bcc/bcc-0.30.0-Revert-Fix-bashreadline-4903.patch

From 0e81f1ef9145b853745fdd56808388c9b295b1f9 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@redhat.com>
Date: Fri, 4 Oct 2024 10:01:54 +0200
Subject: [PATCH] Revert "Fix bashreadline (#4903)"

This reverts commit 706ec4fe3dbbd63f6d7adda8d8d7311afe998cfa.
---
 docker/Dockerfile.ubuntu       |  2 +-
 docker/build/Dockerfile.fedora |  2 +-
 docker/build/Dockerfile.ubuntu |  2 +-
 libbpf-tools/bashreadline.c    | 40 +++-------------------------------
 tools/bashreadline.py          | 18 +--------------
 5 files changed, 7 insertions(+), 57 deletions(-)

diff --git a/docker/Dockerfile.ubuntu b/docker/Dockerfile.ubuntu
index a6afd969..cdb52871 100644
--- a/docker/Dockerfile.ubuntu
+++ b/docker/Dockerfile.ubuntu
@@ -24,6 +24,6 @@ COPY --from=builder /root/bcc/*.deb /root/bcc/
 RUN \
   apt-get update -y && \
   DEBIAN_FRONTEND=noninteractive apt-get install -y python3 python3-pip python-is-python3 binutils libelf1 kmod llvm-12-dev && \
-  pip3 install dnslib cachetools pyelftools  && \
+  pip3 install dnslib cachetools  && \
   dpkg -i /root/bcc/*.deb && \
   apt-get clean
diff --git a/docker/build/Dockerfile.fedora b/docker/build/Dockerfile.fedora
index d135bcea..bf8c2b36 100644
--- a/docker/build/Dockerfile.fedora
+++ b/docker/build/Dockerfile.fedora
@@ -59,7 +59,7 @@ RUN dnf -y install \
 	iperf \
 	netperf
 
-RUN pip3 install pyroute2==0.5.18 netaddr==0.8.0 dnslib==0.9.14 cachetools==3.1.1 pyelftools==0.30
+RUN pip3 install pyroute2==0.5.18 netaddr==0.8.0 dnslib==0.9.14 cachetools==3.1.1
 
 RUN wget -O ruby-install-${RUBY_INSTALL_VERSION}.tar.gz \
          https://github.com/postmodern/ruby-install/archive/v${RUBY_INSTALL_VERSION}.tar.gz && \
diff --git a/docker/build/Dockerfile.ubuntu b/docker/build/Dockerfile.ubuntu
index 50f4788a..7d29b66b 100644
--- a/docker/build/Dockerfile.ubuntu
+++ b/docker/build/Dockerfile.ubuntu
@@ -81,7 +81,7 @@ done \
 && \
       apt-get -y clean'
 
-RUN pip3 install pyroute2==0.5.18 netaddr==0.8.0 dnslib==0.9.14 cachetools==3.1.1 pyelftools==0.30
+RUN pip3 install pyroute2==0.5.18 netaddr==0.8.0 dnslib==0.9.14 cachetools==3.1.1
 
 # FIXME this is faster than building from source, but it seems there is a bug
 # in probing libruby.so rather than ruby binary
diff --git a/libbpf-tools/bashreadline.c b/libbpf-tools/bashreadline.c
index 41b6a600..b069f048 100644
--- a/libbpf-tools/bashreadline.c
+++ b/libbpf-tools/bashreadline.c
@@ -90,41 +90,6 @@ static void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt)
 	warn("lost %llu events on CPU #%d\n", lost_cnt, cpu);
 }
 
-static char *find_readline_function_name(const char *bash_path)
-{
-  bool found = false;
-  int fd = -1;
-  Elf *elf = NULL;
-  Elf_Scn *scn = NULL;
-  GElf_Shdr shdr;
-
-
-  elf = open_elf(bash_path, &fd);
-
-  while ((scn = elf_nextscn(elf, scn)) != NULL && !found) {
-    gelf_getshdr(scn, &shdr);
-    if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
-      Elf_Data *data = elf_getdata(scn, NULL);
-      if (data != NULL) {
-        GElf_Sym *symtab = (GElf_Sym *) data->d_buf;
-        int sym_count = shdr.sh_size / shdr.sh_entsize;
-        for (int i = 0; i < sym_count; ++i) {
-          if(strcmp("readline_internal_teardown", elf_strptr(elf, shdr.sh_link, symtab[i].st_name)) == 0){
-            found = true;
-            break;
-          }
-        }
-    	}
-    }
-  }
-
-  close_elf(elf,fd);
-  if (found)
-    return "readline_internal_teardown";
-  else
-    return "readline";
-}
-
 static char *find_readline_so()
 {
 	const char *bash_path = "/bin/bash";
@@ -135,7 +100,7 @@ static char *find_readline_so()
 	char path[128];
 	char *result = NULL;
 
-	func_off = get_elf_func_offset(bash_path, find_readline_function_name(bash_path));
+	func_off = get_elf_func_offset(bash_path, "readline");
 	if (func_off >= 0)
 		return strdup(bash_path);
 
@@ -194,6 +159,7 @@ int main(int argc, char **argv)
 	err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
 	if (err)
 		return err;
+
 	if (libreadline_path) {
 		readline_so_path = libreadline_path;
 	} else if ((readline_so_path = find_readline_so()) == NULL) {
@@ -221,7 +187,7 @@ int main(int argc, char **argv)
 		goto cleanup;
 	}
 
-	func_off = get_elf_func_offset(readline_so_path, find_readline_function_name(readline_so_path));
+	func_off = get_elf_func_offset(readline_so_path, "readline");
 	if (func_off < 0) {
 		warn("cound not find readline in %s\n", readline_so_path);
 		goto cleanup;
diff --git a/tools/bashreadline.py b/tools/bashreadline.py
index 7e8324a2..cfbf2364 100755
--- a/tools/bashreadline.py
+++ b/tools/bashreadline.py
@@ -17,7 +17,6 @@
 # 12-Feb-2016    Allan McAleavy migrated to BPF_PERF_OUTPUT
 
 from __future__ import print_function
-from elftools.elf.elffile import ELFFile
 from bcc import BPF
 from time import strftime
 import argparse
@@ -33,19 +32,6 @@ args = parser.parse_args()
 
 name = args.shared if args.shared else "/bin/bash"
 
-
-def get_sym(filename):
-    with open(filename, 'rb') as f:
-        elf = ELFFile(f)
-        symbol_table = elf.get_section_by_name(".dynsym")
-        for symbol in symbol_table.iter_symbols():
-            if symbol.name == "readline_internal_teardown":
-                return "readline_internal_teardown"
-    return "readline"
-
-
-sym = get_sym(name)
-
 # load BPF program
 bpf_text = """
 #include <uapi/linux/ptrace.h>
@@ -77,18 +63,16 @@ int printret(struct pt_regs *ctx) {
 """
 
 b = BPF(text=bpf_text)
-b.attach_uretprobe(name=name, sym=sym, fn_name="printret")
+b.attach_uretprobe(name=name, sym="readline", fn_name="printret")
 
 # header
 print("%-9s %-7s %s" % ("TIME", "PID", "COMMAND"))
 
-
 def print_event(cpu, data, size):
     event = b["events"].event(data)
     print("%-9s %-7d %s" % (strftime("%H:%M:%S"), event.pid,
                             event.str.decode('utf-8', 'replace')))
 
-
 b["events"].open_perf_buffer(print_event)
 while 1:
     try:
-- 
2.46.0