instchown: honor DESTDIR

Makefile

@@ -712,9 +712,9 @@ compile instcheck.c strerr.h error.h readwrite.h hier.h
 
 instchown: \
 load instchown.o instuidgid.o fifo.o hier.o auto_qmail.o auto_split.o \
-ids.a strerr.a substdio.a error.a str.a fs.a
+ids.a strerr.a substdio.a error.a str.a env.a fs.a stralloc.a
 	./load instchown instuidgid.o fifo.o hier.o auto_qmail.o auto_split.o \
-	ids.a strerr.a substdio.a error.a str.a fs.a
+	ids.a strerr.a substdio.a error.a str.a env.a fs.a stralloc.a
 
 instchown.o: \
 compile instchown.c strerr.h error.h exit.h hier.h

instchown.c

@@ -1,7 +1,10 @@
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include "env.h"
+#include "stralloc.h"
 #include "strerr.h"
 #include "error.h"
 #include "hier.h"
@@ -10,36 +13,66 @@ extern void init_uidgid();
 
 #define FATAL "instchown: fatal: "
 
+static void die_nomem()
+{
+  strerr_die2sys(111,FATAL,"out of memory");
+}
+
+static void ddhome(stralloc *dd, const char *home)
+{
+  const char *denv = env_get("DESTDIR");
+  if (denv)
+    if (!stralloc_copys(dd,denv)) die_nomem();
+
+  if (!stralloc_catb(dd,home,strlen(home))) die_nomem();
+  if (!stralloc_0(dd)) die_nomem();
+}
+
 void h(char *home, uid_t uid, gid_t gid, int mode)
 {
+  stralloc dh = { 0 };
+  ddhome(&dh, home);
+  home=dh.s;
   if (chown(home,uid,gid) == -1)
     strerr_die4sys(111,FATAL,"unable to chown ",home,": ");
   if (chmod(home,mode) == -1)
     strerr_die4sys(111,FATAL,"unable to chmod ",home,": ");
+  free(dh.s);
 }
 
 void d(char *home, char *subdir, uid_t uid, gid_t gid, int mode)
 {
+  stralloc dh = { 0 };
+  ddhome(&dh, home);
+  home=dh.s;
   if (chdir(home) == -1)
     strerr_die4sys(111,FATAL,"unable to switch to ",home,": ");
   if (chown(subdir,uid,gid) == -1)
     strerr_die6sys(111,FATAL,"unable to chown ",home,"/",subdir,": ");
   if (chmod(subdir,mode) == -1)
     strerr_die6sys(111,FATAL,"unable to chmod ",home,"/",subdir,": ");
+  free(dh.s);
 }
 
 void p(char *home, char *fifo, uid_t uid, gid_t gid, int mode)
 {
+  stralloc dh = { 0 };
+  ddhome(&dh, home);
+  home=dh.s;
   if (chdir(home) == -1)
     strerr_die4sys(111,FATAL,"unable to switch to ",home,": ");
   if (chown(fifo,uid,gid) == -1)
     strerr_die6sys(111,FATAL,"unable to chown ",home,"/",fifo,": ");
   if (chmod(fifo,mode) == -1)
     strerr_die6sys(111,FATAL,"unable to chmod ",home,"/",fifo,": ");
+  free(dh.s);
 }
 
 void c(char *home, char *subdir, char *file, uid_t uid, gid_t gid, int mode)
 {
+  stralloc dh = { 0 };
+  ddhome(&dh, home);
+  home=dh.s;
   if (chdir(home) == -1)
     strerr_die4sys(111,FATAL,"unable to switch to ",home,": ");
   if (chdir(subdir) == -1) {
@@ -56,16 +89,21 @@ void c(char *home, char *subdir, char *file, uid_t uid, gid_t gid, int mode)
   }
   if (chmod(file,mode) == -1)
     strerr_die6sys(111,FATAL,"unable to chmod .../",subdir,"/",file,": ");
+  free(dh.s);
 }
 
 void z(char *home, char *file, int len, uid_t uid, gid_t gid, int mode)
 {
+  stralloc dh = { 0 };
+  ddhome(&dh, home);
+  home=dh.s;
   if (chdir(home) == -1)
     strerr_die4sys(111,FATAL,"unable to switch to ",home,": ");
   if (chown(file,uid,gid) == -1)
     strerr_die6sys(111,FATAL,"unable to chown ",home,"/",file,": ");
   if (chmod(file,mode) == -1)
     strerr_die6sys(111,FATAL,"unable to chmod ",home,"/",file,": ");
+  free(dh.s);
 }
 
 int main(void)