From: Nathan Wagner <nw@hydaspes.if.org>
Date: Sat, 26 Dec 2015 19:50:37 +0000 (+0000)
Subject: add soname program
X-Git-Tag: v0.1.6~210
X-Git-Url: https://pd.if.org/git/?p=zpackage;a=commitdiff_plain;h=a7fc9d1dda7e3d2155b78587c4b1393f15a0ffb4

add soname program
---

diff --git a/Makefile b/Makefile
index 195aca3..5972c35 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,9 @@ CFLAGS=-Wall -std=c99
 elftype: elf/elftype.c
 	$(CC) $(CFLAGS) -o $@ $+
 
+soname: elf/soname.c
+	$(CC) $(CFLAGS) -o $@ $+
+
 install: elftype
 	install -D zpm $(DESTDIR)/bin/zpm
 	install -D zpm-note $(DESTDIR)/bin/zpm-note
diff --git a/elf/soname.c b/elf/soname.c
new file mode 100644
index 0000000..9977015
--- /dev/null
+++ b/elf/soname.c
@@ -0,0 +1,105 @@
+#define _POSIX_C_SOURCE 200112L
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <elf.h>
+
+int main(int ac, char **av) {
+	void *elfbase;
+	int elffd, i;
+	struct stat sbuf;
+	Elf64_Ehdr *hdr;
+	Elf64_Shdr *shdr;
+	Elf64_Shdr *dynsect = 0;
+	Elf64_Shdr *strtab = 0, *dyntab = 0;
+	char *name, *dynname;
+	Elf64_Dyn *dent;
+
+	elffd = open(av[1], O_RDONLY);
+	if (elffd == -1) {
+		exit(1);
+	}
+	if (fstat(elffd, &sbuf) == -1) {
+		exit(1);
+	}
+
+	elfbase = mmap(0, sbuf.st_size, PROT_READ,MAP_PRIVATE, elffd, 0);
+	if (!elfbase) {
+		exit(2);
+	}
+
+	hdr = elfbase;
+	if (hdr->e_ident[EI_MAG0] != ELFMAG0
+			|| hdr->e_ident[EI_MAG1] != ELFMAG1
+			|| hdr->e_ident[EI_MAG2] != ELFMAG2
+			|| hdr->e_ident[EI_MAG3] != ELFMAG3
+	   ) {
+		exit(3);
+	}
+
+	/* only dynamic files will have an soname */
+	if (hdr->e_type != ET_DYN) {
+		exit(4);
+	}
+	
+	switch (hdr->e_ident[EI_CLASS]) {
+		case ELFCLASS64:
+		case ELFCLASS32:
+		case ELFCLASSNONE:
+			break;
+		default:
+			exit(5);
+	}
+
+	/* check endian ness */
+	switch (hdr->e_ident[EI_DATA]) {
+		case ELFDATA2LSB: break;
+		case ELFDATA2MSB: break;
+		default:
+			exit(6);
+	}
+
+	/* find the section header table */
+	for (i = 0; i < hdr->e_shnum; i++) {
+		shdr = (Elf64_Shdr *)((char *)elfbase + hdr->e_shoff + i * hdr->e_shentsize);
+		if (shdr->sh_type == SHT_DYNAMIC) {
+			dynsect = shdr;
+		} else if (shdr->sh_type == SHT_STRTAB && i == hdr->e_shstrndx) {
+			strtab = shdr;
+		}
+	}
+	if (!strtab) {
+		exit(8);
+	}
+	if (!dynsect) {
+		exit(9);
+	}
+
+	name = (char *) elfbase + strtab->sh_offset;
+	for (i = 0; i < hdr->e_shnum; i++) {
+		shdr = (Elf64_Shdr *)((char *)elfbase + hdr->e_shoff + i * hdr->e_shentsize);
+		if (shdr->sh_type == SHT_STRTAB && !strcmp(".dynstr", name+shdr->sh_name)) {
+			dyntab = shdr;
+		}
+	}
+	if (!dyntab) {
+		exit(10);
+	}
+
+	dynname = (char *) elfbase + dyntab->sh_offset;
+	for (dent = (Elf64_Dyn *)((char *)elfbase + dynsect->sh_offset); dent->d_tag != DT_NULL; dent++) {
+		if (dent->d_tag == DT_SONAME) {
+			printf("%s\n", dynname + dent->d_un.d_val);
+			break;
+		}
+	}
+
+	return 0;
+}