Add sys_execve()

src/kernel/emulation/linux/CMakeLists.txt

@@ -57,6 +57,7 @@ set(emulation_sources
 	process/fork.c
 	process/wait4.c
 	process/waitid.c
+	process/execve.c
 	signal/duct_signals.c
 	signal/kill.c
 	signal/sigaltstack.c

src/kernel/emulation/linux/process/execve.c

@@ -0,0 +1,86 @@
+#include "execve.h"
+#include "../base.h"
+#include "../errno.h"
+#include <asm/unistd.h>
+#include "../fcntl/open.h"
+#include "../unistd/read.h"
+#include "../unistd/close.h"
+#include "../unistd/readlink.h"
+#include <stdint.h>
+
+#define MH_MAGIC    0xfeedface
+#define MH_CIGAM    0xcefaedfe
+#define MH_MAGIC_64 0xfeedfacf
+#define MH_CIGAM_64 0xcffaedfe
+#define FAT_MAGIC   0xcafebabe
+#define FAT_CIGAM   0xbebafeca
+
+extern int strcmp(const char *s1, const char *s2);
+
+long sys_execve(char* fname, char** argvp, char** envp)
+{
+	int ret, fd;
+	uint32_t magic;
+	char dyld_path[256];
+
+	// Ideally, if everybody used binfmt_misc to allow direct
+	// execution of Mach-O binaries under Darling, this wouldn't
+	// be necessary. But we cannot rely on that.
+	
+	fd = sys_open(fname, BSD_O_RDONLY, 0);
+	if (fd < 0)
+		return fd;
+
+	ret = sys_read(fd, &magic, sizeof(magic));
+	if (ret != 4)
+		goto no_macho;
+
+	if (magic == MH_MAGIC || magic == MH_CIGAM
+			|| magic == MH_MAGIC_64 || magic == MH_CIGAM_64
+			|| magic == FAT_MAGIC || magic == FAT_CIGAM)
+	{
+		// It is a Mach-O file
+		int len, i;
+		char** modargvp;
+		
+		len = sys_readlink("/proc/self/exe", dyld_path, sizeof(dyld_path)-1);
+		if (len < 0)
+			goto no_macho;
+
+		dyld_path[len] = '\0';
+
+		// Remove 64 or 32 suffix if present
+		if (strcmp(&dyld_path[len - 2], "32") == 0
+				|| strcmp(&dyld_path[len - 2], "64") == 0)
+		{
+			dyld_path[len-2] = '\0';
+		}
+
+		// Prepend dyld path
+		len = 0;
+
+		// Count arguments
+		while (argvp[len++]);
+
+		// Allocate a new argvp, execute dyld_path
+		modargvp = (char**) __builtin_alloca(sizeof(void*) * (len+1));
+		modargvp[0] = dyld_path;
+		modargvp[1] = fname;
+
+		for (i = 2; i < len+1; i++)
+			modargvp[i] = argvp[i-1];
+
+		argvp = modargvp;
+		fname = dyld_path;
+	}
+
+no_macho:
+	sys_close(fd);
+
+	ret = LINUX_SYSCALL(__NR_execve, fname, argvp, envp);
+	if (ret < 0)
+		ret = errno_linux_to_bsd(ret);
+
+	return ret;
+}
+

src/kernel/emulation/linux/process/execve.h

@@ -0,0 +1,7 @@
+#ifndef LINUX_EXECVE_H
+#define LINUX_EXECVE_H
+
+long sys_execve(char* fname, char** argvp, char** envp);
+
+#endif
+

src/kernel/emulation/linux/syscalls.c

@@ -47,6 +47,7 @@
 #include "process/vfork.h"
 #include "process/wait4.h"
 #include "process/waitid.h"
+#include "process/execve.h"
 #include "misc/ioctl.h"
 #include "misc/getrlimit.h"
 #include "misc/thread_selfid.h"
@@ -116,6 +117,7 @@ void* __bsd_syscall_table[512] = {
 	[54] = sys_ioctl,
 	[57] = sys_symlink,
 	[58] = sys_readlink,
+	[59] = sys_execve,
 	[60] = sys_umask,
 	[61] = sys_chroot,
 	[66] = sys_vfork,