1 /************************************************************************
2 Copyright (c) 2015, The Linux Foundation. All rights reserved.
3
4 Redistribution and use in source and binary forms, with or without
5 modification, are permitted provided that the following conditions are
6 met:
7 * Redistributions of source code must retain the above copyright
8 notice, this list of conditions and the following disclaimer.
9 * Redistributions in binary form must reproduce the above
10 copyright notice, this list of conditions and the following
11 disclaimer in the documentation and/or other materials provided
12 with the distribution.
13 * Neither the name of The Linux Foundation nor the names of its
14 contributors may be used to endorse or promote products derived
15 from this software without specific prior written permission.
16
17 THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
18 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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20 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
21 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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28 ************************************************************************/
29
30 /**
31 * @file datatop_fileops.c
32 * @brief Declares functions for reading and writing to files.
33 *
34 * Declares functions called when reading from files which data is collected.
35 * Also contains methods to handle files which will be written to.
36 */
37
38 #include <stdio.h>
39 #include <string.h>
40 #include <stdlib.h>
41 #include <unistd.h>
42 #include <errno.h>
43 #include "datatop_interface.h"
44 #include "datatop_linked_list.h"
45 #include "datatop_opt.h"
46 #include "datatop_fileops.h"
47
48 /**
49 * @brief Reads the lines from files which we are collecting data from.
50 *
51 * @param file File which is read from
52 * @param buffer Pointer to buffer where data will be read. The buffer is allocated
53 * in dt_read_file() and passed back to the caller. Caller should
54 * free this when done.
55 * @param len Maximum amount of data which should be read from the file.
56 * @return Number of bytes of data placed in *buffer.
57 */
dt_read_file(const char * file,char ** buffer,int len)58 int dt_read_file(const char *file, char **buffer, int len)
59 {
60 int read;
61 FILE *fp;
62
63 *buffer = (char *)malloc(len);
64 if (!(*buffer)) {
65 fprintf(stderr, "%s(): malloc(%d) failed\n", __func__, len);
66 return 0;
67 }
68
69 fp = fopen(file, "r");
70 if (!fp) {
71 fprintf(stderr, "%s(): Failed to open %s: ", __func__, file);
72 fprintf(stderr, "Error: %s\n", strerror(errno));
73 free(*buffer);
74 *buffer = 0;
75 return 0;
76 }
77 read = fread(*buffer, sizeof(char), len, fp);
78 fclose(fp);
79
80 return read;
81 }
82
83 /**
84 * @brief Deallocates memory no longer being used.
85 *
86 * @param buffer Buffer to be deallocated.
87 */
dt_free(char ** buffer)88 void dt_free(char **buffer)
89 {
90 free(*buffer);
91 *buffer = 0;
92 }
93
94 /**
95 * @brief Checks for access to a file for writing.
96 *
97 * @param fw File to check access of.
98 * @return INVALID - File already exists or write access denied.
99 * @return VALID - File does not exist and can be written to.
100 */
dtop_check_writefile_access(char * fw)101 int dtop_check_writefile_access(char *fw)
102 {
103 if (!access(fw, F_OK)) {
104 printf("File specified already exists\n");
105 return INVALID;
106 }
107
108 if (!access(fw, W_OK)) {
109 printf("Permission to write to specified file denied\n");
110 return INVALID;
111 }
112
113 return VALID;
114 }
115
116 /**
117 * @brief Opens file and handles possible errors.
118 *
119 * @param fw File path to be opened.
120 * @param to_file Pointer to the *file that is opened.
121 * @return VALID - File opened successfully.
122 * @return INVALID - File could not be opened.
123 */
dtop_open_writing_file(char * fw,FILE ** to_file)124 int dtop_open_writing_file(char *fw, FILE **to_file)
125 {
126 *to_file = fopen(fw, "w");
127 if (*to_file) {
128 return VALID;
129 } else {
130 fprintf(stderr, "Value of errno: %d\n", errno);
131 fprintf(stderr, "Error opening file: %s\n", strerror(errno));
132 fprintf(stderr, "Please try writing to a non-existent file\n");
133 printf("See datatop -h for help\n");
134 return INVALID;
135 }
136 }
137
138 /**
139 * @brief Closes a file if not a standard stream.
140 *
141 * @param fw File to be closed.
142 */
dtop_close_file(FILE * fw)143 void dtop_close_file(FILE *fw)
144 {
145 if (fw != stdout && fw != stderr && fw != stdin)
146 fclose(fw);
147 }
148
149 /**
150 * @brief Helper function to find number of lines in dual_line file.
151 *
152 * @return Number of lines in a dual_line file.
153 */
dtop_get_file_line_amount(char * name)154 int dtop_get_file_line_amount(char *name)
155 {
156 signed char rc = 0;
157 int line_count = 0;
158 FILE *file = fopen(name, "r");
159 while (rc != EOF) {
160 if (rc == '\n')
161 line_count++;
162 rc = fgetc(file);
163 }
164
165 fclose(file);
166 return line_count;
167 }
168