[PATCH v3 05/16] xenctx: Add command line options -b and -l

[Don Slutz <dslutz@verizon.com>]

From: Don Slutz <dslutz@verizon.com>

  -b <bytes>, --bytes-per-line <bytes>
                    change the number of bytes per line output for Stack.
                    note: rounded to native size (4 or 8 bytes).
  -l <lines>, --lines <lines>
                    change the number of lines output for Stack.

Signed-off-by: Don Slutz <dslutz@verizon.com>
---
 tools/xentrace/xenctx.c | 62 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 12 deletions(-)

diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
index 038536b..62ba94c 100644
--- a/tools/xentrace/xenctx.c
+++ b/tools/xentrace/xenctx.c
@@ -36,6 +36,8 @@ static struct xenctx {
     int stack_trace;
     int disp_all;
     int two_pages;
+    int bytes_per_line;
+    int lines;
     int all_vcpus;
     int self_paused;
     xc_dominfo_t dominfo;
@@ -62,6 +64,8 @@ typedef uint64_t guest_word_t;
 #define FMT_64B_WORD "%016lx"
 #endif
 
+#define MAX_BYTES_PER_LINE 128
+
 struct symbol {
     guest_word_t address;
     char *name;
@@ -649,25 +653,30 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
     guest_word_t *p;
     int i;
 
+    if (width)
+        xenctx.bytes_per_line = ((xenctx.bytes_per_line + width - 1) / width) * width;
     stack_limit = ((stack_pointer(ctx) + XC_PAGE_SIZE)
                    & ~((guest_word_t) XC_PAGE_SIZE - 1));
     if (xenctx.two_pages)
         stack_limit += XC_PAGE_SIZE;
     printf("\n");
-    printf("Stack:\n");
-    for (i=1; i<5 && stack < stack_limit; i++) {
-        while(stack < stack_limit && stack < stack_pointer(ctx) + i*32) {
-            p = map_page(ctx, vcpu, stack);
-            if (!p)
-                return -1;
-            word = read_stack_word(p, width);
-            printf(" ");
-            print_stack_word(word, width);
-            stack += width;
+    if (xenctx.lines) {
+        printf("Stack:\n");
+        for (i = 1; i < xenctx.lines + 1 && stack < stack_limit; i++) {
+            while(stack < stack_limit &&
+                  stack < stack_pointer(ctx) + i * xenctx.bytes_per_line) {
+                p = map_page(ctx, vcpu, stack);
+                if (!p)
+                    return -1;
+                word = read_stack_word(p, width);
+                printf(" ");
+                print_stack_word(word, width);
+                stack += width;
+            }
+            printf("\n");
         }
         printf("\n");
     }
-    printf("\n");
 
     if(xenctx.stack_trace)
         printf("Stack Trace:\n");
@@ -827,19 +836,26 @@ static void usage(void)
     printf("  -a, --all          display more registers\n");
     printf("  -C, --all-vcpus    print info for all vcpus\n");
     printf("  -2, --two-pages    assume the kernel was compiled with 8KiB stacks.\n");
+    printf("  -b <bytes>, --bytes-per-line <bytes>\n");
+    printf("                     change the number of bytes per line output for Stack.\n");
+    printf("                     note: rounded to native size (4 or 8 bytes).\n");
+    printf("  -l <lines>, --lines <lines>\n");
+    printf("                     change the number of lines output for Stack.\n");
 }
 
 int main(int argc, char **argv)
 {
     int ch;
     int ret;
-    static const char *sopts = "fs:hak:SC2";
+    static const char *sopts = "fs:hak:SC2b:l:";
     static const struct option lopts[] = {
         {"stack-trace", 0, NULL, 'S'},
         {"symbol-table", 1, NULL, 's'},
         {"frame-pointers", 0, NULL, 'f'},
         {"kernel-start", 1, NULL, 'k'},
         {"two-pages", 0, NULL, '2'},
+        {"bytes-per-line", 1, NULL, 'b'},
+        {"lines", 1, NULL, 'l'},
         {"all", 0, NULL, 'a'},
         {"all-vcpus", 0, NULL, 'C'},
         {"help", 0, NULL, 'h'},
@@ -849,6 +865,9 @@ int main(int argc, char **argv)
 
     int vcpu = 0;
 
+    xenctx.bytes_per_line = 32;
+    xenctx.lines = 5;
+
     while ((ch = getopt_long(argc, argv, sopts, lopts, NULL)) != -1) {
         switch(ch) {
         case 'f':
@@ -866,6 +885,25 @@ int main(int argc, char **argv)
         case '2':
             xenctx.two_pages = 1;
             break;
+        case 'b':
+            xenctx.bytes_per_line = strtol(optarg, NULL, 0);
+            if (xenctx.bytes_per_line < 4 ||
+                xenctx.bytes_per_line > MAX_BYTES_PER_LINE) {
+                fprintf(stderr,
+                        "%s: Unsupported value for --bytes-per-line. Needs to be 4 <= <bytes> <= %d\n",
+                        argv[0], MAX_BYTES_PER_LINE);
+                exit(-1);
+            }
+            break;
+        case 'l':
+            xenctx.lines = strtol(optarg, NULL, 0);
+            if (xenctx.lines < 0) {
+                fprintf(stderr,
+                        "%s: Unsupported value for --lines. Needs to be >= 0\n",
+                        argv[0]);
+                exit(-1);
+            }
+            break;
         case 'C':
             xenctx.all_vcpus = 1;
             break;
-- 
1.8.4