libbpf tcptop: Fix PID column alignment when pids are large (iovisor#…

…5004) Fix PID column alignment when PIDs are large in libbpf-tools/tcptop: Check the maximum width of the PIDs on the system and adjust the format to avoid column misalignment: PID COMM LADDR RADDR RX_KB TX_KB 1987802 wget 127.0.0.1:44960 127.0.0.1:443 6 0 1987815 wget 127.0.0.1:44968 127.0.0.1:443 6 0 2770 stunnel 127.0.0.1:51460 127.0.0.1:80 4 0 2770 stunnel 127.0.0.1:51452 127.0.0.1:80 4 0 1936412 sshd 10.71.56.137:22 10.71.8.14:45682 0 2 1987805 curl 127.0.0.1:44964 127.0.0.1:443 1 0 1987818 curl 127.0.0.1:44972 127.0.0.1:443 1 0 2770 stunnel 127.0.0.1:51456 127.0.0.1:80 0 0 2770 stunnel 127.0.0.1:51464 127.0.0.1:80 0 0 1918977 sshd 10.71.56.137:22 10.71.8.14:51046 0 0 Also fix the alignment of the "TX_KB" label by moving the trailing "\n" character from it to the format string Also add libbpf-tools/tcptop_example.txt documenting the example. Signed-off-by: Bernhard Kaindl <[email protected]>
ego · May 19, 2024 · b0b4239 · b0b4239
1 parent 5bc97bb
commit b0b4239
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Showing 2 changed files with 81 additions and 8 deletions.
diff --git a/libbpf-tools/tcptop.c b/libbpf-tools/tcptop.c
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
 
 /*
- * tcptop Trace sending and received operation over IP.
+ * tcptop: Summarize the top active TCP sessions - like top, but for TCP
  * Copyright (c) 2022 Francis Laniel <[email protected]>
  *
  * Based on tcptop(8) from BCC by Brendan Gregg.
@@ -57,7 +57,7 @@ const char *argp_program_version = "tcptop 0.1";
 const char *argp_program_bug_address =
  "https://github.com/iovisor/bcc/tree/master/libbpf-tools";
 const char argp_program_doc[] =
-"Trace sending and received operation over IP.\n"
+"Summarize the top active TCP sessions - like top, but for TCP\n"
 "\n"
 "USAGE: tcptop [-h] [-p PID] [interval] [count]\n"
 "\n"
@@ -224,6 +224,12 @@ static int print_stat(struct tcptop_bpf *obj)
  int fd = bpf_map__fd(obj->maps.ip_map);
  int rows = 0;
  bool ipv6_header_printed = false;
+ int pid_max_fd = open("/proc/sys/kernel/pid_max", O_RDONLY);
+ int pid_maxlen = read(pid_max_fd, buf, sizeof buf) - 1;
+
+ if (pid_maxlen < 6)
+ pid_maxlen = 6;
+ close(pid_max_fd);
 
  if (!no_summary) {
  f = fopen("/proc/loadavg", "r");
@@ -258,8 +264,9 @@ static int print_stat(struct tcptop_bpf *obj)
  rows++;
  }
 
- printf("%-6s %-12s %-21s %-21s %6s %6s", "PID", "COMM", "LADDR", "RADDR",
- "RX_KB", "TX_KB\n");
+ printf("%-*s %-12s %-21s %-21s %6s %6s\n",
+ pid_maxlen, "PID", "COMM", "LADDR", "RADDR",
+ "RX_KB", "TX_KB");
 
  qsort(infos, rows, sizeof(struct info_t), sort_column);
  rows = rows < output_rows ? rows : output_rows;
@@ -273,8 +280,9 @@ static int print_stat(struct tcptop_bpf *obj)
  /* Width to fit IPv6 plus port. */
  column_width = 51;
  if (!ipv6_header_printed) {
- printf("\n%-6s %-12s %-51s %-51s %6s %6s", "PID", "COMM", "LADDR6",
- "RADDR6", "RX_KB", "TX_KB\n");
+ printf("\n%-*s %-12s %-51s %-51s %6s %6s\n",
+ pid_maxlen, "PID", "COMM", "LADDR6",
+ "RADDR6", "RX_KB", "TX_KB");
  ipv6_header_printed = true;
  }
  }
@@ -298,8 +306,8 @@ static int print_stat(struct tcptop_bpf *obj)
  snprintf(saddr_port, size, "%s:%d", saddr, key->lport);
  snprintf(daddr_port, size, "%s:%d", daddr, key->dport);
 
- printf("%-6d %-12.12s %-*s %-*s %6ld %6ld\n",
- key->pid, key->name,
+ printf("%-*d %-12.12s %-*s %-*s %6ld %6ld\n",
+ pid_maxlen, key->pid, key->name,
  column_width, saddr_port,
  column_width, daddr_port,
  value->received / 1024, value->sent / 1024);

diff --git a/libbpf-tools/tcptop_example.txt b/libbpf-tools/tcptop_example.txt
@@ -0,0 +1,65 @@
+Documentation of tcptop (the Linux BPF CO-RE version).
+It is usually shipped as libbpf-tcptop.
+
+
+Description:
+Trace sending and received operation over IP.
+
+Example output:
+
+# ./tcptop
+12:20:00 loadavg: 0.00 0.00 0.00 1/407 1987822
+
+PID COMM LADDR RADDR RX_KB TX_KB
+1987802 wget 127.0.0.1:44960 127.0.0.1:443 6 0
+1987815 wget 127.0.0.1:44968 127.0.0.1:443 6 0
+2770 stunnel 127.0.0.1:51460 127.0.0.1:80 4 0
+2770 stunnel 127.0.0.1:51452 127.0.0.1:80 4 0
+1936412 sshd 10.71.56.137:22 10.71.8.14:45682 0 2
+1987805 curl 127.0.0.1:44964 127.0.0.1:443 1 0
+1987818 curl 127.0.0.1:44972 127.0.0.1:443 1 0
+2770 stunnel 127.0.0.1:51456 127.0.0.1:80 0 0
+2770 stunnel 127.0.0.1:51464 127.0.0.1:80 0 0
+1918977 sshd 10.71.56.137:22 10.71.8.14:51046 0 0
+
+PID COMM LADDR6 RADDR6 RX_KB TX_KB
+2770 stunnel ::ffff:127.0.0.1:443 ::ffff:127.0.0.1:44960 0 6
+2770 stunnel ::ffff:127.0.0.1:443 ::ffff:127.0.0.1:44968 0 6
+2158 server ::ffff:127.0.0.1:80 ::ffff:127.0.0.1:51452 0 4
+2158 server ::ffff:127.0.0.1:80 ::ffff:127.0.0.1:51460 0 4
+2770 stunnel ::ffff:127.0.0.1:443 ::ffff:127.0.0.1:44964 0 1
+2770 stunnel ::ffff:127.0.0.1:443 ::ffff:127.0.0.1:44972 0 1
+2158 server ::ffff:127.0.0.1:80 ::ffff:127.0.0.1:51464 0 0
+2158 server ::ffff:127.0.0.1:80 ::ffff:127.0.0.1:51456 0 0
+
+USAGE message:
+
+# ./tcptop -h
+Trace sending and received operation over IP.
+
+USAGE: tcptop [-h] [-p PID] [interval] [count]
+
+EXAMPLES:
+ tcptop # TCP top, refresh every 1s
+ tcptop -p 1216 # only trace PID 1216
+ tcptop -c path # only trace the given cgroup path
+ tcptop 5 10 # 5s summaries, 10 times
+
+ -4, --ipv4 trace IPv4 family only
+ -6, --ipv6 trace IPv6 family only
+ -c, --cgroup=/sys/fs/cgroup/unified
+ Trace process in cgroup path
+ -C, --noclear Don't clear the screen
+ -p, --pid=PID Process ID to trace
+ -r, --rows=ROWS Maximum rows to print, default 20
+ -s, --sort=SORT Sort columns, default all [all, sent, received]
+ -S, --nosummary Skip system summary line
+ -v, --verbose Verbose debug output
+ -?, --help Give this help list
+ --usage Give a short usage message
+ -V, --version Print program version
+
+Mandatory or optional arguments to long options are also mandatory or optional
+for any corresponding short options.
+
+Report bugs to https://github.com/iovisor/bcc/tree/master/libbpf-tools.