From: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Date: Mon, 1 Mar 2010 20:04:12 -0800
Subject: [PATCH 04/13][user-cr]: restart: Use ckpt_msg() to log

Rather than implicitly redirecting messages to 'stdout' or 'stderr'
use global variables, 'global_ulogfd' and 'global_uerrfd'. That would
make it easier to implement additional command line options to redirect
these fds to other files, If we also later implement a library interface
to this restart code, it would enable callers to specify fds other than
'stdout' and 'stderr'.

Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
---
 restart.c |   90 ++++++++++++++++++++++++++++++++++++++++++------------------
 1 files changed, 63 insertions(+), 27 deletions(-)

diff --git a/restart.c b/restart.c
index 1839330..c4c2158 100644
--- a/restart.c
+++ b/restart.c
@@ -31,6 +31,7 @@
 #include <sys/syscall.h>
 #include <sys/prctl.h>
 #include <sys/mount.h>
+#include <stdarg.h>
 
 #include <linux/sched.h>
 #include <linux/checkpoint.h>
@@ -101,16 +102,38 @@ static char usage_str[] =
  * of the checkpoint image stream.
  */
 
+#define BUFSIZE  (4 * 4096)
+
+static inline void ckpt_msg(int fd, char *format, ...)
+{
+       va_list ap;
+       char *bufp;
+       if (fd < 0)
+               return;
+
+       va_start(ap, format);
+
+       bufp = malloc(BUFSIZE);
+       if(bufp) {
+               vsnprintf(bufp, BUFSIZE, format, ap);
+               write(fd, bufp, strlen(bufp));
+       }
+       free(bufp);
+
+       va_end(ap);
+}
+
 #ifdef CHECKPOINT_DEBUG
 #define ckpt_dbg(_format, _args...)                                    \
        do {                                                            \
                if (global_debug)                                       \
-                       fprintf(stderr, "<%d>" _format, _gettid(), ##_args); \
+                       ckpt_msg(global_uerrfd, "<%d>" _format,         \
+                                       _gettid(), ##_args);            \
        } while (0)
-#define ckpt_dbg_cont(_format, _args...)                       \
-       do {                                                    \
-               if (global_debug)                               \
-                       fprintf(stderr, _format, ##_args);      \
+#define ckpt_dbg_cont(_format, _args...)                               \
+       do {                                                            \
+               if (global_debug)                                       \
+                       ckpt_msg(global_uerrfd, _format, ##_args);      \
        } while (0)
 #else
 #define ckpt_dbg(_format, _args...)  \
@@ -120,12 +143,12 @@ static char usage_str[] =
 #endif
 
 #define ckpt_err(...)  \
-       fprintf(stderr, __VA_ARGS__)
+       ckpt_msg(global_uerrfd, __VA_ARGS__)
 
-#define ckpt_verbose(...)                      \
-       do {                                    \
-               if (global_verbose)             \
-                       printf(__VA_ARGS__);    \
+#define ckpt_verbose(...)                                      \
+       do {                                                    \
+               if (global_verbose)                             \
+                       ckpt_msg(global_ulogfd, __VA_ARGS__);   \
        } while(0)
 
 #define SIGNAL_ENTRY(signal)  { SIG ## signal, #signal }
@@ -196,8 +219,6 @@ inline static int restart(pid_t pid, int fd, unsigned long 
flags, int klogfd)
        return syscall(__NR_restart, pid, fd, flags, klogfd);
 }
 
-#define BUFSIZE  (4 * 4096)
-
 struct hashent {
        long key;
        void *data;
@@ -270,6 +291,12 @@ struct ckpt_ctx {
        char *freezer;
 };
 
+/*
+ * TODO: Do we need to direct user-space restart messages to two different
+ *      fds (like stdout and stderr) or can we just use one ?
+ */
+int global_ulogfd;
+int global_uerrfd;
 int global_debug;
 int global_verbose;
 pid_t global_child_pid;
@@ -372,7 +399,7 @@ struct args {
 
 static void usage(char *str)
 {
-       fprintf(stderr, "%s", str);
+       ckpt_err("%s", str);
        exit(1);
 }
 
@@ -406,7 +433,7 @@ static long cond_to_mask(const char *cond)
                if (!strcmp(cond, conditions[i].cond))
                        return conditions[i].mask;
 
-       printf("restart: invalid warn/fail condition '%s'\n", cond);
+       ckpt_err("restart: invalid warn/fail condition '%s'\n", cond);
        exit(1);
 }
 
@@ -489,7 +516,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
                case 7:
                        args->infd = str2num(optarg);
                        if (args->infd < 0) {
-                               printf("restart: invalid file descriptor\n");
+                               ckpt_err("restart: invalid file descriptor\n");
                                exit(1);
                        }
                        break;
@@ -499,7 +526,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
                case 8:
                        args->klogfd = str2num(optarg);
                        if (args->klogfd < 0) {
-                               printf("restart: invalid file descriptor\n");
+                               ckpt_err("restart: invalid file descriptor\n");
                                exit(1);
                        }
                        break;
@@ -517,7 +544,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
                        if (sig < 0)
                                sig = str2num(optarg);
                        if (sig < 0 || sig >= NSIG) {
-                               printf("restart: invalid signal\n");
+                               ckpt_err("restart: invalid signal\n");
                                exit(1);
                        }
                        global_send_sigint = sig;
@@ -574,7 +601,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
 
 #ifndef CLONE_NEWPID
        if (args->pidns) {
-               printf("This version of restart was compiled without "
+               ckpt_err("This version of restart was compiled without "
                       "support for --pidns.\n");
                exit(1);
        }
@@ -582,7 +609,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
 
 #ifndef CHECKPOINT_DEBUG
        if (global_debug) {
-               printf("This version of restart was compiled without "
+               ckpt_err("This version of restart was compiled without "
                       "support for --debug.\n");
                exit(1);
        }
@@ -594,7 +621,7 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
 #if 0   /* Defered until __NR_eclone makes it to standard headers */
 #ifndef __NR_eclone
        if (args->pids) {
-               printf("This version of restart was compiled without "
+               ckpt_err("This version of restart was compiled without "
                       "support for --pids.\n");
                exit(1);
        }
@@ -604,17 +631,17 @@ static void parse_args(struct args *args, int argc, char 
*argv[])
        if (args->self &&
            (args->pids || args->pidns || no_pidns ||
             args->show_status || args->copy_status || args->freezer)) {
-               printf("Invalid mix of --self with multiprocess options\n");
+               ckpt_err("Invalid mix of --self with multiprocess options\n");
                exit(1);
        }
 
        if (args->input && args->infd >= 0) {
-               printf("Invalid used of both -i/--input and --input-fd\n");
+               ckpt_err("Invalid use of both -i/--input and --input-fd\n");
                exit(1);
        }
 
        if (klogfile && args->klogfd >= 0) {
-               printf("Invalid used of both -l/--logfile and --logfile-fd\n");
+               ckpt_err("Invalid use of both -l/--logfile and --logfile-fd\n");
                exit(1);
        }
 
@@ -770,6 +797,15 @@ int main(int argc, char *argv[])
        struct args args;
        int ret;
 
+       /*
+        * Initialize the log/error fds early so even parse_args() errors
+        * are redirected here. Even if we later implement command line options
+        * that override these, any errors/messages that occur before those
+        * new options are parsed still go to stdout/stderr
+        */
+       global_ulogfd = fileno(stdout);
+       global_uerrfd = fileno(stderr);
+
        memset(&ctx, 0, sizeof(ctx));
 
        parse_args(&args, argc, argv);
@@ -891,16 +927,16 @@ static int ckpt_parse_status(int status, int mimic, int 
verbose)
        int ret = 0;
 
        if (verbose && global_sent_sigint)
-               printf("Terminated\n");
+               ckpt_verbose("Terminated\n");
        if (WIFSIGNALED(status)) {
                sig = WTERMSIG(status);
                if (verbose && !global_sent_sigint)
-                       printf("Killed %d\n", sig);
+                       ckpt_verbose("Killed %d\n", sig);
                ckpt_dbg("task terminated with signal %d\n", sig);
        } else if (WIFEXITED(status)) {
                ret = WEXITSTATUS(status);
                if (verbose)
-                       printf("Exited %d\n", ret);
+                       ckpt_verbose("Exited %d\n", ret);
                ckpt_dbg("task exited with status %d\n", ret);
        }
 
@@ -1172,7 +1208,7 @@ static int ckpt_coordinator_pidns(struct ckpt_ctx *ctx)
 #else
 static int ckpt_coordinator_pidns(struct ckpt_ctx *ctx)
 {
-       printf("logical error: ckpt_coordinator_pidns unexpected\n");
+       ckpt_err("logical error: ckpt_coordinator_pidns unexpected\n");
        exit(1);
 }
 #endif
-- 
1.6.0.4

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