Maxim Pugachev wrote: > In a case when the shell name is not specified (i.e. just "#!" without > a path), don't run the heavy logic that checks shell, simply return > ENOENT.
I'm not sure whether this is a reasonable thing to do. Someone with more kernel API experience will have to comment. > Also, as a tiny improvement: avoid a loop when calculating shell's > args length. It seems like there's a simpler solution to this: strlen. Also, the assignment that follows the for loop seems dead, as we know *cp will be NUL. The below diff makes that change, removes the useless if condition you noticed, and bumps a few variable initializations into the declaration block. Index: sys/kern/exec_script.c =================================================================== RCS file: /cvs/src/sys/kern/exec_script.c,v retrieving revision 1.37 diff -u -p -r1.37 exec_script.c --- sys/kern/exec_script.c 31 Dec 2015 18:55:33 -0000 1.37 +++ sys/kern/exec_script.c 10 Jan 2016 01:41:55 -0000 @@ -67,9 +67,9 @@ int exec_script_makecmds(struct proc *p, struct exec_package *epp) { - int error, hdrlinelen, shellnamelen, shellarglen; + int error, hdrlinelen, shellnamelen, shellarglen = 0; char *hdrstr = epp->ep_hdr; - char *cp, *shellname, *shellarg, *oldpnbuf; + char *cp, *shellname = NULL, *shellarg = NULL, *oldpnbuf; char **shellargp = NULL, **tmpsap; struct vnode *scriptvp; uid_t script_uid = -1; @@ -110,10 +110,6 @@ exec_script_makecmds(struct proc *p, str if (cp >= hdrstr + hdrlinelen) return ENOEXEC; - shellname = NULL; - shellarg = NULL; - shellarglen = 0; - /* strip spaces before the shell name */ for (cp = hdrstr + EXEC_SCRIPT_MAGICLEN; *cp == ' ' || *cp == '\t'; cp++) @@ -122,8 +118,6 @@ exec_script_makecmds(struct proc *p, str /* collect the shell name; remember its length for later */ shellname = cp; shellnamelen = 0; - if (*cp == '\0') - goto check_shell; for ( /* cp = cp */ ; *cp != '\0' && *cp != ' ' && *cp != '\t'; cp++) shellnamelen++; if (*cp == '\0') @@ -142,9 +136,8 @@ exec_script_makecmds(struct proc *p, str * behaviour. */ shellarg = cp; - for ( /* cp = cp */ ; *cp != '\0'; cp++) - shellarglen++; - *cp++ = '\0'; + shellarglen = strlen(shellarg); + cp += shellarglen + 1; check_shell: /*