diff options
Diffstat (limited to 'mbox.c')
| -rw-r--r-- | mbox.c | 206 |
1 files changed, 206 insertions, 0 deletions
@@ -0,0 +1,206 @@ +/* + * Copyright (c) 2014 Sunil Nimmagadda <sunil@nimmagadda.net> + * + * 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. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <sys/param.h> +#include <sys/types.h> +#include <sys/queue.h> +#include <sys/socket.h> +#include <sys/stat.h> + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <string.h> +#include <syslog.h> +#include <unistd.h> + +#include "pop3d.h" + +static int init(struct mdrop *, size_t *, size_t *); +static int retr(struct mdrop *, unsigned int, size_t *, size_t *); +static int update(struct mdrop *); + +struct m_backend m_backend_mbox = { + init, + retr, + update +}; + +/* + * Parse mbox calculating each message's offset, size and hash. + * A message is identified by "From " at the start of a line. + * Returns 0 on success with nmsgs and sz populated. + */ +int +init(struct mdrop *m, size_t *nmsgs, size_t *sz) +{ + SHA1_CTX ctx; + FILE *fp; + struct msg *msg = NULL; + size_t i, len; + long offset; + char *line; + + *nmsgs = 0; + *sz = 0; + if (flock(m->fd, LOCK_EX|LOCK_NB) == -1) { + switch (errno) { + case EWOULDBLOCK: + logit(LOG_INFO, "mbox: locked by other process"); + return (-1); + default: + fatal("flock(LOCK_EX)"); + } + } + + if ((fp = fdopen(dup(m->fd), "r+")) == NULL) { + logit(LOG_INFO, "mbox: fdopen failed"); + return (-1); + } + + SIMPLEQ_INIT(&m->e.q_msgs); + offset = ftell(fp); + while ((line = fgetln(fp, &len))) { + if ((len > 5) && strncmp("From ", line, 5) == 0) { + if (msg) + SHA1End(&ctx, msg->hash); + + msg = xcalloc(1, sizeof(*msg), "init"); + SHA1Init(&ctx); + msg->u.offset = offset; + m->nmsgs += 1; + SIMPLEQ_INSERT_TAIL(&m->e.q_msgs, msg, e.q_entry); + } else { + if (msg == NULL) + fatalx("mbox corrupted: no \"From \" line"); + + msg->sz += len; + msg->nlines += 1; + SHA1Update(&ctx, (u_int8_t *)line, len); + offset = ftell(fp); + } + } + + if (msg) + SHA1End(&ctx, msg->hash); + + /* allocate space for nmsgs of struct msg pointers */ + m->msgs_index = xcalloc(m->nmsgs, sizeof(msg), "make_index"); + i = 0; + SIMPLEQ_FOREACH(msg, &m->e.q_msgs, e.q_entry) { + m->msgs_index[i++] = msg; + /* calculate mbox size by counting newline as 2 (CRLF) */ + m->sz += msg->sz + msg->nlines; + } + + *nmsgs = m->nmsgs; + *sz = m->sz; + fclose(fp); + return (0); +} + +static int +retr(struct mdrop *m, unsigned int idx, size_t *nlines, size_t *offset) +{ + if (m->msgs_index[idx]->flags & F_DELE) + return (-1); + + *offset = m->msgs_index[idx]->u.offset; + *nlines = m->msgs_index[idx]->nlines; + return (dup(m->fd)); /* imsg closes sender's fd */ +} + +/* + * No resource management as this process is blown away + * upon success or error. + */ +static int +update(struct mdrop *m) +{ + struct msg *cur; + size_t i, j = 0, len, nlines; + char buf[MAXBSIZE], fn[22], *line; + FILE *tmp_fp, *m_fp; + mode_t old_mask; + int tmp_fd; + + for (i = 0; i < m->nmsgs; i++) + if (m->msgs_index[i]->flags & F_DELE) + j += 1; + + if ((m_fp = fdopen(dup(m->fd), "r+")) == NULL) { + logit(LOG_INFO, "mbox: fdopen failed"); + return (-1); + } + + if (j == 0) + return (0); + else if (j == m->nmsgs) { + if (ftruncate(fileno(m_fp), 0) == -1) { + logit(LOG_CRIT, "update: ftruncate failed"); + return (1); + } + + return (0); + } + + strlcpy(fn, "/tmp/pop3d.XXXXXXXXXX", sizeof(fn)); + old_mask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); + if ((tmp_fd = mkstemp(fn)) == -1 || + (tmp_fp = fdopen(tmp_fd, "r+")) == NULL) { + logit(LOG_CRIT, "mbox: mkstemp failed"); + return (1); + } + + umask(old_mask); + for (i = 0; i < m->nmsgs; i++) { + cur = m->msgs_index[i]; + if (cur->flags & F_DELE) + continue; + + if (fseek(m_fp, cur->u.offset, SEEK_SET) == -1) { + logit(LOG_CRIT, "update: fseek failed"); + return (1); + } + /* + * "From " line isn't counted in nlines but offset starts + * there, adjust nlines here + */ + nlines = m->msgs_index[i]->nlines + 1; + while (nlines--) { + if ((line = fgetln(m_fp, &len))) + if (fwrite(line, len, 1, tmp_fp) != 1) + fatalx("update: short write"); + } + } + + fflush(tmp_fp); + rewind(m_fp); + rewind(tmp_fp); + while (!feof(tmp_fp)) { + fread(buf, sizeof(buf), 1, tmp_fp); + if (fwrite(buf, sizeof(buf), 1, m_fp) != 1) + fatalx("update: short write"); + } + + fflush(m_fp); + if (ftruncate(fileno(m_fp), ftello(tmp_fp)) == -1) + fatal("update: failed to truncate"); + + fclose(m_fp); + return (0); +} + |