From 3c05d0baf322f9f47b0894379509f5e3c67e492b Mon Sep 17 00:00:00 2001
From: Nathan Wagner <nw@hydaspes.if.org>
Date: Sat, 28 Feb 2015 19:14:17 +0000
Subject: [PATCH] added program to output the elf type of a file

---
 Makefile      |   8 ++-
 elf/elftype.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 192 insertions(+), 1 deletion(-)
 create mode 100644 elf/elftype.c

diff --git a/Makefile b/Makefile
index 8f84c9d..fb3494e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,9 @@
-install:
+CFLAGS=-Wall -std=c99
+
+elftype: elf/elftype.c
+	$(CC) $(CFLAGS) -o $@ $+
+
+install: elftype
 	install -D zpm $(DESTDIR)/bin/zpm
 	install -D zpm-note $(DESTDIR)/bin/zpm-note
 	install -D zpm-sequence $(DESTDIR)/bin/zpm-sequence
@@ -6,4 +11,5 @@ install:
 	install -d -m2770 -o root -g adm $(DESTDIR)/var/lib/admin/notes
 	install -d -m2770 -o root -g adm $(DESTDIR)/var/lib/admin/notes/open
 	install -d -m2770 -o root -g adm $(DESTDIR)/var/lib/admin/notes/ack
+	install -D elftype $(DESTDIR)/usr/sbin/elftype
 	#SPOOL=$(DESTDIR)/var/lib/admin/notes ./zpm-sequence -c notes
diff --git a/elf/elftype.c b/elf/elftype.c
new file mode 100644
index 0000000..6dece5a
--- /dev/null
+++ b/elf/elftype.c
@@ -0,0 +1,185 @@
+#define _POSIX_C_SOURCE 200112L
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <elf.h>
+
+#define RELOCATABLE 0x1
+#define EXECUTABLE  0x2
+#define DYNAMIC     0x4
+#define CORE        0x8
+#define SYMLINKS    0x10
+
+int readline(FILE *f, char *fn);
+int checkfile(char *fn, unsigned int want, int perr, int quiet);
+
+int errors = 0;
+int zeroterm = 0;
+
+int main(int ac, char **av) {
+	int option;
+	unsigned int want = 0;
+	int quiet = 0;
+	int perr = 0;
+	FILE *list = 0;
+	char fn[PATH_MAX];
+	
+	while ((option = getopt(ac, av, "redclaqp0f:")) != -1) {
+		switch (option) {
+			case 'r': want |= RELOCATABLE; break;
+			case 'e': want |= EXECUTABLE; break;
+			case 'd': want |= DYNAMIC; break;
+			case 'c': want |= CORE; break;
+			case 'l': want |= SYMLINKS; break;
+			case 'a': want = (RELOCATABLE|EXECUTABLE|DYNAMIC|CORE); break;
+			case 'q': quiet++; break;
+			case 'p': perr++; break;
+			case '0': zeroterm = 1; break;
+			case 'f':
+				  if (optarg[0] == '-' && optarg[1] == 0) {
+					  list = stdin;
+				  } else {
+					  list = fopen(optarg, "r");
+				  }
+				  break;
+			default:
+				  exit(1);
+				  break;
+		}
+	}
+	if (list) {
+		quiet = 2;
+		perr = 0;
+		while (readline(list, fn)) {
+			fprintf(stderr, "checking %s\n", fn);
+			if (checkfile(fn, want,perr,quiet)) {
+			       	printf("%s\n", fn);
+			}
+		}
+	} else {
+		fprintf(stderr, "checking %s\n", av[optind]);
+		return !checkfile(av[optind], want,perr,quiet);
+	}
+	return errors ? 1 : 0;
+}
+
+int readline(FILE *f, char *fn) {
+	int ch;
+	int i = 0;
+
+	do {
+		ch = fgetc(f);
+		switch (ch) {
+			case EOF: break;
+			case 0:
+				  if (i == 0) continue;
+				  break;
+			case '\n':
+				  if (!zeroterm) {
+					  if (i == 0) continue;
+					  break;
+				  }
+			default:
+				  fn[i++] = ch;
+				  continue;
+		}
+		if (i >= PATH_MAX) {
+			/* TODO print an error */
+			return 0;
+		}
+		fn[i] = 0;
+		return i;
+	} while (ch != EOF);
+	return 0;
+}
+
+int checkfile(char *fn, unsigned int want, int perr, int quiet) {
+	Elf64_Ehdr hdr;
+	int fd, bytes;
+	int endian = 0;
+	struct stat st;
+
+	if (want & SYMLINKS) {
+		lstat(fn, &st);
+	} else {
+		stat(fn, &st);
+	}
+	if (!S_ISREG(st.st_mode)) {
+		return 0;
+	}
+	
+	fd = open(fn, O_RDONLY);
+	if (fd == -1) {
+		perror("elfcheck");
+		errors++;
+		return 0;
+	}
+	bytes = read(fd, &hdr, sizeof hdr);
+	if (bytes < sizeof hdr) {
+		if (perr) fprintf(stderr, "could not read full elf header (wanted %zu got %d bytes)\n", sizeof hdr, bytes);
+		close(fd);
+		return 0;
+	}
+	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
+	   ) {
+		if (perr) fprintf(stderr, "elf header magic wrong\n");
+		close(fd);
+		return 0;
+	}
+	switch (hdr.e_ident[EI_CLASS]) {
+		case ELFCLASS64:
+		case ELFCLASS32:
+		case ELFCLASSNONE:
+			break;
+		default:
+			if (perr) fprintf(stderr, "elf header unknown class\n");
+		close(fd);
+			return 0;
+	}
+
+	endian = hdr.e_ident[EI_DATA];
+	switch (endian) {
+		case ELFDATA2LSB: break;
+		case ELFDATA2MSB: break;
+				  /* TODO swap endian if needed */
+		default:
+			if (perr) fprintf(stderr, "elf header unknown endian\n");
+		close(fd);
+			return 0;
+	}
+
+	switch (hdr.e_type) {
+		case ET_REL:
+			if (!quiet) printf("relocatable\n");
+			close(fd);
+			return want & RELOCATABLE ? 1 : 0;
+		case ET_EXEC:
+			if (!quiet) printf("executable\n");
+			close(fd);
+			return want & EXECUTABLE ? 1 : 0;
+		case ET_DYN:
+			if (!quiet) printf("dynamic\n");
+			close(fd);
+			return want & DYNAMIC ? 1 : 0;
+		case ET_CORE:
+			if (!quiet) printf("core\n");
+			close(fd);
+			return want & CORE ? 1 : 0;
+		case ET_NONE:
+		default:
+			if (perr) fprintf(stderr, "unknown type\n");
+			close(fd);
+			return 0;
+	}
+
+	close(fd);
+	return 0;
+}
-- 
2.40.0