Commit yaboot 1.3.0

[yaboot.git] / util / elfextract.c

diff --git a/util/elfextract.c b/util/elfextract.c
new file mode 100644 (file)
index 0000000..a153017
--- /dev/null
+++ b/util/elfextract.c
@@ -0,0 +1,106 @@
+/*
+ * Extract the loadable program segment from an elf file.
+ *
+ * Copyright 1996 Paul Mackerras.
+ */
+#include <stdio.h>
+#include <linux/elf.h>
+
+FILE *fi, *fo;
+char *ni, *no;
+char buf[65536];
+
+void
+rd(void *buf, int len)
+{
+    int nr;
+
+    nr = fread(buf, 1, len, fi);
+    if (nr == len)
+       return;
+    if (ferror(fi))
+       fprintf(stderr, "%s: read error\n", ni);
+    else
+       fprintf(stderr, "%s: short file\n", ni);
+    exit(1);
+}
+
+int
+main(int ac, char **av)
+{
+    unsigned nb, len, i;
+    Elf32_Ehdr eh;
+    Elf32_Phdr ph;
+    unsigned long phoffset, phsize, prevaddr;
+
+    if (ac > 3 || (ac > 1 && av[1][0] == '-')) {
+       fprintf(stderr, "Usage: %s [elf-file [image-file]]\n", av[0]);
+       exit(0);
+    }
+
+    fi = stdin;
+    ni = "(stdin)";
+    fo = stdout;
+    no = "(stdout)";
+
+    if (ac > 1) {
+       ni = av[1];
+       fi = fopen(ni, "rb");
+       if (fi == NULL) {
+           perror(ni);
+           exit(1);
+       }
+    }
+
+    rd(&eh, sizeof(eh));
+    if (eh.e_ident[EI_MAG0] != ELFMAG0
+       || eh.e_ident[EI_MAG1] != ELFMAG1
+       || eh.e_ident[EI_MAG2] != ELFMAG2
+       || eh.e_ident[EI_MAG3] != ELFMAG3) {
+       fprintf(stderr, "%s: not an ELF file\n", ni);
+       exit(1);
+    }
+
+    fseek(fi, eh.e_phoff, 0);
+    phsize = 0;
+    for (i = 0; i < eh.e_phnum; ++i) {
+       rd(&ph, sizeof(ph));
+       if (ph.p_type != PT_LOAD)
+           continue;
+       if (phsize == 0 || prevaddr == 0) {
+           phoffset = ph.p_offset;
+           phsize = ph.p_filesz;
+       } else
+           phsize = ph.p_offset + ph.p_filesz - phoffset;
+       prevaddr = ph.p_vaddr;
+    }
+    if (phsize == 0) {
+       fprintf(stderr, "%s: doesn't have a loadable segment\n", ni);
+       exit(1);
+    }
+
+    if (ac > 2) {
+       no = av[2];
+       fo = fopen(no, "wb");
+       if (fo == NULL) {
+           perror(no);
+           exit(1);
+       }
+    }
+
+    fseek(fi, phoffset, 0);
+    for (len = phsize; len != 0; len -= nb) {
+       nb = len;
+       if (nb > sizeof(buf))
+           nb = sizeof(buf);
+       rd(buf, nb);
+       if (fwrite(buf, 1, nb, fo) != nb) {
+           fprintf(stderr, "%s: write error\n", no);
+           exit(1);
+       }
+    }
+
+    fclose(fo);
+    fclose(fi);
+    exit(0);
+}