~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/tools/bpf/bpftool/tracelog.c

Version: ~ [ linux-5.13-rc5 ] ~ [ linux-5.12.9 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.42 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.124 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.193 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.235 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.271 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.271 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2 /* Copyright (c) 2015-2017 Daniel Borkmann */
  3 /* Copyright (c) 2018 Netronome Systems, Inc. */
  4 
  5 #include <errno.h>
  6 #include <limits.h>
  7 #include <signal.h>
  8 #include <stdio.h>
  9 #include <string.h>
 10 #include <unistd.h>
 11 #include <linux/magic.h>
 12 #include <sys/fcntl.h>
 13 #include <sys/vfs.h>
 14 
 15 #include "main.h"
 16 
 17 #ifndef TRACEFS_MAGIC
 18 # define TRACEFS_MAGIC  0x74726163
 19 #endif
 20 
 21 #define _textify(x)     #x
 22 #define textify(x)      _textify(x)
 23 
 24 FILE *trace_pipe_fd;
 25 char *buff;
 26 
 27 static int validate_tracefs_mnt(const char *mnt, unsigned long magic)
 28 {
 29         struct statfs st_fs;
 30 
 31         if (statfs(mnt, &st_fs) < 0)
 32                 return -ENOENT;
 33         if ((unsigned long)st_fs.f_type != magic)
 34                 return -ENOENT;
 35 
 36         return 0;
 37 }
 38 
 39 static bool
 40 find_tracefs_mnt_single(unsigned long magic, char *mnt, const char *mntpt)
 41 {
 42         size_t src_len;
 43 
 44         if (validate_tracefs_mnt(mntpt, magic))
 45                 return false;
 46 
 47         src_len = strlen(mntpt);
 48         if (src_len + 1 >= PATH_MAX) {
 49                 p_err("tracefs mount point name too long");
 50                 return false;
 51         }
 52 
 53         strcpy(mnt, mntpt);
 54         return true;
 55 }
 56 
 57 static bool get_tracefs_pipe(char *mnt)
 58 {
 59         static const char * const known_mnts[] = {
 60                 "/sys/kernel/debug/tracing",
 61                 "/sys/kernel/tracing",
 62                 "/tracing",
 63                 "/trace",
 64         };
 65         const char *pipe_name = "/trace_pipe";
 66         const char *fstype = "tracefs";
 67         char type[100], format[32];
 68         const char * const *ptr;
 69         bool found = false;
 70         FILE *fp;
 71 
 72         for (ptr = known_mnts; ptr < known_mnts + ARRAY_SIZE(known_mnts); ptr++)
 73                 if (find_tracefs_mnt_single(TRACEFS_MAGIC, mnt, *ptr))
 74                         goto exit_found;
 75 
 76         fp = fopen("/proc/mounts", "r");
 77         if (!fp)
 78                 return false;
 79 
 80         /* Allow room for NULL terminating byte and pipe file name */
 81         snprintf(format, sizeof(format), "%%*s %%%zds %%99s %%*s %%*d %%*d\\n",
 82                  PATH_MAX - strlen(pipe_name) - 1);
 83         while (fscanf(fp, format, mnt, type) == 2)
 84                 if (strcmp(type, fstype) == 0) {
 85                         found = true;
 86                         break;
 87                 }
 88         fclose(fp);
 89 
 90         /* The string from fscanf() might be truncated, check mnt is valid */
 91         if (found && validate_tracefs_mnt(mnt, TRACEFS_MAGIC))
 92                 goto exit_found;
 93 
 94         if (block_mount)
 95                 return false;
 96 
 97         p_info("could not find tracefs, attempting to mount it now");
 98         /* Most of the time, tracefs is automatically mounted by debugfs at
 99          * /sys/kernel/debug/tracing when we try to access it. If we could not
100          * find it, it is likely that debugfs is not mounted. Let's give one
101          * attempt at mounting just tracefs at /sys/kernel/tracing.
102          */
103         strcpy(mnt, known_mnts[1]);
104         if (mount_tracefs(mnt))
105                 return false;
106 
107 exit_found:
108         strcat(mnt, pipe_name);
109         return true;
110 }
111 
112 static void exit_tracelog(int signum)
113 {
114         fclose(trace_pipe_fd);
115         free(buff);
116 
117         if (json_output) {
118                 jsonw_end_array(json_wtr);
119                 jsonw_destroy(&json_wtr);
120         }
121 
122         exit(0);
123 }
124 
125 int do_tracelog(int argc, char **argv)
126 {
127         const struct sigaction act = {
128                 .sa_handler = exit_tracelog
129         };
130         char trace_pipe[PATH_MAX];
131         size_t buff_len = 0;
132 
133         if (json_output)
134                 jsonw_start_array(json_wtr);
135 
136         if (!get_tracefs_pipe(trace_pipe))
137                 return -1;
138 
139         trace_pipe_fd = fopen(trace_pipe, "r");
140         if (!trace_pipe_fd) {
141                 p_err("could not open trace pipe: %s", strerror(errno));
142                 return -1;
143         }
144 
145         sigaction(SIGHUP, &act, NULL);
146         sigaction(SIGINT, &act, NULL);
147         sigaction(SIGTERM, &act, NULL);
148         while (1) {
149                 ssize_t ret;
150 
151                 ret = getline(&buff, &buff_len, trace_pipe_fd);
152                 if (ret <= 0) {
153                         p_err("failed to read content from trace pipe: %s",
154                               strerror(errno));
155                         break;
156                 }
157                 if (json_output)
158                         jsonw_string(json_wtr, buff);
159                 else
160                         printf("%s", buff);
161         }
162 
163         fclose(trace_pipe_fd);
164         free(buff);
165         return -1;
166 }
167 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp