[PATCH 2/3] tracing/probes: support '%pD' type for print struct file's name

[Ye Bin]

Similar to '%pD' for printk, use 'pD' for print struct file's name.

Signed-off-by: Ye Bin <yebi...@huawei.com>
---
 kernel/trace/trace_probe.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 460f98b85b1c..400a1dd52c39 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -12,6 +12,7 @@
 #define pr_fmt(fmt)    "trace_probe: " fmt
 
 #include <linux/dcache.h>
+#include <linux/fs.h>
 #include <linux/bpf.h>
 #include "trace_btf.h"
 
@@ -89,6 +90,8 @@ static const struct fetch_type probe_fetch_types[] = {
                            "__data_loc char[]"),
        __ASSIGN_FETCH_TYPE("pd", string, string, sizeof(u32), 1, 1,
                            "__data_loc char[]"),
+       __ASSIGN_FETCH_TYPE("pD", string, string, sizeof(u32), 1, 1,
+                           "__data_loc char[]"),
        /* Basic types */
        ASSIGN_FETCH_TYPE(u8,  u8,  0),
        ASSIGN_FETCH_TYPE(u16, u16, 0),
@@ -1093,18 +1096,26 @@ static int __parse_bitfield_probe_arg(const char *bf,
        return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 }
 
-static char* traceprobe_expand_dentry(const char *argv)
+static char* traceprobe_expand_dentry_file(const char *argv, bool is_dentry)
 {
        #define DENTRY_EXPAND_LEN 7  /* +0xXX() */
+       #define FILE_EXPAND_LEN   15 /* +0xXX(+0xXXX()) */
        char *new_argv;
-       int len = strlen(argv) + 1 + DENTRY_EXPAND_LEN;
+       int len, ret;
 
+       len = strlen(argv) + 1 + (is_dentry ? DENTRY_EXPAND_LEN : 
FILE_EXPAND_LEN);
        new_argv = kmalloc(len, GFP_KERNEL);
        if (!new_argv)
                return NULL;
 
-       if (snprintf(new_argv, len, "+0x%lx(%s)",
-                    offsetof(struct dentry, d_name.name), argv) >= len) {
+       if (is_dentry)
+               ret = snprintf(new_argv, len, "+0x%lx(%s)",
+                              offsetof(struct dentry, d_name.name), argv);
+       else
+               ret = snprintf(new_argv, len, "+0x%lx(+0x%lx(%s))",
+                              offsetof(struct dentry, d_name.name),
+                              offsetof(struct file, f_path.dentry), argv);
+       if (ret >= len) {
                kfree(new_argv);
                return NULL;
        }
@@ -1205,10 +1216,11 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                         parg->count);
        }
 
-       if (!strcmp("pd", parg->type->name)) {
+       if (!strcasecmp("pd", parg->type->name)) {
                char *temp;
 
-               temp = traceprobe_expand_dentry(arg);
+               temp = traceprobe_expand_dentry_file(arg,
+                                                    parg->type->name[1] == 
'd');
                if (!temp)
                        goto out;
                org_arg = arg;
@@ -1277,7 +1289,7 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                        }
                }
 
-               if (!strcmp(parg->type->name, "pd"))
+               if (!strcasecmp(parg->type->name, "pd"))
                        code++;
 
                /* If op == DEREF, replace it with STRING */
-- 
2.31.1