/* ** L2 - OSSP Logging Library ** Copyright (c) 2001 The OSSP Project (http://www.ossp.org/) ** Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/) ** ** This file is part of OSSP L2, a flexible logging library which ** can be found at http://www.ossp.org/pkg/l2/. ** ** Permission to use, copy, modify, and distribute this software for ** any purpose with or without fee is hereby granted, provided that ** the above copyright notice and this permission notice appear in all ** copies. ** ** THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED ** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. ** IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR ** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF ** USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, ** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ** OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ** SUCH DAMAGE. ** ** l2_ch_pipe.c: pipe channel implementation */ #include "l2.h" #include "l2_p.h" /* for TRACE() */ #include #include #include #define L2_PIPE_MODEDIRECT 1 /* direct command execution */ #define L2_PIPE_MODESHELL 2 /* shell command execution */ #define L2_PIPE_WRITEFAIL 6 /* how long before real failure is indicated */ #define L2_PIPE_MAXARGS 256 /* how many args can our piped command have */ /* declare private channel configuration */ typedef struct { pid_t Pid; /* process id of child command */ int iWritefail; /* counter to failed write() operations */ int piFd[2]; /* pipe file descriptor */ int iMode; /* execution mode direct or shell */ char *szCmdpath; /* path to command and arguments */ struct sigaction sigchld; /* initial state of chld signal handler */ struct sigaction sigpipe; /* initial state of pipe signal handler */ } l2_ch_pipe_t; static void catchsignal(int sig, ...) { pid_t Pid; /* for wait() */ int iStatus = 0; /* for wait() */ if (sig == SIGCHLD) { TRACE("SIGCHLD caught"); Pid = waitpid(-1, &iStatus, WUNTRACED); if (WIFEXITED(iStatus)) TRACE("EXITED child"); /* child finished and returned */ else if (WIFSIGNALED(iStatus)) TRACE("SIGNALED child"); /* child finished due to a signal */ else if (WIFSTOPPED(iStatus)) TRACE("STOPPED child"); /* child stopped due to a signal */ else TRACE("SIGNAL Unknown"); /* child stopped due to a signal */ } else if (sig == SIGPIPE); /* noop for now */ } /* * A channel is the central object for a logging stream. It is * implemented by a framework (the code implemented here) which provides * the channel API and which is equal for all channels and a particular * handler which implements the characteristics specific to a particular * channel class. The lifecycle of a channel is illustrated in the * following figure: * * -----BEGIN EMBEDDED OBJECT----- * Content-editor: xfig %s * Content-encoding: gzip:9 base64 * Content-type: application/fig * Content-viewer: xfig %s * Description: L2 Pipe Channel Command Lifecycle * Filename: l2_ch_pipe.fig * Last-modified: 2000-09-28/14:40 * Name: l2_ch_pipe * Version: eo/1.0 * H4sIALKVuDsCA61Z32/cNgx+3v0VAvqwDWgO+mnLz8U2FMiwYW3f9uL4lJ43n+9m * +5rlvx9J2Sc5bRrp1qZxRdvfJ9KkSEp99fPbX5jays1t3e/Gpj65zRvXT27Y/Oqm * oW02t24CibGN4HzL+eZd23/s3OZGboTknMkNZ0qyVw392RRM6tIwWcIjIQQOK2k2 * mnH4MXgRBRPwL1DBK5oBCdPwKw1erOWsGVw9uT85F1+Dwc1CG6YUTkGwY3/ffjwP * LyJhHgVIrYoZeTy5PhFklJi1fBjaKXWqQi6opjuOqaYV1bWmldUVptnqGtOqcpkq * 1TQjDdwrFm/v3DgNx0cC3hQYPwUghCzgwm0Fb5UV3wimkC0Qy5kV73l2Cjm6FBL/ * BlmWBV5EmUIDk3L/9swT3YAhMSmdwqTNWqEga5OhUKFQUmahiWSFH0kVSTRWrLUJ * shUZ2sCUK5ogqyKDxui1UUE2OsOoUq61CXIpM7Sp+FqbIFc8Q5uqekJzkatqoZFE * gSuk9DQ3M5wtAs4iNt9F8Ru+cRxCIQpWI3wK6Ni9QYvVyOfoOboBFFaf5mZZfcbY * 9NVndLVafSTT6jOGZ6w+fHu1+uiGX33GSJ0cqJFCQaZATVWIAjOiCTIFaioNuSui * CTLlglQaiu+IJsgU76k0FBIRTZApF6TS0DLRQq+WDcm0bLQw6csmprnItGxSaSj6 * I5pIVgtN0uqTcll9c7gEV61GxK0rE4/wKaDjKLloUZp4NHuNxyN8CmgoqfObNJod * w+MRPbXGXL53QFf6cjf6kAt6Xk+oJq13IFNQj7XGmquU78PiCs7XBRxftrRQCWeg * RfnQ76A/7I/Doe5Y0w7N+TBOdd+48fXTduBzMikCGfLW7Fay39uTY2/2dd+7jj20 * 054Nrmvru7Zrp8cUTrVwSg7dxnQeerdjxx64ug40nVjv4MZ0ZFP9t2N1/xIpByZZ * mYVUGuzJhsE1U/sJ8PAPkAPdoW77CX5ZO42s2bfdLkXb8kKMrXNzPBygFWen4Qif * cNyyn/6tD6fOsXF/fOi3oVHyGC0RLgtqTo15wXVluXwZreGhd914ck37/3ynC7h8 * E99xu3wNjen+ie8GB+1ifde1456+8QlmSyCFDzOTGuTfnQfYxIC+9139AOzU8GKv * PNTkyd3ZgTcTeKE4Lry4Mah9E7zzrmdtfzpPpOLzTqR6W1gyGuutVWV6vbXSruot * yVRvrawy6i2+vaq3dMPXW6tEer2NFAoy1dtUhSizRjRBpkKZSkNpN6IJMpXtVBqq * IRFNJKsMGkruEU2QqWyn0lDmj2iCTGU7lYaKRUQTZCrbyTTVE5qLTGWbaNK6XbXU * 2zlcgseD01ajooIEb6zxI6y3OJ6/RDBmNSIM1cYwwqeAXmLermpiYakm4tmEFdq8 * lAqLJRPQtv393rHzCLn1UD9C0vrn3A6QYHp3A+t/Ss1aMOvMSQFz5/b1p/Y4bNlb * KDb7FipMPbrXMHSQcCjhfj8m0Ep+odVQHetxPEL6nzBtzaXnUibHU/3Qp+TXS1mh * juXcT21HWRXT7J372PZQx96TnpgY59KWVWHIsfdtD5nfjQv3F/PqC9ari/UWHEWm * Tm44tD18AvbXeZxYfY8HXtFnjdI1ln4MHSH89gwCwwe5YBaDXDzXVGKMI9hv62aa * l7HCY3EgthjG+BRPX7a0zQuUi0Lck+KPkhGrfFYj2hF6OA4jQ5XUyxMDzUWmpX73 * t/B8G1N9DyuW5jzXVGqGPZy65WBqwdXyxCqZa6ovvAvPtzGVOGeNMDVlmuqzXDVn * PrQ08QzWFOU1Z7Aeds0ZLCFzz2AJlHNQSceb2Sg63vSmZR9vEiw+3kw8KM5WkipO * NooOibNQlxCx2EPlh4iHXRMihMwNEQJlH9N7JXOP6a8yjTyQaxrFcbZpFMdZpoU4 * JtjTOLYxUGxNyW00HfUYBY5gtxYp+TyKDo95iQP6ktSIfBm3Ms7gzk7gdKTmcIbW * qD18bqD93EBEkn2Q7xHYQ0PxEg5XAJYQwgmoRdAl5cxFwfJ0LhtwMsJhScEDAVPR * GRZMtmyvf4NG8h02krftvWsem87l+EWhNtl+Uba8zi+UYq7xC7Yc1/iFtgiZftHC * 5vhFcT37hXYri1/+oJMO6EYvfmE/DA67/R9zHIRrNds/uIm5yj/0v3DX+Aeb32v8 * Q0cemf4RqsryD57YkX9g2/BV9/hjS++e/wBMybpdCx8AAA== * -----END EMBEDDED OBJECT----- */ /* create channel */ static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch) { l2_ch_pipe_t *cfg; /* allocate private channel configuration */ if ((cfg = (l2_ch_pipe_t *)malloc(sizeof(l2_ch_pipe_t))) == NULL) return L2_ERR_ARG; /* initialize configuration with reasonable defaults */ cfg->Pid = -1; cfg->iWritefail = 0; cfg->piFd[0] = -1; cfg->piFd[1] = -1; cfg->iMode = -1; cfg->szCmdpath = NULL; memset(&cfg->sigchld, 0, sizeof(cfg->sigchld)); memset(&cfg->sigpipe, 0, sizeof(cfg->sigpipe)); /* link private channel configuration into channel context */ ctx->vp = cfg; return L2_OK; } /* configure channel */ static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list ap) { l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp; l2_param_t pa[3]; l2_result_t rv; char *sz = NULL; /* feed and call generic parameter parsing engine */ L2_PARAM_SET(pa[0], mode, CHARPTR, &sz); L2_PARAM_SET(pa[1], path, STRING, &cfg->szCmdpath); L2_PARAM_END(pa[2]); if ((rv = l2_util_setparams(pa, fmt, ap)) != L2_OK) return rv; if (sz != NULL) { if (strcmp(sz, "direct") == 0) cfg->iMode = L2_PIPE_MODEDIRECT; else if (strcmp(sz, "shell") == 0) cfg->iMode = L2_PIPE_MODESHELL; else return L2_ERR_ARG; } return L2_OK; } /********************************************************** * parse_cmdpath: Helper method to hook_open * * Parses szBuf into an argv-style string vector szArgs * **********************************************************/ static l2_result_t parse_cmdpath (char *szBuf, char *szArgs[]) { int iCnt = 0; if (szBuf == NULL) /* check for bad input before we */ return L2_ERR_ARG; /* dereference and throw a SIGSEV */ while ((iCnt++ < L2_PIPE_MAXARGS) && (*szBuf != '\0')) { while ((*szBuf == ' ') || (*szBuf == '\t')) *szBuf++ = '\0'; /* overwrite whitespace with EOL */ *szArgs++ = szBuf; /* found the start of a new token */ while ((*szBuf != '\0') && (*szBuf != ' ') && (*szBuf != '\t')) szBuf++; } *szArgs = '\0'; /* add a NULL to mark the end of the chain */ if (iCnt <= L2_PIPE_MAXARGS) return L2_OK; else return L2_ERR_ARG; } /* open channel */ static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch) { l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp; char *pVec[L2_PIPE_MAXARGS]; struct sigaction locact; l2_result_t rv; char *sz = NULL; /* consistency check */ if (cfg->szCmdpath == NULL) return L2_ERR_USE; /* initialize auto vars before using them */ memset(pVec, 0, sizeof(pVec)); memset(&locact, 0, sizeof(locact)); locact.sa_handler = (void(*)())catchsignal; sigemptyset(&locact.sa_mask); locact.sa_flags = 0; /* save old signal context before replacing with our own */ if (sigaction(SIGCHLD, &locact, &cfg->sigchld) < 0) return L2_ERR_SYS; if (sigaction(SIGPIPE, &locact, &cfg->sigpipe) < 0) return L2_ERR_SYS; if (pipe(cfg->piFd) == -1) /* open the pipe */ return L2_ERR_SYS; if ((cfg->Pid = fork()) > 0) { /* parent process */ free(sz); /* no exec() in parent */ close(cfg->piFd[0]); /* half-duplex (no reading) */ cfg->piFd[0] = -1; } else if (cfg->Pid == 0) { /* child process */ close(cfg->piFd[1]); /* close the writing end, */ cfg->piFd[1] = -1; /* because we don't use it */ dup2(cfg->piFd[0], fileno(stdin)); /* copy the reading end */ /* the distinction between modes is necessary, because only executing */ /* commands in a shell environment allows usage of variables and such */ if (cfg->iMode == L2_PIPE_MODESHELL) { pVec[0] = "/bin/sh"; pVec[1] = "-c"; pVec[2] = cfg->szCmdpath; pVec[3] = NULL; /* add a NULL to mark the end of the chain */ } else { /* plain direct command execution */ sz = strdup(cfg->szCmdpath); if ((rv = parse_cmdpath(sz, pVec)) != L2_OK) { free(sz); return rv; } } if (execvp(*pVec, pVec) == -1) { /* launch */ TRACE("execvp in child returned -1"); free(sz); /* cleanup in case we fail */ close(cfg->piFd[0]); cfg->piFd[0] = -1; /* if execvp() doesn't swap our context or */ return L2_ERR_SYS; /* if child returns, we have an error */ } } else /* fork failed */ return L2_ERR_SYS; return L2_OK; } /* write to channel, possibly recursively */ static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch, l2_level_t level, const char *buf, size_t buf_size) { l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp; l2_result_t rv; /* write message to channel pipe */ if (write(cfg->piFd[1], buf, buf_size) == -1) { if ((errno == EPIPE) && (cfg->iWritefail++ < L2_PIPE_WRITEFAIL)) { if ((rv = l2_channel_close(ch)) != L2_OK) return rv; if ((rv = l2_channel_open(ch)) != L2_OK) return rv; return hook_write(ctx, ch, level, buf, buf_size); } else { /* not broken pipe problem or over the fail limit */ cfg->iWritefail = 0; /* reset pipe failure counter */ return L2_ERR_SYS; } } else { /* write() to pipe succeeded */ cfg->iWritefail = 0; /* reset pipe failure counter */ return L2_OK; } } /* close channel */ static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch) { l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp; /* restore previous signal context */ if (sigaction(SIGCHLD, &cfg->sigchld, 0) < 0) return L2_ERR_SYS; if (sigaction(SIGPIPE, &cfg->sigpipe, 0) < 0) return L2_ERR_SYS; /* close channel pipe for parent process created in hook_open() */ close(cfg->piFd[1]); cfg->piFd[1] = -1; if ((kill (cfg->Pid, SIGTERM)) && (errno != ESRCH)) return L2_ERR_SYS; cfg->Pid = -1; return L2_OK; } /* destroy channel */ static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch) { l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp; /* destroy channel configuration */ free(cfg->szCmdpath); cfg->szCmdpath = NULL; free(cfg); return L2_OK; } /* exported channel handler structure */ l2_handler_t l2_handler_pipe = { L2_CHANNEL_OUTPUT, hook_create, hook_configure, hook_open, hook_write, NULL, hook_close, hook_destroy };