handle /etc/hostname, sethostname(2), gethostname(2) and uname(2)

kernel-src/arch/x86-64/syscall.asm

@@ -62,6 +62,8 @@ extern syscall_sigaltstack
 extern syscall_sigprocmask
 extern syscall_kill
 extern syscall_sigreturn
+extern syscall_uname
+extern syscall_hostname
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -126,7 +128,9 @@ dq syscall_sigaltstack
 dq syscall_sigprocmask
 dq syscall_kill
 dq syscall_sigreturn
-syscallcount equ 63
+dq syscall_uname
+dq syscall_hostname
+syscallcount equ 65
 section .text
 global arch_syscall_entry
 ; on entry:

kernel-src/arch/x86-64/syscalllog.c

@@ -4,7 +4,7 @@
 
 #ifdef SYSCALL_LOGGING
 
-#define SYSCALL_COUNT 63
+#define SYSCALL_COUNT 65
 #define LOGSTR(x) arch_e9_puts(x)
 
 static char *name[] = {
@@ -70,7 +70,9 @@ static char *name[] = {
 	"sigaltstack",
 	"sigprocmask",
 	"kill",
-	"sigreturn"
+	"sigreturn",
+	"uname",
+	"hostname"
 };
 
 static char *args[] = {
@@ -136,7 +138,9 @@ static char *args[] = {
 	"new %p old %p", // sigaltstack
 	"how %d set %p oldset %p", // sigprocmask
 	"pid %d signal %d", // kill
-	"N/A" // sigreturn
+	"N/A", // sigreturn
+	"utsname %p", // uname
+	"new %p newsize %lu old %p oldsize %lu" // hostname
 };
 
 #endif

kernel-src/include/kernel/abi.h

@@ -164,4 +164,6 @@ typedef struct {
 	unsigned short int rt_irtt;
 } abirtentry_t;
 
+#define HOST_NAME_MAX 64
+
 #endif

kernel-src/sys/syscalls/hostname.c

@@ -0,0 +1,61 @@
+#include <kernel/syscalls.h>
+#include <kernel/abi.h>
+#include <spinlock.h>
+#include <util.h>
+
+static spinlock_t lock;
+static char buffer[HOST_NAME_MAX];
+static size_t bufferlen;
+
+void hostname_get(char *buf) {
+	bool intstatus = interrupt_set(false);
+	spinlock_acquire(&lock);
+
+	memcpy(buf, buffer, bufferlen);
+	buf[bufferlen] = '\0';
+
+	spinlock_release(&lock);
+	interrupt_set(intstatus);
+}
+
+syscallret_t syscall_hostname(context_t *, char *unew, size_t newsize, char *uold, size_t oldsize) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	if ((unew && newsize > HOST_NAME_MAX) || (uold && oldsize == 0)) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	char new[HOST_NAME_MAX];
+	char old[HOST_NAME_MAX + 1];
+
+	if (unew)
+		memcpy(new, unew, newsize);
+
+	interrupt_set(false);
+	spinlock_acquire(&lock);
+
+	if (uold) {
+		size_t copysize = min(oldsize - 1, bufferlen);
+
+		memcpy(old, buffer, copysize);
+		old[copysize] = '\0';
+	}
+
+	if (unew) {
+		bufferlen = newsize;
+		strcpy(buffer, new);
+	}
+
+	spinlock_release(&lock);
+	interrupt_set(true);
+
+	if (uold)
+		strcpy(uold, old);
+
+	ret.errno = 0;
+	ret.ret = 0;
+	return ret;
+}

kernel-src/sys/syscalls/uname.c

@@ -0,0 +1,29 @@
+#include <kernel/syscalls.h>
+#include <build.h>
+
+typedef struct {
+	char sysname[65];
+	char nodename[65];
+	char release[65];
+	char version[65];
+	char machine[65];
+	char domainname[65];
+} utsname_t;
+
+void hostname_get(char *buf);
+
+syscallret_t syscall_uname(context_t *, utsname_t *utsname) {
+	syscallret_t ret = {0};
+
+	char hostname[HOST_NAME_MAX + 1];
+	hostname_get(hostname);
+
+	strcpy(utsname->sysname, "Astral");
+	strcpy(utsname->nodename, hostname);
+	strcpy(utsname->release, "Astral");
+	strcpy(utsname->version, BUILD_DATE);
+	strcpy(utsname->machine, BUILD_TARGET);
+	strcpy(utsname->domainname, hostname);
+
+	return ret;
+}