Date: Thu, 27 Aug 2009 07:07:39 +0000 (UTC) From: Brian Somers <brian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r196576 - stable/8/usr.sbin/ppp Message-ID: <200908270707.n7R77drZ087622@svn.freebsd.org>
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Author: brian Date: Thu Aug 27 07:07:38 2009 New Revision: 196576 URL: http://svn.freebsd.org/changeset/base/196576 Log: MFC: When ``ppp -direct'' is invoked by a program that uses pipe(2) to create stdin and stdout, don't blindly try to use stdin as a bi-directional channel. Instead, detect the pipe and set up a special exec handler that indirects write() calls through stdout. This fixes the problem where ``set device "!ssh -e none host ppp -direct label"'' no longer works with an openssh-5.2 server side as that version of openssh ignores the USE_PIPES config setting and *always* uses pipes (rather than socketpair) for stdin/stdout channels. Approved by: re (kib) Modified: stable/8/usr.sbin/ppp/ (props changed) stable/8/usr.sbin/ppp/exec.c stable/8/usr.sbin/ppp/exec.h stable/8/usr.sbin/ppp/main.c stable/8/usr.sbin/ppp/physical.c Modified: stable/8/usr.sbin/ppp/exec.c ============================================================================== --- stable/8/usr.sbin/ppp/exec.c Thu Aug 27 07:05:46 2009 (r196575) +++ stable/8/usr.sbin/ppp/exec.c Thu Aug 27 07:07:38 2009 (r196576) @@ -35,7 +35,9 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <sysexits.h> #include <sys/wait.h> +#include <sys/stat.h> #include <sys/uio.h> #include <termios.h> #include <unistd.h> @@ -63,24 +65,106 @@ #include "cbcp.h" #include "datalink.h" #include "id.h" +#include "main.h" #include "exec.h" -static struct device execdevice = { + +struct execdevice { + struct device dev; /* What struct physical knows about */ + int fd_out; /* output descriptor */ +}; + +#define device2exec(d) ((d)->type == EXEC_DEVICE ? (struct execdevice *)d : NULL) + +unsigned +exec_DeviceSize(void) +{ + return sizeof(struct execdevice); +} + +static void +exec_Free(struct physical *p) +{ + struct execdevice *dev = device2exec(p->handler); + + if (dev->fd_out != -1) + close(dev->fd_out); + free(dev); +} + +static void +exec_device2iov(struct device *d, struct iovec *iov, int *niov, + int maxiov __unused, int *auxfd, int *nauxfd) +{ + struct execdevice *dev; + int sz = physical_MaxDeviceSize(); + + iov[*niov].iov_base = d = realloc(d, sz); + if (d == NULL) { + log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz); + AbortProgram(EX_OSERR); + } + iov[*niov].iov_len = sz; + (*niov)++; + + dev = device2exec(d); + if (dev->fd_out >= 0) { + *auxfd = dev->fd_out; + (*nauxfd)++; + } +} + +static int +exec_RemoveFromSet(struct physical *p, fd_set *r, fd_set *w, fd_set *e) +{ + struct execdevice *dev = device2exec(p->handler); + int sets; + + p->handler->removefromset = NULL; + sets = physical_RemoveFromSet(p, r, w, e); + p->handler->removefromset = exec_RemoveFromSet; + + if (dev->fd_out >= 0) { + if (w && FD_ISSET(dev->fd_out, w)) { + FD_CLR(dev->fd_out, w); + log_Printf(LogTIMER, "%s: fdunset(w) %d\n", p->link.name, dev->fd_out); + sets++; + } + if (e && FD_ISSET(dev->fd_out, e)) { + FD_CLR(dev->fd_out, e); + log_Printf(LogTIMER, "%s: fdunset(e) %d\n", p->link.name, dev->fd_out); + sets++; + } + } + + return sets; +} + +static ssize_t +exec_Write(struct physical *p, const void *v, size_t n) +{ + struct execdevice *dev = device2exec(p->handler); + int fd = dev->fd_out == -1 ? p->fd : dev->fd_out; + + return write(fd, v, n); +} + +static struct device baseexecdevice = { EXEC_DEVICE, "exec", 0, { CD_NOTREQUIRED, 0 }, NULL, + exec_RemoveFromSet, NULL, NULL, NULL, NULL, NULL, + exec_Free, NULL, - NULL, - NULL, - NULL, - NULL, + exec_Write, + exec_device2iov, NULL, NULL, NULL @@ -88,146 +172,238 @@ static struct device execdevice = { struct device * exec_iov2device(int type, struct physical *p, struct iovec *iov, - int *niov, int maxiov __unused, int *auxfd __unused, - int *nauxfd __unused) + int *niov, int maxiov __unused, int *auxfd, int *nauxfd) { if (type == EXEC_DEVICE) { - free(iov[(*niov)++].iov_base); - physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE); - return &execdevice; + struct execdevice *dev = (struct execdevice *)iov[(*niov)++].iov_base; + + dev = realloc(dev, sizeof *dev); /* Reduce to the correct size */ + if (dev == NULL) { + log_Printf(LogALERT, "Failed to allocate memory: %d\n", + (int)(sizeof *dev)); + AbortProgram(EX_OSERR); + } + + if (*nauxfd) { + dev->fd_out = *auxfd; + (*nauxfd)--; + } else + dev->fd_out = -1; + + /* Refresh function pointers etc */ + memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev); + + physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE); + return &dev->dev; } return NULL; } +static int +exec_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n) +{ + struct physical *p = descriptor2physical(d); + struct execdevice *dev = device2exec(p->handler); + int result = 0; + + if (w && dev->fd_out >= 0) { + FD_SET(dev->fd_out, w); + log_Printf(LogTIMER, "%s: fdset(w) %d\n", p->link.name, dev->fd_out); + result++; + w = NULL; + } + + if (e && dev->fd_out >= 0) { + FD_SET(dev->fd_out, e); + log_Printf(LogTIMER, "%s: fdset(e) %d\n", p->link.name, dev->fd_out); + result++; + } + + if (result && *n <= dev->fd_out) + *n = dev->fd_out + 1; + + return result + physical_doUpdateSet(d, r, w, e, n, 0); +} + +static int +exec_IsSet(struct fdescriptor *d, const fd_set *fdset) +{ + struct physical *p = descriptor2physical(d); + struct execdevice *dev = device2exec(p->handler); + int result = dev->fd_out >= 0 && FD_ISSET(dev->fd_out, fdset); + result += physical_IsSet(d, fdset); + + return result; +} + struct device * exec_Create(struct physical *p) { - if (p->fd < 0 && *p->name.full == '!') { - int fids[2], type; - - p->fd--; /* We own the device but maybe can't use it - change fd */ - type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM; + struct execdevice *dev; - if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0) - log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n", - strerror(errno)); - else { - static int child_status; /* This variable is abused ! */ - int stat, argc, i, ret, wret, pidpipe[2]; - pid_t pid, realpid; - char *argv[MAXARGS]; - - stat = fcntl(fids[0], F_GETFL, 0); - if (stat > 0) { - stat |= O_NONBLOCK; - fcntl(fids[0], F_SETFL, stat); + dev = NULL; + if (p->fd < 0) { + if (*p->name.full == '!') { + int fids[2], type; + + if ((dev = malloc(sizeof *dev)) == NULL) { + log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n", + p->link.name, strerror(errno)); + return NULL; } - realpid = getpid(); - if (pipe(pidpipe) == -1) { - log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n", + dev->fd_out = -1; + + p->fd--; /* We own the device but maybe can't use it - change fd */ + type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM; + + if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0) { + log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n", strerror(errno)); - close(fids[1]); - } else switch ((pid = fork())) { - case -1: - log_Printf(LogPHASE, "Unable to fork for line exec: %s\n", + free(dev); + dev = NULL; + } else { + static int child_status; /* This variable is abused ! */ + int stat, argc, i, ret, wret, pidpipe[2]; + pid_t pid, realpid; + char *argv[MAXARGS]; + + stat = fcntl(fids[0], F_GETFL, 0); + if (stat > 0) { + stat |= O_NONBLOCK; + fcntl(fids[0], F_SETFL, stat); + } + realpid = getpid(); + if (pipe(pidpipe) == -1) { + log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n", strerror(errno)); - close(pidpipe[0]); - close(pidpipe[1]); close(fids[1]); - break; - - case 0: - close(pidpipe[0]); close(fids[0]); - timer_TermService(); -#ifndef NOSUID - setuid(ID0realuid()); -#endif - - child_status = 0; - switch ((pid = vfork())) { - case 0: - close(pidpipe[1]); - break; - - case -1: - ret = errno; - log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n", - strerror(errno)); - close(pidpipe[1]); - _exit(ret); - - default: - write(pidpipe[1], &pid, sizeof pid); - close(pidpipe[1]); - _exit(child_status); /* The error from exec() ! */ - } - - log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base); - - if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv), - PARSE_REDUCE|PARSE_NOHASH)) < 0) { - log_Printf(LogWARN, "Syntax error in exec command\n"); - _exit(ESRCH); - } - - command_Expand(argv, argc, (char const *const *)argv, - p->dl->bundle, 0, realpid); - - dup2(fids[1], STDIN_FILENO); - dup2(fids[1], STDOUT_FILENO); - dup2(fids[1], STDERR_FILENO); - for (i = getdtablesize(); i > STDERR_FILENO; i--) - fcntl(i, F_SETFD, 1); - - execvp(*argv, argv); - child_status = errno; /* Only works for vfork() */ - printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status)); - _exit(child_status); - break; - - default: - close(pidpipe[1]); - close(fids[1]); - if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) != - sizeof p->session_owner) - p->session_owner = (pid_t)-1; - close(pidpipe[0]); - while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR) - ; - if (wret == -1) { - log_Printf(LogWARN, "Waiting for child process: %s\n", + free(dev); + dev = NULL; + } else switch ((pid = fork())) { + case -1: + log_Printf(LogPHASE, "Unable to fork for line exec: %s\n", strerror(errno)); + close(pidpipe[0]); + close(pidpipe[1]); + close(fids[1]); close(fids[0]); - p->session_owner = (pid_t)-1; - break; - } else if (WIFSIGNALED(stat)) { - log_Printf(LogWARN, "Child process received sig %d !\n", - WTERMSIG(stat)); - close(fids[0]); - p->session_owner = (pid_t)-1; break; - } else if (WIFSTOPPED(stat)) { - log_Printf(LogWARN, "Child process received stop sig %d !\n", - WSTOPSIG(stat)); - /* I guess that's ok.... */ - } else if ((ret = WEXITSTATUS(stat))) { - log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base, - strerror(ret)); + + case 0: + close(pidpipe[0]); close(fids[0]); - p->session_owner = (pid_t)-1; + timer_TermService(); + #ifndef NOSUID + setuid(ID0realuid()); + #endif + + child_status = 0; + switch ((pid = vfork())) { + case 0: + close(pidpipe[1]); + break; + + case -1: + ret = errno; + log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n", + strerror(errno)); + close(pidpipe[1]); + _exit(ret); + + default: + write(pidpipe[1], &pid, sizeof pid); + close(pidpipe[1]); + _exit(child_status); /* The error from exec() ! */ + } + + log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base); + + if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv), + PARSE_REDUCE|PARSE_NOHASH)) < 0) { + log_Printf(LogWARN, "Syntax error in exec command\n"); + _exit(ESRCH); + } + + command_Expand(argv, argc, (char const *const *)argv, + p->dl->bundle, 0, realpid); + + dup2(fids[1], STDIN_FILENO); + dup2(fids[1], STDOUT_FILENO); + dup2(fids[1], STDERR_FILENO); + for (i = getdtablesize(); i > STDERR_FILENO; i--) + fcntl(i, F_SETFD, 1); + + execvp(*argv, argv); + child_status = errno; /* Only works for vfork() */ + printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status)); + _exit(child_status); break; - } - p->fd = fids[0]; - log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd); - physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE); - if (p->cfg.cd.necessity != CD_DEFAULT) - log_Printf(LogWARN, "Carrier settings ignored\n"); - return &execdevice; + + default: + close(pidpipe[1]); + close(fids[1]); + if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) != + sizeof p->session_owner) + p->session_owner = (pid_t)-1; + close(pidpipe[0]); + while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR) + ; + if (wret == -1) { + log_Printf(LogWARN, "Waiting for child process: %s\n", + strerror(errno)); + close(fids[0]); + p->session_owner = (pid_t)-1; + break; + } else if (WIFSIGNALED(stat)) { + log_Printf(LogWARN, "Child process received sig %d !\n", + WTERMSIG(stat)); + close(fids[0]); + p->session_owner = (pid_t)-1; + break; + } else if (WIFSTOPPED(stat)) { + log_Printf(LogWARN, "Child process received stop sig %d !\n", + WSTOPSIG(stat)); + /* I guess that's ok.... */ + } else if ((ret = WEXITSTATUS(stat))) { + log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base, + strerror(ret)); + close(fids[0]); + p->session_owner = (pid_t)-1; + break; + } + p->fd = fids[0]; + log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd); + } } - close(fids[0]); } + } else { + struct stat st; + + if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFIFO)) { + if ((dev = malloc(sizeof *dev)) == NULL) + log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n", + p->link.name, strerror(errno)); + else if (p->fd == STDIN_FILENO) { + log_Printf(LogPHASE, "%s: Using stdin/stdout to communicate with " + "parent (pipe mode)\n", p->link.name); + dev->fd_out = dup(STDOUT_FILENO); + + /* Hook things up so that we monitor dev->fd_out */ + p->desc.UpdateSet = exec_UpdateSet; + p->desc.IsSet = exec_IsSet; + } else + dev->fd_out = -1; + } + } + + if (dev) { + memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev); + physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE); + if (p->cfg.cd.necessity != CD_DEFAULT) + log_Printf(LogWARN, "Carrier settings ignored\n"); + return &dev->dev; } return NULL; Modified: stable/8/usr.sbin/ppp/exec.h ============================================================================== --- stable/8/usr.sbin/ppp/exec.h Thu Aug 27 07:05:46 2009 (r196575) +++ stable/8/usr.sbin/ppp/exec.h Thu Aug 27 07:07:38 2009 (r196576) @@ -32,4 +32,4 @@ struct device; extern struct device *exec_Create(struct physical *); extern struct device *exec_iov2device(int, struct physical *, struct iovec *, int *, int, int *, int *); -#define exec_DeviceSize physical_DeviceSize +extern unsigned exec_DeviceSize(void); Modified: stable/8/usr.sbin/ppp/main.c ============================================================================== --- stable/8/usr.sbin/ppp/main.c Thu Aug 27 07:05:46 2009 (r196575) +++ stable/8/usr.sbin/ppp/main.c Thu Aug 27 07:07:38 2009 (r196576) @@ -509,9 +509,11 @@ main(int argc, char **argv) if (!sw.fg) setsid(); } else { - /* -direct - STDIN_FILENO gets used by physical_Open */ + /* + * -direct - STDIN_FILENO gets used by physical_Open. STDOUT_FILENO + * *may* get used in exec/pipe mode. + */ prompt_TtyInit(NULL); - close(STDOUT_FILENO); close(STDERR_FILENO); } } else { Modified: stable/8/usr.sbin/ppp/physical.c ============================================================================== --- stable/8/usr.sbin/ppp/physical.c Thu Aug 27 07:05:46 2009 (r196575) +++ stable/8/usr.sbin/ppp/physical.c Thu Aug 27 07:07:38 2009 (r196576) @@ -1017,6 +1017,7 @@ physical_Open(struct physical *p) p->fd = STDIN_FILENO; for (h = 0; h < NDEVICES && p->handler == NULL && p->fd >= 0; h++) p->handler = (*devices[h].create)(p); + close(STDOUT_FILENO); if (p->fd >= 0) { if (p->handler == NULL) { physical_SetupStack(p, "unknown", PHYSICAL_NOFORCE);
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