path: root/blasms.c

/*
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
    Copyright 2010 Luke Bratch <l_bratch@yahoo.co.uk>
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Remove trailing \n from a string */
void remtrailn(char* line) {
    /* If the last character is a \n, change it into the null
       character (i.e. end of string). */
    if (line[strlen(line) - 1] == '\n') {
        line[strlen(line) - 1] = '\0';
    }
}

/* Replace n characters in source with str at i */
void replacestr(char* source, int i, int n, char* str) {
    /* Temporary string for building */
    char strtmp[1000];

    /* Copy source string into temporary string */
    strcpy(strtmp, source);
    /* Copy the first i characters back into the source string */
    strxfrm(source, strtmp, i);
    source[i] = '\0';
    /* Copy the string to be inserted into the source string */
    strcat(source, str);
    /* Copy the remainder of the temporary string into the source,
       string, skipping over n characters. */
    strcat(source, strtmp + i + n);
}

/* Converts a string to lowercase */
void strtolower(char* destination, char* source) {
    int i;

    /* Loop through each character, converting it into
       lowercase. */
    for (i = 0; i < strlen(source) + 1; i++) {
        destination[i] = tolower(source[i]);
    }
}

/* Set a sender's name as part of their number */
void setname(char* telnum) {
    /* File pointer */
    FILE *fp;
    /* String to read each line of file into */
    char line[1024];
    /* Pointer to store character location searches in */
    char *strchrp;
    /* For keeping track of where we are */
    int offset = 0;

    /* Attempt to open the file */
    fp = fopen("phonebook.conf", "r");

    if (fp == NULL) {
        printf("Error opening blasms.conf.\n");
        return;
    }

    /* Loop through each line of the file */
    while (fgets(line, 1024, fp) != NULL) {
        /* Remove trailing newline */
        remtrailn(line);
        /* Attempt to find the end of the first word */
        if ((strchrp = strchr(line + offset, ' ')) != NULL) {
            /* Convert position of end of first word into an int */
            offset = strchrp - line;
            /* Check if the first word is the same as the given telnum */
            if ((strlen(telnum) == offset) && !strncmp(telnum, line, offset)) {
                /* Find the second word (i.e. the name) */
                if ((strchrp = strchr(line + offset + 1, ' ')) != NULL) {
                    line[strchrp - line] = '\0';
                }
                /* Add " (" to the given telnum */
                strcat(telnum, " (");
                /* Add the found name to the given telnum */
                strcat(telnum, line + offset + 1);
                /* Add ")" to the given telnum */
                strcat(telnum, ")");
                /* Leave this procedure */
                return;
            }
        }
    }
}

/* Set a sender's number as part of their name */
void settelnum(char* telnum, char* sms, int *offsetptr) {
    /* File pointer */
    FILE *fp;
    /* String to read each line of file into */
    char line[1024];
    /* Name to lookup */
    char name[1000];
    /* Current name in phonebook.conf */
    char curname[1000];
    /* Pointer to store character location searches in */
    char *strchrp;
    /* Keep track of where we are, starting from the
       current point in the calling function. */
    int offset = *offsetptr;
    /* Some loop iteration variables */
    int i, j;

    /* Attempt to open the phonebook */
    fp = fopen("phonebook.conf", "r");

    if (fp == NULL) {
        printf("Error opening blasms.conf.\n");
        return;
    }

    /* Set entire given SMS as the target name for now */
    strcpy(name, sms + offset + 1);

    /* Trim the target name to just the first word of the SMS */
    if ((strchrp = strchr(name, ' ')) != NULL) {
        offset = strchrp - name;
        name[offset] = '\0';
    }

    /* If the name is a wildcard, set it as the telnum
       for the calling function and leave this function. */
    if (!strcmp(name, "*")) {
        strcpy(telnum, name);
        /* Advance the offset to go past this wildcard,
           for the calling function. */
        *offsetptr = *offsetptr + 2;
        return;
    }

    /* Convert the name to lowercase for easier comparison */
    strtolower(name, name);

    /* Loop through each line of the file to find a matching name */
    while (fgets(line, 1024, fp) != NULL) {
        /* Remove trailing newline */
        remtrailn(line);
        /* Convert the line to lowercase for easier comparison */
        strtolower(line, line);
        /* Find the end of the first word (i.e. the number which
           we don't want for now. */
        for (i = 0; i < strlen(line); i++) {
            if (line[i] == ' ') {
                break;
            }
        }
        /* Move past the first space */
        offset = i + 1;
        /* Loop through each character in the line, skipping the first
           word (the number). */
        for (i = 0, j = 0; i < strlen(line + offset - 1); i++, j++) {
            /* If this isn't the end of the word or line, build a name
               for comparison. */
            if (line[i + offset] != ' ' && line[i + offset] != '\0') {
                curname[j] = line[i + offset];
            /* Otherwise, the word or line ended, so check for a match. */
            } else {
                /* Terminate the current name string */
                curname[j] = '\0';
                /* Check to see if the names are a match... */
                if (!strcmp(name, curname)) {
                    /* If they match, copy the number from the
                       line into telnum */
                    strncpy(telnum, line, offset - 1);
                    /* Terminate the string */
                    telnum[offset - 1] = '\0';
                    /* Advance the offset paste the name for the
                       calling function */
                    *offsetptr = *offsetptr + strlen(name) + 1;
                    return;
                /* ...if they aren't a match, start building a new
                   name from this line (as it might have multiple
                   names for the current number). */
                } else {
                    j = -1;
                }
            }
        }
    }

    /* If the name wasn't found, then we don't want to send an SMS,
       so exit the program. */
    printf("Error: %s not found in phonebook.conf.\n", name);
    exit(1);
}

int main(int argc, char *argv[]) {
    /* Telephone number (may contain name) */
    char telnum[100];
    /* Unmodified telephone number length */
    int telnumlen;
    /* SMS content */
    char sms[500];
    /* SMS command */
    char smscommand[11];
    /* Command to execute */
    char systemcmd[1000];
    /* Dynamic systemcmd for wildcard matches */
    char wildcardcmd[1000];
    /* Default command to execute */
    char defaultcmd[1000];
    /* Length of command */
    int offset = 0;
    /* Loop counter */
    int i = 0;
    /* Config file pointer */
    FILE *fp;
    /* Config file line */
    char line[1024];
    /* Config file command */
    char configcmd[8];
    /* strchr pointer */
    char *strchrp;
    /* Command match / telnum set */
    short int match = 0;

    /* Stores the positions in systemcmd of wildcards,
       for if multiple phonebook looks are to be done. */
    struct {
        /* Each individual position */
        int pos;
    } wildcard[1000];
    /* Number of wildcards (i.e. number of wildcard structs used) */
    int wildcards = 0;

    /* Print some usage information if --help was used, or if exactly
       two arguments weren't given. */
    if (argc != 3 || !strcmp(argv[argc - 1], "--help")) {
        fprintf(stderr, "Usage: %s sender-number send-date\n"
                        "\n"
                        "SMS content should be passed using stdin.\n"
                        "\n"
                        "blasms.conf is the configuration file and should be in the format:\n"
                        "  default SYSTEM COMMANDS\n"
                        "  CMD1 SYSTEM COMMANDS\n"
                        "  CMD2 SYSTEM COMMANDS\n"
                        "  etc.\n"
                        "\n"
                        "Where SYSTEM COMMANDS can be any command to be executed.  The line starting\n"
                        "with \'default\' must be present, and is the default command in the absense of a\n"
                        "recognised command.  CMD1, CMD2, etc. are commands which can be matched at the\n"
                        "start of SMSes, in order to execute commands other than the default.  Macros\n"
                        "are available, allowing for text replacement.  The macros available are:\n"
                        "  %%N - replaced with the sender-number, and attempts to set a sender name (see\n"
                        "       below)\n"
                        "  %%n - replaced with the sender-number\n"
                        "  %%d - replaced with the send-date\n"
                        "  %%s - replaced with the SMS content\n"
                        "  %%P - attempts to replace the second word in the SMS with a destination number\n"
                        "       from phonebook.conf - SMS not processed if entry not found\n"
                        "\n"
                        "An example blasms.conf might be:\n"
                        "  default echo \\\"SMS from %%N at %%d: %%s\\\"\n"
                        "  LS ls %%s\n"
                        "\n"
                        "Sender names are looked up in phonebook.conf, which should be in the format:\n"
                        "  NUMBER1 NAME1\n"
                        "  NUMBER2 NAME2\n"
                        "  etc.\n"
                        "\n"
                        "An example phonebook.conf might be:\n"
                        "  +447777123456 John\n"
                        "  +447713987654 Bill\n",
                        argv[0]);
        return 1;
    }

    /* Copy first argument into telnum, so it can be manipulated */
    strcpy(telnum, argv[1]);

    /* Print the arguments (usually number/date) */
    printf("Phone number: %s\n", telnum);
    printf("Date        : %s\n", argv[2]);

    /* Get the actual SMS content from standard input */
    fgets(sms, 500, stdin);

    /* Make sure we got something */
    if (sms != NULL) {
        /* Remove trailing newline */
        remtrailn(sms);
        printf("Contents    : %s\n", sms);
    }

    /* Open configuration file */
    fp = fopen("blasms.conf", "r");

    /* Make sure file opened OK */
    if (fp == NULL) {
        printf("Error opening blasms.conf.\n");
        return 1;
    }

    /* Read each line from the file */
    while (fgets(line, 1024, fp) != NULL) {
        /* Remove traliing newline */
        remtrailn(line);
        /* Try to find the end of the first word (i.e. the first space) */
        if ((strchrp = strchr(line, ' ')) != NULL) {
            /* Position = address of space - address of start of line */
            offset = strchrp - line;
            if (offset > 10) {
                printf("Error, command longer than 10 characters in blasms.conf.\n");
                return 1;
            }
            /* Copy that first word into configcmd */
            strxfrm(configcmd, line, offset);
            configcmd[offset] = '\0';
            /* If the command was "default", set it as the default
               command and move to next line in file. */
            if (!strcmp(configcmd, "default")) {
                strcpy(defaultcmd, line + offset + 1);
                continue;
            }
            /* If the SMS command doesn't end here, continue.  (i.e. it
               definitely doesn't match the config file command. */
            if (sms[offset] != ' ') {
                continue;
            }
            /* If it does end here, copy it to smscommand */
            strxfrm(smscommand, sms, offset);
            smscommand[offset] = '\0';
            /* If the commands are the same, stop reading the file */
            if (!strcmp(smscommand, configcmd)) {
                match = 1;
                break;
            }
        }
    }

    /* match was set if a command was found, so set the systemcmd
       to be the remainder of the current config file line */
    if (match) {
        strcpy(systemcmd, line + offset + 1);
    /* If not, use the defaultcmd as set above. */
    } else {
        strcpy(systemcmd, defaultcmd);
        offset = -1;
    }

    /* Reset match to 0 as we use it again */
    match = 0;

    /* Go through each character of systemcmd, looking for
       recognised macros */
    for (i = 0; i < strlen(systemcmd); i++) {
        /* If a % is found, we might be about to find a macro. */
        if (systemcmd[i] == '%') {
            /* Check the next character for recognised macros */
            switch (systemcmd[i+1]) {
                /* Sender number with name lookup */
                case 'N':
                    /* Attempt to look up number to find a name */
                    setname(telnum);
                    /* Insert number (or number + name) into systemcmd */
                    replacestr(systemcmd, i, 2, telnum);
                    break;
                /* Sender number only */
                case 'n':
                    /* Insert number into systemcmd */
                    replacestr(systemcmd, i, 2, telnum);
                    break;
                /* Date */
                case 'd':
                    /* Insert date into systemcmd */
                    replacestr(systemcmd, i, 2, argv[2]);
                    break;
                /* SMS content, minus the initial command (if any) */
                case 's':
                    /* Insert SMS content into systemcmd */
                    replacestr(systemcmd, i, 2, sms + offset + 1);
                    break;
                /* Interpret second word of SMS as a name to be looked up */
                case 'P':
                    /* If name hasn't already been found, try to find it */
                    if (!match) {
                        settelnum(telnum, sms, &offset);
                        /* If found, no need to try again. */
                        match = 1;
                    }
                    /* If telnum was a wildcard, keep track of its position. */
                    if (!strcmp(telnum, "*")) {
                        wildcard[wildcards].pos = i;
                        wildcards++;
                    }
                    /* Insert telnum into systemcmd */
                    replacestr(systemcmd, i, 2, telnum);
                    break;
                /* Intepret the second word (i.e. after the command) of the SMS
                   as a filename, attempt to open the file pending/filename, treating
                   the first word of it as a number, attempting to look up its name,
                   and insert a colon between it and the rest of the file. */
                case 'M':
                    /* Build the path */
                    strcpy(telnum, "pending/");
                    strcat(telnum, sms + offset + 1);

                    /* Open the file */
                    fp = fopen(telnum, "r");

                    /* If the file didn't open, abort this macro. */
                    if (fp == NULL) {
                        printf("Error opening message file.\n");
                        break;
                    }

                    /* If the first line can't be read, abort this macro. */
                    if (fgets(line, 1024, fp) == NULL) {
                        printf("Error reading message file.\n");
                        break;
                    }

                    /* Close the file after reading the first line */
                    fclose(fp);

                    /* Attempt to find the end of the first word */
                    if ((strchrp = strchr(line + offset, ' ')) != NULL) {
                        /* Remove trailing newline */
                        remtrailn(line);
                        /* Copy the first word into telnum */
                        strncpy(telnum, line, strchrp - line);
                        telnum[strchrp - line] = '\0';
                        /* Set the length of the unmodified number */
                        telnumlen = strlen(telnum);
                        /* Attempt to look up the number */
                        setname(telnum);
                    /* If a first word couldn't be determined, abort this macro. */
                    } else {
                        printf("Error, malformed message file.\n");
                        break;
                    }

                    /* Insert the number (or number + name) into systemcmd */
                    replacestr(systemcmd, i, 2, telnum);
                    /* Insert a colon */
                    replacestr(systemcmd, i + strlen(telnum), 0, ":");
                    /* Insert the remainder of the file */
                    replacestr(systemcmd, i + strlen(telnum) + 1, 0, line + telnumlen);

                    break;
            }
        }
    }

    /* Execute a single command, or multiple command, depending on
       whether the systemcmd contained wildcards. */
    if (wildcards) {
        /* Try to open the phonebook to look up each number to send to */
        fp = fopen("phonebook.conf", "r");

        /* Exit if the file couldn't be opened */
        if (fp == NULL) {
            printf("Error opening phonebook.conf.\n");
            return 1;
        }

        /* Read each line in the file */
        while (fgets(line, 1024, fp) != NULL) {
            /* Attempt to find the first word (hopefully a number) */
            if ((strchrp = strchr(line, ' ')) != NULL) {
                /* Set initial offset in systemcmd (1, as in a single *) */
                offset = 1;
                /* Copy systemcmd into wildcardcmd for manipulation */
                strcpy(wildcardcmd, systemcmd);
                line[strchrp - line] = '\0';
                /* Loop through each wildcard that we tracked earlier */
                for (i = 0; i < wildcards; i++) {
                    /* Insert the first word of the phonebook (hopefully a number) into
                       wildcardcmd at each wildcard position.  Adjust the wildcard position
                       each time to take into account the length of the previous inserted
                       number. */
                    replacestr(wildcardcmd, wildcard[i].pos + (int)strlen(line) * i - i, 1, line);
                }
                printf("Executing: %s\n", wildcardcmd);
                /* Execute the command */
                system(wildcardcmd);
            }
        }
    } else {
        printf("Executing: %s\n", systemcmd);
        /* Execute command */
        system(systemcmd);
    }

    return 0;
}