Command line support for altering the log file location

Add command line support for logging to a location other than /tmp/qemu.log.

With logging enabled (command line option -d), the log is written to
the hard-coded path /tmp/qemu.log. This patch adds support for writing
the log to a different location by passing the -D option.

Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

bsd-user/main.c

@@ -690,7 +690,8 @@ static void usage(void)
            "-bsd type         select emulated BSD type FreeBSD/NetBSD/OpenBSD (default)\n"
            "\n"
            "Debug options:\n"
-           "-d options   activate log (logfile=%s)\n"
+           "-d options   activate log (default logfile=%s)\n"
+           "-D logfile   override default logfile location\n"
            "-p pagesize  set the host page size to 'pagesize'\n"
            "-singlestep  always run in singlestep mode\n"
            "-strace      log system calls\n"
@@ -731,6 +732,8 @@ int main(int argc, char **argv)
 {
     const char *filename;
     const char *cpu_model;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     struct image_info info1, *info = &info1;
     TaskState ts1, *ts = &ts1;
@@ -745,9 +748,6 @@ int main(int argc, char **argv)
     if (argc <= 1)
         usage();
 
-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     if ((envlist = envlist_create()) == NULL) {
         (void) fprintf(stderr, "Unable to allocate envlist\n");
         exit(1);
@@ -775,22 +775,15 @@ int main(int argc, char **argv)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            const CPULogItem *item;
-
-            if (optind >= argc)
+            if (optind >= argc) {
                 break;
-
-            r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "E")) {
             r = argv[optind++];
             if (envlist_setenv(envlist, r) != 0)
@@ -867,6 +860,23 @@ int main(int argc, char **argv)
         usage();
     filename = argv[optind];
 
+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        const CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));
 

cpus.c

@@ -1142,6 +1142,11 @@ void set_cpu_log(const char *optarg)
     cpu_set_log(mask);
 }
 
+void set_cpu_log_filename(const char *optarg)
+{
+    cpu_set_log_filename(optarg);
+}
+
 /* Return the virtual CPU time, based on the instruction counter.  */
 int64_t cpu_get_icount(void)
 {

cpus.h

@@ -19,6 +19,7 @@ void vm_state_notify(int running, int reason);
 bool cpu_exec_all(void);
 void set_numa_modes(void);
 void set_cpu_log(const char *optarg);
+void set_cpu_log_filename(const char *optarg);
 void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg);
 
 #endif

darwin-user/main.c

@@ -738,6 +738,8 @@ TaskState *first_task_state;
 int main(int argc, char **argv)
 {
     const char *filename;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     TaskState ts1, *ts = &ts1;
     CPUState *env;
@@ -749,9 +751,6 @@ int main(int argc, char **argv)
     if (argc <= 1)
         usage();
 
-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     optind = 1;
     for(;;) {
         if (optind >= argc)
@@ -764,22 +763,15 @@ int main(int argc, char **argv)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            CPULogItem *item;
-
-        if (optind >= argc)
-        break;
-
-        r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
+            if (optind >= argc) {
+                break;
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "s")) {
             r = argv[optind++];
             stack_size = strtol(r, (char **)&r, 0);
@@ -821,6 +813,23 @@ int main(int argc, char **argv)
         usage();
     filename = argv[optind];
 
+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));
 

linux-user/main.c

@@ -2832,6 +2832,8 @@ int main(int argc, char **argv, char **envp)
 {
     const char *filename;
     const char *cpu_model;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     struct image_info info1, *info = &info1;
     struct linux_binprm bprm;
@@ -2853,9 +2855,6 @@ int main(int argc, char **argv, char **envp)
 
     qemu_cache_utils_init(envp);
 
-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     if ((envlist = envlist_create()) == NULL) {
         (void) fprintf(stderr, "Unable to allocate envlist\n");
         exit(1);
@@ -2894,22 +2893,15 @@ int main(int argc, char **argv, char **envp)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            const CPULogItem *item;
-
-	    if (optind >= argc)
+            if (optind >= argc) {
 		break;
-
-	    r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "E")) {
             r = argv[optind++];
             if (envlist_setenv(envlist, r) != 0)
@@ -3022,6 +3014,23 @@ int main(int argc, char **argv, char **envp)
     filename = argv[optind];
     exec_path = argv[optind];
 
+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        const CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));
 

qemu-options.hx

@@ -2007,6 +2007,15 @@ STEXI
 Output log in /tmp/qemu.log
 ETEXI
 
+DEF("D", HAS_ARG, QEMU_OPTION_D, \
+    "-D logfile      output log to logfile (instead of the default /tmp/qemu.log)\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -D
+@findex -D
+Output log in logfile instead of /tmp/qemu.log
+ETEXI
+
 DEF("hdachs", HAS_ARG, QEMU_OPTION_hdachs, \
     "-hdachs c,h,s[,t]\n" \
     "                force hard disk 0 physical geometry and the optional BIOS\n" \

vl.c

@@ -2067,6 +2067,8 @@ int main(int argc, char **argv, char **envp)
 #endif
     int defconfig = 1;
     const char *trace_file = NULL;
+    const char *log_mask = NULL;
+    const char *log_file = NULL;
 
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
@@ -2441,7 +2443,10 @@ int main(int argc, char **argv, char **envp)
                 break;
 #endif
             case QEMU_OPTION_d:
-                set_cpu_log(optarg);
+                log_mask = optarg;
+                break;
+            case QEMU_OPTION_D:
+                log_file = optarg;
                 break;
             case QEMU_OPTION_s:
                 gdbstub_dev = "tcp::" DEFAULT_GDBSTUB_PORT;
@@ -2907,6 +2912,18 @@ int main(int argc, char **argv, char **envp)
     }
     loc_set_none();
 
+    /* Open the logfile at this point, if necessary. We can't open the logfile
+     * when encountering either of the logging options (-d or -D) because the
+     * other one may be encountered later on the command line, changing the
+     * location or level of logging.
+     */
+    if (log_mask) {
+        if (log_file) {
+            set_cpu_log_filename(log_file);
+        }
+        set_cpu_log(log_mask);
+    }
+
     if (!st_init(trace_file)) {
         fprintf(stderr, "warning: unable to initialize simple trace backend\n");
     }