/*===========================================================================*
* do_exec *
*===========================================================================*/
int do_exec()
{
kipc_msg_t m;
int r;
m.m_type = PM_EXEC;
m.PM_PROC = mp->mp_endpoint;
m.PM_PATH = m_in.exec_name;
m.PM_PATH_LEN = m_in.exec_len;
m.PM_FRAME = m_in.stack_ptr;
m.PM_FRAME_LEN = m_in.stack_bytes;
tell_fs(mp, &m);
/* Do not reply */
return SUSPEND;
}
/*===========================================================================*
* do_stime *
*===========================================================================*/
PUBLIC int do_stime()
{
/* Perform the stime(tp) system call. Retrieve the system's uptime (ticks
* since boot) and store the time in seconds at system boot in the global
* variable 'boottime'.
*/
clock_t uptime;
int s;
if (mp->mp_effuid != SUPER_USER) {
return(EPERM);
}
if ( (s=getuptime(&uptime)) != OK)
panic(__FILE__,"do_stime couldn't get uptime", s);
boottime = (long) m_in.stime - (uptime/HZ);
/* Also inform FS about the new system time. */
tell_fs(STIME, boottime, 0, 0);
return(OK);
}
/*===========================================================================*
* do_exec *
*===========================================================================*/
PUBLIC int do_exec()
{
/* Perform the execve(name, argv, envp) call. The user library builds a
* complete stack image, including pointers, args, environ, etc. The stack
* is copied to a buffer inside MM, and then to the new core image.
*/
register struct mproc *rmp;
struct mproc *sh_mp;
int m, r, fd, ft, sn;
static char mbuf[ARG_MAX]; /* buffer for stack and zeroes */
static char name_buf[PATH_MAX]; /* the name of the file to exec */
char *new_sp, *basename;
vir_bytes src, dst, text_bytes, data_bytes, bss_bytes, stk_bytes, vsp;
phys_bytes tot_bytes; /* total space for program, including gap */
long sym_bytes;
vir_clicks sc;
struct stat s_buf;
vir_bytes pc;
/* Do some validity checks. */
rmp = mp;
stk_bytes = (vir_bytes) stack_bytes;
if (stk_bytes > ARG_MAX) return(ENOMEM); /* stack too big */
if (exec_len <= 0 || exec_len > PATH_MAX) return(EINVAL);
/* Get the exec file name and see if the file is executable. */
src = (vir_bytes) exec_name;
dst = (vir_bytes) name_buf;
r = sys_copy(who, D, (phys_bytes) src,
MM_PROC_NR, D, (phys_bytes) dst, (phys_bytes) exec_len);
if (r != OK) return(r); /* file name not in user data segment */
tell_fs(CHDIR, who, FALSE, 0); /* switch to the user's FS environ. */
fd = allowed(name_buf, &s_buf, X_BIT); /* is file executable? */
if (fd < 0) return(fd); /* file was not executable */
/* Read the file header and extract the segment sizes. */
sc = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
m = read_header(fd, &ft, &text_bytes, &data_bytes, &bss_bytes,
&tot_bytes, &sym_bytes, sc, &pc);
if (m < 0) {
close(fd); /* something wrong with header */
return(ENOEXEC);
}
/* Fetch the stack from the user before destroying the old core image. */
src = (vir_bytes) stack_ptr;
dst = (vir_bytes) mbuf;
r = sys_copy(who, D, (phys_bytes) src,
MM_PROC_NR, D, (phys_bytes) dst, (phys_bytes)stk_bytes);
if (r != OK) {
close(fd); /* can't fetch stack (e.g. bad virtual addr) */
return(EACCES);
}
/* Can the process' text be shared with that of one already running? */
sh_mp = find_share(rmp, s_buf.st_ino, s_buf.st_dev, s_buf.st_ctime);
/* Allocate new memory and release old memory. Fix map and tell kernel. */
r = new_mem(sh_mp, text_bytes, data_bytes, bss_bytes, stk_bytes, tot_bytes);
if (r != OK) {
close(fd); /* insufficient core or program too big */
return(r);
}
/* Save file identification to allow it to be shared. */
rmp->mp_ino = s_buf.st_ino;
rmp->mp_dev = s_buf.st_dev;
rmp->mp_ctime = s_buf.st_ctime;
/* Patch up stack and copy it from MM to new core image. */
vsp = (vir_bytes) rmp->mp_seg[S].mem_vir << CLICK_SHIFT;
vsp += (vir_bytes) rmp->mp_seg[S].mem_len << CLICK_SHIFT;
vsp -= stk_bytes;
patch_ptr(mbuf, vsp);
src = (vir_bytes) mbuf;
r = sys_copy(MM_PROC_NR, D, (phys_bytes) src,
who, D, (phys_bytes) vsp, (phys_bytes)stk_bytes);
if (r != OK) panic("do_exec stack copy err", NO_NUM);
/* Read in text and data segments. */
if (sh_mp != NULL) {
lseek(fd, (off_t) text_bytes, SEEK_CUR); /* shared: skip text */
} else {
load_seg(fd, T, text_bytes);
}
load_seg(fd, D, data_bytes);
#if (SHADOWING == 1)
if (lseek(fd, (off_t)sym_bytes, SEEK_CUR) == (off_t) -1) ; /* error */
if (relocate(fd, (unsigned char *)mbuf) < 0) ; /* error */
pc += (vir_bytes) rp->mp_seg[T].mem_vir << CLICK_SHIFT;
#endif
close(fd); /* don't need exec file any more */
/* Take care of setuid/setgid bits. */
if ((rmp->mp_flags & TRACED) == 0) { /* suppress if tracing */
if (s_buf.st_mode & I_SET_UID_BIT) {
rmp->mp_effuid = s_buf.st_uid;
tell_fs(SETUID,who, (int)rmp->mp_realuid, (int)rmp->mp_effuid);
}
if (s_buf.st_mode & I_SET_GID_BIT) {
rmp->mp_effgid = s_buf.st_gid;
tell_fs(SETGID,who, (int)rmp->mp_realgid, (int)rmp->mp_effgid);
}
}
/* Save offset to initial argc (for ps) */
rmp->mp_procargs = vsp;
/* Fix 'mproc' fields, tell kernel that exec is done, reset caught sigs. */
for (sn = 1; sn <= _NSIG; sn++) {
if (sigismember(&rmp->mp_catch, sn)) {
sigdelset(&rmp->mp_catch, sn);
rmp->mp_sigact[sn].sa_handler = SIG_DFL;
sigemptyset(&rmp->mp_sigact[sn].sa_mask);
}
}
rmp->mp_flags &= ~SEPARATE; /* turn off SEPARATE bit */
rmp->mp_flags |= ft; /* turn it on for separate I & D files */
new_sp = (char *) vsp;
tell_fs(EXEC, who, 0, 0); /* allow FS to handle FD_CLOEXEC files */
/* System will save command line for debugging, ps(1) output, etc. */
basename = strrchr(name_buf, '/');
if (basename == NULL) basename = name_buf;
else basename++;
sys_exec(who, new_sp, rmp->mp_flags & TRACED, basename, pc);
return(OK);
}
/*===========================================================================*
* do_fork *
*===========================================================================*/
PUBLIC int do_fork()
{
/* The process pointed to by 'mp' has forked. Create a child process. */
register struct mproc *rmp; /* pointer to parent */
register struct mproc *rmc; /* pointer to child */
pid_t new_pid;
static int next_child;
int i, n = 0, r, s;
endpoint_t child_ep;
message m;
/* If tables might fill up during FORK, don't even start since recovery half
* way through is such a nuisance.
*/
rmp = mp;
if ((procs_in_use == NR_PROCS) ||
(procs_in_use >= NR_PROCS-LAST_FEW && rmp->mp_effuid != 0))
{
printf("PM: warning, process table is full!\n");
return(EAGAIN);
}
/* Find a slot in 'mproc' for the child process. A slot must exist. */
do {
next_child = (next_child+1) % NR_PROCS;
n++;
} while((mproc[next_child].mp_flags & IN_USE) && n <= NR_PROCS);
if(n > NR_PROCS)
panic(__FILE__,"do_fork can't find child slot", NO_NUM);
if(next_child < 0 || next_child >= NR_PROCS
|| (mproc[next_child].mp_flags & IN_USE))
panic(__FILE__,"do_fork finds wrong child slot", next_child);
/* Memory part of the forking. */
if((s=vm_fork(rmp->mp_endpoint, next_child, &child_ep)) != OK) {
printf("PM: vm_fork failed: %d\n", s);
return s;
}
/* PM may not fail fork after call to vm_fork(), as VM calls sys_fork(). */
rmc = &mproc[next_child];
/* Set up the child and its memory map; copy its 'mproc' slot from parent. */
procs_in_use++;
*rmc = *rmp; /* copy parent's process slot to child's */
rmc->mp_parent = who_p; /* record child's parent */
if (!(rmc->mp_trace_flags & TO_TRACEFORK)) {
rmc->mp_tracer = NO_TRACER; /* no tracer attached */
rmc->mp_trace_flags = 0;
sigemptyset(&rmc->mp_sigtrace);
}
/* inherit only these flags */
rmc->mp_flags &= (IN_USE|PRIV_PROC|DELAY_CALL);
rmc->mp_child_utime = 0; /* reset administration */
rmc->mp_child_stime = 0; /* reset administration */
rmc->mp_exitstatus = 0;
rmc->mp_sigstatus = 0;
rmc->mp_endpoint = child_ep; /* passed back by VM */
for (i = 0; i < NR_ITIMERS; i++)
rmc->mp_interval[i] = 0; /* reset timer intervals */
/* Find a free pid for the child and put it in the table. */
new_pid = get_free_pid();
rmc->mp_pid = new_pid; /* assign pid to child */
m.m_type = PM_FORK;
m.PM_PROC = rmc->mp_endpoint;
m.PM_PPROC = rmp->mp_endpoint;
m.PM_CPID = rmc->mp_pid;
tell_fs(rmc, &m);
/* Tell the tracer, if any, about the new child */
if (rmc->mp_tracer != NO_TRACER)
sig_proc(rmc, SIGSTOP, TRUE /*trace*/);
/* Do not reply until FS is ready to process the fork
* request
*/
return SUSPEND;
}
/*===========================================================================*
* do_getset *
*===========================================================================*/
PUBLIC int do_getset()
{
/* Handle GETUID, GETGID, GETPID, GETPGRP, SETUID, SETGID, SETSID. The four
* GETs and SETSID return their primary results in 'r'. GETUID, GETGID, and
* GETPID also return secondary results (the effective IDs, or the parent
* process ID) in 'reply_res2', which is returned to the user.
*/
register struct mproc *rmp = mp;
register int r;
switch(call_nr) {
case GETUID:
r = rmp->mp_realuid;
rmp->mp_reply.reply_res2 = rmp->mp_effuid;
break;
case GETGID:
r = rmp->mp_realgid;
rmp->mp_reply.reply_res2 = rmp->mp_effgid;
break;
case GETPID:
r = mproc[who].mp_pid;
rmp->mp_reply.reply_res2 = mproc[rmp->mp_parent].mp_pid;
break;
case SETUID:
if (rmp->mp_realuid != (uid_t) m_in.usr_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
rmp->mp_realuid = (uid_t) m_in.usr_id;
rmp->mp_effuid = (uid_t) m_in.usr_id;
tell_fs(SETUID, who, rmp->mp_realuid, rmp->mp_effuid);
r = OK;
break;
case SETGID:
if (rmp->mp_realgid != (gid_t) m_in.grp_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
rmp->mp_realgid = (gid_t) m_in.grp_id;
rmp->mp_effgid = (gid_t) m_in.grp_id;
tell_fs(SETGID, who, rmp->mp_realgid, rmp->mp_effgid);
r = OK;
break;
case SETSID:
if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
rmp->mp_procgrp = rmp->mp_pid;
tell_fs(SETSID, who, 0, 0);
/* fall through */
case GETPGRP:
r = rmp->mp_procgrp;
break;
default:
r = EINVAL;
break;
}
return(r);
}
/*===========================================================================*
* do_fork *
*===========================================================================*/
PUBLIC int do_fork()
{
/* The process pointed to by 'mp' has forked. Create a child process. */
register struct mproc *rmp; /* pointer to parent */
register struct mproc *rmc; /* pointer to child */
int i, child_nr, t;
char *sptr, *dptr;
long prog_bytes;
phys_clicks prog_clicks, child_base;
long parent_abs, child_abs;
extern phys_clicks alloc_mem();
/* If tables might fill up during FORK, don't even start since recovery half
* way through is such a nuisance.
*/
rmp = mp;
if (procs_in_use == NR_PROCS) return(EAGAIN);
if (procs_in_use >= NR_PROCS - LAST_FEW && rmp->mp_effuid != 0)return(EAGAIN);
/* Determine how much memory to allocate. */
prog_clicks = (phys_clicks) rmp->mp_seg[T].mem_len + rmp->mp_seg[D].mem_len +
rmp->mp_seg[S].mem_len;
#ifdef i8088
prog_clicks += rmp->mp_seg[S].mem_vir - rmp->mp_seg[D].mem_len; /* gap too */
#endif
prog_bytes = (long) prog_clicks << CLICK_SHIFT;
if ( (child_base = alloc_mem(prog_clicks)) == NO_MEM) return(EAGAIN);
/* Create a copy of the parent's core image for the child. */
child_abs = (long) child_base << CLICK_SHIFT;
parent_abs = (long) rmp->mp_seg[T].mem_phys << CLICK_SHIFT;
i = mem_copy(ABS, 0, parent_abs, ABS, 0, child_abs, prog_bytes);
if ( i < 0) panic("do_fork can't copy", i);
/* Find a slot in 'mproc' for the child process. A slot must exist. */
for (rmc = &mproc[0]; rmc < &mproc[NR_PROCS]; rmc++)
if ( (rmc->mp_flags & IN_USE) == 0) break;
/* Set up the child and its memory map; copy its 'mproc' slot from parent. */
child_nr = rmc - mproc; /* slot number of the child */
procs_in_use++;
sptr = (char *) rmp; /* pointer to parent's 'mproc' slot */
dptr = (char *) rmc; /* pointer to child's 'mproc' slot */
i = sizeof(struct mproc); /* number of bytes in a proc slot. */
while (i--) *dptr++ = *sptr++;/* copy from parent slot to child's */
rmc->mp_parent = who; /* record child's parent */
rmc->mp_seg[T].mem_phys = child_base;
rmc->mp_seg[D].mem_phys = child_base + rmc->mp_seg[T].mem_len;
rmc->mp_seg[S].mem_phys = rmc->mp_seg[D].mem_phys +
(rmp->mp_seg[S].mem_phys - rmp->mp_seg[D].mem_phys);
rmc->mp_exitstatus = 0;
rmc->mp_sigstatus = 0;
/* Find a free pid for the child and put it in the table. */
do {
t = 0; /* 't' = 0 means pid still free */
next_pid = (next_pid < 30000 ? next_pid + 1 : INIT_PROC_NR + 1);
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++)
if (rmp->mp_pid == next_pid) {
t = 1;
break;
}
rmc->mp_pid = next_pid; /* assign pid to child */
} while (t);
/* Tell kernel and file system about the (now successful) FORK. */
sys_fork(who, child_nr, rmc->mp_pid);
tell_fs(FORK, who, child_nr, 0);
/* Report child's memory map to kernel. */
sys_newmap(child_nr, rmc->mp_seg);
/* Reply to child to wake it up. */
reply(child_nr, 0, 0, NIL_PTR);
return(next_pid); /* child's pid */
}
/*===========================================================================*
* do_fork *
*===========================================================================*/
PUBLIC int do_fork()
{
/* The process pointed to by 'mp' has forked. Create a child process. */
register struct mproc *rmp; /* pointer to parent */
register struct mproc *rmc; /* pointer to child */
int i, child_nr, t;
phys_clicks prog_clicks, child_base;
phys_bytes prog_bytes, parent_abs, child_abs; /* Intel only */
/* If tables might fill up during FORK, don't even start since recovery half
* way through is such a nuisance.
*/
rmp = mp;
if (procs_in_use == NR_PROCS) return(EAGAIN);
if (procs_in_use >= NR_PROCS-LAST_FEW && rmp->mp_effuid != 0)return(EAGAIN);
/* Determine how much memory to allocate. Only the data and stack need to
* be copied, because the text segment is either shared or of zero length.
*/
prog_clicks = (phys_clicks) rmp->mp_seg[S].mem_len;
prog_clicks += (rmp->mp_seg[S].mem_vir - rmp->mp_seg[D].mem_vir);
prog_bytes = (phys_bytes) prog_clicks << CLICK_SHIFT;
if ( (child_base = alloc_mem(prog_clicks)) == NO_MEM) return(ENOMEM);
/* Create a copy of the parent's core image for the child. */
child_abs = (phys_bytes) child_base << CLICK_SHIFT;
parent_abs = (phys_bytes) rmp->mp_seg[D].mem_phys << CLICK_SHIFT;
i = sys_copy(ABS, 0, parent_abs, ABS, 0, child_abs, prog_bytes);
if (i < 0) panic("do_fork can't copy", i);
/* Find a slot in 'mproc' for the child process. A slot must exist. */
for (rmc = &mproc[0]; rmc < &mproc[NR_PROCS]; rmc++)
if ( (rmc->mp_flags & IN_USE) == 0) break;
/* Set up the child and its memory map; copy its 'mproc' slot from parent. */
child_nr = (int)(rmc - mproc); /* slot number of the child */
procs_in_use++;
*rmc = *rmp; /* copy parent's process slot to child's */
rmc->mp_parent = who; /* record child's parent */
rmc->mp_flags &= (IN_USE|SEPARATE); /* inherit only these flags */
/* A separate I&D child keeps the parents text segment. The data and stack
* segments must refer to the new copy.
*/
if (!(rmc->mp_flags & SEPARATE)) rmc->mp_seg[T].mem_phys = child_base;
rmc->mp_seg[D].mem_phys = child_base;
rmc->mp_seg[S].mem_phys = rmc->mp_seg[D].mem_phys +
(rmp->mp_seg[S].mem_vir - rmp->mp_seg[D].mem_vir);
rmc->mp_exitstatus = 0;
rmc->mp_sigstatus = 0;
/* Find a free pid for the child and put it in the table. */
do {
t = 0; /* 't' = 0 means pid still free */
next_pid = (next_pid < 30000 ? next_pid + 1 : INIT_PID + 1);
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++)
if (rmp->mp_pid == next_pid || rmp->mp_procgrp == next_pid) {
t = 1;
break;
}
rmc->mp_pid = next_pid; /* assign pid to child */
} while (t);
/* Tell kernel and file system about the (now successful) FORK. */
sys_fork(who, child_nr, rmc->mp_pid);
tell_fs(FORK, who, child_nr, rmc->mp_pid);
/* Report child's memory map to kernel. */
sys_newmap(child_nr, rmc->mp_seg);
/* Reply to child to wake it up. */
setreply(child_nr, 0);
return(next_pid); /* child's pid */
}
/*===========================================================================*
* do_exec *
*===========================================================================*/
PUBLIC int do_exec()
{
/* Perform the execve(name, argv, envp) call. The user library builds a
* complete stack image, including pointers, args, environ, etc. The stack
* is copied to a buffer inside PM, and then to the new core image.
*/
/*
* 执行 execve(name, argv, envp) 调用. 用户库函数构造了一个完整的栈映像,
* 包括指针, 命令行参数, 环境变量等等. 栈先复制到 PM 内的一个缓冲区中,
* 再复制给新的堆栈映像.
*/
register struct mproc *rmp;
struct mproc *sh_mp;
int m, r, fd, ft, sn;
static char mbuf[ARG_MAX]; /* buffer for stack and zeroes */
static char name_buf[PATH_MAX]; /* the name of the file to exec */
char *new_sp, *name, *basename;
vir_bytes src, dst, text_bytes, data_bytes, bss_bytes, stk_bytes, vsp;
phys_bytes tot_bytes; /* total space for program, including gap */
long sym_bytes;
vir_clicks sc;
struct stat s_buf[2], *s_p;
vir_bytes pc;
/* Do some validity checks. */
rmp = mp; // rmp = mp = 当前进程的 struct mproc 结构
stk_bytes = (vir_bytes) m_in.stack_bytes;
if (stk_bytes > ARG_MAX) return(ENOMEM); /* stack too big */
if (m_in.exec_len <= 0 || m_in.exec_len > PATH_MAX) return(EINVAL);
/* Get the exec file name and see if the file is executable. */
src = (vir_bytes) m_in.exec_name;
dst = (vir_bytes) name_buf;
// 将可执行文件的路径名从主调进程复制到 PM 的 name_buf[] 中.
r = sys_datacopy(who, (vir_bytes) src,
PM_PROC_NR, (vir_bytes) dst, (phys_bytes) m_in.exec_len);
if (r != OK) return(r); /* file name not in user data segment */
/* Fetch the stack from the user before destroying the old core image. */
// 将主调进程的栈复制到 mbuf[], 在毁掉旧的核心映像之前
src = (vir_bytes) m_in.stack_ptr;
dst = (vir_bytes) mbuf;
r = sys_datacopy(who, (vir_bytes) src,
PM_PROC_NR, (vir_bytes) dst, (phys_bytes)stk_bytes);
/* can't fetch stack (e.g. bad virtual addr) */
if (r != OK) return(EACCES);
r = 0; /* r = 0 (first attempt), or 1 (interpreted script) */
name = name_buf; /* name of file to exec. */
do {
s_p = &s_buf[r];
// 切换到主调进程的当前工作目录
tell_fs(CHDIR, who, FALSE, 0); /* switch to the user's FS environ */
// 检查文件是否可执行, 如果可执行, 返回文件描述符
fd = allowed(name, s_p, X_BIT); /* is file executable? */
if (fd < 0) return(fd); /* file was not executable */
/* Read the file header and extract the segment sizes. */
sc = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
// 读取文件头部数据, 并赋值给相应参数
m = read_header(fd, &ft, &text_bytes, &data_bytes, &bss_bytes,
&tot_bytes, &sym_bytes, sc, &pc);
if (m != ESCRIPT || ++r > 1) break;
} while ((name = patch_stack(fd, mbuf, &stk_bytes, name_buf)) != NULL);
if (m < 0) {
close(fd); /* something wrong with header */
return(stk_bytes > ARG_MAX ? ENOMEM : ENOEXEC);
}
/* Can the process' text be shared with that of one already running? */
sh_mp = find_share(rmp, s_p->st_ino, s_p->st_dev, s_p->st_ctime);
/* Allocate new memory and release old memory. Fix map and tell kernel. */
r = new_mem(sh_mp, text_bytes, data_bytes, bss_bytes, stk_bytes, tot_bytes);
if (r != OK) {
close(fd); /* insufficient core or program too big */
return(r);
}
/* Save file identification to allow it to be shared. */
rmp->mp_ino = s_p->st_ino;
rmp->mp_dev = s_p->st_dev;
rmp->mp_ctime = s_p->st_ctime;
/* Patch up stack and copy it from PM to new core image. */
vsp = (vir_bytes) rmp->mp_seg[S].mem_vir << CLICK_SHIFT;
vsp += (vir_bytes) rmp->mp_seg[S].mem_len << CLICK_SHIFT;
vsp -= stk_bytes;
patch_ptr(mbuf, vsp);
src = (vir_bytes) mbuf;
r = sys_datacopy(PM_PROC_NR, (vir_bytes) src,
who, (vir_bytes) vsp, (phys_bytes)stk_bytes);
if (r != OK) panic(__FILE__,"do_exec stack copy err on", who);
/* Read in text and data segments. */
if (sh_mp != NULL) {
lseek(fd, (off_t) text_bytes, SEEK_CUR); /* shared: skip text */
} else {
rw_seg(0, fd, who, T, text_bytes);
}
rw_seg(0, fd, who, D, data_bytes);
close(fd); /* don't need exec file any more */
/* Take care of setuid/setgid bits. */
if ((rmp->mp_flags & TRACED) == 0) { /* suppress if tracing */
if (s_buf[0].st_mode & I_SET_UID_BIT) {
rmp->mp_effuid = s_buf[0].st_uid;
tell_fs(SETUID,who, (int)rmp->mp_realuid, (int)rmp->mp_effuid);
}
if (s_buf[0].st_mode & I_SET_GID_BIT) {
rmp->mp_effgid = s_buf[0].st_gid;
tell_fs(SETGID,who, (int)rmp->mp_realgid, (int)rmp->mp_effgid);
}
}
/* Save offset to initial argc (for ps) */
rmp->mp_procargs = vsp;
/* Fix 'mproc' fields, tell kernel that exec is done, reset caught sigs. */
for (sn = 1; sn <= _NSIG; sn++) {
if (sigismember(&rmp->mp_catch, sn)) {
sigdelset(&rmp->mp_catch, sn);
rmp->mp_sigact[sn].sa_handler = SIG_DFL;
sigemptyset(&rmp->mp_sigact[sn].sa_mask);
}
}
rmp->mp_flags &= ~SEPARATE; /* turn off SEPARATE bit */
rmp->mp_flags |= ft; /* turn it on for separate I & D files */
new_sp = (char *) vsp;
tell_fs(EXEC, who, 0, 0); /* allow FS to handle FD_CLOEXEC files */
/* System will save command line for debugging, ps(1) output, etc. */
basename = strrchr(name, '/');
if (basename == NULL) basename = name; else basename++;
strncpy(rmp->mp_name, basename, PROC_NAME_LEN-1);
rmp->mp_name[PROC_NAME_LEN] = '\0';
sys_exec(who, new_sp, basename, pc);
/* Cause a signal if this process is traced. */
if (rmp->mp_flags & TRACED) check_sig(rmp->mp_pid, SIGTRAP);
return(SUSPEND); /* no reply, new program just runs */
}
/**
* Perform the exec() system call.
*
* @return Zero if successful, otherwise -1.
*****************************************************************************/
PUBLIC int do_exec()
{
/* get parameters from the message */
int name_len = mm_msg.NAME_LEN; /* length of filename */
int src = mm_msg.source; /* caller proc nr. */
assert(name_len < MAX_PATH);
char pathname[MAX_PATH];
phys_copy((void*)va2la(TASK_MM, pathname),
(void*)va2la(src, mm_msg.PATHNAME),
name_len);
pathname[name_len] = 0; /* terminate the string */
/* change the directory of task fs to the caller's work directory */
tell_fs(CHDIR, src, 0, 0);
/* get the file size */
struct stat s;
int ret = stat(pathname, &s);
if (ret != 0) {
printl("{MM} MM::do_exec()::stat() returns error. %s", pathname);
return -1;
}
/* read the file */
int fd = open(pathname, O_RDWR);
if (fd == -1)
return -1;
assert(s.st_size < MMBUF_SIZE);
read(fd, mmbuf, s.st_size);
close(fd);
/* setup the arg stack */
int orig_stack_len = mm_msg.BUF_LEN;
char stackcopy[PROC_ORIGIN_STACK];
phys_copy((void*)va2la(TASK_MM, stackcopy),
(void*)va2la(src, mm_msg.BUF),
orig_stack_len);
/* clean up the image of the current process */
free_mem(src);
/* the information about elf32 */
u32 start_text = 0, end_text = 0, start_data = 0, end_data = 0;
/* overwrite the current proc image with the new one */
Elf32_Ehdr* elf_hdr = (Elf32_Ehdr*)(mmbuf);
int i;
for (i = 0; i < elf_hdr->e_phnum; i++) {
Elf32_Phdr* prog_hdr = (Elf32_Phdr*)(mmbuf + elf_hdr->e_phoff +
(i * elf_hdr->e_phentsize));
if (prog_hdr->p_type == PT_LOAD) {
assert(prog_hdr->p_vaddr + prog_hdr->p_memsz <
PROC_IMAGE_SIZE_DEFAULT);
phys_copy((void*)va2la(src, (void*)prog_hdr->p_vaddr),
(void*)va2la(TASK_MM,
mmbuf + prog_hdr->p_offset),
prog_hdr->p_filesz);
if ((PF_R | PF_W) == prog_hdr->p_flags) {
//the data segment
// printl("elf32 .data start %d, size %d\n", prog_hdr->p_vaddr
// , prog_hdr->p_memsz);
start_data = prog_hdr->p_vaddr;
end_data = start_data + prog_hdr->p_memsz;
} else if ((PF_R | PF_X) == prog_hdr->p_flags) {
//the text segment
// printl("elf32 .text start %d, size %d\n", prog_hdr->p_vaddr
// , prog_hdr->p_memsz);
start_text = prog_hdr->p_vaddr;
end_text = start_text + prog_hdr->p_memsz;
}
}
}
/* setup the arg stack */
// int orig_stack_len = mm_msg.BUF_LEN;
// char stackcopy[PROC_ORIGIN_STACK];
// phys_copy((void*)va2la(TASK_MM, stackcopy),
// (void*)va2la(src, mm_msg.BUF),
// orig_stack_len);
initial_brk(src, start_text, end_text, start_data, end_data);
int * orig_stack = (int*)(VM_SIZE - PROC_ORIGIN_STACK);
int delta = (int)orig_stack - (int)mm_msg.BUF;
int argc = 0;
if (orig_stack_len) { /* has args */
char **q = (char**)stackcopy;
for (; *q != 0; q++,argc++)
*q += delta;
}
phys_copy((void*)va2la(src, orig_stack),
(void*)va2la(TASK_MM, stackcopy),
orig_stack_len);
proc_table[src].regs.ecx = argc; /* argc */
proc_table[src].regs.eax = (u32)orig_stack; /* argv */
/* setup eip & esp */
proc_table[src].regs.eip = elf_hdr->e_entry; /* @see _start.asm */
proc_table[src].regs.esp = VM_SIZE - PROC_ORIGIN_STACK;
strcpy(proc_table[src].name, pathname);
return 0;
}