Add sethostname(2).

Not very useful, but helps building stuff like toybox out of the box.

Change-Id: I110e39030452bd093a84278e019c5752d293718d

libc/SYSCALLS.TXT

@@ -313,6 +313,8 @@ int __set_tid_address:set_tid_address(int*)  all
 int setfsgid(gid_t)  all
 int setfsuid(uid_t)  all
 
+int sethostname(const char*, size_t)  all
+
 pid_t wait4(pid_t, int*, int, struct rusage*)  all
 int __waitid:waitid(int, pid_t, struct siginfo_t*, int, void*)  all
 

libc/arch-arm/syscalls/sethostname.S

@@ -0,0 +1,14 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    mov     ip, r7
+    ldr     r7, =__NR_sethostname
+    swi     #0
+    mov     r7, ip
+    cmn     r0, #(MAX_ERRNO + 1)
+    bxls    lr
+    neg     r0, r0
+    b       __set_errno_internal
+END(sethostname)

libc/arch-arm64/syscalls/sethostname.S

@@ -0,0 +1,14 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    mov     x8, __NR_sethostname
+    svc     #0
+
+    cmn     x0, #(MAX_ERRNO + 1)
+    cneg    x0, x0, hi
+    b.hi    __set_errno_internal
+
+    ret
+END(sethostname)

libc/arch-mips/syscalls/sethostname.S

@@ -0,0 +1,19 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    .set noreorder
+    .cpload t9
+    li v0, __NR_sethostname
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    la t9,__set_errno_internal
+    j t9
+    nop
+    .set reorder
+END(sethostname)

libc/arch-mips64/syscalls/sethostname.S

@@ -0,0 +1,25 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    .set push
+    .set noreorder
+    li v0, __NR_sethostname
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    move t0, ra
+    bal     2f
+    nop
+2:
+    .cpsetup ra, t1, 2b
+    LA t9,__set_errno_internal
+    .cpreturn
+    j t9
+    move ra, t0
+    .set pop
+END(sethostname)

libc/arch-x86/syscalls/sethostname.S

@@ -0,0 +1,26 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    pushl   %ebx
+    .cfi_def_cfa_offset 8
+    .cfi_rel_offset ebx, 0
+    pushl   %ecx
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset ecx, 0
+    mov     12(%esp), %ebx
+    mov     16(%esp), %ecx
+    movl    $__NR_sethostname, %eax
+    int     $0x80
+    cmpl    $-MAX_ERRNO, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno_internal
+    addl    $4, %esp
+1:
+    popl    %ecx
+    popl    %ebx
+    ret
+END(sethostname)

libc/arch-x86_64/syscalls/sethostname.S

@@ -0,0 +1,15 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(sethostname)
+    movl    $__NR_sethostname, %eax
+    syscall
+    cmpq    $-MAX_ERRNO, %rax
+    jb      1f
+    negl    %eax
+    movl    %eax, %edi
+    call    __set_errno_internal
+1:
+    ret
+END(sethostname)

libc/include/unistd.h

@@ -183,7 +183,8 @@ extern unsigned int alarm(unsigned int);
 extern unsigned int sleep(unsigned int);
 extern int usleep(useconds_t);
 
-extern int gethostname(char *, size_t);
+int gethostname(char*, size_t);
+int sethostname(const char*, size_t);
 
 extern void *__brk(void *);
 extern int brk(void *);

tests/unistd_test.cpp

@@ -470,3 +470,11 @@ class unistd_DeathTest : public BionicDeathTest {};
 TEST_F(unistd_DeathTest, abort) {
   ASSERT_EXIT(abort(), testing::KilledBySignal(SIGABRT), "");
 }
+
+TEST(unistd, sethostname) {
+  // The permissions check happens before the argument check, so this will
+  // fail for a different reason if you're running as root than if you're
+  // not, but it'll fail either way. Checking that we have the symbol is about
+  // all we can do for sethostname(2).
+  ASSERT_EQ(-1, sethostname("", -1));
+}