[Minios-devel] [UNIKRAFT PATCH v2 1/1] Revisit process.c functions

[Costin Lupu <costin.lupu@xxxxxxxxx>]

This patch revisits the functions in process.c, redistributes some of them and
implement the others. The remaining functions may very well be moved into an
internal "process" related library, but we will do this at another time. It's
worth saying that we set the PID of the unikernel to 1, saving the PID 0 for its
"parent", an invisibile process that is also not shown on Linux.

Redistributed functions:
- kill() and killpg() are moved to signal.c
- times() is moved to time.c

Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
 include/uk/process.h |  43 +++++++++++
 process.c            | 165 ++++++++++++++++++++++++++++++-------------
 signal.c             |  18 +++++
 time.c               |   6 ++
 4 files changed, 182 insertions(+), 50 deletions(-)
 create mode 100644 include/uk/process.h

diff --git a/include/uk/process.h b/include/uk/process.h
new file mode 100644
index 0000000..67208e3
--- /dev/null
+++ b/include/uk/process.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2019, University Politehnica of Bucharest. All rights 
reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
+ */
+
+#ifndef __UK_PROCESS_H__
+#define __UK_PROCESS_H__
+
+#define UNIKRAFT_PID      1
+#define UNIKRAFT_PPID     0
+#define UNIKRAFT_SID      0
+#define UNIKRAFT_PGID     0
+
+#endif /* __UK_PROCESS_H__ */
diff --git a/process.c b/process.c
index c4e3664..e26110d 100644
--- a/process.c
+++ b/process.c
@@ -3,7 +3,7 @@
  * libnewlib glue code
  *
  * Authors: Felipe Huici <felipe.huici@xxxxxxxxx>
- *
+ *          Costin Lupu <costin.lupu@xxxxxxxxx>
  *
  * Copyright (c) 2017, NEC Europe Ltd., NEC Corporation. All rights reserved.
  *
@@ -35,134 +35,199 @@
  * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
  */
 
-#include <time.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <sys/resource.h>
+#include <uk/process.h>
+#include <uk/print.h>
 #undef errno
 extern int errno;
 
-int execve(char *name __unused, char **argv __unused, char **env __unused)
+
+int fork(void)
 {
-       errno = ENOMEM;
+       /* fork() is not supported on this platform */
+       errno = ENOSYS;
        return -1;
 }
 
-int execv(const char *path __unused, char *const argv[] __unused)
+static
+void exec_warn(const char *func,
+               const char *path, char *const argv[], char *const envp[])
 {
-       return 0;
-}
+       int i;
 
-int system(const char *command __unused)
-{
-       return 0;
-}
+       uk_pr_warn("%s(): path=%s", func, path);
 
-FILE *popen(const char *command __unused, const char *type __unused)
-{
-       return NULL;
-}
+       /* print arguments */
+       i = 0;
+       uk_pr_warn(" argv=[");
+       while (argv[i]) {
+               uk_pr_warn("%s%s", (i > 0 ? ", " : ""), argv[i]);
+               i++;
+       }
+       uk_pr_warn("]");
 
-int pclose(FILE *stream __unused)
-{
-       return 0;
+       /* print environment variables */
+       if (envp) {
+               i = 0;
+               uk_pr_warn(" envp=[");
+               while (envp[i]) {
+                       uk_pr_warn("%s%s", (i > 0 ? ", " : ""), envp[i]);
+                       i++;
+               }
+               uk_pr_warn("]");
+       }
+
+       uk_pr_warn("\n");
 }
 
-int fork(void)
+int execve(const char *path, char *const argv[], char *const envp[])
 {
-       errno = EAGAIN;
+       exec_warn(__func__, path, argv, envp);
+       errno = ENOSYS;
        return -1;
 }
 
-int getpid(void)
+int execv(const char *path, char *const argv[])
 {
-       return 1;
+       exec_warn(__func__, path, argv, NULL);
+       errno = ENOSYS;
+       return -1;
 }
 
-pid_t getppid(void)
+int system(const char *command)
 {
-       return 0;
+       uk_pr_warn("%s: %s\n", __func__, command);
+       errno = ENOSYS;
+       return -1;
 }
 
-int kill(int pid __unused, int sig __unused)
+FILE *popen(const char *command, const char *type __unused)
 {
-       errno = EINVAL;
-       return -1;
+       uk_pr_warn("%s: %s\n", __func__, command);
+       errno = ENOSYS;
+       return NULL;
 }
 
-int times(struct tm *buf __unused)
+int pclose(FILE *stream __unused)
 {
+       errno = EINVAL;
        return -1;
 }
 
 int wait(int *status __unused)
 {
+       /* No children */
        errno = ECHILD;
        return -1;
 }
 
-int setpgrp(void)
-{
-       return 0;
-}
-
-
-int killpg(int pgrp __unused, int sig __unused)
+pid_t waitpid(pid_t pid __unused, int *wstatus __unused, int options __unused)
 {
-       return 0;
+       /* No children */
+       errno = ECHILD;
+       return -1;
 }
 
-
 pid_t wait3(int *wstatus __unused, int options __unused,
                struct rusage *rusage __unused)
 {
-       return 0;
+       /* No children */
+       errno = ECHILD;
+       return -1;
 }
 
 pid_t wait4(pid_t pid __unused, int *wstatus __unused, int options __unused,
                struct rusage *rusage __unused)
 {
-       return 0;
+       /* No children */
+       errno = ECHILD;
+       return -1;
 }
 
-pid_t waitpid(pid_t pid __unused, int *wstatus __unused, int options __unused)
+int getpid(void)
 {
-       return 0;
+       return UNIKRAFT_PID;
+}
+
+pid_t getppid(void)
+{
+       return UNIKRAFT_PPID;
 }
 
 pid_t setsid(void)
 {
-       return 0;
+       /* We have a single "session" with a single "process" */
+       errno = EPERM;
+       return (pid_t) -1;
 }
 
-pid_t getsid(pid_t pid __unused)
+pid_t getsid(pid_t pid)
 {
-       return 0;
+       if (pid != 0) {
+               /* We support only calls for the only calling "process" */
+               errno = ESRCH;
+               return (pid_t) -1;
+       }
+       return UNIKRAFT_SID;
 }
 
-int setpgid(pid_t pid __unused, pid_t pgid __unused)
+int setpgid(pid_t pid, pid_t pgid)
 {
+       if (pid != 0) {
+               /* We support only calls for the only calling "process" */
+               errno = ESRCH;
+               return (pid_t) -1;
+       }
+       if (pgid != 0) {
+               /* We have a single "group" with a single "process" */
+               errno = EPERM;
+               return (pid_t) -1;
+       }
        return 0;
 }
 
 pid_t getpgid(pid_t pid)
 {
-       return 0;
+       if (pid != 0) {
+               /* We support only calls for the only calling "process" */
+               errno = ESRCH;
+               return (pid_t) -1;
+       }
+       return UNIKRAFT_PGID;
 }
 
+pid_t getpgrp(void)
+{
+       return UNIKRAFT_PGID;
+}
 
-int tcsetpgrp(int fd __unused, pid_t pgrp __unused)
+int setpgrp(void)
 {
-       return 0;
+       return setpgid(0, 0);
 }
 
-pid_t tcgetpgrp(int fd __unused)
+int tcsetpgrp(int fd __unused, pid_t pgrp)
 {
+       /* TODO check if fd is BADF */
+       if (pgrp != UNIKRAFT_PGID) {
+               errno = EINVAL;
+               return -1;
+       }
        return 0;
 }
 
+pid_t tcgetpgrp(int fd)
+{
+       /* We have a single "process group" */
+       return UNIKRAFT_PGID;
+}
+
 int nice(int inc __unused)
 {
-       return 0;
+       /* We don't support priority updates for unikernels */
+       errno = EPERM;
+       return -1;
 }
diff --git a/signal.c b/signal.c
index 680bcaf..3afc168 100644
--- a/signal.c
+++ b/signal.c
@@ -32,6 +32,8 @@
  * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
  */
 
+#include <uk/process.h>
+#include <errno.h>
 #include <signal.h>
 
 int sigaction(int sig __unused, const struct sigaction *restrict act __unused,
@@ -54,3 +56,19 @@ int siginterrupt(int sig __unused, int flag __unused)
 {
        return 0;
 }
+
+int kill(int pid, int sig __unused)
+{
+       /* TODO check sig */
+       if (pid != UNIKRAFT_PID)
+               errno = ESRCH;
+       return -1;
+}
+
+int killpg(int pgrp, int sig __unused)
+{
+       /* TODO check sig */
+       if (pgrp != UNIKRAFT_PGID)
+               errno = ESRCH;
+       return -1;
+}
diff --git a/time.c b/time.c
index a79691c..3470591 100644
--- a/time.c
+++ b/time.c
@@ -172,3 +172,9 @@ int clock_settime(clockid_t clk_id __unused, const struct 
timespec *tp __unused)
 {
        return 0;
 }
+
+int times(struct tm *buf __unused)
+{
+       errno = ENODATA;
+       return -1;
+}
-- 
2.20.1


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