040362e379
. make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
#define _SYSTEM 1
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#include <minix/type.h>
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#include <minix/const.h>
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#include <sys/param.h>
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#include <assert.h>
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#include <unistd.h>
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#include <errno.h>
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#include <libexec.h>
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#include <string.h>
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#include <assert.h>
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#include <minix/ipc.h>
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#include <minix/com.h>
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#include <minix/callnr.h>
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#include <machine/elf.h>
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void libexec_patch_ptr(char stack[ARG_MAX], vir_bytes base)
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{
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/* When doing an exec(name, argv, envp) call, the user builds up a stack
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* image with arg and env pointers relative to the start of the stack. Now
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* these pointers must be relocated, since the stack is not positioned at
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* address 0 in the user's address space.
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*/
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char **ap, flag;
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vir_bytes v;
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flag = 0; /* counts number of 0-pointers seen */
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ap = (char **) stack; /* points initially to 'nargs' */
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ap++; /* now points to argv[0] */
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while (flag < 2) {
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if (ap >= (char **) &stack[ARG_MAX]) return; /* too bad */
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if (*ap != NULL) {
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v = (vir_bytes) *ap; /* v is relative pointer */
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v += base; /* relocate it */
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*ap = (char *) v; /* put it back */
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} else {
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flag++;
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}
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ap++;
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}
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}
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int libexec_pm_newexec(endpoint_t proc_e, struct exec_info *e)
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{
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int r;
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message m;
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m.m_type = PM_NEWEXEC;
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m.EXC_NM_PROC = proc_e;
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m.EXC_NM_PTR = (char *)e;
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if ((r = sendrec(PM_PROC_NR, &m)) != OK) return(r);
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e->allow_setuid = !!(m.m1_i2 & EXC_NM_RF_ALLOW_SETUID);
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return(m.m_type);
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}
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