[hackers] [scc] [driver] use random filenames for temporary object || Quentin Rameau

[git]

commit fe098f45fcb3847ae558bb7027c7701b6d2bc15f
Author:     Quentin Rameau <quinq@fifth.space>
AuthorDate: Thu Jun 30 17:21:46 2016 +0200
Commit:     Quentin Rameau <quinq@fifth.space>
CommitDate: Thu Jun 30 17:37:04 2016 +0200

    [driver] use random filenames for temporary object
    
    Those are generated in the form scc-XXXXXX and written in PWD or TMPDIR
    if it is set.

diff --git a/driver/posix/scc.c b/driver/posix/scc.c
index a68b796..a1cf9a8 100644
--- a/driver/posix/scc.c
+++ b/driver/posix/scc.c
@@ -1,5 +1,6 @@
 /* See LICENSE file for copyright and license details. */
 #define _POSIX_SOURCE
+#define _XOPEN_SOURCE 500
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -48,7 +49,9 @@ static struct tool {
 };
 
 char *argv0;
-static char *arch, *outfile;
+static char *arch, *objfile, *outfile;
+static char *tmpdir;
+static size_t tmpdirln;
 static struct items objtmp, objout;
 static int Eflag, Sflag, cflag, kflag, sflag;
 
@@ -136,28 +139,31 @@ inittool(int tool)
 static char *
 outfilename(char *path, char *ext)
 {
-       char *new, *name, *dot;
-       size_t newsz, nameln;
-       int n;
-
-       if (!(name = strrchr(path, '/')))
-               name = path;
-       else
-               ++name;
-
-       nameln = strlen(name);
-
-       if (!(dot = strrchr(name, '.')))
-               dot = &name[nameln];
-
-       nameln = nameln - strlen(dot);
-       newsz  = nameln + strlen(ext) + 1 + 1;
+       char *new, *fmt, *p;
+       size_t newsz, pathln;
+       int tmpfd, n;
+
+       if (path) {
+               fmt = "%.0s%.*4$s.%s";
+               if (p = strrchr(path, '/'))
+                       path = p + 1;
+               pathln = strlen(path);
+               if (p = strrchr(path, '.'))
+                       pathln -= strlen(p);
+               newsz = pathln + 1 + strlen(ext) + 1;
+       } else {
+               fmt = "%s/%s";
+               path = "scc-XXXXXX";
+               newsz = tmpdirln + 1 + strlen(path) + 1;
+       }
 
        new = xmalloc(newsz);
-
-       n = snprintf(new, newsz, "%.*s.%s", nameln, name, ext);
+       n = snprintf(new, newsz, fmt, tmpdir, path, ext, pathln);
        if (n < 0 || n >= newsz)
                die("scc: wrong output filename");
+       if ((tmpfd = mkstemp(new)) < 0 && errno != EINVAL)
+               die("scc: could not create output file");
+       close(tmpfd);
 
        return new;
 }
@@ -184,8 +190,13 @@ settool(int tool, char *infile, int nexttool)
                addarg(tool, t->outfile);
                break;
        case AS:
-               t->outfile = (cflag && outfile) ? outfile :
-                            outfilename(infile, "o");
+               if (cflag && outfile) {
+                       objfile = outfile;
+               } else {
+                       objfile = (cflag || kflag) ? infile : NULL;
+                       objfile = outfilename(objfile, "o");
+               }
+               t->outfile = xstrdup(objfile);
                addarg(tool, t->outfile);
                break;
        case LD:
@@ -290,6 +301,8 @@ validatetools(void)
                            !WIFEXITED(st) || WEXITSTATUS(st) != 0) {
                                failure = 1;
                                failed = tool;
+                               free(objfile);
+                               objfile = NULL;
                        }
                        if (tool >= failed && t->outfile)
                                unlink(t->outfile);
@@ -348,7 +361,7 @@ build(char *file)
        }
 
        if (validatetools())
-               newitem(objs, outfilename(file, "o"));
+               newitem(objs, objfile);
 }
 
 static void
@@ -433,6 +446,10 @@ main(int argc, char *argv[])
        if (Eflag && (Sflag || kflag) || argc > 1 && cflag && outfile || !argc)
                usage();
 
+       if (!(tmpdir = getenv("TMPDIR")) || !tmpdir[0])
+               tmpdir = ".";
+       tmpdirln = strlen(tmpdir);
+
        for (; *argv; ++argv)
                build(*argv);