Improve system calls

- Wrap clock_getres()
- Wrap sched_setscheduler()
- Make sleep() api conformant
- Polyfill sleep() using select()
- Improve clock_gettime() polyfill
- Make nanosleep() POSIX conformant
- Slightly improve some DNS functions
- Further strengthen pledge() sandboxing
- Improve rounding of timeval / timespec
- Allow layering of pledge() calls on Linux
- Polyfill sched_yield() using select() on XNU
- Delete more system constants we probably don't need

libc/calls/struct/bpf.h

@@ -6,8 +6,8 @@ COSMOPOLITAN_C_START_
 #define BPF_MAXINSNS 4096
 
 #define BPF_CLASS(code) ((code)&0x07)
-#define BPF_LD          0x00 /* load ops */
-#define BPF_LDX         0x01 /* load into register */
+#define BPF_LD          0x00 /* load into accumulator */
+#define BPF_LDX         0x01 /* load into index register */
 #define BPF_ST          0x02 /* store from immediate */
 #define BPF_STX         0x03 /* store from register */
 #define BPF_ALU         0x04 /* 32-bit arithmetic */
@@ -19,6 +19,7 @@ COSMOPOLITAN_C_START_
 #define BPF_W          0x00 /* 32-bit */
 #define BPF_H          0x08 /* 16-bit */
 #define BPF_B          0x10 /*  8-bit */
+#define BPF_DW         0x18 /* 64-bit (eBPF only) */
 
 #define BPF_MODE(code) ((code)&0xe0)
 #define BPF_IMM        0x00 /* 64-bit immediate */
@@ -52,7 +53,6 @@ COSMOPOLITAN_C_START_
 
 #define BPF_JMP32   0x06
 #define BPF_ALU64   0x07
-#define BPF_DW      0x18
 #define BPF_ATOMIC  0xc0
 #define BPF_XADD    0xc0
 #define BPF_MOV     0xb0

libc/calls/struct/rusage.h

@@ -25,6 +25,7 @@ struct rusage {
 int getrusage(int, struct rusage *);
 int wait3(int *, int, struct rusage *);
 int wait4(int, int *, int, struct rusage *);
+void _addrusage(struct rusage *, const struct rusage *);
 
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_CALLS_STRUCT_RUSAGE_H_ */

libc/calls/struct/sched_param.h

@@ -6,5 +6,12 @@ struct sched_param {
   int32_t sched_priority;
 };
 
+int sched_get_priority_max(int);
+int sched_get_priority_min(int);
+int sched_getparam(int, struct sched_param *);
+int sched_getscheduler(int);
+int sched_setparam(int, const struct sched_param *);
+int sched_setscheduler(int, int, const struct sched_param *);
+
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_CALLS_STRUCT_SCHED_PARAM_H_ */

libc/calls/struct/timespec.h

@@ -8,6 +8,9 @@ struct timespec {
 };
 
 int sys_futex(int *, int, int, const struct timespec *, int *);
+bool _timespec_gt(struct timespec, struct timespec);
+struct timespec _timespec_add(struct timespec, struct timespec);
+struct timespec _timespec_sub(struct timespec, struct timespec);
 
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_CALLS_STRUCT_TIMESPEC_H_ */

libc/calls/struct/timespec_gt.c

@@ -0,0 +1,34 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/timespec.h"
+
+/**
+ * Returns true if timespec `x` is greater than `y`.
+ */
+bool _timespec_gt(struct timespec x, struct timespec y) {
+  if (x.tv_sec > y.tv_sec) {
+    return true;
+  }
+  if (x.tv_sec == y.tv_sec) {
+    if (x.tv_nsec > y.tv_nsec) {
+      return true;
+    }
+  }
+  return false;
+}

libc/calls/struct/timeval.h

@@ -8,6 +8,7 @@ struct timeval {
 };
 
 int lutimes(const char *, const struct timeval[2]);
+struct timeval _timeval_add(struct timeval, struct timeval);
 
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_CALLS_STRUCT_TIMEVAL_H_ */