[dev] [st][PATCH] better plumbing on linux: find child shell cwd without shell gymnastics

[John Soros]

 config.def.h |  6 +++++
 x.c          | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/config.def.h b/config.def.h
index 87ebdbb..265a4ff 100644
--- a/config.def.h
+++ b/config.def.h
@@ -467,3 +467,9 @@ static char ascii_printable[] =
        " !\"#$%&'()*+,-./0123456789:;<=>?"
        "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
        "`abcdefghijklmnopqrstuvwxyz{|}~";
+
+/*
+ * plumber_cmd is run on mouse button 3 click, with argument set to
+ * current selection and with cwd set to the cwd of the active shell
+ */
+static char *plumber_cmd = "plumb";
diff --git a/x.c b/x.c
index 4345892..f319129 100644
--- a/x.c
+++ b/x.c
@@ -5,6 +5,9 @@
 #include <locale.h>
 #include <signal.h>
 #include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <dirent.h>
 #include <time.h>
 #include <unistd.h>
 #include <libgen.h>
@@ -644,6 +647,77 @@ xsetsel(char *str)
        setsel(str, CurrentTime);
 }

+char *
+subprocwd()
+{
+       struct dirent* dent;
+       DIR* srcdir = opendir("/proc/self/task");
+       char path[PATH_MAX];
+       FILE *fp;
+       int chpid;
+
+       if (srcdir == NULL)
+       {
+               return NULL;
+       }
+
+       while((dent = readdir(srcdir)) != NULL)
+       {
+               struct stat st;
+               char newdir[PATH_MAX];
+
+               if(strcmp(dent->d_name, ".") == 0 || strcmp(dent->d_name, "..") 
== 0)
+                       continue;
+               if (snprintf(newdir, PATH_MAX, "%s/%s", "/proc/self/task",
dent->d_name) < 0)
+                       return NULL;
+               if (stat(newdir, &st) < 0)
+                       continue;
+
+               if (S_ISDIR(st.st_mode)) break;
+       }
+       closedir(srcdir);
+       if (snprintf(path, PATH_MAX, "/proc/self/task/%s/children",
dent->d_name) < 0)
+               return NULL;
+       if (!(fp = fopen(path, "r")))
+               return NULL;
+       if (fscanf(fp, "%d", &chpid) != 1) {
+               fclose(fp);
+               return NULL;
+       }
+       fclose(fp);
+       if (snprintf(path, PATH_MAX, "/proc/%d/cwd", chpid) < 0)
+               return NULL;
+       return realpath(path, NULL);
+}
+
+void
+plumb(char *sel) {
+       if (sel == NULL)
+               return;
+       char *cwd;
+       char *cmd;
+       pid_t child;
+       cwd = subprocwd();
+       if (cwd == NULL)
+               return;
+
+       switch(child = fork()) {
+               case -1:
+                       return;
+               case 0:
+                       if (cwd == NULL)
+                               exit(1);
+                       cmd = malloc(PATH_MAX+100);
+                       if (snprintf(cmd, PATH_MAX+100, "(cd %s ; %s %s)", cwd, 
plumber_cmd,
sel) < 0)
+                               exit(1);
+                       free(cwd);
+                       execvp("sh", (char *const []){"sh", "-c", cmd, 0});
+                       exit(0);
+               default:
+                       waitpid(child, NULL, 0);
+       }
+}
+
 void
 brelease(XEvent *e)
 {
@@ -656,6 +730,8 @@ brelease(XEvent *e)
                selpaste(NULL);
        else if (e->xbutton.button == Button1)
                mousesel(e, 1);
+       else if (e->xbutton.button == Button3)
+               plumb(xsel.primary);
 }

 void