(vdso_base + ehdr->e_phoff);
+		vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
+		vdso->phnum = ehdr->e_phnum;
 		for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
 			if (phdr->p_type == PT_DYNAMIC)
 				vdso->dynv = (void *)(vdso_base + phdr->p_offset);
@@ -1051,6 +1061,7 @@ void *dlopen(const char *file, int mode)
 	orig_tail = tail;
 end:
 	__release_ptc();
+	if (p) gencnt++;
 	pthread_rwlock_unlock(&lock);
 	if (p) do_init_fini(orig_tail);
 	pthread_setcancelstate(cs, 0);
@@ -1166,6 +1177,33 @@ void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
 	pthread_rwlock_unlock(&lock);
 	return res;
 }
+
+int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
+{
+	struct dso *current;
+	struct dl_phdr_info info;
+	int ret = 0;
+	for(current = head; current;) {
+		info.dlpi_addr      = (Addr)current->base;
+		info.dlpi_name      = current->name;
+		info.dlpi_phdr      = current->phdr;
+		info.dlpi_phnum     = current->phnum;
+		info.dlpi_adds      = gencnt;
+		info.dlpi_subs      = 0;
+		info.dlpi_tls_modid = current->tls_id;
+		info.dlpi_tls_data  = current->tls_image;
+
+		ret = (callback)(&info, sizeof (info), data);
+
+		if (ret != 0) break;
+
+		pthread_rwlock_rdlock(&lock);
+		current = current->next;
+		pthread_rwlock_unlock(&lock);
+	}
+	return ret;
+}
 #else
 void *dlopen(const char *file, int mode)
 {