From: Alan Cox <alan@linux.intel.com>
Date: Wed, 17 Feb 2016 21:47:47 +0000 (+0000)
Subject: exec: add core dump support
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=8a431429227092e1b13c29bb44f12da11989f976;p=FUZIX.git

exec: add core dump support

This adds some minimalistic core dump support to the 16bit code base.
---

diff --git a/Kernel/include/kernel.h b/Kernel/include/kernel.h
index c5ad4ca3..ee540125 100644
--- a/Kernel/include/kernel.h
+++ b/Kernel/include/kernel.h
@@ -47,6 +47,8 @@ From UZI by Doug Braun and UZI280 by Stefan Nitschke.
 	(udata.u_ptab->p_uid == (p)->p_uid || super())
 #define pathbuf()	tmpbuf()
 #define pathfree(tb)	brelse(tb)
+#define dump_core(sig)
+
 #endif
 
 #define CPM_EMULATOR_FILENAME    "/usr/cpm/emulator"
@@ -445,6 +447,8 @@ typedef struct u_data {
 #ifdef CONFIG_LEVEL_2
     uint16_t    u_groups[NGROUP]; /* Group list */
     uint8_t	u_ngroup;
+    uint8_t	u_flags;
+#define U_FLAG_NOCORE		1	/* Set if no core dump */
     struct rlimit u_rlimit[NRLIMIT];	/* Resource limits */
 #endif
 } u_data;
diff --git a/Kernel/include/level2.h b/Kernel/include/level2.h
index 35f45c41..3aa77cf0 100644
--- a/Kernel/include/level2.h
+++ b/Kernel/include/level2.h
@@ -60,4 +60,21 @@ extern arg_t _setpgid(void);
 extern arg_t _setsid(void);
 extern arg_t _getsid(void);
 
+/* Provided by the execve support */
+extern void write_core_image(void);
+
+/* This will change a lot in future ! */
+struct coredump {
+	uint16_t ch_magic1;
+#define MAGIC1 0xDEAD
+	uint16_t ch_magic2;
+#define MAGIC2 0xC0DE
+	uint8_t ch_type;	/* For now 16 or 32 bit number of bits - will
+				   change! */
+	uint32_t ch_base;
+	uint32_t ch_break;
+	uint32_t ch_sp;
+	uint32_t ch_top;
+};
+
 #endif
diff --git a/Kernel/process.c b/Kernel/process.c
index 38eb74c5..dec30727 100644
--- a/Kernel/process.c
+++ b/Kernel/process.c
@@ -433,6 +433,18 @@ void sgrpsig(uint16_t pgrp, uint8_t sig)
 	}
 }
 
+#ifdef CONFIG_LEVEL_2
+static void dump_core(uint8_t sig)
+{
+        if (!(udata.u_flags & U_FLAG_NOCORE) && ((sig == SIGQUIT || sig == SIGILL || sig == SIGTRAP ||
+            sig == SIGABRT || sig == SIGBUS || sig == SIGFPE ||
+            sig == SIGSEGV || sig == SIGXCPU || sig == SIGXFSZ ||
+            sig == SIGSYS))) {
+        	write_core_image();
+	}
+}
+#endif                                    
+
 /* This sees if the current process has any signals set, and handles them.
  */
 void chksigs(void)
@@ -477,6 +489,7 @@ void chksigs(void)
 #ifdef DEBUG
 			kprintf("process terminated by signal %d\n", j);
 #endif
+                        dump_core(j);
 			doexit((uint16_t)j << 8);
 		} else if (*svec != SIG_IGN) {
 			/* Arrange to call the user routine at return */
diff --git a/Kernel/syscall_exec16.c b/Kernel/syscall_exec16.c
index 46e77e67..aa477874 100644
--- a/Kernel/syscall_exec16.c
+++ b/Kernel/syscall_exec16.c
@@ -111,6 +111,15 @@ arg_t _execve(void)
 		goto nogood;
 	}
 
+	/* Core dump and ptrace permission logic */
+#ifdef CONFIG_LEVEL_2
+	if ((!getperm(ino) & OTH_RD) ||
+		(ino->c_node.i_mode & (SET_UID | SET_GID)))
+		udata.u_flags |= U_FLAG_NOCORE;
+	else
+		udata.u_flags &= ~U_FLAG_NOCORE;
+#endif
+
 	setftime(ino, A_TIME);
 
 	if (ino->c_node.i_size == 0) {
@@ -334,3 +343,56 @@ arg_t _memfree(void)
 	udata.u_error = ENOMEM;
 	return -1;
 }
+
+#ifdef CONFIG_LEVEL_2
+
+/*
+ *	Core dump
+ */
+
+static struct coredump corehdr = {
+	0xDEAD,
+	0xC0DE,
+	16,
+};
+
+void write_core_image(void)
+{
+	inoptr parent = NULLINODE;
+	inoptr ino;
+
+	ino = kn_open("core", &parent);
+	if (ino) {
+		i_deref(parent);
+		return;
+	}
+	if (parent && (ino = newfile(parent, "core"))) {
+		ino->c_node.i_mode = F_REG | 0400;
+		setftime(ino, A_TIME | M_TIME | C_TIME);
+		wr_inode(ino);
+		f_trunc(ino);
+
+		/* FIXME: need to add some arch specific header bits, and
+		   also pull stuff like the true sp and registers out of
+		   the return stack properly */
+
+		corehdr.ch_base = MAPBASE;
+		corehdr.ch_break = udata.u_break;
+		corehdr.ch_sp = udata.u_syscall_sp;
+		corehdr.ch_top = PROGTOP;
+		udata.u_offset = 0;
+		udata.u_base = (uint8_t *)&corehdr;
+		udata.u_sysio = true;
+		udata.u_count = sizeof(corehdr);
+		writei(ino, 0);
+		udata.u_sysio = false;
+		udata.u_base = MAPBASE;
+		udata.u_count = udata.u_break - MAPBASE;
+		writei(ino, 0);
+		udata.u_base = udata.u_sp;
+		udata.u_count = PROGTOP - udata.u_sp;
+		writei(ino, 0);
+		i_deref(ino);
+	}
+}
+#endif