ref: 549703b901b087653d06b5b760ff39f8b9fe8dff
parent: b5ab8a5cebc607a77a049bef64767766538d9698
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Tue Nov 25 18:33:07 EST 2025
kernel: Allow scripts as #! interpreter in sysexec() Previously, the #! interpreter needed to be a binary file as only one level of interpreter arguments was handled by sysexec(). This changes the inmplementation of sysexec() to use the new stack segment to stash interpreter arguments, allowing an arbitrary number (up to 8) of #! indirections.
--- a/sys/src/9/port/sysproc.c
+++ b/sys/src/9/port/sysproc.c
@@ -308,13 +308,10 @@
} ehdr;
char buf[256];
} u;
- char line[256];
- char *progarg[32+1];
- volatile char *args, *elem, *file0;
- char **argv, **argp, **argp0;
- char *a, *e, *charp, *file;
- int i, n, indir;
- ulong magic, ssize, nargs, nbytes;
+ char *progarg[32+1], **argv, **argp;
+ char *file, *elem, *args, *charp, *a, *e;
+ int i, n, indir, nargs;
+ ulong magic, ssize, nbytes, argc;
uintptr entry, text, data, bss, adata, abss, ebss, tstk, align;
Segment *s, *ts;
Image *img;
@@ -322,98 +319,159 @@
Chan *tc;
Fgrp *f;
- args = elem = nil;
- file0 = va_arg(list, char*);
- validaddr((uintptr)file0, 1, 0);
- argp0 = va_arg(list, char**);
- evenaddr((uintptr)argp0);
- validaddr((uintptr)argp0, 2*BY2WD, 0);
- if(*argp0 == nil)
+ file = va_arg(list, char*);
+ validaddr((uintptr)file, 1, 0);
+ argp = va_arg(list, char**);
+ evenaddr((uintptr)argp);
+ validaddr((uintptr)argp, 2*BY2WD, 0);
+ if(*argp == nil)
error(Ebadarg);
- file0 = validnamedup(file0, 1);
+
if(waserror()){- free(file0);
- free(elem);
- free(args);
/* Disaster after commit */
if(up->seg[SSEG] == nil)
pexit(up->errstr, 1);
+ qlock(&up->seglock);
+ s = up->seg[ESEG];
+ up->seg[ESEG] = nil;
+ qunlock(&up->seglock);
+ if(s != nil) {+ putseg(s);
+ flushmmu();
+ }
nexterror();
}
- align = BY2PG-1;
- indir = 0;
- file = file0;
- for(;;){- tc = namec(file, Aopen, OEXEC, 0);
- if(waserror()){- cclose(tc);
- nexterror();
- }
- if(!indir)
- kstrdup(&elem, up->genbuf);
+ file = validnamedup(file, 1);
+ if(waserror()){+ free(file);
+ nexterror();
+ }
+
+ tc = namec(file, Aopen, OEXEC, 0);
+
+ /* Last path element becomes up->text (and argv[0] for script) */
+ elem = nil;
+ kstrdup(&elem, up->genbuf);
+
+ poperror();
+ if(waserror()){+ free(elem);
+ free(file);
+ nexterror();
+ }
+ if(waserror()){+ cclose(tc);
+ nexterror();
+ }
+
+ /* Attach new stack segment, place it below current stack */
+ qlock(&up->seglock);
+ if(waserror()){+ qunlock(&up->seglock);
+ nexterror();
+ }
+ s = up->seg[SSEG];
+ do {+ tstk = s->base;
+ if(tstk <= USTKSIZE)
+ error(Enovmem);
+ } while((s = isoverlap(tstk-USTKSIZE, USTKSIZE)) != nil);
+ up->seg[ESEG] = newseg(SG_STACK | SG_NOEXEC, tstk-USTKSIZE, USTKSIZE/BY2PG);
+ qunlock(&up->seglock);
+ poperror(); /* up->seglock */
+
+ /* Setup TOS; paged in on demand */
+ tos = (Tos*)(tstk - sizeof(Tos));
+ memset(tos, 0, sizeof(Tos));
+ tos->cyclefreq = m->cyclefreq;
+
+ /* Stash interpreter args below TOS */
+ charp = (char*)tos;
+ argc = 0;
+
+ /* Read a.out(6) header */
+ for(indir=0;;indir++){n = devtab[tc->type]->read(tc, u.buf, sizeof(u.buf), 0);
if(n >= sizeof(Exec)) {magic = beswal(u.ehdr.magic);
- if(magic == AOUT_MAGIC) {- if(magic & HDR_MAGIC) {- if(n < sizeof(u.ehdr))
- error(Ebadexec);
- entry = beswav(u.ehdr.hdr[0]);
- text = UTZERO+sizeof(u.ehdr);
- } else {- entry = beswal(u.ehdr.entry);
- text = UTZERO+sizeof(Exec);
- }
- if(entry < text)
- error(Ebadexec);
- text += beswal(u.ehdr.text);
- if(text <= entry || text >= (USTKTOP-USTKSIZE))
- error(Ebadexec);
-
- switch(magic){- case S_MAGIC: /* 2MB segment alignment for amd64 */
- align = 0x1fffff;
- break;
- case P_MAGIC: /* 16K segment alignment for spim */
- case V_MAGIC: /* 16K segment alignment for mips */
- align = 0x3fff;
- break;
- case R_MAGIC: /* 64K segment alignment for arm64 */
- align = 0xffff;
- break;
- }
+ if(magic == AOUT_MAGIC)
break; /* for binary */
- }
}
- if(indir++)
+ /* Process #! /bin/sh args ... */
+ if(n <= 2 || u.buf[0] != '#' || u.buf[1] != '!'
+ || (a = memchr(u.buf+2, '\n', n-2)) == nil)
error(Ebadexec);
+ *a = '\0';
- /*
- * Process #! /bin/sh args ...
- */
- memmove(line, u.buf, n);
- if(n <= 2 || line[0] != '#' || line[1] != '!'
- || (a = memchr(line+2, '\n', n-2)) == nil)
+ /* First arg becomes complete file name */
+ if(indir == 0) {+ argc++;
+ n = strlen(file)+1;
+ charp -= n;
+ if(charp <= (char*)tstk-USTKSIZE)
+ error(Enovmem);
+ memmove(charp, file, n);
+ } else if(indir >= 8)
error(Ebadexec);
- *a = '\0';
- n = tokenize(line+2, progarg, nelem(progarg)-1);
- if(n < 1 || n >= nelem(progarg)-1)
+
+ i = tokenize(u.buf+2, progarg, nelem(progarg));
+ if(i < 1 || i >= nelem(progarg))
error(Ebadexec);
- /*
- * First arg becomes complete file name
- */
- progarg[n++] = file;
- progarg[n] = nil;
- argp0++;
- file = progarg[0];
- progarg[0] = elem;
- poperror();
+ /* Push interpreter args in reverse order */
+ argc += i;
+ while(--i >= 0) {+ a = progarg[i];
+ n = strlen(a)+1;
+ charp -= n;
+ if(charp <= (char*)tstk-USTKSIZE)
+ error(Enovmem);
+ memmove(charp, a, n);
+ }
cclose(tc);
+ poperror(); /* tc */
+
+ /* Open interpreter */
+ tc = namec(progarg[0], Aopen, OEXEC, 0);
+ if(waserror()){+ cclose(tc);
+ nexterror();
+ }
}
+ /* Process a.out(6) header */
+ if(magic & HDR_MAGIC) {+ if(n < sizeof(u.ehdr))
+ error(Ebadexec);
+ entry = beswav(u.ehdr.hdr[0]);
+ text = UTZERO+sizeof(u.ehdr);
+ } else {+ entry = beswal(u.ehdr.entry);
+ text = UTZERO+sizeof(Exec);
+ }
+ if(entry < text)
+ error(Ebadexec);
+ text += beswal(u.ehdr.text);
+ if(text <= entry || text >= (USTKTOP-USTKSIZE))
+ error(Ebadexec);
+
+ switch(magic){+ case S_MAGIC: /* 2MB segment alignment for amd64 */
+ align = 0x1fffff;
+ break;
+ case P_MAGIC: /* 16K segment alignment for spim */
+ case V_MAGIC: /* 16K segment alignment for mips */
+ align = 0x3fff;
+ break;
+ case R_MAGIC: /* 64K segment alignment for arm64 */
+ align = 0xffff;
+ break;
+ default:
+ align = BY2PG-1;
+ }
+
adata = (text+align) & ~align;
text -= UTZERO;
data = beswal(u.ehdr.data);
@@ -425,35 +483,35 @@
if(adata >= (USTKTOP-USTKSIZE) || abss >= (USTKTOP-USTKSIZE) || ebss >= (USTKTOP-USTKSIZE))
error(Ebadexec);
- /*
- * Args: pass 1: count
- */
- nbytes = sizeof(Tos); /* hole for profiling clock at top of stack (and more) */
- nargs = 0;
+ /* Replace argv[0] with script name */
if(indir){- argp = progarg;
- while(*argp != nil){- a = *argp++;
- nbytes += strlen(a) + 1;
- nargs++;
- }
+ n = strlen(charp)+1;
+ charp += n;
+ n = strlen(elem)+1;
+ charp -= n;
+ if(charp <= (char*)tstk-USTKSIZE)
+ error(Enovmem);
+ memmove(charp, elem, n);
+ argp++;
}
- argp = argp0;
- while(*argp != nil){- a = *argp++;
- if(((uintptr)argp&(BY2PG-1)) < BY2WD)
- validaddr((uintptr)argp, BY2WD, 0);
+
+ /* Count user arguments */
+ nbytes = (char*)tstk - charp;
+ for(i = 0; (a = argp[i]) != nil; i++) {validaddr((uintptr)a, 1, 0);
- e = vmemchr(a, 0, USTKSIZE);
- if(e == nil)
+ if((e = vmemchr(a, 0, USTKSIZE-nbytes)) == nil)
error(Ebadarg);
nbytes += (e - a) + 1;
if(nbytes >= USTKSIZE)
error(Enovmem);
- nargs++;
+ /* crossing page boundary? */
+ if(((uintptr)&argp[i]&(BY2PG-1)) >= BY2PG-BY2WD)
+ validaddr((uintptr)&argp[i+1], BY2WD, 0);
}
- ssize = BY2WD*(nargs+1) + ((nbytes+(BY2WD-1)) & ~(BY2WD-1));
+ argc += i;
+ ssize = BY2WD*(argc+1) + ((nbytes+(BY2WD-1)) & ~(BY2WD-1));
+
/*
* 8-byte align SP for those (e.g. sparc) that need it.
* execregs() will subtract another 4 bytes for argc.
@@ -464,87 +522,58 @@
if(PGROUND(ssize) >= USTKSIZE)
error(Enovmem);
- /*
- * Build the stack segment, putting it in kernel virtual for the moment
- */
- qlock(&up->seglock);
- if(waserror()){- qunlock(&up->seglock);
- nexterror();
- }
- s = up->seg[SSEG];
- do {- tstk = s->base;
- if(tstk <= USTKSIZE)
- error(Enovmem);
- } while((s = isoverlap(tstk-USTKSIZE, USTKSIZE)) != nil);
- up->seg[ESEG] = newseg(SG_STACK | SG_NOEXEC, tstk-USTKSIZE, USTKSIZE/BY2PG);
- qunlock(&up->seglock);
+ /* save interpreter args */
+ a = charp;
- if(waserror()){- qlock(&up->seglock);
- s = up->seg[ESEG];
- if(s != nil){- up->seg[ESEG] = nil;
- putseg(s);
- }
- nexterror();
- }
-
/*
- * Args: pass 2: assemble; the pages will be faulted in
+ * Now we know the actual stack size and argument count,
+ * copy in the strings to charp and build argv[] array.
*/
- tos = (Tos*)(tstk - sizeof(Tos));
- tos->cyclefreq = m->cyclefreq;
- tos->kcycles = 0;
- tos->pcycles = 0;
- tos->clock = 0;
-
argv = (char**)(tstk - ssize);
- charp = (char*)(tstk - nbytes);
- if(indir)
- argp = progarg;
- else
- argp = argp0;
+ charp = (char*)tstk - nbytes;
- for(i=0; i<nargs; i++){- if(indir && *argp==nil) {- indir = 0;
- argp = argp0;
- }
- *argv++ = charp + (USTKTOP-tstk);
+ i = 0;
+ if(indir) /* move interpreter args down before user args */
+ for(; i < argc && a < (char*)tos; i++) {+ n = strlen(a) + 1;
+ memmove(charp, a, n);
+ argv[i] = charp + (USTKTOP-tstk);
+ charp += n;
+ a += n;
+ }
+ for(; i < argc; i++) {a = *argp++;
- if(indir)
- e = strchr(a, 0);
- else {- if(charp >= (char*)tos)
- error(Ebadarg);
- validaddr((uintptr)a, 1, 0);
- e = vmemchr(a, 0, (char*)tos - charp);
- if(e == nil)
- error(Ebadarg);
- }
+ validaddr((uintptr)a, 1, 0);
+ if(charp >= (char*)tos
+ || (e = vmemchr(a, 0, (char*)tos-charp)) == nil)
+ error(Ebadarg);
n = (e - a) + 1;
memmove(charp, a, n);
+ argv[i] = charp + (USTKTOP-tstk);
charp += n;
}
- *argv = nil;
+ argv[i] = nil;
- /* copy args; easiest from new process's stack */
- a = (char*)(tstk - nbytes);
- n = charp - a;
- if(n > 128) /* don't waste too much space on huge arg lists */
- n = 128;
- args = smalloc(n);
- memmove(args, a, n);
- if(n>0 && args[n-1]!='\0'){+ /* Copy args for proc(3); easiest from new process's stack */
+ a = (char*)tstk - nbytes;
+ nargs = charp - a;
+ if(nargs > 128) /* don't waste too much space on huge arg lists */
+ nargs = 128;
+ if((args = malloc(nargs)) == nil)
+ error(Enomem);
+ if(waserror()){+ free(args);
+ nexterror();
+ }
+ memmove(args, a, nargs);
+ if(nargs>0 && args[nargs-1]!='\0'){/* make sure last arg is NUL-terminated */
/* put NUL at UTF-8 character boundary */
- for(i=n-1; i>0; --i)
- if(fullrune(args+i, n-i))
+ for(i=nargs-1; i>0; --i)
+ if(fullrune(args+i, nargs-i))
break;
- args[i] = 0;
- n = i+1;
+ args[i] = '\0';
+ nargs = i+1;
}
/* Attach text segment */
@@ -566,7 +595,7 @@
ts->flen = text;
img->s = ts;
unlock(img);
- poperror();
+ poperror(); /* img */
}
/*
@@ -574,8 +603,11 @@
* Free old memory.
* Special segments are maintained across exec
*/
- poperror();
qlock(&up->seglock);
+ if(waserror()){+ qunlock(&up->seglock);
+ nexterror();
+ }
for(i = SSEG; i <= BSEG; i++) {s = up->seg[i];
@@ -608,9 +640,7 @@
/* BSS. Zero fill on demand */
up->seg[BSEG] = newseg(SG_BSS, abss, (ebss - abss)>>PGSHIFT);
- /*
- * Move the stack
- */
+ /* Move the stack */
s = up->seg[ESEG];
up->seg[ESEG] = nil;
qlock(s);
@@ -620,8 +650,13 @@
qunlock(s);
up->seg[SSEG] = s;
qunlock(&up->seglock);
- poperror(); /* seglock */
+ poperror(); /* up->seglock */
+ poperror(); /* args */
+ poperror(); /* tc */
+ poperror(); /* elem, file */
+ poperror(); /* up->seg[SSEG] */
+
if(tc == img->c){/* avoid double caching */
tc->flag &= ~CCACHE;
@@ -628,14 +663,9 @@
cclunk(tc);
}
cclose(tc);
- poperror(); /* tc */
+ free(file);
- free(file0);
- poperror(); /* file0 */
-
- /*
- * Close on exec
- */
+ /* Close on exec */
if((f = up->fgrp) != nil) {for(i=0; i<=f->maxfd; i++)
fdclose(i, CCEXEC);
@@ -646,7 +676,7 @@
up->text = elem;
free(up->args);
up->args = args;
- up->nargs = n;
+ up->nargs = nargs;
up->setargs = 0;
freenotes(up);
@@ -672,7 +702,7 @@
if(up->hang)
up->procctl = Proc_stopme;
- return execregs(entry, ssize, nargs);
+ return execregs(entry, ssize, argc);
}
int
--
⑨