mirror of
https://git.FreeBSD.org/src.git
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Now kvm_getenvv() and kvm_getargv() don't need procfs(5).
MFC after: 2 weeks
This commit is contained in:
Mikolaj Golub
parent
e99272c732
commit
ee5169dc9d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=227839
@ -32,7 +32,7 @@
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.\" @(#)kvm_getprocs.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd September 27, 2003
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.Dd November 22, 2011
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.Dt KVM_GETPROCS 3
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.Os
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.Sh NAME
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@ -172,10 +172,3 @@ on failure.
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.Xr kvm_write 3
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.Sh BUGS
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These routines do not belong in the kvm interface.
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.Pp
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In order for
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.Xr kvm_getenvv 3
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to function correctly,
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.Xr procfs 5
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must be mounted on
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.Pa /proc .
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@ -72,9 +72,6 @@ __FBSDID("$FreeBSD$");
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#include <nlist.h>
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#include <kvm.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <sys/sysctl.h>
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#include <limits.h>
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@ -623,276 +620,16 @@ _kvm_realloc(kvm_t *kd, void *p, size_t n)
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return (np);
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}
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#ifndef MAX
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#define MAX(a, b) ((a) > (b) ? (a) : (b))
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#endif
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/*
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* Read in an argument vector from the user address space of process kp.
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* addr if the user-space base address of narg null-terminated contiguous
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* strings. This is used to read in both the command arguments and
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* environment strings. Read at most maxcnt characters of strings.
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* Get the command args or environment.
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*/
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static char **
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kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, u_long addr, int narg,
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int maxcnt)
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{
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char *np, *cp, *ep, *ap;
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u_long oaddr = -1;
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int len, cc;
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char **argv;
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/*
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* Check that there aren't an unreasonable number of arguments,
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* and that the address is in user space. Special test for
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* VM_MIN_ADDRESS as it evaluates to zero, but is not a simple zero
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* constant for some archs. We cannot use the pre-processor here and
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* for some archs the compiler would trigger a signedness warning.
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*/
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if (narg > 512 || addr + 1 < VM_MIN_ADDRESS + 1 || addr >= VM_MAXUSER_ADDRESS)
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return (0);
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/*
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* kd->argv : work space for fetching the strings from the target
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* process's space, and is converted for returning to caller
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*/
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if (kd->argv == 0) {
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/*
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* Try to avoid reallocs.
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*/
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kd->argc = MAX(narg + 1, 32);
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kd->argv = (char **)_kvm_malloc(kd, kd->argc *
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sizeof(*kd->argv));
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if (kd->argv == 0)
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return (0);
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} else if (narg + 1 > kd->argc) {
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kd->argc = MAX(2 * kd->argc, narg + 1);
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kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
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sizeof(*kd->argv));
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if (kd->argv == 0)
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return (0);
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}
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/*
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* kd->argspc : returned to user, this is where the kd->argv
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* arrays are left pointing to the collected strings.
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*/
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if (kd->argspc == 0) {
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kd->argspc = (char *)_kvm_malloc(kd, PAGE_SIZE);
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if (kd->argspc == 0)
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return (0);
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kd->arglen = PAGE_SIZE;
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}
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/*
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* kd->argbuf : used to pull in pages from the target process.
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* the strings are copied out of here.
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*/
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if (kd->argbuf == 0) {
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kd->argbuf = (char *)_kvm_malloc(kd, PAGE_SIZE);
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if (kd->argbuf == 0)
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return (0);
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}
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/* Pull in the target process'es argv vector */
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cc = sizeof(char *) * narg;
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if (kvm_uread(kd, kp, addr, (char *)kd->argv, cc) != cc)
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return (0);
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/*
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* ap : saved start address of string we're working on in kd->argspc
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* np : pointer to next place to write in kd->argspc
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* len: length of data in kd->argspc
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* argv: pointer to the argv vector that we are hunting around the
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* target process space for, and converting to addresses in
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* our address space (kd->argspc).
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*/
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ap = np = kd->argspc;
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argv = kd->argv;
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len = 0;
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/*
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* Loop over pages, filling in the argument vector.
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* Note that the argv strings could be pointing *anywhere* in
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* the user address space and are no longer contiguous.
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* Note that *argv is modified when we are going to fetch a string
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* that crosses a page boundary. We copy the next part of the string
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* into to "np" and eventually convert the pointer.
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*/
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while (argv < kd->argv + narg && *argv != 0) {
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/* get the address that the current argv string is on */
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addr = (u_long)*argv & ~(PAGE_SIZE - 1);
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/* is it the same page as the last one? */
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if (addr != oaddr) {
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if (kvm_uread(kd, kp, addr, kd->argbuf, PAGE_SIZE) !=
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PAGE_SIZE)
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return (0);
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oaddr = addr;
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}
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/* offset within the page... kd->argbuf */
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addr = (u_long)*argv & (PAGE_SIZE - 1);
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/* cp = start of string, cc = count of chars in this chunk */
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cp = kd->argbuf + addr;
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cc = PAGE_SIZE - addr;
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/* dont get more than asked for by user process */
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if (maxcnt > 0 && cc > maxcnt - len)
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cc = maxcnt - len;
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/* pointer to end of string if we found it in this page */
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ep = memchr(cp, '\0', cc);
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if (ep != 0)
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cc = ep - cp + 1;
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/*
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* at this point, cc is the count of the chars that we are
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* going to retrieve this time. we may or may not have found
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* the end of it. (ep points to the null if the end is known)
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*/
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/* will we exceed the malloc/realloced buffer? */
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if (len + cc > kd->arglen) {
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int off;
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char **pp;
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char *op = kd->argspc;
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kd->arglen *= 2;
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kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
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kd->arglen);
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if (kd->argspc == 0)
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return (0);
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/*
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* Adjust argv pointers in case realloc moved
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* the string space.
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*/
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off = kd->argspc - op;
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for (pp = kd->argv; pp < argv; pp++)
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*pp += off;
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ap += off;
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np += off;
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}
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/* np = where to put the next part of the string in kd->argspc*/
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/* np is kinda redundant.. could use "kd->argspc + len" */
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memcpy(np, cp, cc);
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np += cc; /* inc counters */
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len += cc;
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/*
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* if end of string found, set the *argv pointer to the
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* saved beginning of string, and advance. argv points to
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* somewhere in kd->argv.. This is initially relative
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* to the target process, but when we close it off, we set
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* it to point in our address space.
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*/
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if (ep != 0) {
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*argv++ = ap;
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ap = np;
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} else {
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/* update the address relative to the target process */
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*argv += cc;
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}
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if (maxcnt > 0 && len >= maxcnt) {
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/*
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* We're stopping prematurely. Terminate the
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* current string.
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*/
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if (ep == 0) {
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*np = '\0';
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*argv++ = ap;
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}
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break;
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}
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}
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/* Make sure argv is terminated. */
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*argv = 0;
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return (kd->argv);
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}
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static void
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ps_str_a(struct ps_strings *p, u_long *addr, int *n)
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{
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*addr = (u_long)p->ps_argvstr;
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*n = p->ps_nargvstr;
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}
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static void
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ps_str_e (struct ps_strings *p, u_long *addr, int *n)
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{
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*addr = (u_long)p->ps_envstr;
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*n = p->ps_nenvstr;
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}
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/*
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* Determine if the proc indicated by p is still active.
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* This test is not 100% foolproof in theory, but chances of
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* being wrong are very low.
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*/
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static int
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proc_verify(const struct kinfo_proc *curkp)
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{
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struct kinfo_proc newkp;
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int mib[4];
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size_t len;
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mib[0] = CTL_KERN;
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mib[1] = KERN_PROC;
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mib[2] = KERN_PROC_PID;
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mib[3] = curkp->ki_pid;
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len = sizeof(newkp);
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if (sysctl(mib, 4, &newkp, &len, NULL, 0) == -1)
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return (0);
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return (curkp->ki_pid == newkp.ki_pid &&
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(newkp.ki_stat != SZOMB || curkp->ki_stat == SZOMB));
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}
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static char **
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kvm_doargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr,
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void (*info)(struct ps_strings *, u_long *, int *))
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{
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char **ap;
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u_long addr;
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int cnt;
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static struct ps_strings arginfo;
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static u_long ps_strings;
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size_t len;
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if (ps_strings == 0) {
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len = sizeof(ps_strings);
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if (sysctlbyname("kern.ps_strings", &ps_strings, &len, NULL,
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0) == -1)
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ps_strings = PS_STRINGS;
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}
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/*
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* Pointers are stored at the top of the user stack.
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*/
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if (kp->ki_stat == SZOMB ||
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kvm_uread(kd, kp, ps_strings, (char *)&arginfo,
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sizeof(arginfo)) != sizeof(arginfo))
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return (0);
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(*info)(&arginfo, &addr, &cnt);
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if (cnt == 0)
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return (0);
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ap = kvm_argv(kd, kp, addr, cnt, nchr);
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/*
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* For live kernels, make sure this process didn't go away.
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*/
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if (ap != 0 && ISALIVE(kd) && !proc_verify(kp))
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ap = 0;
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return (ap);
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}
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/*
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* Get the command args. This code is now machine independent.
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*/
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char **
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kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
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kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
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{
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int oid[4];
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int i;
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size_t bufsz;
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static unsigned long buflen;
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static int buflen;
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static char *buf, *p;
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static char **bufp;
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static int argc;
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@ -903,24 +640,28 @@ kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
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return (0);
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}
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if (!buflen) {
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bufsz = sizeof(buflen);
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i = sysctlbyname("kern.ps_arg_cache_limit",
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&buflen, &bufsz, NULL, 0);
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if (i == -1) {
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buflen = 0;
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} else {
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buf = malloc(buflen);
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if (buf == NULL)
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buflen = 0;
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argc = 32;
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bufp = malloc(sizeof(char *) * argc);
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if (nchr == 0 || nchr > ARG_MAX)
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nchr = ARG_MAX;
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if (buflen == 0) {
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buf = malloc(nchr);
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if (buf == NULL) {
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_kvm_err(kd, kd->program, "cannot allocate memory");
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return (0);
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}
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buflen = nchr;
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argc = 32;
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bufp = malloc(sizeof(char *) * argc);
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} else if (nchr > buflen) {
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p = realloc(buf, nchr);
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if (p != NULL) {
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buf = p;
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buflen = nchr;
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}
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}
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if (buf != NULL) {
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oid[0] = CTL_KERN;
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oid[1] = KERN_PROC;
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oid[2] = KERN_PROC_ARGS;
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oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
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oid[3] = kp->ki_pid;
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bufsz = buflen;
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i = sysctl(oid, 4, buf, &bufsz, 0, 0);
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@ -940,65 +681,17 @@ kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
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return (bufp);
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}
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}
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if (kp->ki_flag & P_SYSTEM)
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return (NULL);
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return (kvm_doargv(kd, kp, nchr, ps_str_a));
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return (NULL);
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}
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char **
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kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
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{
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return (kvm_argv(kd, kp, 0, nchr));
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}
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char **
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kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
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{
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return (kvm_doargv(kd, kp, nchr, ps_str_e));
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}
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/*
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* Read from user space. The user context is given by p.
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*/
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ssize_t
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kvm_uread(kvm_t *kd, const struct kinfo_proc *kp, u_long uva, char *buf,
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size_t len)
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{
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char *cp;
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char procfile[MAXPATHLEN];
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ssize_t amount;
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int fd;
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if (!ISALIVE(kd)) {
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_kvm_err(kd, kd->program,
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"cannot read user space from dead kernel");
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return (0);
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}
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sprintf(procfile, "/proc/%d/mem", kp->ki_pid);
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fd = open(procfile, O_RDONLY, 0);
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if (fd < 0) {
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_kvm_err(kd, kd->program, "cannot open %s", procfile);
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return (0);
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}
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cp = buf;
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while (len > 0) {
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errno = 0;
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if (lseek(fd, (off_t)uva, 0) == -1 && errno != 0) {
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_kvm_err(kd, kd->program, "invalid address (%lx) in %s",
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uva, procfile);
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break;
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}
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amount = read(fd, cp, len);
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if (amount < 0) {
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_kvm_syserr(kd, kd->program, "error reading %s",
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procfile);
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break;
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}
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if (amount == 0) {
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_kvm_err(kd, kd->program, "EOF reading %s", procfile);
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break;
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}
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cp += amount;
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uva += amount;
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len -= amount;
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}
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close(fd);
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return ((ssize_t)(cp - buf));
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return (kvm_argv(kd, kp, 1, nchr));
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}
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