nixpkgs/pkgs/applications/networking/sniffers/wireshark/wireshark-lookup-dumpcap-in-path.patch

From 5bef9deeff8a2e4401de0f45c9701cd6f98f29d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Forsman?= <bjorn.forsman@gmail.com>
Date: Thu, 26 Nov 2015 21:03:35 +0100
Subject: [PATCH] Lookup dumpcap in PATH

NixOS patch: Look for dumpcap in PATH first, because there may be a
dumpcap wrapper that we want to use instead of the default
non-setuid dumpcap binary.

Also change execv() to execvp() because we've set argv[0] to "dumpcap"
and have to enable PATH lookup. Wireshark is not a setuid program, so
looking in PATH is not a security issue.

Signed-off-by: Franz Pletz <fpletz@fnordicwalking.de>
---
 capchild/capture_sync.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/capchild/capture_sync.c b/capchild/capture_sync.c
index 970688e..49914d5 100644
--- a/capchild/capture_sync.c
+++ b/capchild/capture_sync.c
@@ -332,7 +332,18 @@ init_pipe_args(int *argc) {
 #ifdef _WIN32
     exename = g_strdup_printf("%s\\dumpcap.exe", progfile_dir);
 #else
-    exename = g_strdup_printf("%s/dumpcap", progfile_dir);
+    /*
+     * NixOS patch: Look for dumpcap in PATH first, because there may be a
+     * dumpcap wrapper that we want to use instead of the default
+     * non-setuid dumpcap binary.
+     */
+    if (system("command -v dumpcap >/dev/null") == 0) {
+        /* Found working dumpcap */
+        exename = g_strdup_printf("dumpcap");
+    } else {
+        /* take Wireshark's absolute program path and replace "Wireshark" with "dumpcap" */
+        exename = g_strdup_printf("%s/dumpcap", progfile_dir);
+    }
 #endif
 
     /* Make that the first argument in the argument list (argv[0]). */
@@ -729,7 +740,7 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, voi
          */
         dup2(sync_pipe[PIPE_WRITE], 2);
         ws_close(sync_pipe[PIPE_READ]);
-        execv(argv[0], argv);
+        execvp(argv[0], argv);
         g_snprintf(errmsg, sizeof errmsg, "Couldn't run %s in child process: %s",
                    argv[0], g_strerror(errno));
         sync_pipe_errmsg_to_parent(2, errmsg, "");
@@ -997,7 +1008,7 @@ sync_pipe_open_command(char** argv, int *data_read_fd,
         dup2(sync_pipe[PIPE_WRITE], 2);
         ws_close(sync_pipe[PIPE_READ]);
         ws_close(sync_pipe[PIPE_WRITE]);
-        execv(argv[0], argv);
+        execvp(argv[0], argv);
         g_snprintf(errmsg, sizeof errmsg, "Couldn't run %s in child process: %s",
                    argv[0], g_strerror(errno));
         sync_pipe_errmsg_to_parent(2, errmsg, "");
-- 
2.6.3